JPS6363009B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an automatic switching valve for a filter. The present inventor invented it earlier in 1974.
26027, even when the filtration process is stopped, high closing pressure may be applied to the main valve body on the raw water side in the filtration tank and automatic switching valve. For example, when filtered water is pumped directly to an elevated tank for water supply, when a filter is installed in a basement and a receiving tank for filtered water is installed on a high floor or rooftop, when a tall activated carbon filtration tower or a This happens when the filtration tank, filtration basin, or filtration layer of the filtration machine becomes clogged with a large amount of suspended matter, and even if the filtration pump is stopped, the water permeability is lost and the pressurized state persists forever. In such cases, even if you stop the filtration pump for the purpose of backwashing the filtration layer and start the backwash pump after a certain timing, the main valve body may not move and the valve may not be switched. .
This is because the high water head pressure acts in the direction of closing the main valve body on the raw water side, and the discharge pressure generated by the rotation of the liner of the backwash pump is smaller than the former, and the main valve body rebels against this pressing force. This is because the valve body cannot be pushed back. In this situation, the inside of the filtration tank becomes a sealed container, and the discharge pressure of the backwash pump also acts on the surface of the main valve body on the raw water side, so the force relationship between the two is balanced and the main valve body does not move at all. It cannot be done. Furthermore, when a high-pressure backwash pump is used, the discharge pressure rises to the maximum and then suddenly switches, resulting in intense impact noise and vibration.

The present invention solves all these drawbacks. That is, in the present invention, the main valve bodies 8, 8', which reciprocate and slide inside the cylindrical body 2, 2' having three openings, an inlet, an outlet, and an outlet, are changed in position and stopped at a predetermined position. A valve V that enables switching between communication with the inlet/outlet and communication between the inlet/outlet and the outlet,
V'2 are provided individually or integrally so that the sliding directions of the main valve bodies are the same, and the valves V, V'2
In a switching valve in which the main valve bodies are connected by a reciprocating shaft that slidably passes through two opposing partition walls, a first valve that passes through the main valve body 8 is provided inside the main valve body 8 on the raw water side.
A first auxiliary valve body 12A is formed with a through hole 14A, the first through hole 14A is opened and closed on the raw water side of the main valve body 8, and a second through hole 14B is provided inside, and the first auxiliary valve body 12A is arranged on the raw water side of the reciprocating shaft 7. In order to transmit the movement to the main valve body 8, the main valve body 8
The first auxiliary valve body 12 is moved by the first valve moving tool 16A provided in the
A is movably held, a reciprocating shaft 7 is inserted into the first through hole 14A and the second through hole 14B, and a second auxiliary valve body opens and closes the second through hole 14B at the raw water side end of the reciprocating shaft 7. 12B, and in order to transmit the movement of the reciprocating shaft 7 toward the raw water side to the first auxiliary valve body 12A, the second auxiliary valve body 12B is moved by a second valve moving tool 16B provided on the first auxiliary valve body 12A. This invention relates to an automatic switching valve for a filter that is movably held.

The drawings will be explained in detail. Fig. 1 is a schematic cross-sectional view of the automatic switching valve, Figs. 2, 3, 4, and 5 are detailed partial cross-sectional views showing the operation of the valve, and Fig. 6 is a schematic cross-sectional view of the automatic switching valve of the present invention. An example is shown in a cross-sectional schematic diagram of an incorporated filter.

