JP6258822B2 - Filtration device - Google Patents

Description

  The present invention relates to, for example, a filtration device that includes a water storage chamber in an upper portion of a filtration chamber and has a function of backwashing a filter medium in the filtration chamber with treated water stored in the water storage chamber.

  Recently, a filtration device (backwash water self-contained pressure filtration device) having a water storage chamber at the top of the filtration chamber and having a function of backwashing the filter medium with treated water stored in the water storage chamber has been developed (for example, , See Patent Document 1 below).

  And at the time of the normal filtration which filters raw | natural water with the said filtration apparatus, raw | natural water is introduce | transduced into an upper filtration chamber. The raw water introduced into the upper filtration chamber passes through the filter medium layer downward, passes through the strainer and becomes treated water and flows into the lower filtration chamber. And the filtered treated water is discharged | emitted from the inside of a filtration tank.

  If the filtration device is used for a long time, the filter medium is clogged, and efficient filtration treatment cannot be performed. For this reason, the operation | work which removes the pollutant adhering to a filter medium, what is called a back washing operation (back washing) is performed. In such backwashing, the treated water in the lower filtration chamber is introduced into the upper filtration chamber in the opposite direction to the filtration to wash the filter medium, and the washed water is discharged from the filtration tank.

  The filtration device is provided with a single pressure detection unit (a pressure switch or a pressure gauge having a single contact) in the upper filtration chamber to monitor clogging of the filter medium. When the filter medium is clogged, the pressure in the filter chamber rises, and when the contact of the pressure switch is turned on, the filter medium cleaning system starts the filter medium cleaning process.

JP 2012-86141 A

  In the current filter medium cleaning system, it is difficult to assume that a trouble occurs in the pressure switch having a simple structure. However, when water is taken in a sea area where the water quality is too bad, the filter medium is frequently washed due to pressure increase. . As a result, it has been found that the problem of contact deterioration in the pressure switch occurs. When such a pressure switch failure occurs, backwashing is not performed. If backwashing is not performed appropriately, the filtration pressure may exceed the pressure resistance value of the filtration device, and the filtration device may be damaged.

  In general, a plurality of filtration devices are installed. When a plurality of filtration devices are installed, there is a case where an interlock that does not backwash the plurality of filter media at the same time is effective so that the supply of treated water does not stop. Normally, before the pressure of this unit rises to the pressure resistance value of the filtration device, the filter unit cleaning process of the previous unit (the other unit that performs the filter medium cleaning step before this unit) has been completed. The filter medium washing process of this machine can be performed while supplying treated water. As a result, the pressure of the present machine can be reduced, but in rare cases, the cleaning cycle may not be in time, and the pressure may rise to near the pressure resistance value.

  As described above, if the filter medium is continuously used in a state where it cannot be washed, the filter device itself may not withstand pressure and may be damaged. Also, if you continue to use it in a state that exceeds the normal pressure, dirt will enter the depth of the filter medium. As a result, there is a problem that the dirt cannot be removed only by washing the filter medium (back washing), and the exchange cycle of the filter medium is shortened.

  Therefore, in view of the above problems, the present invention performs filtration that allows the filter medium to be backwashed moderately and accurately, prevents the filtration pressure from exceeding the pressure resistance value of the filtration device, and allows efficient use of the filter medium over a long period of time. An object is to provide an apparatus.

