JP7811698B2 - Water treatment equipment and three-way valve for liquids - Google Patents

Description

This disclosure relates to a water treatment device that purifies water through filtration and chemical addition.

Conventionally, oxidizing agents are supplied to water treatment systems using chemical supply devices that bring solid oxidizing agents into contact with water. For example, when purifying well water, a chemical supply device that gradually dissolves solid calcium hypochlorite can be used to oxidize the raw water to be purified.

In systems that inject drugs using a metering pump, or in drug supply devices that dissolve a constant amount of drug regardless of flow rate, it is necessary to change the flow rate of the metering pump to match the flow rate of the injection pipe, which is very expensive.

Figure 9 is a schematic diagram showing the configuration of a conventional water treatment device. As shown in Figure 9, in a solid drug supply device 101, raw water flows in through a water intake 102 and contacts a water-soluble solid drug 103. When water flows into the drug contact phase 104, the amount of water-soluble solid drug 103 that comes into contact with the raw water increases as the flow rate increases within a certain flow rate range. This mechanism allows the drug to elute when the flow rate increases, and suppresses drug elution when the flow rate is stopped (see, for example, Patent Document 1).

Japanese Utility Model Publication No. 58-49836

In such water treatment devices, it is necessary to switch the chemical concentration depending on the device's operating mode. For example, chemicals are added in the raw water filtering mode. Furthermore, chemicals are not added in the filter media cleaning mode, and chlorine addition must be switched accordingly. In particular, it is desirable to be able to switch between the presence and absence of chemicals as described above using a simple configuration.

The purpose of this disclosure is to provide a water treatment device that can limit contact between chemicals and water by controlling the flow of water inside the water treatment device, thereby obtaining a chemical solution of the desired concentration.

The water treatment device according to the present disclosure comprises a filtration unit containing a filter material, a raw water inlet pipe for inflowing raw water into the filtration unit, a chemical supply unit for adding chemicals within the raw water inlet pipe, a purified water discharge pipe for extracting filtered treated water from the filtration unit, a bypass pipe for bypassing the chemical supply unit within the raw water inlet pipe, and a bypass valve for adjusting the amount of water flowing within the bypass pipe and the amount of water flowing through the chemical supply unit , and further comprises a backwash drain pipe for draining wastewater from the filtration unit, and a switching valve for switching the communication between at least one of the raw water inlet pipe, the purified water discharge pipe, and the backwash drain pipe connected to the filtration unit and an opening within the filtration unit, and the bypass valve opens and closes in conjunction with the operation of the switching valve .

According to the present disclosure, in a water treatment device, the amount of water flowing from the raw water inlet pipe through the bypass pipe and the amount of water flowing through the chemical supply section can be adjusted to supply the chemical solution required for each operating mode.

FIG. 1 is a schematic diagram of the overall configuration of a water treatment device according to embodiment 1-1 of the present disclosure. FIG. 2 is a schematic diagram showing the flow of water during backwashing treatment in the water treatment device. FIG. 3 is a schematic diagram showing the flow of water during the rinsing treatment in the water treatment apparatus. FIG. 4 is a cross-sectional view of the filtration unit and the switching valve of the water treatment device. FIG. 5 is a cross-sectional view of the chemical supply unit of the water treatment device. FIG. 6 is a schematic diagram of the overall configuration of a water treatment device according to embodiment 1-2 of the present disclosure. FIG. 7 is a schematic diagram showing the flow of water during backwashing treatment in the water treatment device. FIG. 8 is a schematic diagram of the air injection section of the water treatment device. FIG. 9 is a schematic diagram showing the configuration of a conventional water treatment device. FIG. 10 is a schematic diagram of the overall configuration of a water treatment device according to embodiment 2-1 of the present disclosure. FIG. 11 is a schematic diagram showing the flow of water during backwashing treatment in the water treatment device. FIG. 12 is a schematic diagram showing the flow of water during the rinsing process of the water treatment device. FIG. 13 is a cross-sectional view of the filtration unit and the switching valve of the water treatment device. FIG. 14 is a cross-sectional view of the chemical supply unit of the water treatment device. FIG. 15A is a cross-sectional view of the bypass valve of the water treatment device when the pressure is low. FIG. 15B is a horizontal cross-sectional view of the shaft collar of the bypass valve. FIG. 16 is a cross-sectional view of the bypass valve of the water treatment device under high pressure. FIG. 17 is a schematic diagram of the overall configuration of a water treatment device according to embodiment 2-2 of the present disclosure. FIG. 18 is a cross-sectional view of the bypass valve of the water treatment device when the pressure is low. FIG. 19 is a cross-sectional view of the bypass valve of the water treatment device under high pressure. FIG. 20 is a schematic diagram showing the configuration of a conventional water treatment device.

(Embodiment 1)
Hereinafter, the first embodiment will be described with reference to the drawings.

The water treatment device 1 of embodiment 1 uses well water or water stored in a water tank as raw water, performs a filtration process to remove metal ions and turbidity components contained in this raw water, and performs a backwash process to discharge metal ion aggregates and turbidity components that have accumulated in the system due to the filtration process out of the system.

Note that embodiment 1 includes at least the following embodiments 1-1 and 1-2.

(Embodiment 1-1)
FIG. 1 is a schematic diagram showing the overall configuration of a water treatment device 1 according to the present embodiment, and also showing the flow of water during filtration treatment.

As shown in Figure 1, the water treatment device 1 has a filtration section 2 containing a filter material and a chemical supply section 3 that adds chemicals to the raw water, and is configured by connecting the filtration section 2 and the chemical supply section 3 with piping as described below.

The filtration unit 2 purifies raw water by removing metal ions and turbidity components. It is the heart of the water treatment device 1. Contaminants accumulated in the filtration unit 2 are discharged outside the device through backwashing and rinsing processes, keeping the filtration unit 2 clean and allowing for repeated use. Backwashing involves flowing raw water in the reverse direction through the filtration unit 2 to discharge the contaminants. Rinse processing involves flowing raw water through the filtration unit 2 in the filtration direction after backwashing, discharging the separated contaminants outside the device. The raw water inlet piping 10 is the piping that sends raw water to the filtration unit 2, the purified water outlet piping 20 is the piping that discharges water purified by the filtration unit 2, and the backwash drain pipe 40 is the piping that discharges contaminants during backwashing and rinsing operations. The purified water is stored in a purified water tank 6 or similar located outside the water treatment device 1 and can be used as domestic water when needed.

Raw water is delivered to the water treatment device 1 by an electric pump 4 connected to the inlet side of the raw water inlet pipe 10 (opposite the filtration section 2). Instead of using an electric pump 4, a water tank storing raw water may be installed at an elevated location, and the raw water may be delivered to the water treatment device 1 by utilizing the difference in elevation between the tank and the water treatment device 1. Alternatively, tap water jointly operated in a local area may be directly connected. In this embodiment, the water source includes wells, water tanks, waterworks, etc., as well as devices that deliver raw water.

The electric pump 4 is a motor-driven pump that draws up and discharges well water or water stored in a water tank. Examples include centrifugal pumps such as centrifugal pumps and turbine pumps, vortex pumps (cascade pumps), jet pumps, axial flow pumps, and mixed flow pumps. Furthermore, if the well water level is low, it is better to use a submersible pump rather than a suction pump. For general household use, the well depth must be approximately 1 to 10 meters for shallow wells and 10 to 30 meters or more for deep wells. Considering the head loss of downstream piping and water treatment equipment, a pump with a head of 20 meters or more is preferable, with a vortex pump or jet pump being more preferable. The discharge flow rate of an electric pump is, for example, approximately 5 to 100 liters per minute, but for general household use, a pump with a flow rate characteristic of approximately 5 to 50 liters per minute is more preferable.

The raw water inlet pipe 10 and the purified water outlet pipe 20 may be made of any material and have any structure that can withstand the water pressure of the electric pump 4. Specifically, due to their durability and ease of processing, straight pipes or pipe fittings made of polyvinyl chloride resin or steel pipes, or composite materials of these, can be used. The nominal diameter is preferably large to reduce head loss; for example, a nominal diameter of 13 to 50 mm and a thickness of approximately 1 to 5 mm are preferred. If it is difficult to select materials that can withstand the maximum pressure of the electric pump 4, it is a good idea to install a pressure reducing valve, pressure regulating valve, or relief valve between the electric pump 4 and the water treatment device 1.

The chemical supply unit 3 is provided within the raw water inlet pipe 10. As will be described in more detail below, the chemical supply unit 3 adds an oxidizing agent to the raw water, causing metal ions contained in the raw water to coagulate as substances that are difficult to dissolve in water, making them easier to capture in the filtration unit 2.

(Filtration section related)
Next, the filtration unit 2 and the switching valve 5, which are components related to the filtration unit, will be described with reference to Fig. 4. Fig. 2 is a schematic diagram showing the flow of water during backwash processing in the water treatment device 1. Fig. 3 is a schematic diagram showing the flow of water during rinse processing in the water treatment device 1. Fig. 4 is a cross-sectional view of the filtration unit 2 and the switching valve 5 of the water treatment device 1.

The filtration unit 2 contains filter media and a water collection pipe 70, and purifies raw water by passing it through. The filter media inside the filtration unit 2 consists of an upper layer 71, which primarily filters out impurities, and a lower layer 72, which has a rectifying effect. The filter media used in the upper layer 71 includes activated carbon, manganese sand, anthracite, etc., and approximately one to four types are used in layers depending on the quality of the raw water. In this embodiment, the filtration function of the filtration unit 2 is centered around the upper layer 71. The filter media used in the lower layer 72 is composed of gravel or coarse-pore resin to disperse water entering and exiting the water collection pipe. The lower layer 72 has a relatively large gravel layer at the bottom to improve water flow and prevent the filter media from leaking out from the bottom of the water collection pipe 70. The amount of filter media in the lower layer 72 should be approximately 1/2 to 1 times the diameter of the filtration unit 2. The combined filling amount of the filter material in the upper layer 71 and the lower layer 72 is preferably about 1/4 to 4/5 times the internal volume of the filtration section 2 .

The filtration section 2 is connected at the top to external piping (raw water inlet piping 10, purified water outlet piping 20, backwash drain pipe 40). Inside the filtration section 2, an inlet 73 and an outlet 74 are provided, and the outlet 74 is connected to the water collection pipe 70.

