JP6581807B2 - Filtration device and control method of filtration device - Google Patents

Description

  The present invention relates to a filtration device for removing iron and manganese contained in water and a method for controlling the filtration device.

  At present, there is known a technique of using raw water such as well water by increasing the pressure with a pump to use it as domestic water for household use or industrial water for a factory. However, in raw water, for example, iron and manganese are dissolved as impurities. For this reason, in order to use it as domestic water or industrial water, a filtration device capable of removing iron and manganese by removing raw water by filtering the raw water with a filter medium is known (for example, see Patent Document 1). ).

  Such a filtration device capable of removing iron and manganese is, for example, a cylindrical filtration tank provided by laminating a plurality of filter media, and a chemical solution that is an oxidizing agent such as sodium hypochlorite. A chemical solution supply device for supplying raw water. The filtration device performs the manganese removal treatment with one of the plurality of filtration media and the iron removal treatment with one of the plurality of filtration media by injecting the chemical solution into the raw water, The raw water is treated with iron and manganese and the treated water is supplied to the secondary side.

JP 2003-269630 A

  The above-described filtration device has the following problems. That is, if the injection amount of the chemical solution is insufficient, normal iron removal and manganese removal treatment is not performed. One example of the cause of the shortage of the injection amount of the chemical solution is a change in the concentration of a substance that consumes the chemical solution (oxidant) such as iron and manganese in the raw water. However, it is difficult to predict fluctuations in the concentration of the substance in raw water.

  In order to perform normal iron removal and manganese removal treatment, there is a method to solve the shortage of injection amount by increasing the injection amount of the chemical solution, but the surplus that was not used for iron removal and manganese removal treatment in the treated water There is a problem that the concentration of the chemical solution becomes high. For this reason, it is also conceivable to treat an excess chemical solution by installing an activated carbon filter tank on the secondary side of the filter tank. However, it is necessary to secure a space for installing the activated carbon filtration tank, and the manufacturing cost of the filtration device increases.

  Then, an object of this invention is to provide the control method of the filtration apparatus which can correct | amend the injection amount of a chemical | medical solution, and a filtration apparatus.

As one aspect of the present invention, a filtration device is based on a pump device that supplies water from a supply source, a flow rate detection device that detects a flow rate on the secondary side of the pump device, and a flow rate detected by the flow rate detection device. A chemical injection device that injects a chemical solution that is an oxidant into the water discharged from the pump device, a filtration tank that is provided on the secondary side of the pump device and processes the water injected with the chemical solution, A concentration detection device for detecting the concentration of the chemical solution of the water discharged from the filtration tank, a drain pipe connected to a drainage section provided on the secondary side of the filtration tank, connected to the filtration tank, A water supply pipe connected to the supply destination, a flow path that passes through the filtration tank from the secondary side of the pump device and connects to the water supply pipe, and the filter tank flows backward from the secondary side of the pump device to The flow path connected to the drain pipe and the pump device And channel switching means for switching a flow path connected to the drain pipe through the filtration tank from the secondary side, a predetermined concentration of the chemical solution of the water discharged from the filtration tank is stored as a threshold value memory And the flow path switching means to control the water supplied by the pump device and the chemical solution supplied by the chemical solution injection device from the secondary side of the pump device through the filtration tank and the water. A normal operation of passing through a flow path connecting a water supply pipe, the normal operation for a predetermined time, and then controlling the flow path switching means to supply the water supplied by the pump device to the secondary side of the pump device. Back flow operation through which the filtration tank flows backward and passes through the flow path connected to the drain pipe, and after the back washing operation, the flow path switching means is controlled and supplied by the pump device, and the chemical solution injection device The water supplied with the chemical solution in Cleaning operation for passing through the filtration tank from the secondary side and passing through the flow path connected to the drain pipe for drainage, and the concentration of the chemical liquid in the water supplied with the chemical liquid and treated in the filtration tank When detecting the concentration of the chemical solution supplied by the pump device and detecting the concentration of the chemical solution supplied by the chemical solution injection device, the flow switching means is controlled. A control unit that performs a drainage operation to pass through the flow path connected to the drain pipe through the filtration tank from the side and drain the water, and the control unit is set after the cleaning operation or the preset After a lapse of a predetermined time for detecting the concentration in the treated water, the drainage operation is performed, the concentration of the chemical solution detected by the concentration detection device and the threshold value are compared, and the concentration of the chemical solution is different from the threshold value In the next normal operation, That controls the liquid injector in set value as the normal concentration in the liquid.

As one aspect of the present invention, a pump device that supplies water from a supply source , a flow rate detection device that detects a flow rate on the secondary side of the pump device, and the pump based on the flow rate detected by the flow rate detection device A chemical injection device that injects a chemical solution that is an oxidant into the water discharged from the device; a filtration tank that is provided on the secondary side of the pump device and that processes the water into which the chemical solution has been injected; and Concentration detection device for detecting the concentration of the discharged chemical of the water, a drain pipe connected to a drainage section provided on the secondary side of the filtration tank, connected to the filtration tank, and connected to a supply destination A water supply pipe, a flow path connecting to the water supply pipe through the filtration tank from the secondary side of the pump device, and connecting the drainage pipe by flowing back the filtration tank from the secondary side of the pump device From the secondary side of the pump device A flow path switching means for switching a flow path that passes through the filtration tank and connects to the drain pipe, and a storage unit that stores a predetermined concentration of the chemical solution of the water discharged from the filtration tank as a threshold value. The flow control means is controlled to supply water supplied by the pump device and supplied with the chemical solution by the chemical solution injection device from the secondary side of the pump device through the filtration tank to the water supply. A normal operation for passing through a flow path connecting pipes and the normal operation for a predetermined time, and then controlling the flow path switching means to supply the water supplied by the pump device from the secondary side of the pump device. After the backwash operation for allowing the flow through the filtration tank to pass through the flow path connected to the drain pipe, after the backwash operation, the flow path switching means is controlled and supplied by the pump device. The water supplied with the chemical solution is supplied to the pump device. A cleaning operation for draining by passing through the filtration tank from the next side and passing through the flow path connected to the drain pipe, and detecting the concentration of the chemical in the water supplied with the chemical and treated in the filtration tank In the case of controlling the flow path switching means, the treated water for detecting the concentration of the chemical solution supplied by the pump device and supplied by the chemical solution injection device from the secondary side of the pump device is supplied. through the filtration tank is passed through a flow path connected to the drain pipe, the control method of the filtration apparatus for performing water discard operation for drainage, the water discharged from the prior SL pump device, in the flow rate detecting device the drug solution was injected by the liquid injector based on the flow rate of the secondary-side detected the pump unit, by the filtration bath, the treated drug solution is injected water, set the rear cleaning operation or in advance The concentration in the treated water After a predetermined time to output, it performs the water discard operation, the concentration of the chemical in the water discharged from the filtration tank detected by the concentration detecting device, and compares the threshold value, of the chemical When the concentration is different from the threshold value, the chemical solution injection device is controlled, and the chemical solution injection amount of the chemical solution injection device is controlled at the next normal operation to obtain a normal concentration of the chemical solution.