1 in FIG. 1 is the automatic switching valve main body according to the present invention. 2 is a cylindrical body on the raw water side, and 2' is a cylindrical body on the backwash side, which is made of metal, synthetic resin, or a composite thereof.
3 is a sealed bearing made of metal, synthetic resin, or a composite thereof. 4 is the raw water side inlet, 4' is the backwash side inlet, 5 is the raw water side inlet, 5' is the backwash side inlet,
6 is an outlet on the raw water side, and 6' is an outlet on the backwash side. 7 is a reciprocating shaft made of metal or synthetic resin, and is preferably lightweight and has a smooth surface for sliding. 8 is the main valve body on the raw water side, 8' is the main valve body on the backwash side,
The position shown by the solid line is the time of filtration, and the position shown by the dotted line is the time of backwashing. The material of the valve body is metal, synthetic resin, or a composite thereof. The force with which this valve body operates is equal to the weight of this valve body plus the weight of the reciprocating shaft 7 multiplied by the coefficient of friction, so in order to make this valve body easy to operate, it must be lightweight. is desirable. 9 is an elastic body on the raw water side, 9' is an elastic body on the backwash side, 9 is fixed to the main valve body 8, and 9' is fixed to the main valve body 8', respectively, and they are integrated.
The material of the elastic body is made of synthetic rubber such as neoprene, Viton, Hiker (registered trademark), natural rubber, or synthetic resin, and it tightly adheres to the other side and seals it against water. The hardness of the elastic body is preferably around 60 degrees. If it is too soft with a hardness of about 20 degrees, it is undesirable because it may sink into the valve seat 10 side and cause abnormal deformation when high water pressure is applied during filtration, and may cause downward movement due to abnormal resistance during switching. If the main valve bodies 8 and 8' are made of soft or elastic bodies, the elastic bodies 9 and 9' can be omitted. 10 is a valve seat on the raw water side, and 10' is a valve seat on the backwash side, and elastic bodies 9 and 9' are in close contact with each other to seal the water. Since 9,9' is an elastic body, 10,1
0' is preferably a rigid body. 11 is a seal ring O-
Rings or V-rings are used. The material is preferably neoprene, Viton, Hiker Rubber (registered trademark), etc., which has water resistance, chemical resistance, oil resistance, weather resistance, and does not lose its elasticity even at low temperatures. 12A is a first auxiliary valve body, and 12B is a second auxiliary valve body, both of which are made of metal, synthetic resin, or a composite thereof, and 12B is fixed to the reciprocating shaft 7. Since 12B and 12A contact 12A and 12A to form a water seal, respectively, it is preferable that one contact surface be a rigid body and the other contact surface be an elastic body. The hardness of the elastic body is preferably around 60 degrees. If it is too soft, with a hardness of around 20 degrees, when high water pressure is applied on the filtration side, it may sink into the other side that is in contact and cause abnormal deformation, which may cause non-operation due to abnormal resistance when switching, which is undesirable. .
A first through hole 14A is provided in the center of the main valve body 8 and passes through the main valve body 8. Reference numeral 14B denotes a second through hole that is provided to penetrate through the center of the first auxiliary valve body 12A. 15 is a bearing part which is a part of the main valve body 8, and the reciprocating shaft 7 passes through the central hole in a slidable state;
The main valve body 8 is supported on the shaft 7. A first valve moving device 16A is made of metal, synthetic resin, or a composite thereof, and is integrated with the main valve body 8, and transmits the movement of the shaft 7 to the main valve body 8 via the first auxiliary valve body 12A. do. 16B is a second valve moving device made of the same material as 16A, and is integrated with the first auxiliary valve body 12A, and transmits the movement of the shaft 7 to the first auxiliary valve body 12A via the second auxiliary valve body 12B. do. 17A is a first guide made of metal, synthetic resin, or a composite thereof;
A hollow cylinder having one or several rod-like bodies or a large number of holes is used, and one end is fixed to the main valve body 8, and the first valve moving tool 16A is fixed to the other end. The inner side of the guide 17A is slidably fitted to the outer circumferential surface of the first auxiliary valve body 12A, and serves to maintain a correct posture parallel to the reciprocating axis 7 when the main valve body 8 moves. . The guide 17A also serves as a support for the main valve body 8 of the first valve moving tool 16A. 1
7B is a second guide and is similar to the first guide 17A. One end is fixed to the first auxiliary valve body 12A, and the second valve moving tool 16B is fixed to the value end. The inside of the guide 17B is slidably fitted to the outer circumferential surface of the second auxiliary valve body 12B, and when the first auxiliary valve body 12A moves, it maintains a correct posture parallel to the reciprocating axis 7. . The guide 17B also serves as a support for the first auxiliary valve body 12A of the second valve moving tool 16B.

FIG. 2 shows a detailed partial cross-sectional view of the raw water side cylindrical body 2 of FIG. 1, and the reference numerals are the same as in FIG. 1. 2
5 is the raw/drainage pipe, 26 is the backwash water discharge pipe, 25,2
The details of both are shown in the usage example in FIG.

Figure 3 shows the second auxiliary valve body 12B from the state shown in Figure 2.
This shows the state when it is open, which is the first stage of operation.
The arrow → indicates the flow of water, and the arrow ← indicates the direction in which the reciprocating shaft 7 moves.