A switching valve 5 is attached to the top of the filtration section 2, and connects the external piping (raw water inlet piping 10, purified water outlet piping 20, backwash drain pipe 40) to the inlet 73 and outlet 74 within the filtration section 2. Operation of the switching valve 5 switches the communication between the external piping and the inlet 73 and outlet 74. The switching valve 5 is equipped with a flow path switching top 75 that switches the flow path; rotating the flow path switching top 75 changes the direction of communication with the connected piping and openings. The flow path switching top 75 can be rotated with an external handle or moved by an external motor.

During filtration, the flow path switching piece 75 is operated to connect the raw water inlet pipe 10 to the inlet 73, and to connect the outlet 74 to the purified water discharge pipe 20. During backwashing, the flow path switching piece 75 is operated to connect the raw water inlet pipe 10 to the outlet 74, and to connect the inlet 73 to the backwash drain pipe 40. During rinsing, the flow path switching piece 75 is operated to connect the raw water inlet pipe 10 to the inlet 73, and to connect the outlet 74 to the backwash drain pipe 40.

Various types of operation are possible depending on the type of piping connected to the switching valve 5. For example, by connecting the raw water inlet piping 10 and the purified water outlet piping 20, raw water can be sent directly to the purified water tank 6.

In this embodiment, a switching valve 5 is used, but in addition to using a switching valve 5, the flow path can also be switched by using multiple valves.

In this configuration, we will explain the water flow during filtration and backwashing. During filtration, water flows within the filtration section 2 as follows, and purified water is obtained from the outlet 74.

[Flow path within filtration unit 2 during filtration process]
Inflow port 73 → Upper layer 71 → Lower layer 72 → Water collection pipe 70 → Outlet port 74
During the rinsing process, water flows through the filtration section 2 in the same manner as during the filtration process, but water containing dirt after the backwash process (described later) flows out from the outlet 74. Therefore, the outlet 74 is connected to the backwash drain pipe 40 and is discharged to the outside.

In addition, dirt accumulated in the filtration section 2 during the filtration process can be discharged by backwashing. During backwashing, water flows as follows, and dirt is discharged from the outlet 74.

[Flow path in filtration section 2 during backwashing process]
Outlet 74 → Water collection pipe 70 → Lower layer 72 → Upper layer 71 → Inlet 73
(Medicine Supply Department)
Next, the chemical supply unit 3 will be described using FIGS. 1 and 5. FIG. 5 is a cross-sectional view of the chemical supply unit 3 of the water treatment device 1. The chemical supply unit 3 is provided to promote the aggregation of metal ions contained in the raw water by the chemical contained therein, facilitating their capture by the filtration unit 2. The chemical supply unit 3 has an inlet channel 31, a chemical supply channel 32, a bypass channel 33, and an outlet channel 34. The inlet channel 31 is connected to the raw water inlet pipe 10 and allows raw water to flow into the chemical supply unit 3. The chemical supply channel 32 branches off from the inlet channel 31 and dissolves the chemical. The bypass channel 33 also branches off from the inlet channel 31 via a throttle section 33a and is provided to adjust the chemical solution to the required concentration. After branching off from the inlet channel 31, the bypass channel 33 is connected to the inlet side of the outlet channel 34. Outlet path 34 merges with chemical path 32 and bypass path 33 and is connected again to raw water inlet pipe 10, sending out chemical-containing raw water to raw water inlet pipe 10. As shown in Figure 5, chemical path 32 is composed of spray pipe 52 that branches and then rises vertically, chemical placement section 53 that comes into contact with the chemical at the top of spray pipe 52 and dissolves the chemical, and recovery section 54 that is located on the outer periphery of spray pipe 52 and inside housing 51.

The spray pipe 52 is a small-diameter pipe that stands upright and has a chemical placement section 53 at the top. The diameter of the spray pipe 52 is reduced at the bottom, and the chemical placement section 53 is located at the top of the spray pipe 52, allowing the raw water to come into contact with the chemical at the desired flow rate. The chemical placement section 53 is sized to ensure the amount (number) of chemical placed so that the desired concentration of chemical solution is obtained for the raw water flow rate.

The chemical solution containing the dissolved chemical flows out into the recovery section 54. In the recovery section 54, the chemical solution containing the dissolved chemical accumulates at the bottom of the housing 51, and then flows out of the recovery opening 55 into the outflow channel 34. Because the diameter of the ejection pipe 52 is small and a sufficient distance is maintained between the ejection pipe 52 and the inner wall surface of the housing 51, the liquid level of the raw water containing the dissolved chemical that flows down into the housing 51 can be set to about half the height of the housing 51 or even lower. By accumulating the chemical solution at the desired depth within the housing 51, the ratio at which it mixes with the raw water in the outflow channel 34 can be adjusted.

The flow rate of raw water flowing through chemical path 32 can be adjusted by the flow rate of raw water flowing through bypass path 33. That is, the ratio of the flow rates of raw water flowing through chemical path 32 and bypass path 33 can be adjusted by adjusting the diameter of throttle section 33a of bypass path 33. In this way, the chemical concentration in outflow path 34 after merging can be adjusted to the desired concentration. Note that instead of throttle section 33a, a flow control valve can be used to adjust the flow rate of raw water flowing through bypass path 33.

By keeping the amount of raw water flowing into the chemical supply unit 3 within a predetermined range and setting the liquid level in the chemical supply unit 3 to the desired height, the chemical concentration in the raw water flowing out of the chemical supply unit 3 can be adjusted to within the desired range.

It is advisable to ensure that there is always an air layer inside the housing 51 of the chemical supply unit 3. The housing 51 is an airtight space except for the connection with the raw water inlet pipe 10, so once the air is removed and the housing 51 is filled with water, the chemical 60 will be constantly in contact with the water and continue to dissolve. Therefore, in order to send air to the chemical supply unit 3, it is advisable to attach an air supply pipe or a valve such as a check valve to the raw water inlet pipe 10.

The chemical placement section 53 is equipped with a water-soluble, solid chemical 60. It is preferable to use a tablet or granular chemical 60, as this increases the surface area of the chemical 60 and allows for a stable solvent concentration. For tablets, a diameter of 30 mm and a height of 10-20 mm is recommended, while for granules, a diameter of 5-15 mm is recommended. If the chemical 60 is small, adjacent chemicals may come into contact with water at the same time, causing them to stick together. This adhesion can result in only the lower portions of the chemical coming into contact with water, making it impossible to obtain a chemical solution of the desired concentration. Alternatively, if the chemical 60 is small, the contact area with the water supplied from the ejection pipe 52 increases, making it impossible to obtain a chemical solution of the desired concentration. Therefore, chemicals 60 of the above-mentioned sizes are used to supply a chemical solution of the desired concentration.

As mentioned above, chemical 60 oxidizes metal ions contained in the raw water to produce flocculants that are difficult to dissolve in water. Various oxidizing agents can be used as chemical 60, but depending on the desired water purification performance, inorganic or polymeric flocculants such as PAC (polyaluminum chloride) or chitosan may also be used. When adding chemicals to raw water, chemical 60 that is easily soluble in water is preferable, but it is also preferable that the chemical remains in a solid form and does not flow out of chemical placement section 53 during shutdown or backwash processing, i.e., when chemical addition is interrupted. In this embodiment, trichloroisocyanuric acid is used.

Because each component of the drug supply unit 3 may be in contact with the drug for extended periods of time, it is recommended to select materials with low reactivity to the drug, such as PVC (polyvinyl chloride), PMMA (polymethyl methacrylate), or PP (polypropylene). Meanwhile, the ejection tube 52 must be strong enough to support the drug placement unit 53. Considering compatibility with the drug, it is preferable to select materials for the ejection tube 52 that are stronger than PP, such as polyvinyl chloride or ABS (acrylonitrile butadiene styrene). The outer diameter of the ejection tube 52 should be no more than one-quarter the inner diameter of the base 51a and upper cover 51b. As mentioned above, a space (recovery unit 54) can be provided outside the ejection tube 52 to temporarily store the solution discharged from the placement unit outlet 58 after drug supply, preventing the water level in the housing 51 from rising too rapidly and reaching the drug placement unit 53. For example, if the inner diameter of the base 51a is 130 mm, a PVC pipe with an outer diameter of approximately 25 to 40 mm should be used.

(Piping configuration)
The most characteristic feature of this embodiment will be described.

As described above, the water treatment device 1 of this embodiment includes a filtration unit 2, a raw water inlet pipe 10, a purified water discharge pipe 20, and a backwash drain pipe 40 (Figure 1). The raw water inlet pipe 10 is connected at its inlet to the discharge port of the electric pump 4, which serves as the water source, and at its outlet to the switching valve 5 of the filtration unit 2. The raw water inlet pipe 10 is provided with a chemical supply unit 3 and a bypass pipe 14 that bypasses the chemical supply unit 3. This bypass pipe 14 branches (first branch 12) at the raw water inlet pipe 10 upstream of the chemical supply unit 3, bypasses the chemical supply unit 3, and merges with the raw water inlet pipe 10 downstream of the chemical supply unit 3 (second branch 13). A bypass valve 15 is provided in the bypass pipe 14 to open/close the bypass pipe 14 or adjust the flow rate through the bypass pipe 14. In other words, the bypass valve 15 can adjust the amount of water flowing through the bypass valve 15 (can open or close the water passage in the bypass valve 15).

The filtration unit 2 has two outlets, one of which is connected to a purified water discharge pipe 20 that extracts purified water. The other outlet is connected to a backwash drain pipe 40 that discharges particulate matter (dirt, turbid components, metal aggregates, etc.) captured by the filtration unit 2 out of the system during backwash and rinse processes.

Next, the piping configuration within the water treatment device 1 and the water flow during filtration and backwashing processes will be explained using Figures 1 to 4. Figure 4 is a cross-sectional schematic diagram of the filtration section 2, with Figure 4(a) showing an overall view during filtration, Figure 4(b) showing the state of the switching valve 5 during backwashing, and Figure 4(c) showing the state of the switching valve 5 during rinsing.