  ADVANTAGE OF THE INVENTION According to this invention, the control method of the filtration apparatus and filtration apparatus which can correct | amend the injection amount of a chemical | medical solution can be provided.

Explanatory drawing which shows the structure of the filtration apparatus which concerns on one Embodiment of this invention. The flowchart which shows an example of the filtration method using the filtration apparatus. The flowchart which shows an example of the filtration method using the filtration apparatus. The flowchart which shows an example of the filtration method using the filtration apparatus.

Hereinafter, the filtration apparatus 1 which concerns on one Embodiment of this invention is demonstrated using FIG.1 and FIG.2.
FIG. 1 is an explanatory view schematically showing a configuration of a filtration device 1 according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing an example of a filtration method using the filtration device 1.

  As shown in FIG. 1, the filtering device 1 includes a pump device 11 provided in the raw water supply source 100, a chemical solution injection device 12 provided on the secondary side of the pump device 11, and a secondary of the chemical solution injection device 12. The filter unit 13 is provided on the side, connected to the supply destination 110, the concentration detection device 14 connected to the filter unit 13, and the control panel 15.

  The filtration device 1 is formed such that a chemical solution is injected into the raw water by the chemical solution injection device 12 and iron and manganese contained in the raw water are removed by the filtration unit 13 and solids such as sand existing in the raw water can be removed. ing.

  Here, the supply source 100 is, for example, a well. The supply destination 110 is connected to the secondary side of the filtration unit 13. The supply destination 110 is composed of a plurality of faucets 111, for example.

  The pump device 11 is, for example, a submersible pump for a well. The pump device 11 includes a pump and a motor that drives the pump. The pump device 11 has a motor connected to the control panel 15 via a signal line 99. The pump device 11 is connected to the filtration unit 13 via the pipe 20.

  The chemical injection device 12 includes a chemical solution tank 21, an injection pump 22, a flow rate detection device 23, and a first control unit (control unit) 24.

  The chemical solution tank 21 stores therein a chemical solution containing an oxidizing agent, specifically sodium hypochlorite. The infusion pump 22 is a diaphragm pump driven by a solenoid, for example. The infusion pump 22 is connected to the chemical tank 21. The injection pump 22 is configured to be able to inject a predetermined amount of chemical into the pipe 20 connected to the pump device 11.

  The first control unit 24 includes, for example, a first storage unit (storage unit) 24a that stores a plurality of concentration groups of chemicals to be injected for each flow rate so that the concentration of the chemicals with respect to the raw water becomes a preset concentration. is doing. The first control unit 24 is connected to the infusion pump 22 and the flow rate detection device 23 via a signal line 99. The first control unit 24 is connected to the control panel 15 via a signal line 99.

  The first control unit 24 is based on the chemical solution concentration group selected from the plurality of chemical solution concentration groups stored in the first storage unit 24 a and the flow rate in the pipe 20 detected by the flow rate detection device 23. The discharge amount (injection amount) of the chemical is controllable. Here, the concentration group of the chemical solution is a plurality of preset set values at which the concentration of the chemical solution in the treated water becomes a normal concentration.

  The filtration unit 13 includes a filtration tank 31, a suction pipe 32, a discharge pipe 33, a first branch pipe 34, a first three-way valve 35, a first drain pipe (drain pipe) 36, an on-off valve 37, A second three-way valve 38, a second branch pipe 39, a third three-way valve 40, a water supply pipe 41, a second drain pipe (drain pipe) 42, and a pressure detection device 43 are provided.

  The filter tank 31 has a plurality of filter media stacked therein. One of the plurality of filter media is configured to be able to remove iron from raw water into which a chemical solution has been injected. One of the plurality of filter media is configured to be able to remove manganese from raw water into which a chemical solution has been injected. One of the plurality of filter media is formed so that solids contained in the raw water can be removed.

  The suction pipe 32 is connected to the filtration tank 31. The end of the suction pipe 32 is disposed above the uppermost layer of the plurality of filter media. The suction pipe 32 is provided with a pressure detection device 43.

  The discharge pipe 33 is connected to the filtration tank 31. The end of the discharge pipe 33 is disposed below the lowest layer of the plurality of filter media.

  The 1st branch pipe 34 is connected to the piping 20 connected to the pump apparatus 11, and branches a flow path to two directions in the middle part.

  The first three-way valve 35 is an electromagnetic valve and is connected to the control panel 15 via a signal line 99. The first three-way valve 35 has three ports, and connects any two of these ports by switching the internal flow path. The first three-way valve 35 has a first port connected to one flow path of the first branch pipe 34. The first three-way valve 35 has a second port connected to the suction pipe 32. The first three-way valve 35 has a third port connected to the first drain pipe 36.

  The first drain pipe 36 is connected to the first drain 120.

  The on-off valve 37 is provided in the middle of the first drain pipe 36 and is configured to be able to open and close the flow path of the first drain pipe 36. The on-off valve 37 is configured to be manually switchable between open and closed.

  The second three-way valve 38 is an electromagnetic valve and is connected to the control panel 15 through a signal line 99. The second three-way valve 38 has three ports, and connects any two of these ports by switching the internal flow path. The second port of the second three-way valve 38 is connected to the discharge pipe 33. The second port of the second three-way valve 38 is connected to the second branch pipe 39. The second port of the second three-way valve 38 is connected to the other flow path of the first branch pipe 34.

  The second branch pipe 39 branches the flow path in two directions in the middle. One flow path of the second branch pipe 39 is connected to the concentration detection device 14.

  The third three-way valve 40 is an electromagnetic valve and is connected to the control panel 15 via a signal line 99. The third three-way valve 40 has three ports, and connects any two of these ports by switching the internal flow path. The third three-way valve 40 has a first port connected to the other flow path of the second branch pipe 39. The third three-way valve 40 has a second port connected to the water supply pipe 41. The third port of the third three-way valve 40 is connected to the second drain pipe 42.

  The water supply pipe 41 connects the second port of the third three-way valve 40 and the supply destination 110.