FIG. 4 shows a state in which the first auxiliary valve body 12A is opened, which is the next stage from the state shown in FIG. 3, and is the second stage of operation.

FIG. 5 shows a state in which the main valve body 8 moves further from the state shown in FIG. 4, which is the third stage of operation.

FIG. 6 is a schematic cross-sectional view of a filter equipped with the automatic switching valve 1 of the present invention as an example of use, and shows a tall filter such as an activated carbon filtration tower. 18 is a filtration tank, and 19 is a filtration layer in which silica sand, granular activated carbon, anthracite, zeolite, various mineral particles, natural or artificial filtration media such as siyamoto, synthetic resin particles, synthetic fibers, etc. are used individually according to various filtration purposes. Or, it is used by laminating multiple layers. 20 is a filtration pump, 2
1 is a backwashing pump, and a land-based centrifugal pump, an axial flow pump, a mixed flow pump, a submersible pump, etc. are used, respectively. 22 is an elevated water tank from which water is supplied to various locations. Reference numeral 23 denotes a washing drainage basin, and 24 denotes a raw water pipe through which raw water to be filtered is sent toward the filter. 25 is a raw/drainage pipe through which raw water flows upward and backwash wastewater flows downward. 26 is a backwash water discharge pipe, 27 is a water purification pipe, and the filtered water is in the filtration tank 1.
The backwash water flows in opposite directions from the lower part of the switching valve 8 toward the automatic switching valve 1, and from the switching valve 1 toward the lower part of the filtration tank 18, respectively. 28 is a filtrate delivery pipe, 29
30 is a water pipe for backwashing, and 30 is an exhaust valve for exhausting the air in the filtration tank 18 and for allowing air to flow into the tank 18 as required. 31 is a check valve that prevents the water in the pipes 24 and 25 from flowing back toward the pump 20 when the pump 20 is stopped. 32 is a check valve, when the pump 21 is stopped, the pipes 27,
This is because the water in the pump 29 does not flow back toward the pump 21. Reference numeral 33 denotes a check valve, which is provided in a part of the filtered water delivery pipe 28. This check valve is the filtration pump 20
Once stopped, the water in the pipe 28 flows into the filtration tank 1.
This prevents the flow from flowing back toward the filter 8 in the opposite direction to filtration. The reason for this is that if the water flows backward, the fixed bed of the filtration layer 19 may be loosened, and the accuracy of the filtrate may be temporarily lowered when the filtration pump 20 is started next time. If the top of the pipe 28 is equal to or lower than the top of the filtration tank, no backflow phenomenon will occur and the check valve 33 is not required. However, in this case, when the pump 20 stops, there is a risk that a siphon phenomenon will occur and the water in the tank 18 will be discharged, so a siphon cut valve is installed at the top of the pipe 28 to suck in air. 34 is an opening which the raw/drainage pipe 25 opens at the upper part of the filtration tank 18, and serves as an outlet for the raw water during filtration, and an inlet through which the wastewater that has backwashed the filtration layer 19 flows into the pipe 25 during backflow. becomes. The distance between the upper surface of the opening 34 and the upper surface of the filtration layer 19 is called the sand water depth, and is typically 50 to 60 cm. 35 is a raw water chamber. Ht is when the filtration tank 18 is full of water,
The hydrostatic head applied to the main valve body 8 is expressed, Hl is the hydrostatic head applied to the main valve body 8 when water is pumped to the elevated water layer 22 for water supply, and Hi is the hydrostatic head applied to the main valve body 8 from the automatic switching valve 1 to the pump 21.
This is the static water head applied to the area.

Next, the operation and function of the automatic switching valve according to the present invention will be explained in detail using the drawings. In Figures 1 and 6, the positions of the main valve bodies 8 and 8' indicated by solid lines represent the states during filtration and when filtration is stopped, and the positions indicated by dotted lines indicate the states during backwashing and when backwashing is stopped. This shows the state immediately after stopping. The conditions under which the valve bodies 8 and 8' can be moved from the filtration position shown by the solid line to the backwash position shown by the dotted line by starting the backwash pump 21 will be described.