The present invention has been made in order to solve the above-mentioned problems, a filtration tank having a filtration chamber, a filter bed that divides the filtration chamber into an upper filtration chamber on the upper side and a lower filtration chamber on the lower side, A filter medium layer comprising a filter medium provided on the upper surface of the filter bed, and the raw water introduced into the upper filtration chamber passes through the filter medium to introduce water filtered into the lower filtration chamber and In the filtration device that discharges water from the filtration tank, guides the water in the lower filtration chamber to the upper filtration chamber opposite to the time of filtration, cleans the filter medium, and discharges the washed water from the filtration tank, the internal pressure of the upper filtration chamber A pressure detection unit for detecting water, a raw water on-off valve that introduces raw water into the upper filtration chamber by being opened, and a control unit that performs backwash start control or abnormal value control based on a signal from the pressure detection unit with the door, the pressure detection unit, a predetermined pressure A first pressure sensor for detecting, and a second pressure sensor for detecting the abnormal pressure of the pressure higher than the predetermined pressure, the control unit, other filtration vessel can determine whether it is being backwashed When the first pressure sensor detects the predetermined pressure and the second pressure sensor does not detect the abnormal pressure, and the other filtration tank is backwashing, the other When the backwashing of the filter tank is completed, the filter medium is backwashed, the first pressure sensor detects the predetermined pressure, and the second pressure sensor detects the abnormal pressure. If the other filtration tank is being backwashed, as the abnormal value control, the raw water on-off valve is closed, and the backwashing of the filter medium is waited until the backwashing of the other filtration tank is completed. It is characterized by that.

  In the filtration device, at least one of the first pressure sensor and the second pressure sensor is a semiconductor pressure gauge.

  The present invention can appropriately and accurately back-wash the filter medium to prevent the filtration pressure from exceeding the pressure resistance value of the filtration device. Moreover, there exists an advantage which can use a filter medium efficiently over a long period of time.

Drawing 1 is a mimetic diagram showing the filtration device main part in the filtration device of the present invention concerning an embodiment. FIG. 2 shows (a) when taking raw water, (b) when supplying treated water (supply amount <raw water intake amount), and (c) when supplying treated water (supply amount> raw water intake amount). , And (d) It is explanatory drawing which shows each state at the time of backwashing. FIG. 3 is a block diagram showing the filtration device of the present invention according to the embodiment. FIG. 4 is a flowchart showing control at the time of supplying treated water in the filtration device of the present invention according to the embodiment. FIG. 5 is a flowchart showing control during backwashing in the filtration device of the present invention according to the embodiment. FIG. 6 is a flowchart showing the pressure detection unit. FIG. 7 is a flowchart showing another pressure detection unit. FIGS. 8A and 8B are schematic views showing another filtering device of the present invention.

  Hereinafter, an embodiment of the filtration device 1 of the present invention will be described. In addition, although the multiple filtration apparatus 1 of this invention is installed, it is not limited to this embodiment.

  As shown in FIG. 1, the filtration device main body A includes a hollow filtration tank 2, a partition wall 21 that divides the inside of the filtration tank 2 into an upper water storage chamber 3 and a lower filtration chamber 4, and the filtration chamber 4 Is further divided into an upper filtration chamber 41 on the upper side and a lower filtration chamber 42 on the lower side, a raw water intake pipe 6 for taking raw water into the upper filtration chamber 41, and treated water that has passed through the filter material 5. A treated water supply pipe 7 provided with a treated water opening / closing valve 71 for supplying from the lower filtration chamber 42, and a water collection pipe for transporting the treated water that is excessive relative to the capacity of the lower filtration chamber 42 into the water storage chamber 3. 8, a backwash water drain pipe 9 having a backwash on / off valve 91 that communicates with the upper filtration chamber 41 through the wall surface of the filtration tank 2 and opens into the upper filtration chamber 41, and water storage in the water storage chamber 3. And a water amount detection unit 10 (10H, 10L) for detecting the amount.

  The filtration device main body A has a hollow cylindrical filtration tank 2 as a main body. The filtration tank 2 is partitioned into a water storage chamber 3 on the upper side and a filtration chamber 4 on the lower side by a partition wall 21 that divides the inside of the filtration tank 2 up and down.

  The water storage chamber 3 is provided with an opening 22 in the ceiling, and is designed so that the air pressure inside and outside the water storage chamber 3 is always equal. That is, since no extreme internal pressure is generated in the water storage chamber 3 in the filtration device 1 according to this embodiment, it is sufficient for the strength of the water storage chamber 3 to be rigid enough to store treated water. Accordingly, the outer wall of the water storage chamber 3 can be formed using a relatively inexpensive material such as general-purpose plastic.