  The second drain pipe 42 is connected to the second drain 130.

  The pressure detection device 43 is connected to the control panel 15 via a signal line 99. The pressure detection device 43 is configured to detect the pressure in the suction pipe 32 and to output a signal of the detected pressure to the control panel 15.

  The concentration detection device 14 includes a concentration detection sensor 51, a third drain pipe 52 connected to the concentration detection sensor 51, and a second control unit (control unit) 53 connected to the concentration detection sensor 51 via a signal line 99. And.

  The concentration detection sensor 51 is configured to be able to detect the concentration of the chemical solution of water flowing from the second branch pipe 39. The concentration detection sensor 51 is connected to the second control unit 53 via the signal line 99 and is configured to be able to output information on the detected concentration of the chemical solution to the second control unit 53.

  The third drain pipe 52 is connected to the third drain 140. Here, the 1st drain 120, the 2nd drain 130, and the 3rd drain 140 are comprised so that the water from each drainage pipe 36,42,52 can be drained. The first drain 120 and the second drain 130 are drain grooves, for example, and may be separate or integrated.

  The second control unit 53 is configured to receive information detected by the concentration detection sensor 51 and output the information to the first control unit 24 and the control panel 15. The second control unit 53 is configured to control the concentration detection sensor 51 so that the concentration of the chemical solution can be detected by the concentration detection sensor 51 every predetermined time.

  The control panel 15 includes a storage unit 61, a notification device 62, and a main control unit (control unit) 63.

  The storage unit 61 is configured to be able to store information detected by the flow rate detection device 23, the pressure detection device 43, and the concentration detection sensor 51. The storage unit 61 stores the number of times detected by the concentration detection sensor 51. The storage unit 61 stores arbitrarily set first threshold, second threshold, third threshold, fourth threshold, and arbitrarily set predetermined times t1, t2, and t3. In addition, the storage unit 61 stores a predetermined arbitrary time during which the concentration detection sensor 51 periodically detects the concentration.

  The first threshold value is a value for selecting whether to correct the injection amount of the chemical solution or to determine whether to stop the operation of the filtration device 1 according to the number of times the concentration detection sensor 51 detects the concentration of the chemical solution. . The first threshold is the number n of times when the concentration of the drug solution set arbitrarily is detected.

  A 2nd threshold value is a normal density | concentration of the chemical | medical solution in process water. The normal concentration of the chemical solution is a concentration of the chemical solution that can remove iron and manganese from the raw water and meets the use requirement of the treated water. The second threshold is a density band in which an upper limit and a lower limit are set in the normal range. Specifically, the second threshold value is a flow rate detected by the flow rate detection device 23 of a concentration group of a chemical solution arbitrarily selected from a plurality of concentration groups of the chemical solution stored in the first storage unit 24a. There is a corresponding density range in which a permissible range (upper limit value and lower limit value) is set. The second threshold value is appropriately changed according to the concentration group of the selected chemical solution and the detected flow rate.

  The third threshold value is the concentration of the chemical solution that cannot perform the required iron removal and manganese removal when the chemical solution in the treated water treated in the filtration tank 31 has a low concentration, and the supply destination depends on the concentration of the chemical solution. This is the concentration of the chemical solution that is determined to be unusable for the treated water supplied to 110.

  The predetermined time t1 is a time when the concentration detector 14 starts to detect the concentration of the chemical in the treated water during the predetermined operation of the filtration device 1.

  The predetermined time t2 is a time for detecting the concentration of the chemical solution by the concentration detection device 14, and is arbitrarily set.

  The predetermined time t3 is a standby time for preventing chattering after setting any one of a plurality of chemical concentration groups stored in the first storage unit 24a, and is arbitrarily set.

  The notification device 62 is configured to be able to notify information to the outside by sound, light, text, or the like. When the abnormality occurs in the concentration of the chemical in the treated water, the notification device 62 warns (informs) the abnormality to the outside.

  The main control unit 63 is configured to be able to switch between the first three-way valve 35, the second three-way valve 38, and the third three-way valve 40. The main control unit 63 is configured to be able to vary the rotational speed of the pump by controlling the motor of the pump device 11. The main control unit 63 is configured to control the pump device 11 based on the pressure detected by the pressure detection device 43.

  The main control unit 63 is configured to control the concentration detection sensor 51 via the second control unit 53 and to detect the concentration of the chemical in the treated water processed in the filtration tank 31 every predetermined period. Here, the predetermined period is, for example, when the back washing operation and the washing operation for periodically washing the filtration tank 31 are performed, or when a predetermined arbitrary time stored in the storage unit 61 is reached. When is either.

  The main control unit 63 is configured to be able to count the number of times that the density detection sensor 51 has detected the density, and to reset the number of times counted.

  Further, the main control unit 63 has the following functions (1) to (6).

  Function (1) Function to perform normal operation to filter raw water.

  Function (2) A function of performing a backwash operation in which the water in the filtration tank 31 is caused to flow backward to wash the inside of the filtration tank.

  Function (3) A function for performing a washing operation for washing the flow path after the back washing operation.

  Function (4) A function of performing a drain operation for forcibly treating water by the filtration tank 31.

  Function (5) A function for correcting the amount of the chemical to be injected.

  Function (6) A function for determining the continuation of the operation of the filtration device 1.

Next, functions (1) to (6) included in the main control unit 63 will be described.
The function (1) is a function of performing a normal operation of driving the filtration device 1 to inject a chemical solution into the raw water and filtering the raw water by removing impurities composed of iron, manganese and solids from the raw water. . Specifically, the flow path from the primary side to the secondary side flows in the order of the pipe 20, the first branch pipe 34, the suction pipe 32, the filtration tank 31, the discharge pipe 33, the second branch pipe 39, and the water supply pipe 41. Then, the first three-way valve 35, the second three-way valve 38, and the third three-way valve 40 are switched.

  In this state, by driving the pump device 11 and the injection pump 22, the chemical solution is injected into the raw water according to the flow rate, and the raw water into which the chemical solution is injected passes through the filtration tank 31. Thereby, while the said raw | natural water removes the iron and manganese which are contained in raw | natural water with the filter material in the filtration tank 31, the solid substance in raw | natural water is filtered. Thus, function (1) is a function of removing iron, removing manganese and filtering from raw water.