During filtration, as shown in Figures 1 and 4(a), the raw water inlet pipe 10 connects from the raw water inlet 11 on the water source side to the filtration section 2 via the chemical supply section 3. In the filtration section 2, the switching valve 5 is operated to switch the connections so that the raw water inlet pipe 10 is connected to the inlet 73 and the outlet 74 is connected to the purified water discharge pipe 20.

With this piping configuration, water will flow as follows during filtration:

[Flow path during filtration process]
Raw water inlet 11 → (raw water inlet piping 10) → first branch 12 → chemical supply unit 3 → second branch 13 → switching valve 5 → filtration unit 2 → switching valve 5 → (purified water discharge piping 20) → purified water outlet 21
A check valve 62 is provided in the path of the purified water discharge piping 20. The purified water taken out from the purified water outlet 21 is often connected to a purified water tank 6 installed at an elevated location. The check valve 62 stops the reverse flow of purified water from the purified water tank 6 installed at an elevated location, and prevents water from flowing back into the filtration unit 2.

Next, the water flow during backwashing will be explained using Figures 2 and 4(b). During backwashing, the bypass valve 15 is opened, and the raw water inlet pipe 10 is connected from the raw water inlet 11 on the water source side to the filtration section 2 via the bypass pipe 14, bypassing the chemical supply section 3. In the filtration section 2, the selector valve 5 is operated to switch the connections so that the raw water inlet pipe 10 is connected to the outlet 74 and the inlet 73 is connected to the backwash drain pipe 40. At this time, the water flow within the filtration section 2 is reversed from that during filtration. In the water treatment device 1 according to this embodiment, by switching the selector valve 5 and bypass valve 15, the water source (electric pump 4) can be combined into one, allowing filtration and backwashing to be performed.

During backwashing, water will flow as follows:

[Flow path during backwashing process]
Raw water inlet 11 → (raw water inlet pipe 10) → first branch 12 → (bypass pipe 14) → bypass valve 15 → (bypass pipe 14) → second branch 13 → switching valve 5 → filtration unit 2 → switching valve 5 → backwash drain pipe 40
In this way, during backwashing, the raw water is discharged outside the device after passing through the filtration unit 2, so there is no need to add chemicals to aggregate metal ions, etc. Therefore, during backwashing, the raw water is sent to the filtration unit 2 via bypass piping 14, which bypasses the chemical supply unit 3. Then, during backwashing, the elution of chemicals is suppressed, and water in a state close to that of the raw water is supplied to the filtration unit 2, and the inside of the filtration unit 2 is cleaned.

In addition, a large flow rate is required when performing backwashing. Therefore, by increasing the diameter of the bypass piping 14, a large flow rate of raw water can be ensured during backwashing. On the other hand, during filtration, the flow rate is set according to the capacity of the filtration unit 2. For this reason, a throttle unit 24 is provided in part of the piping through which the water passes during filtration, i.e., in the route of the purified water discharge piping 20, to reduce the flow rate during filtration. The combination of this throttle unit 24 and the electric pump 4 sets the flow rate during filtration to the desired design value. The diameter of the bypass piping 14 is made larger than the throttle unit 24 to ensure the flow rate of water passing through the bypass piping 14 during backwashing.

In addition, in order to discharge the large flow rate during backwashing processing as is, the backwashing drain pipe 40 has a larger diameter than the constriction section 24.

The bypass valve 15 may also be designed to open and close by detecting the pressure or flow rate in the raw water inlet pipe 10 and the purified water discharge pipe 20. Because the backwashing process and the filtration process use different paths, a difference in pressure will also occur in the raw water inlet pipe 10. This pressure difference can be used to open and close the bypass valve 15. In other words, the bypass valve 15 may be a pressure switch installed in the raw water inlet pipe 10 or the purified water discharge pipe 20, or a solenoid valve or motor-operated valve that opens and closes in response to a signal from a flow meter installed in the pipes within the water treatment device 1.

In addition, when controlling the switching valve 5 and the electric pump 4 together, it is possible to change the flow path by interlocking the bypass valve 15 and the switching valve 5. Alternatively, the bypass valve 15 may be opened and closed in conjunction with the operation of the switching valve 5.

The water treatment device 1 of this embodiment can perform a "rinse process" to remove foreign matter remaining in the piping during the backwash process. This rinse process will be explained using Figures 3 and 4(c). The rinse process is possible by changing the flow path of the switching valve 5. Specifically, the bypass valve 15 is opened. The switching valve 5 is switched so that the raw water inlet piping 10 communicates with the inlet 73 and the outlet 74 communicates with the backwash drain pipe 40. In this state, water flows in the filtration section 2 in the same direction as the filtration process, and water that has passed through the filtration section 2 is discharged through the backwash drain pipe 40.

By operating the valves in this way, water will flow as follows during the rinsing process.

[Flow path during rinsing process]
Raw water inlet 11 → (raw water inlet pipe 10) → first branch 12 → (bypass pipe 14) → second branch 13 → switching valve 5 → filtration unit 2 → switching valve 5 → backwash drain pipe 40
Immediately after the backwashing process is completed, foreign matter washed out by the backwashing of the filtration unit 2 remains in the filtration unit 2 or in the piping of the water treatment device 1. Therefore, the foreign matter can be discharged by the rinsing process. In this embodiment, the bypass valve 15 is opened during the rinsing process so that no chemicals are added, and water is allowed to flow through the bypass piping 14, thereby reducing the amount of chemicals 60 used. However, the bypass valve 15 may be closed and the chemicals 60 may be added to the flowing water.

As such, the chemical supply unit 3 used in the water treatment device 1, which has several operating modes, needs to be able to switch between adding and not adding chemicals as needed. Therefore, by connecting the chemical supply unit 3, which can switch between adding and not adding chemicals depending on the flow rate, to a bypass pipe 14 that bypasses the chemical supply unit 3, it is possible to add chemicals during filtration operation and not add chemicals during backwash operation.

(Embodiment 1-2)
FIG. 6 is a schematic diagram showing the overall configuration of the water treatment device 1 of embodiment 1-2 and the flow of water during filtration treatment. FIG. 7 is a schematic diagram showing the flow of water during backwash treatment in this embodiment. Components similar to those in embodiment 1-1 are given the same reference numerals, and detailed descriptions thereof will be omitted. As shown in FIGS. 6 and 7, the differences from embodiment 1-1 are the position of the bypass valve 15 and the air injection unit 80.

The bypass valve 15 may be located within the raw water inlet pipe 10. Specifically, the raw water inlet pipe 10 has a first branch 12 that branches off from the raw water inlet pipe 10 to the bypass pipe 14, and a second branch 13 that merges with the bypass pipe 14. The bypass valve 15 is provided in the raw water inlet pipe 10 between the first branch 12 and the chemical supply unit 3, or in the raw water inlet pipe 10 between the chemical supply unit 3 and the second branch 13. The bypass valve 15 is capable of adjusting the amount of water flowing through the bypass valve 15 (the water channel within the bypass valve 15 can be opened or closed). In this embodiment, the bypass valve 15 is provided in the raw water inlet pipe 10 between the chemical supply unit 3 and the second branch 13.

The air injection section 80 is installed inside the bypass pipe 14 and can inject air into the bypass pipe 14. A venturi structure may be used for this air injection section.

Figure 8 is a schematic diagram of the air injection section 80 of the water treatment device 1. Figure 8 shows the configuration when a venturi structure is used, and explains the principle by which the air injection section 80 functions.

The air injection section 80 is provided midway along the bypass piping 14. The air injection section 80 has a first pipe section 81, a second pipe section 82, a third pipe section 83, a first inclined pipe section 84, a second inclined pipe section 85, and an air pipe 86.

The first pipe section 81 has a pipe shape with a central axis extending horizontally. The speed of the water flowing through the first pipe section 81 is fastest at the air injection section 80.

The second pipe section 82 is located upstream of the first pipe section 81 in the water flow through the first pipe section 81, and is tubular in shape with a central axis extending horizontally. The cross-sectional area through which water flows in the second pipe section 82 is larger than the cross-sectional area through which water flows in the first pipe section 81. The second pipe section 82 and the first pipe section 81 are connected by the first inclined pipe section 84.

The first inclined pipe section 84 has a pipe shape whose central axis extends horizontally and whose cross-sectional area through which water flows becomes smaller as it moves from the second pipe section 82 to the first pipe section 81.

The third pipe section 83 is located downstream of the first pipe section 81 in the water flow through the first pipe section 81, and is tubular in shape with a central axis extending horizontally. The cross-sectional area through which water flows in the third pipe section 83 is larger than the cross-sectional area through which water flows in the first pipe section 81. The third pipe section 83 and the first pipe section 81 are connected by the second inclined pipe section 85.

The second inclined pipe section 85 has a pipe shape whose central axis extends horizontally and whose cross-sectional area through which water flows increases as it moves from the first pipe section 81 to the third pipe section 83.

The air pipe 86 is tubular and extends upward from the top surface of the first pipe section 81. The upper end of the air pipe 86 opens to the atmosphere and communicates with the inside of the first pipe section 81. The cross-sectional area of the air pipe 86 is smaller than the cross-sectional area of the first pipe section 81. A check valve may be provided in the air pipe 86.

Water flowing through the air injection section 80 flows into the second pipe section 82, passes through the first inclined pipe section 84, the first pipe section 81, and the second inclined pipe section 85 in sequence, and then flows out from the third pipe section 83.

The first pipe section 81, the second pipe section 82, the third pipe section 83, the first inclined pipe section 84, the second inclined pipe section 85, and the air pipe 86 are integrally formed. The central axes of the first pipe section 81, the second pipe section 82, the third pipe section 83, the first inclined pipe section 84, and the second inclined pipe section 85 are aligned in a straight line.

When water flows from the second pipe section 82 to the third pipe section 83 in the air injection section 80, the flow velocity in the first pipe section 81 is greater than the flow velocity in the second pipe section 82. Meanwhile, water possesses three types of energy: velocity head, pressure head, and position head, and the total energy is conserved in the second pipe section 82, first inclined pipe section 84, and first pipe section 81. When the central axis of the air injection section 80 is horizontal, the position heads of the second pipe section 82, first inclined pipe section 84, and first pipe section 81 are equivalent, so the flow velocity in the first pipe section 81 increases, and the pressure head decreases by the amount of the increase in velocity head. If this decrease in pressure head is significant, the first pipe section 81 becomes negative pressure. When the first pipe section 81 becomes negative pressure and becomes lower than atmospheric pressure, air is attracted from the air pipe, mixed into the first pipe section 81, and after mixing with water, it is discharged from the third pipe section 83 via the second inclined pipe section 85.