The surface of the main valve body 8 on the raw water side that receives water pressure (hereinafter referred to as pressure receiving surface) is A cm ² , and the water pressure is HKg/cm ² . Assuming that the pressure receiving surface of the main valve body 8' on the backwash side is A'cm ² and the water pressure at startup of the backwash pump ²¹ is HpKg/cm2, the moving force is at least Hp・A′>H・A+reciprocating shaft 7 is the sliding resistance. To describe the relationship between A and A', in the case of a pressurized filter such as the filter tank 18 shown in FIG. 5, A=A'. In the case of an open type rapid filtration basin, A>
It becomes A′. The size of area A is determined depending on the flow resistance value of the backwash flow rate. This is because a pressurized type can easily obtain a high head, but an open type cannot obtain a high head because backwashing water is discharged using a natural head. The next condition is that if there is no water flow in the pipe from the backwash pump 5, the pressure Hp that presses the main valve body 8' will not be generated. The gap between the outer circumferential surface of the valve body 8' and the inner wall surface of the cylindrical body 2' is about 2 to 4 mm in large diameter and 1 to 2 mm in small diameter, and water can flow through this gap. The water flowing through the gap when the pump 21 is activated flows into the filtration tank 18 or into the filtrate delivery pipe 28. If water cannot flow into either of the two, that is, if there is no place for water to escape, the water in the pipe 29 will not flow, and no energy will be obtained to push the valve body 8'. Even if the water in the pipe 29 flows, the main valve body 8' may remain stationary without moving. In this state, if the lift of the backwash pump 21 is sufficiently high, water flows through the gap between the outer peripheral surface of the main valve body 8' and the inner wall of the cylindrical body 2', and rises in the pipe 28 from the outlet 6'. , the check valve 33 is pushed up and water is vigorously discharged from the mouth at the tip of the pipe 28. In such a state, the force pushing the main valve body 8' to the left is
This is because it is smaller than the force acting in the direction of closing. The force in this closing direction is the pressure per unit area x
Since it is a pressure receiving area, if the main valve body 8 has a small pressure receiving area, the force acting in the closing direction will be small, whereas the force trying to push it open will be large, so naturally it will be easier to open. On the other hand, in view of the flow rate required for backwashing, it is not permissible to make the main valve body 8 extremely smaller than 8'.

In the present invention, without reducing the size of the main valve body 8 compared to the main valve body 8', as shown in FIGS. 1 to 5, the main valve body 8 has a first auxiliary valve body 12A and a Two auxiliary valve bodies 12B are provided. Auxiliary valve body 12
Since the pressure-receiving areas of A and 12B are small as shown in the drawing, the force required to open them is small, and they can be easily opened by the pushing force of the main valve body 8'.
First, when the second auxiliary valve body 12B opens, water starts to be discharged through the second through hole 14B and the first through hole 14A.
When flowing water occurs, water pressure in the opposite direction is applied to the back surface of the second auxiliary valve body 12B and the back surface, that is, the right side, of the first auxiliary valve body 12A, so that it acts in the direction to close the first auxiliary valve body 12A, that is, to the right. The power to do so decreases. Further, since the pressure receiving area of the valve body 12A is small, the first auxiliary valve body 12A can be easily opened by the pushing force of the main valve body 8'. When the auxiliary valve body 12B and 12A open,
The flow rate of water discharged through the first through hole 14A increases.
Since water pressure in the opposite direction is applied to the back surface of the first auxiliary valve body 12A and the back surface, that is, the right side, of the main valve body 8, the force acting in the direction to close the main valve body 8, that is, to the right, is reduced as in the former case. be. Furthermore, the remaining pressure receiving area of the main valve body 8 becomes smaller. Therefore, the force acting on the main valve body 8 in the closing direction becomes small, and the main valve body 8 can be easily moved in the opening direction by the pushing force of the main valve body 8'.