  The function (2) is a function of performing a back washing operation in which the raw water is caused to flow from the discharge pipe 33 toward the suction pipe 32 in the filtration tank 31 so that the water flows back into the filtration tank and the inside of the filtration tank 31 is washed. is there. Specifically, the first flow path from the primary side to the secondary side flows in the order of the pipe 20, the first branch pipe 34, the discharge pipe 33, the filtration tank 31, the suction pipe 32, and the first drain pipe 36. The three-way valve 35 and the second three-way valve 38 are switched.

  In this state, by driving the pump device 11 for a predetermined time, the raw water passes back through the filtration tank 31 and the contaminated water used for backwashing is discharged through the first drain pipe 36 to the first drain. Drain to 120. Thereby, the impurities in the filtration tank 31 and the iron and manganese adhering to the filter medium are removed, and the inside of the filtration tank 31 is washed. Thus, the function (2) is a function of washing the inside of the filtration tank 31 by causing the raw water to flow backward and passing through the filtration tank 31. Note that the backwash operation is performed, for example, when the accumulated time of the normal operation has passed a predetermined time.

  Function (3) is a function for performing a cleaning operation for cleaning the inside of the suction pipe 32, the filtration tank 31, and the discharge pipe 33 after the backwashing operation according to the function (2). Specifically, the flow path from the primary side to the secondary side includes the pipe 20, the first branch pipe 34, the suction pipe 32, the filtration tank 31, the discharge pipe 33, the second branch pipe 39, and the second drain pipe 42. The first three-way valve 35, the second three-way valve 38, and the third three-way valve 40 are switched so as to flow sequentially.

  In this state, by driving the pump device 11 and the injection pump 22 for a predetermined time, the raw water into which the chemical solution has been injected passes through the filtration tank 31. Thereby, the raw water into which the chemical solution has been injected is drained from the second drain pipe 42 to the second drain 130 through the suction pipe 32, the filtration tank 31, and the discharge pipe 33. As a result, the contaminated water generated during the backwash operation is drained to the second drain 130 and the inside of the flow path is washed. Thus, the function (3) is a function for cleaning the contaminated water remaining in the flow path after the backwash operation.

  Function (4) is forcibly using the filtration tank 31 to generate treated water for detecting the concentration in the case of detecting the concentration of the chemical solution in the treated water treated in the filtration tank 31 by the concentration detector 14. This is a function of performing a wastewater operation for treating the water and then draining the treated water.

  Specifically, the function (4) is similar to the cleaning operation in that the flow path from the primary side to the secondary side includes the pipe 20, the first branch pipe 34, the suction pipe 32, the filtration tank 31, the discharge pipe 33, The first three-way valve 35, the second three-way valve 38, and the third three-way valve 40 are switched so that the second branch pipe 39 and the second drain pipe 42 flow in this order. In this state, by driving the pump device 11 and the injection pump 22 for a predetermined time, the raw water into which the chemical solution has been injected passes through the filtration tank 31. Thereby, the raw water into which the chemical solution has been injected is drained from the second drain pipe 42 to the second drain 130 through the suction pipe 32, the filtration tank 31, and the discharge pipe 33. As a result, treated water is forcibly generated, passed through the second branch pipe 39, and then drained to the second drain 130, whereby the treated water is supplied to the concentration detection sensor 51, and the concentration of the treated water is reduced. This is a function that can be detected.

  For example, the wastewater operation is performed when the next concentration in the treated water is detected when a predetermined time has elapsed since the previous concentration in the treated water was detected. The predetermined time is an arbitrary set time stored in the storage unit 61, and is set as appropriate in use conditions and the like.

  The function (5) is a function for correcting the amount of the chemical solution injected into the raw water according to the flow rate. Specifically, in the function (5), after the cleaning operation by the function (3) is performed for a predetermined time, or a predetermined time for detecting the concentration in the treated water set in the main control unit 63 in advance has elapsed. Sometimes, the number of times of detecting the concentration of the chemical in the treated water (number of times of measurement) is compared with the first threshold value. When the number of times of measurement is less than or equal to the first threshold value, the concentration detection sensor 51 detects the concentration of the treated water that has been treated in the filtration tank 31 after the end of the cleaning operation or the start of the drainage operation and when the predetermined time t1 has elapsed. .

  Next, it is determined whether or not the detected density is included in the range of the second threshold stored in the storage unit 61 in advance. When the detected concentration is within the range of the second threshold, the amount of the chemical solution injected into the raw water is not corrected as a normal concentration. If the detected concentration is within the range of the second threshold, the chemical in the treated water is determined as an abnormal concentration. In addition, the storage unit 61 stores information indicating that the concentration is normal or abnormal.

  Next, it is determined whether the detected density is lower than the second threshold value or higher than the second threshold value. Of the plurality of chemical solution concentration groups stored in the first storage unit 24a according to the determination result, the concentration group of the chemical solution whose treatment water concentration is higher or lower than that at the time of the determination is the first storage unit. Select from 24a. In the next normal operation, the chemical solution is injected into the raw water based on the selected concentration group of the chemical solution. In addition, it is a function of storing the detected density level with respect to the second threshold value.

  As described above, the function (5) is a function of correcting the amount of the chemical solution to be injected based on the concentration of the chemical solution in the treated water detected by the concentration detection sensor 51.

  The function (6) is a function for determining the continuation of the operation of the filtering device 1 every time the concentration detection sensor 51 detects the concentration a predetermined number of times. Specifically, in the function (6), after performing the cleaning operation by the function (3) for a predetermined time, or a predetermined time for detecting the concentration in the treated water set in the main control unit 63 in advance has elapsed. Sometimes, the number of times of detecting the concentration of the chemical in the treated water (number of times of measurement) is compared with the first threshold value. In the case where the number of times the concentration of the chemical solution in the treated water is detected and the first threshold value are the same, the normality of the concentration detected by the concentration detection sensor 51 by the number of times of the first threshold value stored in the storage unit 61 and The abnormality and the level of concentration at the time of abnormality are judged.

  At this time, if the concentration is abnormal for the first threshold value, that is, n times continuously and the concentration at the time of abnormality is n times consecutively lower than the second threshold value, these concentrations are the third. It is determined whether or not it is equal to or less than a threshold value. When these concentrations are all below the third threshold, it is a concentration at which the operation of the filtration device 1 cannot be continued, and it is determined that there is an abnormality, the filtration device 1 is forcibly stopped, the notification device 62 is controlled, Alarm the abnormality. At the same time, the number of times detected by the density detection sensor 51 is reset.

  If at least one of the concentrations is greater than or equal to the third threshold, the number of corrections is reset, and the abnormality is alerted to the outside by the notification device 62, but the operation of the filtration device 1 continues.