The greater the difference in flow velocity between the first pipe section 81 and the second pipe section 82, the greater the pressure drop in the first pipe section 81. Therefore, when the flow rate of the bypass piping 14 is high, the first pipe section 81 is more likely to become negative pressure. Furthermore, because the pressure in the first pipe section 81 is determined by the pressure difference with the second pipe section 82, the lower the pressure in the second pipe section 82, the more likely it is to become negative pressure. In other words, the lower the pressure resistance downstream of the air injection section 80, the more likely it is to become negative pressure and the easier it is to suck in air. Furthermore, to generate negative pressure in the first pipe section 81, it is recommended that the inner diameter ratio of the first pipe section 81 to the second pipe section 82 be approximately 1:3 to 1:10. The central axes of the first pipe section 81, second pipe section 82, third pipe section 83, first inclined pipe section 84, and second inclined pipe section 85 do not have to be horizontal. In this case, it is advisable to determine the inner diameter ratio between the first pipe section 81 and the second pipe section 82 so that the first pipe section 81 is under sufficiently negative pressure, taking into consideration the change in the positional head of the first pipe section 81 and the second pipe section 82.

When the bypass valve 15 is located within the raw water inlet pipe 10, the pressure loss in the bypass pipe 14 is extremely important. For example, if the pressure loss in the bypass pipe 14 is small, all of the raw water will flow into the bypass pipe 14, and the flow rate on the chemical supply unit 3 side will be zero. In this case, it is a good idea to provide a throttle in the bypass pipe 14 to increase the pressure loss in the bypass pipe 14 and supply raw water to the chemical supply unit 3. This is because the branch flow rate of raw water is determined by the ratio of the pressure loss in the bypass pipe 14 to the pressure loss in the chemical supply unit 3. Using this principle, the flow rate on the chemical supply unit 3 side during filtration can be determined by the pressure loss in the bypass pipe 14, and by adjusting the flow rate on the chemical supply unit 3 side, the concentration of the chemical being supplied can also be adjusted.

On the other hand, much of the pressure loss in the bypass piping 14 is determined by the air injection section 80. Therefore, the air injection section 80 must be designed taking into account both the amount of air injected and the pressure loss.

The operation of each operating mode in embodiment 1-2 is described below.

During filtration, as shown in Figures 6 and 4(a), the bypass valve 15 is opened and the raw water inlet pipe 10 is connected from the raw water inlet 11 on the water source side to the filtration section 2 via the chemical supply section 3 or the bypass pipe 14. In the filtration section 2, the switching valve 5 is operated to switch the connections so that the raw water inlet pipe 10 is connected to the inlet 73 and the outlet 74 is connected to the purified water discharge pipe 20.

In the case of filtration, the bypass valve 15 is opened to create the following flow path.

[Flow path during filtration]
Raw water inlet 11 → (raw water inlet piping 10) → first branch 12 → chemical supply unit 3 + bypass piping 14 → second branch 13 → switching valve 5 → filtration unit 2 → switching valve 5 → (purified water discharge piping 20) → throttle unit 24 + purified water outlet 21
In this flow path, the flow path branches into the drug supply section 3 and the bypass pipe 14 at the first branch section 12, making it possible to supply a drug.

During the filtration process, water also flows through the air injection section 80, but air is not injected. This is because, as explained above, in order for air to be drawn through the air injection section 80, it is important that the flow rate through the air injection section 80 is high and that the pressure in the second pipe section 82 of the air injection section 80 is low (equivalent to the pressure before and after the air injection section). During the filtration process, the flow rate through the air injection section 80 decreases because the flow is divided into the flow rate on the drug supply section 3 side and the flow rate on the bypass piping 14 side. Furthermore, as water passes through the throttle section 24, the pressure in the bypass piping 14 increases, and the pressure in the second pipe section 82 also increases simultaneously, causing the speed of the water flow through the bypass piping 14 to become slower than the specified speed. These two points make it possible to prevent air from being drawn in.

Next, the water flow during backwashing will be explained using Figures 7 and 4(b). During backwashing, the bypass valve 15 is closed, and the raw water inlet pipe 10 is connected from the raw water inlet 11 on the water source side, bypassing the bypass valve 15, to the filtration section 2 via the bypass pipe 14. In the filtration section 2, the selector valve 5 is operated to switch the connections so that the raw water inlet pipe 10 is connected to the outlet 74 and the inlet 73 is connected to the backwash drain pipe 40. At this time, the water flow within the filtration section 2 is reversed from that during filtration. In the water treatment device 1 according to this embodiment, by switching the selector valve 5 and bypass valve 15, the water source (electric pump 4) can be combined into one and filtration and backwashing can be performed.

In the case of backwashing, the bypass valve 15 is closed to create the following flow path.

[Flow path during backwashing]
Raw water inlet 11 → (raw water inlet pipe 10) → first branch 12 → bypass pipe 14 → second branch 13 → switching valve 5 → filtration section 2 → switching valve 5 → backwash drain pipe 40
The flow rate on the chemical supply unit 3 side is completely blocked by the bypass valve 15, making it possible to prevent the chemical from leaking out during backwashing.

Furthermore, during backwashing, the flow rate in the bypass piping 14 increases, and air is injected through the air injection section 80. This is because, as explained above, when the flow rate in the bypass piping 14 is high, the difference in flow velocity between the second pipe section 82 and the first pipe section 81 of the air injection section 80 increases, resulting in a significant pressure drop in the first pipe section 81. As a result, air is sucked into the first pipe section 81 from the air pipe 86. The sucked air enters the filtration section 2 via the switching valve 5. The upward force of the air that has entered the lower part of the filter media breaks down dirt accumulated in the filtration section 2, making it possible to increase the efficiency of the backwashing process.

(Embodiment 2)
Conventionally, chemical supply devices that bring solid chemicals into contact with water have been used to supply chemicals such as oxidizers to water treatment equipment. For example, when purifying well water, a chemical supply device that gradually dissolves solid calcium hypochlorite can be used to oxidize the raw water to be purified.

In systems that inject drugs using a metering pump, or in drug supply devices that dissolve a constant amount of drug regardless of flow rate, it is necessary to change the flow rate of the metering pump to match the flow rate of the injection pipe, which is very expensive.

Figure 20 is a schematic diagram showing the configuration of a conventional water treatment device. As shown in Figure 20, in the solid drug supply device 1101, raw water flows in through the water intake 1102 and contacts the water-soluble solid drug 1103. When water flows into the drug contact phase 1104, the amount of water-soluble solid drug 1103 that comes into contact with the raw water increases as the flow rate increases within a certain flow rate range. This mechanism allows the drug to elute when the flow rate increases, and suppresses the elution of the drug when the flow rate is stopped (see, for example, Patent Document 1).

In such water treatment devices, it is necessary to switch the chemical concentration depending on the device's operating mode. For example, chemicals are added in the raw water filtering mode. Furthermore, chemicals are not added in the filter media cleaning mode; it is necessary to switch whether or not chemicals are added, and the amount of chemicals added. In particular, it is desirable to be able to switch the chemical concentrations as described above using a simple configuration.

The purpose of this disclosure is to provide a water treatment device that can limit contact between chemicals and water by controlling the flow of water inside the water treatment device, thereby obtaining a chemical solution of the desired concentration for each operating mode of the device.

The water treatment device disclosed herein comprises a filtration unit containing a filter medium, a raw water inlet pipe that introduces raw water into the filtration unit, a chemical supply unit that adds chemicals within the raw water inlet pipe, a purified water discharge pipe that extracts filtered treated water from the filtration unit, a bypass pipe that bypasses the chemical supply unit within the raw water inlet pipe, and a bypass valve provided within the bypass pipe. The bypass valve adjusts the flow rate of raw water flowing through the bypass pipe by sensing the pressure within the raw water inlet pipe and opening and closing the bypass pipe.

According to the present disclosure, in a water treatment device, by suppressing the inflow of raw water from the raw water inlet pipe to the chemical supply section, it is possible to supply the chemical solution required for each operating mode.

Embodiment 2 of the present disclosure will be described below with reference to the drawings. Note that embodiment 2 includes at least embodiment 2-1 and embodiment 2-2 below.

(Embodiment 2-1)
The water treatment device 1001 of this embodiment uses well water or water stored in a water tank as raw water, and performs a filtration process to remove metal ions and turbid components contained in this raw water, and a backwash process to discharge metal ion aggregates and turbid components that have accumulated in the system due to the filtration process out of the system.

Figure 10 is a schematic diagram showing the overall configuration of the water treatment device 1001 of this embodiment and the flow of water during filtration processing.

As shown in Figure 10, the water treatment device 1001 has a filtration section 1002 containing a filter material and a chemical supply section 1003 that adds chemicals to the raw water. The filtration section 1002 and the chemical supply section 1003 are connected by piping as described below. The filtration section 1002 purifies the raw water by removing metal ions and turbid components from the raw water, and is, so to speak, the heart of the water treatment device 1001. Dirt accumulated in the filtration section 1002 is discharged outside the device through backwashing and rinsing processes, keeping the filtration section 1002 clean and allowing for repeated use. The backwashing process is a process in which raw water is flowed in the opposite direction through the filtration section 1002 to discharge the dirt. The rinsing process is a process in which, after the backwashing process, raw water is flowed through the filtration section 1002 in the filtration direction to discharge the separated dirt outside the device. The pipe that sends raw water to this filtration unit 1002 is called raw water inlet pipe 1010, the pipe that sends out water purified by filtration unit 1002 from filtration unit 1002 is called purified water discharge pipe 1020, and the pipe that discharges dirt by backwash and rinse operation is called backwash drain pipe 1040. The purified water is stored in a purified water tank 1006 or the like provided outside the water treatment device 1001, and can be used as domestic water when needed.