Next, the operation and function of the valve bodies 8 and 8' will be explained in detail using FIGS. 1 to 5. FIG. 1 shows a filtration state in which the main valve body 8 is closed. The raw water side elastic body 9 is in close contact with the raw water side valve seat 10, and the auxiliary valve body 1
The elastic body 13, which is a part of the valve body 2, is in close contact with the main valve body 8 and seals the through hole 14 with water. When filtration is being carried out, raw water enters the raw water side cylindrical body 2 through the raw water side inlet 4, exits through the raw water side inlet/outlet 5, and is fed into the filter. The filtered water enters the backwash side cylindrical body 2' through the backwash side inlet/outlet 5', exits through the backwash side outlet 6', and is sent to a target location. FIG. 2 shows an enlarged view of the main valve body 8 in the state shown in FIG.
When switching from filtration to backwashing, first stop feeding raw water from the raw water side inlet 4 shown in Figure 1, lower the water pressure applied to the main valve body 8 on the raw water side to the lowest level, and then switch from the backwash side inlet 4'. Send backwash water. This water flow pressurizes the pressure receiving surface on the right side of the main valve body 8' on the backwash side and pushes the main valve body 8' to the left, and the reciprocating shaft 7 moves to the left to open the second auxiliary valve body 12B. FIG. 3 shows the operation of this first stage of switching. Second auxiliary valve body 12B
The left surface of the valve body 12B comes into contact with the right surface of the second valve moving tool 16B fixed to the first auxiliary valve body 12A via the second guide 17B, and the valve body 12B stops opening. The distance between the right side of the second auxiliary valve body 12B and the left side of the first auxiliary valve body 12A, which was water-sealed by the second auxiliary valve body 12B, is
When the outside diameter of B is 40mm, approximately 2cm is appropriate, and when the outside diameter is 70mm, approximately 3cm is appropriate. The flow of water when the second auxiliary valve body 12B opens is indicated by an arrow →. That is, the water in the pipe 25 is transferred from the raw water side inlet/outlet 5 to the raw water side cylindrical body 2.
Inside → gap between second auxiliary valve body 12B and first auxiliary valve body 12A → second through hole 14B → first through hole 14A → right side of main valve body 8 → raw water side outlet 6 → pipe 6.

FIG. 4 shows that the second auxiliary valve body 12B is connected to the second valve moving tool 1.
6B, the first auxiliary valve body 12A is pulled and separated from the main valve body 8 to the left through the second guide 17B, and the second stage operation is shown in which the valve body 12A is opened. A first valve moving tool 1 in which the left side of the valve body 12A is fixed to the main valve body 8 via a first guide 17A.
The opening of the valve body 12A stops when it comes into contact with the right side of the valve body 6A. The appropriate distance between the right side of the first auxiliary valve body 12A and the left side of the water-sealed main valve body 8 is about 3 to 4 cm when the outer diameter of the valve body 12A is 100 mm. The flow of water when the auxiliary valve bodies 12B, 12A are opened is indicated by an arrow →. The arrow ← represents the direction in which the reciprocating shaft 7 moves. The flow of water is from the pipe 25 → raw water side inlet/outlet 5 → inside the raw water side cylindrical body 2 → from the gap between the second auxiliary valve body 12B and the first auxiliary valve body 12A to the second through hole 14B and the first auxiliary valve body 12A. The gap between the main valve body 8 and the first through hole 14A → the right side of the main valve body 8 → the raw water side outlet 6 → the pipe 26.

FIG. 5 shows that the first auxiliary valve body 12A is the first valve moving tool 1.
6A, the main valve body 8 is pulled to the left from the valve seat 10 via the first guide 17A, and the third stage operation is shown in which the main valve body 8 is opened. Arrow →
indicates the flow of water, and the arrow ← indicates the direction in which the reciprocating shaft 7 moves. The flow of water is from the pipe 25 → raw water side inlet/outlet 5 → inside the raw water side cylindrical body 2 → from the gap between the second auxiliary valve body 12B and the first auxiliary valve body 12A to the second through hole 14B and the first auxiliary valve body 12A. The gap between the main valve body 8 and the first through hole 14A, the inner wall of the cylindrical body 2 and the main valve body 8
The gap with the outer circumferential surface of the main valve body 8 → the right side of the main valve body 8 → the raw water side outlet 6 → the pipe 26. The movement of the main valve body 8 further progresses until it reaches the position shown by the dotted line in FIG. 1, and the valve switching movement from filtration to backwashing is completed. At this time, the backwash side main valve body 8' is in close contact with the backwash side valve seat 10'. Communication between the ports during backwashing is between the raw water side inlet 5 and raw water side outlet 6 in the raw water side cylindrical body 2, and the backwash side inlet 4' and backwash side inlet 5' in the backwash side cylindrical body 2'. be. For communication between each port during filtration, the main valve bodies 8 and 8' are located at the positions shown by solid lines,
The raw water side cylindrical body 2 has a raw water side inlet 4 and the raw water side inlet/outlet 5, and the backwash side cylindrical body 2' has a backwash side inlet/outlet 5' and a backwash side outlet 6'. 14, in the drawing, a large number of holes are drilled radially to the outer peripheral surface of the reciprocating shaft 7 in the vicinity of the bearing part 15, but this shape is not the only one. It may also be provided through. However, in order not to increase water flow resistance, the cross-sectional area should be equal to or slightly larger than the inlet cross-sectional area of the first through hole 14A. In the drawing, the first guide 17A guides the posture of the main valve body 8 on the outer peripheral surface of the first auxiliary valve body 12A, and the second guide 17B
is the outer peripheral surface of the second auxiliary valve body 12B and the first auxiliary valve body 1
Although it guides the posture of 2A, it is not limited to this shape only. Near the inlets of the through holes 14A, 14B where the auxiliary valve bodies 12A, 12B come into contact, a wide opening area may be provided using a method such as a bearing portion 15, and a part of the outer peripheral surface of the reciprocating shaft 7 may be guided. In this case, the illustrated guides 17A, 17B become part of the valve moving tools 16A, 16B.