  If the concentration is not abnormal continuously n times, or if the concentration is abnormal continuously n times and the concentration at the time of abnormality is not lower than the second threshold value n times continuously, The number of times the concentration is detected by the detection sensor 51 is reset, and the operation of the filtration device 1 is continued.

  As described above, the function (6) is a function for forcibly stopping the operation of the filtration device 1 when the concentration is lower than the second threshold and lower than the third threshold continuously n times.

  Next, the control method of such a filtration apparatus 1 is demonstrated below using the flowchart shown in FIG. 2 thru | or FIG.

  As shown in FIG. 2, first, power is supplied to the filtration device 1 to drive the filtration device 1 (step ST1). Next, the main control unit 63 performs normal operation of the filtration device 1 (step ST2). Specifically, the main control unit 63 switches the first three-way valve 35, the second three-way valve 38, and the third three-way valve 40, and based on the flow rate and pressure detected by the flow rate detection device 23 and the pressure detection device 43. The pump device 11 and the infusion pump 22 are driven.

  During normal operation, for example, when the pressure detected by the pressure detection device 43 is a predetermined value or more, it is determined that water is not used at the supply destination 110, the pump device 11 and the infusion pump 22 are stopped, When the pressure detected by the pressure detection device 43 falls below a predetermined value, it is determined that water is used at the supply destination 110, and the pump device 11 is variably controlled according to the pressure, and the infusion pump 22 is used. Is driven, and a predetermined amount of chemical solution is injected into the raw water according to the flow rate.

  Next, it is determined whether or not a backwash operation is performed (step ST3). When the backwash operation is not performed such as when the accumulated time of the normal operation is shorter than the predetermined time (NO in step ST3), it is determined whether or not the arbitrary set time stored in the storage unit 61 has been reached. Perform (step ST4).

  If the arbitrary set time has not been reached (NO in step ST4), the process returns to step ST3 to perform the backwash operation (YES in step ST3), or the arbitrary set time is reached (YES in step ST4). Until normal operation.

  When the accumulated time of the normal operation is performed for a predetermined time and the backwash operation is performed (YES in step ST3), the main control unit 63 performs the backwash operation (step ST5). After the backwash operation is performed for a predetermined time, the cleaning operation is subsequently performed (step ST6). When the operation time of the specified cleaning operation ends (step ST7), the main control unit 63 maintains the cleaning operation for a predetermined time t1 stored in the storage unit 61. When the cleaning operation is maintained for a predetermined time t1 (step ST8), the main control unit 63 determines whether or not the number of measurements of the concentration of the chemical in the treated water is equal to or greater than the first threshold (step ST9).

  When the backwash operation is not performed (NO in step ST3) and when an arbitrary set time is reached (YES in step ST4), the main control unit 63 starts the water drain operation (step ST10). When the predetermined time t1 has elapsed after the start of the water discarding operation (step ST11), the main control unit 63 determines whether or not the number of times of measurement of the concentration of the chemical in the treated water is equal to or greater than the first threshold value, similar to after the cleaning operation. Is determined (step ST9).

  When the number of times of measurement is less than n that is the first threshold (NO in step ST9), as shown in the flowchart of FIG. 3, the concentration in the treated water is measured by the concentration detection sensor 51 (step ST21). At this time, the concentration in the treated water is measured for a predetermined time t2 (step ST22).

  After a predetermined time t2 has elapsed, after the concentration detection sensor 51 measures the concentration of the chemical solution remaining in the treated water (residual concentration), the main control unit 63 compares the concentration of the chemical solution remaining in the treated water with the second threshold, It is determined whether or not the concentration of the chemical in the treated water is abnormal (step ST23).

  When the concentration of the chemical in the treated water is within the second threshold range, the main control unit 63 determines that the concentration of the chemical in the treated water is normal (NO in step ST23), and returns to step ST2. Then, normal operation is performed again, and the processes after step ST3 are performed. In addition, the number of times of measurement is counted, and information indicating the normality is stored in the storage unit 61.

  When the concentration of the chemical in the treated water is outside the second threshold range, the main control unit 63 determines that the concentration of the chemical in the treated water is abnormal (YES in step ST23), and the concentration of the chemical in the treated water It is determined whether the density is low or high (step ST24). Specifically, it is determined whether or not the concentration of the chemical remaining in the treated water is higher than the second threshold value.

  If the concentration of the chemical remaining in the treated water is higher than the second threshold (YES in step ST24), it is determined that the concentration of the chemical remaining in the treated water is high (step ST25), and the determination result is stored in the storage unit. 61 is stored.

  Based on the concentration of the chemical solution, the main control unit 63 selects one chemical solution concentration group from the plurality of chemical solution concentration groups stored in the first storage unit 24a of the first control unit 24. The injection amount of the chemical solution for normal operation is set (step ST26). The main control unit 63 transmits information on the concentration group of one selected chemical solution to the first control unit 24. At the same time, the number of measurements detected by the concentration detection sensor 51 is counted (step ST27). In step ST26, after a predetermined amount of time t3 has elapsed after setting the injection amount of the chemical solution (step ST28), the process returns to step ST2 and normal operation is performed.

  If the concentration of the chemical remaining in the treated water is lower than the second threshold (NO in step ST24), it is determined that the concentration of the chemical remaining in the treated water is low (step ST29), and the determination result is stored in the storage unit. 61 is stored.

  Based on the concentration of the chemical solution, the main control unit 63 selects one chemical solution concentration group from the plurality of chemical solution concentration groups stored in the first storage unit 24a of the first control unit 24, and next time The injection amount of the chemical solution for the subsequent normal operation is set (step ST30). At the same time, the number of measurements detected by the concentration detection sensor 51 is counted (step ST31). In step ST30, after a predetermined amount of time t3 has elapsed after setting the injection amount of the chemical solution (step ST32), the process returns to step ST2 and normal operation is performed.

  In step ST9, when the number of times of continuous detection of the concentration of the chemical in the treated water is equal to or greater than the first threshold (YES in step ST9), information stored in the storage unit 61 as shown in FIG. Therefore, it is determined whether or not the concentration of the chemical solution remaining in the treated water is a low concentration continuously n times (step ST41). Of the detections n times by the concentration detection sensor 51, when the concentration of the chemical remaining in the treated water is normal, or when the concentration is high even if it is abnormal (step ST42) The number of measurements detected by the concentration detection sensor 51 is reset (n = 0) (step ST42). Then, it returns to step ST2 and performs normal operation again.

  If the concentration of the chemical solution remaining in the treated water is low for n consecutive times (YES in step ST41), the main control unit 63 determines whether or not to continue the operation of the filtration device 1 ( Step ST43).