Raw water is delivered to the water treatment device 1001 by an electric pump 1004 connected to the inlet side of the raw water inlet pipe 1010 (opposite the filtration section 1002). Instead of using the electric pump 1004, a water tank storing raw water may be installed at an elevated location, and the raw water may be delivered to the water treatment device 1001 by utilizing the elevation difference between the water tank and the water treatment device 1001. Alternatively, tap water jointly operated in a local area may be directly connected. In this embodiment, the water source includes wells, water tanks, waterworks, etc., as well as devices that deliver raw water.

The electric pump 1004 is a motor-driven pump that draws up and discharges well water or water stored in a water tank. Examples include centrifugal pumps such as centrifugal pumps and turbine pumps, vortex pumps (cascade pumps), jet pumps, axial flow pumps, and mixed flow pumps. Furthermore, if the well water level is low, it is better to use a submersible pump or other submersible pump rather than a suction pump. For general household use, the well depth must be approximately 1 to 10 meters for shallow wells and 10 to 30 meters or more for deep wells. Considering the head loss of downstream piping and water treatment equipment, a pump with a head of 20 meters or more is preferable, with a vortex pump or jet pump being more preferable. The discharge flow rate of an electric pump is, for example, approximately 5 to 100 liters per minute. For general household use, a pump with a flow rate characteristic of approximately 5 to 50 liters per minute is more preferable.

The raw water inlet pipe 1010 and the purified water outlet pipe 1020 may be made of any material and have any structure that can withstand the water pressure of the electric pump 1004. Specifically, due to their durability and ease of processing, straight pipes or pipe fittings made of polyvinyl chloride resin or steel pipes, or composite materials of these, can be used. The nominal diameter is preferably large to reduce head loss; for example, a nominal diameter of 13 to 50 mm and a thickness of approximately 1 to 5 mm are preferred. If it is difficult to select materials that can withstand the maximum pressure of the electric pump 1004, it is a good idea to install a pressure reducing valve, pressure regulating valve, or relief valve between the electric pump 1004 and the water treatment device 1001.

The chemical supply unit 1003 is provided within the raw water inlet pipe 1010. As will be described in more detail below, the chemical supply unit 1003 adds an oxidizing agent to the raw water, causing metal ions contained in the raw water to coagulate as substances that are difficult to dissolve in water, making them easier to capture in the filtration unit 1002.

(Filtration section related)
Next, the filtration unit-related components, filtration unit 1002 and switching valve 1005, will be described with reference to Fig. 13. Fig. 11 is a schematic diagram showing the flow of water during backwash processing in water treatment device 1001. Fig. 12 is a schematic diagram showing the flow of water during rinse processing in water treatment device 1001. Fig. 13 is a cross-sectional view of filtration unit 1002 and switching valve 1005 of water treatment device 1001.

The filtration unit 1002 contains filter media and a water collection pipe 1070, and purifies raw water by passing it through. The filter media inside the filtration unit 1002 is composed of an upper layer 1071, which primarily filters out impurities, and a lower layer 1072, which has a rectifying effect. The filter media used in the upper layer 1071 include activated carbon, manganese sand, anthracite, etc., and approximately one to four types are used in layers depending on the raw water quality. In this embodiment, the filtration function of the filtration unit 1002 is centered around this upper layer 1071. The filter media used in the lower layer 1072 is composed of gravel and coarse-pore resin, which disperses water entering and exiting the water collection pipe. The lower layer 1072 has a relatively large gravel layer at the bottom, which improves water flow and prevents the filter media from leaking out from the bottom of the water collection pipe 1070. The amount of filter material in the lower layer 1072 is preferably about 1/2 to 1 time the diameter of the filtration section 1002. The combined filling amount of the filter material in the upper layer 1071 and the lower layer 1072 is preferably about 1/4 to 4/5 times the internal volume of the filtration section 1002.

The filtration section 1002 is connected at the top to external piping (raw water inlet piping 1010, purified water outlet piping 1020, backwash drain pipe 1040). Inside the filtration section 1002, there are an inlet 1073 and an outlet 1074, which serve as openings. The outlet 1074 is connected to the water collection pipe 1070.

A switching valve 1005 is attached to the top of the filtration section 1002, and connects the external piping (raw water inlet piping 1010, purified water outlet piping 1020, backwash drain pipe 1040) to the inlet 1073 and outlet 1074 within the filtration section 1002. Operation of the switching valve 1005 switches the communication between the external piping and the inlet 1073 and outlet 1074. The switching valve 1005 is equipped with a flow path switching top 1075 that switches the flow path, and by rotating the flow path switching top 1075, the direction of communication with the connected piping and openings is changed. The flow path switching top 1075 can be rotated with an external handle or moved by an external motor.

During filtration, the flow path switching top 1075 is operated to connect the raw water inlet pipe 1010 to the inlet 1073, and to connect the outlet 1074 to the purified water discharge pipe 1020. During backwashing, the flow path switching top 1075 is operated to connect the raw water inlet pipe 1010 to the outlet 1074, and to connect the inlet 1073 to the backwash drain pipe 1040. During rinsing, the flow path switching top 1075 is operated to connect the raw water inlet pipe 1010 to the inlet 1073, and to connect the outlet 1074 to the backwash drain pipe 1040.

Various operations are possible depending on the type of piping connected to the switching valve 1005. For example, by connecting the raw water inlet piping 1010 and the purified water outlet piping 1020, raw water can be sent directly to the purified water tank 1006.

In this embodiment, a switching valve 1005 is used, but the flow path can also be switched by using multiple valves other than the switching valve 1005.

In this configuration, the flow of water during filtration and backwashing processes will be explained. During filtration, water flows within the filtration section 1002 as follows, and purified water is obtained from the outlet 1074.

[Flow path in filtration unit 1002 during filtration process]
Inlet 1073 → Upper layer 1071 → Lower layer 1072 → Water collection pipe 1070 → Outlet 1074
During the rinsing process, water flows through the filtration unit 1002 in the same manner as during the filtration process, but water containing dirt after the backwash process (described later) flows out from the outlet 1074. Therefore, the outlet 1074 is connected to the backwash drain pipe 1040 and is discharged to the outside.

In addition, dirt accumulated in the filtration section 1002 during the filtration process can be discharged by backwashing. During the backwashing process, water flows as follows, and dirt is discharged from the outlet 1074.

[Flow path in filtration section 1002 during backwashing process]
Outlet 1074 → Water collection pipe 1070 → Lower layer 1072 → Upper layer 1071 → Inlet 1073
(Medicine Supply Department)
Next, chemical supply unit 1003 will be described with reference to Figures 10 and 14. Figure 14 is a cross-sectional view of chemical supply unit 1003 of water treatment device 1001.

The chemical supply unit 1003 is provided to promote the aggregation of metal ions contained in the raw water by the chemical contained therein, making it easier for them to be captured by the filtration unit 1002. The chemical supply unit 1003 has an inlet channel 1031, a chemical channel 1032, a bypass channel 1033, and an outlet channel 1034. The inlet channel 1031 is connected to the raw water inlet pipe 1010 and allows raw water to flow into the chemical supply unit 1003. The chemical channel 1032 branches off from the inlet channel 1031 and dissolves the chemical. The bypass channel 1033 also branches off from the inlet channel 1031 via a throttle section 1033a and is provided to adjust the chemical solution to the required concentration. After branching off from the inlet channel 1031, the bypass channel 1033 is connected to the inlet side of the outlet channel 1034. Outlet path 1034 merges with chemical path 1032 and bypass path 1033 and is connected again to raw water inlet pipe 1010, thereby sending out chemical-containing raw water to raw water inlet pipe 1010. As shown in Figure 14, chemical path 1032 is composed of spray pipe 1052 that branches and then rises vertically, chemical placement section 1053 that comes into contact with the chemical at the top of spray pipe 1052 and dissolves the chemical, and recovery section 1054 that is on the outer periphery of spray pipe 1052 and is inside housing 1051.

The ejection pipe 1052 is a small-diameter pipe that stands upright and has a chemical placement section 1053 at the top. The ejection pipe 1052 has a smaller diameter at the bottom, and the chemical placement section 1053 is provided at the top of the ejection pipe 1052, allowing the raw water to come into contact with the chemical at the desired flow rate. The chemical placement section 1053 is sized to ensure the amount (number) of chemical to be placed so that the desired concentration of chemical solution can be obtained for the raw water flow rate.

The chemical solution with the dissolved chemical flows out into the recovery section 1054. In the recovery section 1054, the chemical solution with the dissolved chemical accumulates at the bottom of the housing 1051, and then flows out of the recovery opening 1055 into the outflow path 1034. Because the diameter of the ejection pipe 1052 is small and a certain distance is maintained from the inner wall surface of the housing 1051, the liquid level of the raw water with the dissolved chemical that flows down into the housing 1051 can be set to about half the height of the housing 1051 or even lower. By accumulating the chemical solution at the desired depth within the housing 1051, the ratio at which it mixes with the raw water in the outflow path 1034 can be adjusted.

The flow rate of raw water flowing through chemical path 1032 can be adjusted by the flow rate of raw water flowing through bypass path 1033. That is, the ratio of the flow rates of raw water flowing through chemical path 1032 and bypass path 1033 can be adjusted by adjusting the diameter of throttle section 1033a of bypass path 1033. In this way, the chemical concentration in outflow path 1034 after merging can be adjusted to the desired concentration. Note that instead of throttle section 1033a, a flow control valve may be used to adjust the flow rate of raw water flowing through bypass path 1033.

Then, by keeping the amount of raw water flowing into the chemical supply section 1003 within a predetermined range and setting the liquid level in the chemical supply section 1003 to the desired height, the chemical concentration in the raw water flowing out from the chemical supply section 1003 can be adjusted to within the desired range.

It is advisable to ensure that an air layer always exists within the housing 1051 of the chemical supply unit 1003. The housing 1051 is an airtight space except for the connection with the raw water inlet pipe 1010, so once the air is removed and the housing 1051 is filled with water, the chemical 1060 will always be in contact with the water and continue to dissolve. Therefore, in order to send air to the chemical supply unit 1003, it is advisable to attach an air supply pipe or a valve such as a check valve to the raw water inlet pipe 1010.