  On the other hand, the internal pressure of the filtration chamber 4 changes depending on the supply amount of raw water, the intake amount of treated water, the degree of clogging of the filter medium 5, and the like. For this reason, in this embodiment, the filtration chamber 4 is formed by FRP with high rigidity. In addition, the partition wall 21 that vertically partitions the interior of the water storage chamber 3 has a dome shape that gently swells upward from the peripheral portion toward the center portion, and rounds the corners of the bottom wall of the filtration chamber 4 by rounding the corners of the filtration chamber 4. Improves pressure resistance.

  Further, the filtration chamber 4 is provided with a pressure detector 11 that detects (measures) the internal pressure of the upper filtration chamber 41 in the filtration chamber 4. In addition, the filtration chamber 4 is provided with a relief valve 43 that automatically opens when the internal pressure of the filtration chamber 4 exceeds an allowable level, so that the internal pressure of the filtration chamber 4 does not become extremely large. I am doing so.

  The filter medium 5 is a layer of sand laid on the filter medium mounting base 51 disposed in the filter chamber 4 so as to have a constant laminated thickness. The filter medium installation base 51 is obtained by fitting strainers 54 to a plurality of through holes 53 provided in a plate-shaped installation base main body 52. That is, the filter medium mounting base 51 is provided with water permeability by the strainer 54.

  The raw water intake pipe 6 includes a raw water on-off valve 61, and when the raw water on-off valve 61 is opened, raw water is introduced into the upper filtration chamber 41 through the raw water intake pipe 6. The pumping of the raw water is performed by the pump P. In the present embodiment, the open end 62 of the raw water intake pipe 6 that opens in the upper filtration chamber 41 is bent upward. Thereby, raw | natural water is discharged toward the upper direction of the upper filtration chamber 41, and falls sequentially, diffusing. That is, the raw water is prevented from being biased to a part of the filter medium 5 during water intake.

  The treated water supply pipe 7 includes a treated water on-off valve 71, and the treated water stored in the lower filtration chamber 42 is passed through the treated water supply pipe 7 by opening the treated water on-off valve 71. Supplied.

  A plurality of the water collecting pipes 8 are erected through the partition wall 21, the filter medium 5, and the filter medium installation base 51. The lower end of the water collecting pipe 8 that passes through the filter medium mounting base 51 and protrudes into the lower filtration chamber 42 is bent toward the periphery of the lower filtration chamber 42. Moreover, the position (height) of the upper end opening 81 of the water collecting pipe 8 that penetrates the partition wall 21 and protrudes into the water storage chamber 3 is set to be the position (height) of the top of the dome-shaped partition wall 21. ing.

  The backwash water drain pipe 9 includes a backwash on / off valve 91. The backwash water drain pipe 9 passes through the partition wall 21, the filter medium 5, and the filter medium installation base 51 in the vertical direction along the central axis of the cylindrical filter tank 2, and is bent in the horizontal direction in the lower filtration chamber 42, It passes through the wall surface of the filtration tank 2 (the wall surface of the lower filtration chamber 42) and communicates with the outside. The upper end protruding through the partition wall 21 in the backwash water drain pipe 9 is closed, and the drain opening toward the inside of the upper filtration chamber 41 at a position near the lower surface of the partition wall 21 in the backwash water drain pipe 9. An outlet 92 is provided. An upper end portion of the backwash water drain pipe 9 protruding into the water storage chamber 3 communicates with an air vent valve 93 disposed on the outer wall of the filtration tank 2.