  Specifically, the main control unit 63 determines whether or not the concentration of the chemical solution remaining in the treated water stored in the storage unit 61 is lower than the third threshold value. In all cases, when the concentration of the chemical remaining in the treated water is lower than the third threshold value, the main control unit 63 determines that the operation of the filtration device 1 cannot be continued (NO in step ST43). Thereafter, the main control unit 63 resets the number of measurements (n = 0) (step ST44), alerts the abnormality to the outside by the notification device 62 (step ST45), and forcibly stops the filtering device 1 (step ST46). ).

  When the concentration of the chemical solution remaining in the treated water stored in the storage unit 61 is at least once higher than the third threshold, the main control unit 63 resets the number of measurements (n = 0) (step ST47). . Next, the main controller 63 warns the outside that the residual concentration is continuously low by the notification device 62 (step ST48), returns to step ST2, and performs normal operation.

  The filtration device 1 repeats the above steps until it is forcibly stopped in step ST46 or until a stop instruction is input from the outside.

  According to the filtration device 1 configured as described above, the main control unit 63 determines whether the concentration is normal or abnormal from the concentration of the chemical contained in the treated water detected by the concentration detection sensor 51, and at the time of abnormality. Thus, it is possible to correct the injection amount of the chemical solution based on the level of concentration. Thereby, since it becomes possible for the filtration apparatus 1 to correct | amend a chemical | medical solution automatically, while being able to continue the process of normal iron removal and manganese removal, it is possible for the filter material in the filter tank 31 to be continued. Lifespan can be improved.

  Moreover, since the work of constantly monitoring the residual chlorine concentration by personnel is not necessary, the running cost of the filtration device 1 can be reduced. Moreover, since the density | concentration of the chemical | medical solution in process water can be correct | amended to a normal state, the filtration apparatus 1 can additionally install the activated carbon filtration tank etc. for removing an excessive chemical | medical solution in the secondary side of the filtration tank 31. It becomes unnecessary, and the installation space, manufacturing cost, and maintenance cost can be reduced.

  In addition, when the concentration of the chemical in the treated water is continuously low for the predetermined number of times set to the first threshold value, the filtration device 1 warns the outside and notifies the fact that the concentration is higher than the third threshold value. In the case of a low concentration, it is further configured to be forcibly stopped.

  For this reason, when the concentration of the chemical in the treated water is continuously low, the information can be notified to the outside. In addition, when the treated water is not subjected to appropriate iron removal and manganese removal treatment in the filtration tank 31, in other words, when treated water outside the range of use requirement, that is, unusable treated water is supplied. By forcibly stopping the filtration device 1, it is possible to prevent the unusable treated water from being supplied. Thus, since the filtration apparatus 1 can supply the treated water in which the process of iron removal and manganese removal within the range of use requirement is performed, it has high reliability.

  As described above, according to the filtering device 1 according to the embodiment of the present invention, the amount of chemical injection can be corrected, and when the treated water is continuously out of the range of use requirement, it is forcibly stopped. It becomes possible to do.

  The present invention is not limited to the above embodiment. For example, in the above-described example, the filtration device 1 is forcibly stopped when the concentration of the chemical in the treated water is low and continuously lower than the third threshold value a predetermined number of times. However, the present invention is not limited to this. Similarly, even when the concentration of the chemical in the treated water is continuously high a predetermined number of times and is higher than a threshold that is a high concentration outside the preset use range, filtration is performed. The apparatus 1 may be configured to forcibly stop.

  Moreover, although the chemical | medical solution injection apparatus 12 demonstrated the structure which supplies a chemical | medical solution only to the primary side of the filtration tank 31 in the example mentioned above, it is not limited to this. For example, the chemical liquid injector 12 may be configured to further supply the chemical liquid to the secondary side of the filtration tank 31 and to the secondary side of the position detected by the concentration detection sensor 51.

  Further, in the above-described example, the filtering device 1 returns to step ST2 again after a predetermined time t3 has passed in step ST28 and step ST32 after setting the injection amount of the chemical solution in step ST26 and step ST30 (step ST28). Although the structure which performs a normal driving | operation was demonstrated, it is not limited to this.

  After a predetermined time t3 elapses in step ST28 and step ST32, the process returns to step ST9 again, and the chemical of the treated water treated by the washing operation or the draining operation after setting the injection amount of the chemical liquid has a normal concentration, or The structure may be repeated until the number of times of measurement of the concentration of the chemical in the treated water reaches the first threshold (YES in step ST9).

  Furthermore, in the above-described example, the filtering device 1 describes the configuration including the first storage unit 24a and the storage unit 61, and the configuration including the first control unit 24, the second control unit 53, and the main control unit 63. However, it is not limited to this. For example, the first storage unit 24a and the storage unit 61 may be configured to include one storage unit, and the first control unit 24, the second control unit 53, and the main control unit 63 are similarly one control unit. It may be.