The chemical placement section 1053 is provided with a water-soluble, solid chemical 1060. It is preferable to use a tablet or granular chemical 1060, as this increases the surface area of the chemical 1060 and allows for a stable solvent concentration. For tablets, a diameter of 30 mm and a height of 10-20 mm is recommended, while for granules, a diameter of 5-15 mm is recommended. If the chemical 1060 is small, adjacent chemicals may come into contact with water at the same time, causing them to stick together. This adhesion can result in only the lower portions of the chemical coming into contact with water, making it impossible to obtain a chemical solution of the desired concentration. Alternatively, if the chemical 1060 is small, the contact area with the water supplied from the ejection pipe 1052 increases, making it impossible to obtain a chemical solution of the desired concentration. Therefore, chemicals 1060 of the above-mentioned sizes are used to supply a chemical solution of the desired concentration.

As mentioned above, chemical 1060 oxidizes metal ions contained in the raw water to produce flocculants that are difficult to dissolve in water. Various oxidizing agents can be used as chemical 1060, but depending on the desired water purification performance, inorganic or polymeric flocculants such as PAC (polyaluminum chloride) or chitosan may also be used. When adding chemicals to raw water, chemical 1060 that is easily soluble in water is preferable, but it is also preferable that the chemical remains in a solid form and does not flow out of chemical placement section 1053 during shutdown or backwash treatment, i.e., when chemical addition is interrupted. In this embodiment, trichloroisocyanuric acid is used.

Because each component of the drug supply unit 1003 may be in contact with the drug for extended periods of time, it is recommended to select materials with low reactivity to the drug, such as PVC (polyvinyl chloride), PMMA (polymethyl methacrylate), or PP (polypropylene). On the other hand, the ejection pipe 1052 must be strong enough to support the drug placement unit 1053. Therefore, considering compatibility with the drug, it is preferable to select materials for the ejection pipe 1052 that are stronger than PP, such as polyvinyl chloride or ABS (acrylonitrile butadiene styrene). The outer diameter of the ejection pipe 1052 should be no more than one-quarter the inner diameter of the base 1051a and the upper cover 1051b. As mentioned above, a space (collection unit 1054) can be provided outside the ejection pipe 1052 to temporarily store the solution discharged from the placement unit outlet 1058 after drug supply, preventing the water level in the housing 1051 from rising too rapidly and reaching the drug placement unit 1053. For example, if the inner diameter of the base 1051a is 130 mm, it is advisable to use a PVC pipe or the like with an outer diameter of about 25 to 40 mm.

(Piping configuration)
As described above, water treatment device 1001 of this embodiment includes filtration section 1002, raw water inlet pipe 1010, purified water discharge pipe 1020, and backwash drain pipe 1040 ( FIG. 10 ). Raw water inlet pipe 1010 has an inlet connected to the discharge port of electric pump 1004, which serves as a water source, and an outlet connected to switching valve 1005 of filtration section 1002. Raw water inlet pipe 1010 includes chemical supply section 1003 and bypass pipe 1014, which bypasses chemical supply section 1003. This bypass pipe 1014 branches (at branch section 1012) from raw water inlet pipe 1010 upstream of chemical supply section 1003, bypasses chemical supply section 1003, and merges (at branch section 1013) with raw water inlet pipe 1010 downstream of chemical supply section 1003. A bypass valve 1015a is provided in the path of the bypass piping 1014. The bypass valve 1015a, which will be described in detail later, is a two-way valve that senses the pressure upstream of the bypass valve 1015a and opens and closes it. That is, the bypass valve 1015a has a mechanism that opens the path of the bypass piping 1014 when the pressure upstream is lower than a predetermined pressure P, and closes the path of the bypass piping 1014 when the pressure exceeds the predetermined pressure P.

The filtration section 1002 has two outlets, one of which is connected to a purified water discharge pipe 1020 that extracts purified water. The other outlet is connected to a backwash drain pipe 1040 that discharges particulate matter (dirt, turbid components, metal aggregates, etc.) captured by the filtration section 1002 outside the system during backwash and rinse processes.

Next, the piping configuration within the water treatment device 1001 and the water flow during filtration and backwashing processes will be explained using Figures 10 to 13. Figure 13 is a schematic cross-sectional view of the filtration section 1002, with Figure 13(a) showing an overall view during filtration, Figure 13(b) showing the state of the switching valve 1005 during backwashing, and Figure 13(c) showing the state of the switching valve 1005 during rinsing.

First, we will explain the flow of water during filtration using Figures 10 and 13 (a).

During filtration, the filtration unit 1002 switches the connection by operating the selector valve 1005 so that the raw water inlet pipe 1010 is connected to the inlet 1073 and the outlet 1074 is connected to the purified water discharge pipe 1020. A throttle section 1024 is provided in the purified water discharge pipe 1020. This is because, to achieve the desired filtration performance, the flow rate during filtration must be controlled to a flow rate set by the capacity of the filtration unit 1002. By combining this throttle section 1024 with the electric pump 1004, the flow rate during filtration can be set to the desired design value. In a route passing through the throttle section 1024, the pressure loss in the piping is greater than in the route during backwashing, described below, resulting in higher pressure in the raw water inlet pipe 1010. Furthermore, during filtration, water must be transported to the purified water tank 1006, and the higher the installation position of the purified water tank 1006, the higher the pressure in the raw water inlet pipe 1010. When the pressure in the raw water inlet pipe 1010 increases and exceeds a predetermined pressure P, the bypass valve 1015a closes the bypass pipe 1014, and the raw water inlet pipe 1010 is connected from the raw water inlet 1011 on the water source side to the filtration section 1002 via the chemical supply section 1003.

With this piping configuration, water will flow as follows during filtration:

[Flow path during filtration process]
Raw water inlet 1011 → (raw water inlet piping 1010) → branching section 1012 → chemical supply section 1003 → branching section 1013 → switching valve 1005 → filtration section 1002 → switching valve 1005 → (purified water discharge piping 1020) → purified water outlet 1021
A check valve 1062 is provided in the path of purified water discharge piping 1020. The purified water taken out from purified water outlet 1021 is often connected to a purified water tank 1006 provided at an elevated location. Check valve 1062 prevents the reverse flow of purified water from purified water tank 1006 provided at an elevated location, and prevents water from flowing back into filtration unit 1002.

Next, we will explain the water flow during backwashing using Figures 11 and 13 (b).

During backwashing, the filtration section 1002 switches connections by operating the selector valve 1005 so that the raw water inlet pipe 1010 and outlet 1074 are connected, and the inlet 1073 and backwash drain pipe 1040 are connected. Because a large flow rate is required during backwashing, the backwash drain pipe 1040 has a larger diameter than the throttle section 1024. This path reduces pressure loss in the pipe, resulting in low pressure within the raw water inlet pipe 1010. When the pressure within the raw water inlet pipe 1010 is low and does not exceed a predetermined pressure P, the bypass valve 1015a opens, and the raw water inlet pipe 1010 connects from the raw water inlet 1011 on the water source side to the filtration section 1002, bypassing the chemical supply section 1003 and via the bypass pipe 1014. The diameter of the bypass pipe 1014 is larger than that of the pipe within the chemical supply section 1003. As a result, the pressure loss in bypass piping 1014 is smaller than that in drug supply unit 1003, so that most of the flow rate flows to bypass piping 1014 without blocking the path leading to drug supply unit 1003, and the flow rate flowing to drug supply unit 1003 is small. The flow rate on the drug supply unit 1003 side further branches into drug path 1032 and bypass path 1033, so the flow rate in drug path 1032 is minute, and drug 1060 and water hardly come into contact with each other.

At this time, the water flow within the filtration section 1002 is reversed from that during filtration. In the water treatment device 1001 of this embodiment, by switching the switching valve 1005, the water source (electric pump 1004) can be combined into one, allowing filtration and backwashing to be performed.

During backwashing, water will flow as follows:

[Flow path during backwashing process]
Raw water inlet 1011 → (raw water inlet pipe 1010) → branching section 1012 → (bypass pipe 1014) → bypass valve 1015a → (bypass pipe 1014) → branching section 1013 → switching valve 1005 → filtration section 1002 → switching valve 1005 → backwash drain pipe 1040
In this way, during backwashing, the water is discharged outside the device after passing through filtration section 1002, so there is no need to add chemicals to aggregate metal ions, etc. Therefore, during backwashing, the raw water is sent to filtration section 1002 via bypass piping 1014, which bypasses chemical supply section 1003. Then, during backwashing, the elution of chemicals is suppressed, and water that remains close to the raw water is supplied to filtration section 1002, and the inside of filtration section 1002 is cleaned.

As described above, due to differences in the piping configuration, a difference occurs in the pressure inside the raw water inlet pipe 1010 during filtration treatment and backwash treatment, with the pressure inside the raw water inlet pipe 1010 being higher during filtration treatment than during backwash treatment. By utilizing this, it is possible to bypass the chemical supply unit 1003 during backwash treatment, which does not require chemicals, using the bypass valve 1015a, which closes when the pressure exceeds a predetermined pressure P. The predetermined pressure P is determined under conditions such as the depth of the well that the water treatment device 1001 can use and the installation height of the purified water tank 1006.
Pressure in the raw water inlet pipe 1010 during filtration treatment>predetermined pressure P
The pressure P is determined based on the capacity of the electric pump 1004 so that the predetermined pressure P is greater than the pressure in the raw water inlet pipe 1010 during backwashing treatment.

The water treatment device 1001 of this embodiment can perform a "rinse process" to remove foreign matter remaining in the piping during the backwash process. This rinse process will be described using Figures 12 and 13(c). The rinse process is possible by changing the flow path of the switching valve 1005. The switching valve 1005 switches so that the raw water inlet piping 1010 is connected to the inlet 1073 and the outlet 1074 is connected to the backwash drain pipe 1040. In this state, water flows through the filtration section 1002 in the same direction as the filtration process, and water that passes through the filtration section 1002 is discharged through the backwash drain pipe 1040. Furthermore, because the water is discharged through the backwash drain pipe with a larger diameter without passing through the throttle section 1024, the pressure in the raw water inlet piping 1010 becomes as low as during the backwash process, and the bypass valve 1015a is opened.

By operating the valves in this way, water will flow as follows during the rinsing process.