  The water amount detection unit 10 includes a high water level detection unit 10H and a low water level detection unit 10L. The high water level detection unit 10 </ b> H is disposed at a position corresponding to the reference water storage amount in the water storage chamber 3, and the low water level detection unit 10 </ b> L is disposed at a position corresponding to the minimum water storage amount in the water storage chamber 3. The reference water storage amount and the minimum water storage amount are determined so that the difference between the water amounts is sufficient to backwash the filter medium 5. In the present embodiment, the position of the low water level detection unit 10L is arranged according to the position of the air vent valve 93, and the arrangement of the high water level detection unit 10H is determined based on this position.

  The water amount detection unit 10 is not particularly limited as long as it can measure the amount of treated water stored in the water storage chamber 3. For example, a float may be floated in the water storage chamber 3 and the amount of water stored may be measured according to the float position of the float in the water storage chamber 3. In addition, a water pressure sensor may be provided in the lower part of the water storage chamber 3 to measure the water amount according to the water pressure that changes according to the amount of treated water stored. Further, the amount of water stored in the water storage chamber 3 may be calculated by converting the capacity of the filtration chamber 4, the amount of raw water taken, the amount of treated water supplied, the amount of treated water used for backwashing, and the like. good.

  The pressure detection unit 11 includes a first pressure sensor 11a and a second pressure sensor 11b that are pressure sensors. The pressure set value of the first pressure sensor 11a is, for example, 0.06 Mpa. The pressure set value of the second pressure sensor 11b is, for example, 0.10 Mpa. Thus, two different set pressures are set by the first pressure sensor 11a and the second pressure sensor 11b. That is, the set pressure of the first pressure sensor 11a is set to the cleaning start pressure P1. The set pressure of the second pressure sensor 11b is set to an abnormal pressure P2, and the cleaning start pressure P1 of the first pressure sensor 11a is set to be smaller than the abnormal pressure P2 of the second pressure sensor 11b.

  The pressure sensor includes a mechanical or electronic pressure switch or pressure gauge, and exemplifies a device that measures the pressure of a fluid with a pressure-sensitive element via a diaphragm, converts the pressure into an electric signal, and outputs the electric signal. it can. A semiconductor system and a capacitance system can be mentioned. Both the first pressure sensor 11a and the second pressure sensor 11b may be semiconductor pressure gauges, one may be a semiconductor pressure gauge, and at least one is preferably a semiconductor pressure gauge. .

  As shown in FIG. 2A, in the filtering apparatus main body A, the raw water is introduced into the upper filtration chamber 41 by opening the raw water on-off valve 61 after operating the pump P ( The amount of water taken per unit time of this raw water is assumed to be X). The raw water introduced into the upper filtration chamber 41 is filtered by passing through the filter medium 5 from the upper part toward the lower part by pump pressure or gravity, and is stored in the lower filtration chamber 42 as treated water.

  At this time, the air accumulated in the upper portion of the upper filtration chamber 41 is sequentially discharged out of the filtration tank 2 through the discharge port 92 and the air vent valve 93. The air vent valve 93 is automatically closed when there is no more air to be discharged.

  In this state, when the treated water opening / closing valve 71 provided in the treated water supply pipe 7 is opened, treated water is supplied from the lower filtration chamber 42 via the treated water supply pipe 7 (this treated water supply). Let the amount be Y).

  That is, in the filtration apparatus main body A, the treated water that has passed through the filter medium 5 and accumulated in the lower filtration chamber 42 passes directly from the lower filtration chamber 42 via the treated water supply pipe 7 that communicates with the lower filtration chamber 42. Can supply.

  Here, when the supply amount Y of treated water per unit time is smaller than the intake amount X of raw water per unit time (Y <X), as shown in FIG. The treated water that has become excessive with respect to the capacity of the water is transported to the water storage chamber 3 through the water collecting pipe 8 by the introduction pressure of the raw water by the pump P and stored. Note that the filtration device main body A is provided with an overflow pipe 31 having one end opened in the upper part of the water storage chamber 3 and the other end communicated with the outside of the filtration tank 2. If the stored treated water exceeds the upper opening end of the overflow pipe 31, the surplus treated water is discharged out of the filtration tank 2 through the overflow pipe 31.