Moreover, although the filtration apparatus 1 mentioned above demonstrated the structure which has the 1st three-way valve 35, the 2nd three-way valve 38, and the 3rd three-way valve 40 as a flow-path switching means, it is not limited to this. That is, the number and configuration of the flow path switching means can be appropriately changed as long as the flow path capable of the above-described normal operation, backwash operation, and washing operation (drainage operation) can be configured. The design of the configuration for forming the flow path such as the first branch pipe 34 and the second branch pipe 39 can be changed as appropriate. In addition, various modifications can be made without departing from the scope of the present invention.
Below, the description equivalent to the invention described in the scope of claims of the present application is appended. [1] a pump device for supplying water from a supply source;
A flow rate detection device for detecting a flow rate on the secondary side of the pump device;
Based on the flow rate detected by the flow rate detection device, a chemical solution injection device that injects a chemical solution that is an oxidant into the water discharged from the pump device,
A filtration tank that is provided on the secondary side of the pump device and that treats water into which the chemical solution has been injected,
A concentration detection device for detecting the concentration of the chemical solution of the water discharged from the filtration tank;
A storage unit in which a predetermined concentration of the chemical solution of water discharged from the filtration tank is stored as a threshold;
Control that compares the concentration of the chemical solution detected by the concentration detection device with the threshold value, and controls the chemical solution injection device to a set value that is a normal concentration of the chemical solution when the concentration of the chemical solution is different from the threshold value And
A filtration apparatus comprising:
[2] A drain pipe connected to a drain provided on the secondary side of the filtration tank;
A water supply pipe connected to the filtration tank and connected to the supply destination;
A flow path that passes through the filtration tank from the secondary side of the pump device and connects to the water supply pipe, a flow path that flows backward from the filtration tank and connects to the drain pipe from the secondary side of the pump apparatus, and A flow path switching means for switching a flow path passing through the filtration tank and connecting to the drain pipe from the secondary side of the pump device,
The control unit controls the flow path switching unit to pass water supplied by the pump device and supplied with the chemical solution by the chemical solution injection device from the secondary side of the pump device to the filtration tank. The normal operation for passing through the flow path connecting the water supply pipe and the normal operation are performed for a predetermined time, and then the flow path switching means is controlled to supply the water supplied by the pump device to the second of the pump device. Backwash operation that allows the flow path connected to the drain pipe to flow backward through the filtration tank from the secondary side, and after the backwash operation, controls the flow path switching means, and is supplied by the pump device, A cleaning operation or a draining operation is performed in which water supplied with the chemical solution by the chemical injection device passes through the filtration tank from the secondary side of the pump device and passes through a flow path connected to the drain pipe. The filtration device according to [1].
[3] The filtration device according to [2], wherein the concentration detection device detects the concentration of the chemical solution during the cleaning operation or the water draining operation.
[4] In the storage unit, an arbitrary number of measurements of the concentration of the chemical solution is stored as a first threshold value,
The threshold is a second threshold;
The control unit compares the concentration of the chemical solution detected by the concentration detection device with the threshold value when the number of times of measurement of the concentration of the chemical solution is less than the first threshold value, and the concentration of the chemical solution is different from the threshold value. In this case, the chemical solution injection device is controlled with a set value at which the chemical solution has a normal concentration, the level of the concentration of the chemical solution with respect to the second threshold is determined, and the determination result is stored in the storage unit. The filtration device according to [3], wherein
[5] When the number of times of measurement of the concentration of the chemical solution is the same as the first threshold value, the control unit determines whether the concentration of the chemical solution stored in the storage unit is high or low with respect to the second threshold value. [4] The filtration device according to [4], wherein the normal operation is performed when the concentration is at least once, which is higher than the normal concentration or the second threshold value.
[6] In the storage unit, the concentration of the chemical solution that is lower than the second threshold and does not satisfy the use requirement of water treated in the filtration tank is stored as a third threshold,
The control unit determines whether the concentration of the chemical solution stored in the storage unit is high or low with respect to the second threshold when the number of times of measurement of the concentration of the chemical solution is the same as the first threshold, and the same number as the first threshold When the concentration of the chemical solution is continuously lower than the second threshold value by the number of times of measurement, the concentration of the chemical solution stored in the storage unit is compared with the third threshold value, and the chemical solution When the concentration of the liquid is higher than the third threshold, the normal operation is performed, and when the concentration of the chemical solution is lower than the third threshold, the pump device is stopped. The filtration device according to [5], which is characterized.
[7] Provide notification means for reporting information to the outside,
When the state in which the concentration of the chemical solution is lower than the second threshold continues for the same number of measurements as the first threshold, the concentration of the chemical is lower than the second threshold by the notification unit. The filtration apparatus according to [6], wherein the outside is notified of the concentration.
[8] The control unit compares the concentration of the chemical solution detected by the concentration detection device with the second threshold value, and determines that the concentration of the chemical solution is normal when the concentration of the chemical solution is different from the second threshold value. The chemical solution injection device is controlled so that the concentration of the chemical solution is detected by the concentration detection device, the chemical solution injection device is controlled until the chemical solution reaches the normal concentration, and the injection amount of the chemical solution is controlled. The filtration device according to [4], wherein:
[9] A chemical solution, which is an oxidant, is injected into the water discharged from the pump device that supplies water from a supply source by the chemical solution injection device based on the flow rate on the secondary side of the pump device detected by the flow rate detection device. And
The filtration tank provided on the secondary side of the pump device treats the water into which the chemical solution has been injected,
The concentration of the chemical solution discharged from the filtration tank detected by the concentration detection device and the threshold value stored in the storage unit and the predetermined concentration of the chemical solution discharged from the filtration tank. When the concentration of the chemical solution is different from the threshold, the chemical solution injection device is controlled, and the normal concentration of the chemical solution is controlled by controlling the injection amount of the chemical solution.
A control method for a filtration device.

DESCRIPTION OF SYMBOLS 1 ... Filtration apparatus, 11 ... Pump apparatus, 12 ... Chemical solution injection apparatus, 13 ... Filtration unit, 14 ... Concentration detection apparatus, 15 ... Control panel, 20 ... Pipe, 21 ... Chemical solution tank, 22 ... Injection pump, 23 ... Flow detection Apparatus 24 ... 1st control part (control part), 24a ... 1st memory | storage part (memory | storage part), 31 ... Filtration tank, 32 ... Suction pipe, 33 ... Discharge pipe, 34 ... 1st branch pipe, 35 ... 1st Three-way valve, 36: first drain pipe (drain pipe), 37: On-off valve, 38: Second three-way valve, 39: Second branch pipe, 40: Third three-way valve, 41: Water supply pipe, 42: Second drain Pipe (drainage pipe), 43 ... Pressure detection device, 51 ... Concentration detection sensor, 52 ... Third drainage pipe, 53 ... Second control unit (control unit), 61 ... Storage unit, 62 ... Notification device, 63 ... Main control Part (control part), 99 ... signal line, 100 ... supply source, 110 ... supply destination, 111 ... faucet, 120 ... first drain 130 ... second drain, 140 ... third drain.

Claims (7)