[Flow path during rinsing process]
Raw water inlet 1011 → (raw water inlet pipe 1010) → branching section 1012 → (bypass pipe 1014) → branching section 1013 → switching valve 1005 → filtration section 1002 → switching valve 1005 → backwash drain pipe 1040
Immediately after the backwashing process is completed, foreign matter that was washed out by the backwashing of the filtration unit 1002 remains in the filtration unit 1002 or in the piping of the water treatment device 1001. Therefore, the foreign matter can be discharged by the rinsing process.

(bypass valve)
The configuration of bypass valve 1015a will now be described with reference to Figures 15A to 16. Figure 15A is a cross-sectional view of bypass valve 1015a when water treatment device 1001 is at low pressure. Figure 15B is a horizontal cross-sectional view of the shaft collar of bypass valve 1015a. Figure 16 is a cross-sectional view of bypass valve 1015a when water treatment device 1001 is at high pressure.

In order to adjust the flow rate in the bypass pipe 1014, the bypass valves that can be used include a two-way valve type bypass valve 1015a (this embodiment) installed in the bypass pipe 1014 and a three-way valve type bypass valve 1015b (embodiment 2-2 described below) installed at the branch point 1012 between the raw water inlet pipe 1010 and the bypass pipe 1014.

Figure 15A is a cross-sectional view of bypass valve 1015a at low pressure, and Figure 16 is a cross-sectional view of bypass valve 1015a at high pressure.

As described above, bypass valve 1015a is provided in bypass piping 1014. Bypass piping 1014 branches off from raw water inlet piping 1010 at branch 1012, bypasses chemical supply unit 1003, and merges with raw water inlet piping 1010 at branch 1013, located downstream of chemical supply unit 1003 (Figures 10, 11, and 12). Bypass valve 1015a includes an inlet pipe 1080 through which raw water flows in from branch 1012, an outlet pipe 1081 through which raw water flows out into raw water inlet piping 1010, and an on-off valve 1090. On-off valve 1090 includes a base 1091, a lid 1092 attached to the base, a diaphragm 1093, a shaft 1094, a spring 1095, a valve element 1096, and a valve seat 1097.

The periphery of the diaphragm 1093 is fixed by being sandwiched between the base 1091 and the lid 1092. A pressure-receiving space 1098 is provided between the diaphragm 1093 and the base 1091, and the pressure-receiving space 1098 and the inlet pipe 1080 are connected by a pressure-receiving pipe 1099. The diaphragm 1093 is driven by the pressure of the raw water that flows into the pressure-receiving space 1098.

The shaft 1094 is arranged to pass through the pressure-receiving pipe 1099 and the outflow pipe 1081 near their central axes, with the diaphragm 1093 attached to the pressure-receiving pipe 1099 side and the valve body 1096 attached to the outflow pipe 1081 side. The valve seat 1097 is provided on the outflow pipe 1081 side of the base 1091 and has an opening opposite the valve body 1096. This opening connects the inflow pipe 1080 and the outflow pipe 1081 and is opened and closed by the valve body 1096. The shaft 1094 slides the valve body 1096 in conjunction with the movement of the diaphragm 1093, opening and closing the opening of the valve seat 1097 that leads to the outflow pipe 1081.

In Figures 15A and 16, the valve body 1096 and shaft 1094 slide vertically inside the bypass valve 1015a. The spring 1095 is provided above the diaphragm 1093 so as to press the diaphragm 1093 downward. In this embodiment, the diameter of the pressure-receiving tube 1099 is made smaller than the diameter of the surface where the spring 1095 presses against the diaphragm 1093, and the force of the spring 1095 is received by the base 1091. If the diameter of the pressure-receiving tube 1099 were larger than the diameter of the surface where the spring 1095 presses against the diaphragm 1093, the diaphragm 1093 would always be deformed by the force of the spring 1095, which would place a heavy load on the material strength. Therefore, by reducing the diameter of the pressure-receiving pipe 1099 and receiving the spring force at the base 1091, deformation of the diaphragm 1093 at low pressure (including when operation is stopped) is suppressed, ensuring durability.

In addition, the diaphragm 1093 and base 1091 are in close contact with each other, so as not to block the flow path of the pressure-receiving pipe 1099, and the inlet pipe 1080 and the pressure-receiving space 1098 are in communication with each other. That is, as shown in Figures 15A and 15B, the shaft 1094 has a flange 1100 located between the diaphragm 1093 and base 1091, and the flange 1100 is sandwiched between the diaphragm 1093 and base 1091. The flange 1100 is composed of several protrusions that protrude radially from the axis of the shaft 1094, and the protrusions are designed to catch on the opening of the pressure-receiving pipe 1099. Furthermore, the protrusions are sized and positioned so as not to block the flow path of the pressure-receiving pipe 1099. Such a structure prevents the diaphragm 1093 and the base 1091 from coming into close contact with each other, ensures a flow path for the pressure-receiving pipe 1099 , and allows the inlet pipe 1080 and the pressure-receiving space 1098 to communicate with each other.

As will be described later, when a large pressure is applied to the diaphragm 1093 and it is pushed up, the shaft 1094 and the valve element 1096 are also pushed up in conjunction, and the valve element 1096 is pressed against the valve seat 1097, blocking the outflow pipe 1081. In this way, the on-off valve 1090 is a two-way valve that opens and closes the outflow pipe 1081.

In order for this movement to occur, the area of the diaphragm 1093 in contact with the pressure-receiving space 1098 must be larger than the area of the valve body 1096. The pressure received by these two surfaces is the same, and the larger the area, the greater the resultant force exerted by the pressure. In other words, forces act in the direction in which the diaphragm 1093 and valve body 1096 pull on the shaft 1094, causing the shaft 1094 to slide in the direction in which the force is greater. In this way, in order to push up the diaphragm 1093, which is pressed down by the spring 1095, and close the outflow pipe 1081, the area of the diaphragm 1093 that is subjected to pressure must be larger than the valve body 1096.

In addition, since the diaphragm 1093 is located on the flow path of the water treatment device 1001, it is advisable to select a rubber material that is resistant to chemicals, such as fluororubber or silicone rubber. The reaction force of the spring 1095 is adjusted so that the bypass valve 1015a closes when the pressure in the raw water inlet pipe 1010 reaches or exceeds a predetermined pressure P.

With this configuration, pressure loss is small, and in operating modes (during backwashing and rinsing) where the pressure in the raw water inlet pipe 1010 does not exceed a predetermined pressure P, as shown in FIG. 15A, the diaphragm 1093 is pressed against the base 1091 by the reaction force of the spring 1095, opening the flow path of the outlet pipe 1081. In other words, the bypass valve 1015a is opened. As a result, water flows into the bypass pipe 1014, bypassing the chemical supply unit 1003. On the other hand, in operating modes (during filtration) where the pressure in the raw water inlet pipe 1010 increases and exceeds the predetermined pressure P, as shown in FIG. 16, the diaphragm 1093 is pushed up, and the shaft 1094 and valve element 1096 also move upward in conjunction, blocking the outlet pipe 1081. In other words, the bypass pipe 1014 is blocked, and water flows into the chemical supply unit 1003.

In this way, the water treatment device 1001 of this embodiment operates by switching between operating modes, namely, when chemical solution is supplied to the chemical supply unit 1003 via raw water (filtration process) and when no chemical solution is required and the chemical supply unit 1003 is bypassed (backwash process). Therefore, the system is configured to utilize the difference in pressure loss between the piping paths in each operating mode to switch the opening and closing of the bypass valve 1015a, which senses the pressure in the raw water inlet piping 1010, depending on the operating mode. This configuration allows switching between the flow path through the chemical supply unit 1003 and the flow path through the bypass piping 1014, which bypasses the chemical supply unit 1003, making it possible to add chemicals during filtration operation and not add chemicals during backwash operation.

(Embodiment 2-2)
Next, a water treatment device 1001 according to a second embodiment of the present disclosure will be described with reference to Figures 17 to 19. Figure 17 is a schematic diagram of the overall configuration of water treatment device 1001 according to this embodiment 2-2. Figure 18 is a cross-sectional view of bypass valve 1015b of water treatment device 1001 at low pressure. Figure 19 is a cross-sectional view of bypass valve 1015b of water treatment device 1001 at high pressure.

In this embodiment, the differences from embodiment 1 will be mainly described. In this embodiment, a three-way type bypass valve 1015b is used at the branch point 1012 of the bypass pipe 1014 in the raw water inlet pipe 1010 to adjust the flow rate of the bypass pipe 1014.

As described above, bypass valve 1015b is a three-way valve with one inlet (inlet pipe 1080) and two outlets (outlet pipes 1081a and 1081b). As in the first embodiment, inlet pipe 1080 allows raw water to flow in from raw water inlet pipe 1010. Outlet pipe 1081a allows raw water to flow out to the chemical supply section 1003. Outlet pipe 1081b allows raw water to flow out to bypass pipe 1014. Bypass valve 1015b switches between the outlets (outlet pipes 1081a and 1081b) depending on the pressure applied to inlet pipe 1080.

The bypass valve 1015b, like the bypass valve 1015a, has an on-off valve 1090. A feature of the three-way type bypass valve 1015b is that the pressure-receiving space 1098 is connected to the outflow pipe 1081a. Furthermore, the communication between the pressure-receiving space 1098 and the outflow pipe 1081a is opened and closed by the operation of the diaphragm 1093. Note that with regard to other components of the on-off valve 1090, parts that are the same as those in the bypass valve 1015a are numbered the same and detailed explanations will be omitted.

The operation of the bypass valve 1015b configured as described above will now be explained. When the pressure in the raw water inlet pipe 1010 is lower than a predetermined pressure P, the diaphragm 1093 is pressed against the base 1091, and the outlet pipe 1081a is blocked by the diaphragm 1093. At this time, the outlet pipe 1081b is open, and the raw water flowing through the bypass valve 1015b flows to the outlet pipe 1081b, i.e., the bypass pipe 1014 side.

On the other hand, when the pressure in the raw water inlet pipe 1010 exceeds a predetermined pressure P, the diaphragm 1093 is pushed up, opening the outlet pipe 1081a. At the same time, the shaft 1094 and valve body 1096 are also pushed up in conjunction with the diaphragm 1093, forcing the valve body 1096 against the valve seat 1097 and blocking the outlet pipe 1081b. In other words, the raw water flowing through the bypass valve 1015b flows to the chemical supply section 1003 side of the outlet pipe 1081a. In this way, the on-off valve 1090 is a three-way valve that opens the outlet pipe 1081b at low pressure and opens the outlet pipe 1081a at high pressure.