The operation and functions of the filter in the usage example shown in FIG. 6 will be explained in detail. When backwashing is completed, the main valve bodies 8 and 8' in the automatic switching valve 1 are in the position shown by the dotted lines.
When entering the filtration process, the filtration pump 20 is started. Raw water, which is water to be filtered, is sucked into the pump 20 and pressurized, flows through the check valve 31 and the pipe 24, and is ejected from the raw water side inlet 4 into the raw water side cylindrical body 2. This jet stream pressurizes the left surfaces of the auxiliary valve bodies 12B, 12A and the main valve body 8 on the raw water side, and pushes the main valve body 8 to the right. The main valve body 8' on the backwash side also moves to the right via the reciprocating shaft 7. The raw water side main valve body 8 is fixed on the raw water side valve seat 10 as shown by the solid line, and the auxiliary valve body 12B is fixed to the raw water side valve seat 10 as shown by the solid line.
12A is in close contact with the main valve body 8 and seals the raw water sent by the pump 20, respectively. The raw water in the cylindrical body 2 exits the raw water side entrance 5, ascends the raw water/drainage pipe 25, and enters the raw water chamber 35 in the upper part of the filtration tank 18 through the opening 34. The raw water pressurized by the pump 20 is filtered while flowing down the filtration layer 19 which is a fixed bed, and flows into the water purification pipe 27 from the lower part of the filtration tank 18 as filtered water. The filtrated water that has risen through the pipe 27 enters the backwash side cylindrical body 2' from the backwash side inlet/outlet 5', and flows into the filtrate delivery pipe 2 from the backwash side outlet 6'.
8, go up and push open the check valve 33, and open the pipe 2.
The water is supplied into the elevated water tank 22 from the tip of the water tank 8 . When the filtration layer 19 becomes clogged with suspended matter, the filtration flow rate decreases, so filtration is stopped and a backwashing process begins. As a method for detecting when to perform backwashing, when a predetermined filtration resistance value is reached, an electrical signal is generated and sent to the control supervisor. Alternatively, there is a method in which a program timer is built into the control panel and commands are given once or several times every month, week, or day.
Of course, the operation may be carried out manually by looking at the pointer of the filtration pressure gauge by the driver or by looking at the instantaneous filtration flow meter. First, the filtration pump 20 is stopped. Stand still for several to ten seconds until the pressure inside the filtration tank 18 reaches its lowest level. Next, the backwash pump 21 is started. The backwash water sucked in by the pump 21 is pressurized, opens the check valve 32, ascends the pipe 29, and is ejected into the backwash side cylindrical body 2' from the backwash water inlet 4'. This jet pressurizes the right surface of the main valve body 8' on the backwash side, and the main valve body 8' receives this force and starts moving to the left. Via the reciprocating shaft 7, the second auxiliary valve body 12B first opens (as shown in FIG. 3), and then the first auxiliary valve body 12A opens (as shown in FIG. 4). Subsequently, the main valve body 8 is pulled to the left (as shown in FIG. 5) and begins to move. Both the valve bodies 8 and 8' move to the positions indicated by dotted lines in FIGS. 1 and 6, and the switching from filtration to backwashing is completed. The backwash water that has entered the backwash side cylindrical body 2' flows from the lower part of the filtration tank 18 through the water purification pipe 27, expands the filtration layer 19 clogged with turbidity, and backwashes the filtration layer 19. The dirty washing water that has come out to the raw water chamber 35 is drained from the opening 34 to the raw water chamber 35.
It flows down the drain pipe 25, enters the raw water side cylindrical body 2 from the raw water side inlet/outlet 5, flows down the backwash water discharge pipe 26 from the raw water side outlet 6, and is discharged to the washing drainage basin 23. Inside the cylindrical body 2, there is a gap between its inner wall and the outer peripheral surface of the main valve body 8, but since there is a check valve 31, the backwashed wastewater will not flow back into the pump 20 through the pipe 24. . The conditions under which the backwash pump 21 generates a water flow in the pipe that pressurizes the main valve body 8' will be explained. When the filtrate delivery pipe 12 pumps water to the elevated water tank 22 located higher than the filtration tank 18,
When the filtration is stopped and at rest, a water head pressure of Hl is applied to the main valve body 8, and the water head pressure of Hl is applied to the backwash pump 21.
Hi water head pressure is applied. Therefore, the pump 21
In order to start the pump and obtain the required amount of water flow in the pipe, the pump head Hp must be higher than Hl + Hi + pipe flow resistance value. When filtered water is not sent directly to the elevated water tank 22 but to a water storage tank located lower than the filtration tank 18, the water head pressure applied to the main valve body 8 is Ht when the filtration is stopped and the water is at rest. The water head pressure applied to the backwash pump 21 becomes Ht+Hi.
In this case, select a pump whose head Hp is greater than Ht + Hi piping water resistance value.