A pump device for supplying water from a supply source;
A flow rate detection device for detecting a flow rate on the secondary side of the pump device;
Based on the flow rate detected by the flow rate detection device, a chemical solution injection device that injects a chemical solution that is an oxidant into the water discharged from the pump device,
A filtration tank that is provided on the secondary side of the pump device and that treats water into which the chemical solution has been injected,
A concentration detection device for detecting the concentration of the chemical solution of the water discharged from the filtration tank;
A drain pipe connected to a drainage section provided on the secondary side of the filtration tank;
A water supply pipe connected to the filtration tank and connected to the supply destination;
A flow path that passes through the filtration tank from the secondary side of the pump device and connects to the water supply pipe, a flow path that flows backward from the filtration tank and connects to the drain pipe from the secondary side of the pump apparatus, and A flow path switching means for switching a flow path that passes through the filtration tank and connects to the drain pipe from the secondary side of the pump device;
A storage unit in which a predetermined concentration of the chemical solution of water discharged from the filtration tank is stored as a threshold;
By controlling the flow path switching means, the water supplied by the pump device and supplied with the chemical solution by the chemical solution injection device passes through the filtration tank from the secondary side of the pump device and passes through the water supply pipe. After performing a normal operation for passing through the flow path to be connected and the normal operation for a predetermined time, the flow switching means is controlled to filter the water supplied by the pump device from the secondary side of the pump device. After the backwash operation in which the tank flows backward and passes through the flow path connected to the drain pipe, the flow path switching means is controlled after the backwash operation, and is supplied by the pump device. Cleaning operation for draining the supplied water from the secondary side of the pump device through the filtration tank and passing through the flow path connected to the drain pipe, and the chemical solution is supplied in the filtration tank. A place to detect the concentration of the chemical in treated water In addition, the flow path switching means is controlled to filter the treated water, which is supplied by the pump device and detects the concentration of the chemical solution supplied by the chemical solution injection device, from the secondary side of the pump device. A control unit that performs a drainage operation to pass through a tank and pass through a flow path connected to the drain pipe, and drain the water,
The control unit performs the drainage operation after the cleaning operation or after a predetermined time for detecting the concentration in the treatment water set in advance, and the concentration of the chemical solution detected by the concentration detection device and the concentration comparing the threshold value, if the concentration of the chemical is different from the threshold value, the next of the normal operation, filtration characterized by the Turkey controls the liquid injector in set value as the normal concentration of the chemical apparatus. In the storage unit, an arbitrary number of measurements of the concentration of the chemical solution is stored as a first threshold value,
The threshold is a second threshold;
The control unit compares the concentration of the chemical solution detected by the concentration detection device with the second threshold value when the number of times of measurement of the concentration of the chemical solution is less than the first threshold, and the concentration of the chemical solution is the first concentration . When the threshold value is different from two threshold values, the chemical solution injection device is controlled with a set value that is a normal concentration of the chemical solution, and the level of the concentration of the chemical solution with respect to the second threshold value is determined, and the determination is made in the storage unit The filtration apparatus according to claim 1 , wherein the result is stored. The control unit determines whether the concentration of the chemical stored in the storage unit is higher or lower than the second threshold when the number of times of measurement of the concentration of the chemical is the same as the first threshold, and the concentration of the chemical is at least The filtration apparatus according to claim 2 , wherein the normal operation is performed once when the normal concentration or the concentration is higher than the second threshold value. In the storage unit, the concentration of the chemical solution that is lower than the second threshold value and the water treated in the filtration tank does not satisfy the use requirement is stored as a third threshold value.
The control unit determines whether the concentration of the chemical solution stored in the storage unit is high or low with respect to the second threshold when the number of times of measurement of the concentration of the chemical solution is the same as the first threshold, and the same number as the first threshold When the concentration of the chemical solution is continuously lower than the second threshold value by the number of times of measurement, the concentration of the chemical solution stored in the storage unit is compared with the third threshold value, and the chemical solution When the concentration of the liquid is higher than the third threshold, the normal operation is performed, and when the concentration of the chemical solution is lower than the third threshold, the pump device is stopped. The filtration device according to claim 3 , wherein Provided with an informing means for informing the outside,
When the state in which the concentration of the chemical solution is lower than the second threshold continues for the same number of measurements as the first threshold, the concentration of the chemical is lower than the second threshold by the notification unit. The filtration device according to claim 4 , wherein a notification of the concentration is given to the outside. The control unit compares the concentration of the chemical solution detected by the concentration detection device with the second threshold value, and when the concentration of the chemical solution is different from the second threshold value, the concentration of the chemical solution becomes normal. Controlling the chemical solution injection device, detecting the concentration of the chemical solution with the concentration detection device, controlling the chemical solution injection device until the chemical solution reaches the normal concentration, and controlling the injection amount of the chemical solution The filtration device according to claim 2 , wherein A pump device for supplying water from a supply source;
A flow rate detection device for detecting a flow rate on the secondary side of the pump device;
Based on the flow rate detected by the flow rate detection device, a chemical solution injection device that injects a chemical solution that is an oxidant into the water discharged from the pump device,
A filtration tank that is provided on the secondary side of the pump device and that treats water into which the chemical solution has been injected,
A concentration detection device for detecting the concentration of the chemical solution of the water discharged from the filtration tank;
A drain pipe connected to a drainage section provided on the secondary side of the filtration tank;
A water supply pipe connected to the filtration tank and connected to the supply destination;
A flow path that passes through the filtration tank from the secondary side of the pump device and connects to the water supply pipe, a flow path that flows backward from the filtration tank and connects to the drain pipe from the secondary side of the pump apparatus, and A flow path switching means for switching a flow path that passes through the filtration tank and connects to the drain pipe from the secondary side of the pump device;
A storage unit in which a predetermined concentration of the chemical solution of water discharged from the filtration tank is stored as a threshold value,
By controlling the flow path switching means, the water supplied by the pump device and supplied with the chemical solution by the chemical solution injection device passes through the filtration tank from the secondary side of the pump device and passes through the water supply pipe. After performing a normal operation for passing through the flow path to be connected and the normal operation for a predetermined time, the flow switching means is controlled to filter the water supplied by the pump device from the secondary side of the pump device. After the backwash operation in which the tank flows backward and passes through the flow path connected to the drain pipe, the flow path switching means is controlled after the backwash operation, and is supplied by the pump device. Cleaning operation for draining the supplied water from the secondary side of the pump device through the filtration tank and passing through the flow path connected to the drain pipe, and the chemical solution is supplied in the filtration tank. A place to detect the concentration of the chemical in treated water In addition, the flow path switching means is controlled to filter the treated water, which is supplied by the pump device and detects the concentration of the chemical solution supplied by the chemical solution injection device, from the secondary side of the pump device. It is a control method of a filtration device that performs a drainage operation for passing through a tank and passing through a flow path connected to the drain pipe and draining,
The water discharged from the prior SL pump device, the drug solution was injected by the liquid injector based on the flow rate of the secondary side of the detected by the flow rate detecting device the pump device,
By the Filtration bath, treated water in which the chemical solution is injected,
After the washing operation or after elapse of a predetermined time for detecting the concentration of the treatment water set in advance, the draining operation is performed, and the water discharged from the filtration tank detected by the concentration detection device is used. the concentration of the chemical solution, and compares the threshold value, if the concentration of the chemical is different from the threshold value, controls the liquid injector, the next of the normal operation, the injection amount of the liquid medicine of the liquid injector By controlling, the normal concentration of the chemical solution,
A control method for a filtration device.