By using a bypass valve 1015b configured in this manner, in operating modes (during backwashing and rinsing) in which the pressure in the raw water inlet pipe 1010 is lower than a predetermined pressure P, the flow path through the chemical supply unit 1003 is blocked and only the flow path through the bypass pipe 1014 is open, allowing water to flow into the bypass pipe 1014 and bypass the chemical supply unit 1003. On the other hand, in operating modes (during filtration) in which the pressure in the raw water inlet pipe 1010 is higher than the predetermined pressure P, the flow path through the bypass pipe 1014 is blocked and only the flow path through the chemical supply unit 1003 is open, allowing water to flow into the chemical supply unit 1003.

The three-way type bypass valve 1015b is useful in cases where the flow path through the chemical supply unit 1003 is blocked during backwashing, so the difference in pressure loss between filtration and backwashing is small, and water would flow into the chemical supply unit 1003 if the flow path on the chemical supply unit 1003 side were left open.

Bypass valve 1015b can also be used as a two-way valve that detects pressure and opens and closes by blocking the downstream side of outflow pipe 1081a or outflow pipe 1081b. When the downstream side of outflow pipe 1081a is blocked, the valve opens outflow pipe 1081b at low pressure and closes it at high pressure. In this way, three-way type bypass valve 1015b can be used as a two-way valve. Conversely, when the opposite side of outflow pipe 1081b is blocked, the valve closes outflow pipe 1081a at low pressure and opens it at high pressure. In this case, for example, a bypass route directly connecting raw water inlet pipe 1010 and backwash drain pipe 1040 can be provided, and the relief valve can be installed in that bypass route. With this configuration, if the raw water inlet pipe 1010 becomes high pressure, for example, because the performance of the electric pump 1004 is too high, the bypass route can be opened to discharge the excess pressure and flow rate, thereby making it possible to achieve the desired pressure and flow rate within the water treatment device 1001.

In this way, the same configuration can be used for multiple valves with different functions, reducing the number of different parts and cutting mold costs, etc.

The first outlet described in the claims corresponds to the outlet pipe 1081a of the bypass valve 1015b, and the second outlet corresponds to the outlet pipe 1081b of the bypass valve 1015b. The first valve body described in the claims corresponds to the diaphragm 1093, and the second valve body corresponds to the valve body 1096.

The water treatment device disclosed herein is capable of supplying a sufficient amount of clean backwash water for backwashing and can be installed in a smaller space than conventional products, making it useful as a small household water treatment device used to purify well water and stored water.

REFERENCE SIGNS LIST 1 Water treatment device 2 Filtration section 3 Chemical supply section 4 Electric pump 5 Switching valve 6 Purified water tank 10 Raw water inlet piping 11 Raw water inlet 12 First branch section 13 Second branch section 14 Bypass piping 15 Bypass valve 20 Purified water discharge piping 21 Purified water outlet 24 Throttle section 31 Inlet channel 32 Chemical channel 33 Bypass channel 33a Throttle section 34 Outlet channel 40 Backwash drain pipe 51 Housing 51a Base 51b Upper cover 52 Spray pipe 53 Chemical placement section 54 Recovery section 55 Recovery opening 58 Placement section outlet 60 Chemical 62 Check valve 70 Water collection pipe 71 Upper layer 72 Lower layer 73 Inlet 74 Outlet 75 Flow path switching piece 80 Air injection section 81 First pipe section 82 Second pipe section 83 Third pipe section 84 First inclined pipe section 85 Second inclined pipe section 86 Air pipe 101 Solid chemical supply device 102 Water intake port 103 Water-soluble solid chemical 104 Chemical contact phase 1001 Water treatment device 1002 Filtration section 1003 Chemical supply section 1004 Electric pump 1005 Switching valve 1006 Purified water tank 1010 Raw water inlet piping 1011 Raw water inlet 1012 Branch section 1013 Branch section 1014 Bypass piping 1015a, 1015b Bypass valve 1020 Purified water discharge piping 1021 Purified water outlet 1024 Throttle section 1031 Inlet channel 1032 Chemical channel 1033 Bypass channel 1033a Throttle section 1034 Outlet path 1040 Backwash drain pipe 1051 Housing 1051a Base 1051b Upper cover 1052 Spray pipe 1053 Chemical placement section 1054 Recovery section 1055 Recovery opening 1058 Placement section outlet 1060 Chemical 1062 Check valve 1070 Water collection pipe 1071 Upper layer 1072 Lower layer 1073 Inlet 1074 Outlet 1075 Flow path switching piece 1080 Inlet pipe 1081, 1081a, 1081b Outlet pipe 1090 Opening/closing valve 1091 Base 1092 Lid section 1093 Diaphragm 1094 Shaft 1095 Spring 1096 Valve body 1097 Valve seat 1098: Pressure-receiving space 1099: Pressure-receiving pipe 1100: Collar 1101: Solid drug supply device 1102: Water intake port 1103: Water-soluble solid drug 1104: Drug contact phase

Claims (9)

A filtration section containing a filter material;
A raw water inlet pipe for introducing raw water into the filtration section;
A chemical supply unit that adds a chemical within the raw water inlet piping;
A purified water discharge pipe that extracts filtered treated water from the filtration unit;
a bypass pipe that bypasses the chemical supply unit within the raw water inlet pipe;
a bypass valve that adjusts the amount of raw water flowing through the bypass piping and the amount of raw water flowing through the chemical supply unit ;
A backwash drain pipe through which drainage water from the filtration unit flows;
Further provided is a switching valve that switches communication between at least one of the raw water inlet pipe, the purified water discharge pipe, and the backwash drain pipe connected to the filtration unit and an opening in the filtration unit;
The bypass valve opens and closes in conjunction with the operation of the switching valve . A filtration section containing a filter material;
A raw water inlet pipe for introducing raw water into the filtration section;
A chemical supply unit that adds a chemical within the raw water inlet piping;
A purified water discharge pipe that extracts filtered treated water from the filtration unit;
a bypass pipe that bypasses the chemical supply unit within the raw water inlet pipe;
a bypass valve that adjusts the amount of raw water flowing through the bypass piping and the amount of raw water flowing through the chemical supply unit ;
The purified water discharge pipe is provided with a throttle portion,
a sensor for detecting the pressure or flow rate in the raw water inlet pipe or the purified water outlet pipe;
The bypass valve opens and closes depending on the output of the sensor . A filtration section containing a filter material;
A raw water inlet pipe for introducing raw water into the filtration section;
A chemical supply unit that adds a chemical within the raw water inlet piping;
A purified water discharge pipe that extracts filtered treated water from the filtration unit;
a bypass pipe that bypasses the chemical supply unit within the raw water inlet pipe;
a bypass valve that adjusts the amount of raw water flowing through the bypass piping and the amount of raw water flowing through the chemical supply unit ;
During the filtration process, the raw water flows through the chemical supply unit, the filtration unit, and the purified water discharge pipe in this order,
During backwashing treatment, the raw water flows through the bypass piping, the filtration section, and the backwash drain pipe in this order,
an air injection section for injecting air is provided in the bypass piping,
The air injection unit injects air into the bypass pipe during the backwashing process . The bypass valve is provided in the bypass piping and is capable of adjusting the amount of the raw water flowing through the bypass valve.
The water treatment device according to any one of claims 1 to 3 . A first branch portion in the raw water inlet pipe that branches off to the bypass pipe;
Further provided is a second branch portion in the raw water inlet pipe that joins the bypass pipe,
The bypass valve is provided in the raw water inlet pipe between the first branch and the chemical supply unit, or in the raw water inlet pipe between the chemical supply unit and the second branch, and is capable of adjusting the amount of raw water flowing through the bypass valve.
The water treatment device according to any one of claims 1 to 3 . The bypass valve adjusts the amount of the raw water flowing through the bypass valve according to the pressure on the upstream side of the bypass valve.
The water treatment device according to any one of claims 1 to 5 . The purified water discharge pipe is provided with a throttle portion that reduces the water flow speed below a predetermined speed,
The air injection unit injects air into the bypass piping when the speed of the raw water flowing through the bypass piping becomes greater than a predetermined speed.
The water treatment device according to claim 6 . a bypass pipe that is located within the raw water inlet pipe and branches at a first branch between a water source storing the raw water and the chemical supply unit, bypasses the chemical supply unit, and is connected to a second branch between the chemical supply unit and the filtration unit;
Further provided is a switching valve that is provided above the filtration unit, connects the raw water inlet pipe, the purified water discharge pipe, or the backwash drain pipe to an inlet or an outlet in the filtration unit, and switches communication between the inlet and the outlet in the filtration unit,
During the filtration process,
the first branch portion communicates the water source with the chemical supply portion;
the second branch portion communicates the medicine supply portion with the switching valve;
The switching valve communicates the inlet of the chemical supply unit and the filtration unit, and the outlet of the filtration unit and the purified water discharge pipe,
During the backwashing process,
the first branch portion communicates the water source with the bypass pipe;
the second branch portion communicates the bypass pipe with the switching valve,
The switching valve communicates the outflow port of the chemical supply unit and the filtration unit, and the inflow port of the filtration unit and the backwash drain pipe.
The water treatment device according to claim 6 or 7 . The air injection unit is
a first tubular portion having a tubular shape;
a second pipe portion having a pipe shape and a cross-sectional area larger than that of the first pipe portion, the second pipe portion being provided upstream of the first pipe portion in the water flow of the first pipe portion;
a first inclined pipe portion provided between the second pipe portion and the first pipe portion, the first inclined pipe portion having a pipe shape whose cross-sectional area decreases from the second pipe portion toward the first pipe portion;
a third pipe portion having a tubular shape and provided downstream of the first pipe portion in the water flow of the first pipe portion;
a second inclined pipe portion provided between the first pipe portion and the third pipe portion and having a pipe shape in which a cross-sectional area increases from the first pipe portion toward the third pipe portion;
a tubular air pipe extending from the first pipe portion;
The first pipe portion and the air pipe are in communication with each other,
The cross-sectional area of the air pipe is smaller than the cross-sectional area of the first pipe portion.
The water treatment device according to any one of claims 6 to 8 .