  On the other hand, when the supply amount Y of the treated water per unit time exceeds the intake amount X of the raw water per unit time (Y> X), as shown in FIG. Substantial water storage in the treated water is lowered through the water collecting pipe 8 due to the water head pressure generated between the water level of the treated water stored in the water storage chamber 3 and the position of the upper end opening 81 of the water collecting pipe 8. Returned to the filtration chamber 42.

  That is, the filtration apparatus main body A arranges the water storage chamber 3 at a position above the filtration chamber 4, and sequentially stores the treated water in an excess amount with respect to the capacity of the lower filtration chamber 42 in the water storage chamber 3, and unit time When the supply amount of treated water per unit exceeds the intake amount of raw water per unit time, the treated water stored in the water storage chamber 3 is filtered through the collecting pipe 8 by the difference between the supply amount and the intake amount. It is configured to be returned to the chamber 42. Thereby, even when the supply amount of the treated water per unit time exceeds the intake amount of the raw water per unit time, the treated water stored in the lower filtration chamber 42 and the treated water stored in the water storage chamber 3 are stored. The treated water can be stably obtained until the substantial water storage is completely supplied.

  Further, as described above, in the filtering apparatus main body A, the position (height) of the upper end opening 81 of the water collecting pipe 8 that penetrates the partition wall 21 and protrudes into the water storage chamber 3 is set at the top of the dome-shaped partition wall 21. The position (height) is set. That is, in the filtering apparatus main body A, the processing of the water stored in the water storage chamber 3 is performed by setting the position of the upper end opening 81 of the water collecting pipe 8 as low as possible in the water storage chamber 3 (near the upper surface of the partition wall 21). The ratio of the substantial water storage to the amount of water is improved so that the treated water stored in the water storage chamber 3 can be used without waste.

  As shown in FIG. 2D, when the raw water on-off valve 61 and the treated water on-off valve 71 are closed and the backwash on-off valve 91 is opened, the treated water stored in the water storage chamber 3 is stored in the water storage chamber. 3 is returned to the lower filtration chamber 42 via the water collection pipe 8 due to the head pressure generated between the water level of the treated water stored in 3 and the upper end opening 81 of the water collection pipe 8. The treated water returned to the lower filtration chamber 42 passes from the lower part of the filter medium 5 toward the upper part, and is filtered through the backwash water drain pipe 9 from the discharge port 92 provided at the upper part of the back wash water drain pipe 9. It is discharged out of the tank 2. Thus, the filter medium 5 is backwashed with the treated water stored in the water storage chamber 3.

  In the present embodiment, since the lower end of the water collecting pipe 8 that passes through the filter medium mounting base 51 and opens into the lower filtration chamber 42 is bent toward the periphery of the lower filtration chamber 42, the water collection pipe 8 is The treated water returned to the lower filtration chamber 42 is diffused in the lower filtration chamber 42. Thus, the treated water passes through the entire surface of the filter medium 5 without unevenness.

  In addition, since the treated water used for the back washing soars the sand constituting the filter medium 5 into the upper filtration chamber 41 together with the dirt adhering to the filter medium 5, the discharge port 92 is as high as possible in the upper filtration chamber 41. It is preferable to provide at a position close to. Moreover, it is preferable to provide a plurality of outlets 92 around the backwash water drain pipe 9 so that treated water subjected to backwash is introduced into the backwash water drain pipe 9 from multiple directions.

  The filtration device 1 according to the present embodiment is configured such that each of the raw water on-off valve 61, the treated water on-off valve 71, and the backwash on-off valve 91 is supplied to the filtration device main body A according to the amount of water detected by the water amount detection unit 10. The control part B which commands opening / closing of the is provided.