In the drawing, two auxiliary valve bodies 12 are installed on the main valve body 8 on the raw water side.
A and 12B are provided, but if a high hydrostatic head is applied to the main valve body 8 when filtration is stopped, or if the outer diameter of the main valve body 8 is as large as 30 cm, 40 cm, or 50 cm, three or more If several auxiliary valve bodies are provided and the auxiliary valve body with the smallest diameter is sequentially opened to the main valve body, valve switching can be performed effectively.

Although the present invention describes an integrated automatic switching valve 1 in which a common sealed bearing 3 is provided in the center of the raw water side cylindrical body 2 and the backwash side cylindrical body 2', it is not limited to this. It's not something you can do. The switching valve described in Japanese Utility Model Publication No. 56-52449 can also be effectively applied to an automatic switching valve provided separately for the raw water side and the backwash side as shown in the drawing.

Applications of the automatic switching valve according to the present invention include not only water, oil, and solvent filters that require switching between filtration and backwashing, but also equipment that requires switching between flow in the opposite direction, such as liquid receivers. It can also be effectively used as an automatic switching valve for a mixing device for mixing two or several types of liquids contained in a tank.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical cross-sectional view showing one embodiment of the automatic switching valve of the present invention. 2-5 are partially cutaway cross-sectional views showing various stages of operation of the automatic switching valve of FIG. 1; FIG. FIG. 6 is a schematic cross-sectional view of a filter incorporating the automatic switching valve of FIG. 1.

Claims (1)

[Claims] 1. By changing the position of the main valve body 8, 8' which slides back and forth inside the cylindrical body 2, 2' having three openings, an inlet, an outlet and an outlet, and stopping at a predetermined position. ,
Two valves V and V′ that enable switching between communication between the inlet and the outlet and communication between the inlet and the outlet are provided individually or integrally so that the sliding direction of the main valve body matches, In the switching valve in which the main valve body is connected by a reciprocating shaft that slidably passes through the two opposing partition walls of the valves V and V', the main valve body 8 is provided inside the main valve body 8 on the raw water side. A first auxiliary valve body 12A is formed, which opens and closes the first through hole 14A on the raw water side of the main valve body 8, and has a second through hole 14B inside. In order to transmit the movement of the shaft 7 toward the raw water side to the main valve body 8, the first valve moving tools 16A and 17A provided on the main valve body 8
The auxiliary valve body 12A is movably held, and the first through hole 1
A reciprocating shaft 7 is inserted into the reciprocating shaft 4A and the second through hole 14B, and a second auxiliary valve body 12B that opens and closes the second through hole 14B is disposed at the raw water side end of the reciprocating shaft 7. In order to transmit the movement to the first auxiliary valve body 12A,
The second valve moving tool 16 provided on the first auxiliary valve body 12A
An automatic switching valve for a filter, in which a second auxiliary valve body 12B is movably held by B and 17B.