  As shown in the block diagram of FIG. 3, the raw water on-off valve 61, the treated water on-off valve 71, and the backwash on-off valve 91 in the filtration device main body A are opened / closed by a control unit B equipped with an arithmetic logic unit. Is controlled by. The control unit B is disposed on the external operation panel C together with the treated water supply start switch C1 and the backwash start switch C2.

  The timing of opening / closing varies depending on the amount of treated water stored in the water storage chamber 3, but when the treated water supply start switch C1 on the external operation panel C is operated, the control unit B opens the raw water on / off valve 61. Order. In response to this command, the raw water on-off valve 61 is opened and intake of raw water is started. On the other hand, the control part B commands opening of the treated water on-off valve 71. In response to this command, the treated water on-off valve 71 is opened and the supply of treated water is started.

  Further, although the timing of opening / closing changes depending on the amount of treated water stored in the water storage chamber 3, when the backwash start switch C2 on the external operation panel C is operated, the control unit B causes the raw water on-off valve 61 and the processing water to flow. Command to close the water on / off valve 71 and to open the backwash on / off valve 91. In response to this command, the raw water on-off valve 61 and the treated water on-off valve 71 are closed, and the backwash on-off valve 91 is opened to start back plugging.

  The water amount detection unit 10 in the filtration apparatus main body A detects the amount of treated water stored in the water storage chamber and gives a signal related to the detected water storage amount to the control unit B. In this embodiment, when the water level of the treated water stored in the water storage chamber 3 corresponds to the position of the high water level detection unit 10H, the water amount detection unit 10 transmits a signal to that effect to the control unit B. On the other hand, when the water level of the treated water stored in the water storage chamber 3 corresponds to the position of the low water level detection unit 10L, a signal to that effect is transmitted to the control unit B. Receiving the signal, the control unit B commands opening / closing of the raw water on-off valve 61, the treated water on-off valve 71, and the backwash on-off valve 91.

  The pressure detection unit 11 includes a first pressure sensor 11a that detects the cleaning start pressure P1 and a second pressure sensor 11b that detects an abnormal pressure P2 that is higher than the cleaning start pressure. The control unit B is configured to perform backwash start control or abnormal value control.

Hereinafter, the control of each valve by the control unit B will be described with reference to the flowcharts of FIGS. For convenience of explanation, it is assumed that the pump P for pumping raw water operates with the raw water on-off valve 61 open and stops with the raw water on-off valve 61 closed. In addition, the amount of raw water taken is greater than the amount of treated water supplied.
<Control during treatment water supply>
As shown in the flowchart of FIG. 4, when the treated water supply start switch C1 in the external operation panel C is operated (ON) and a treated water supply start command is given (S20), the control unit B first performs treated water supply. The raw water on / off valve 61 is commanded to be opened while the on / off valve 71 is kept closed (S21). As a result, the raw water on-off valve 61 is opened, and the raw water is introduced into the upper filtration chamber 41.

  Then, the control part B confirms the signal from the water quantity detection part 10, and judges whether the minimum water storage amount is satisfy | filled (S22). While the minimum water storage amount is not satisfied, the treated water on / off valve 71 is kept closed. When the minimum water storage amount is satisfied, the control unit B commands opening of the treated water on-off valve 71 (S23). As a result, the treated water on-off valve 71 is opened and treated water is supplied from the lower filtration chamber 42.

  After starting the supply of treated water, the control unit B checks the signal from the water amount detection unit 10 and determines whether or not the reference water storage amount is satisfied (S24). When the reference water storage amount is satisfied, the raw water on-off valve 61 is instructed to be closed (S25).

  After the raw water on-off valve 61 is closed, the control unit B determines whether or not the minimum water storage amount is satisfied (S26). The supply of treated water continues while the minimum water reserve is being met.

  When the minimum water storage amount is no longer satisfied, the control unit commands to close the treated water on-off valve 71 and also to open the raw water on-off valve (S21).

Thereafter, S21 to S26 are repeated until the treated water supply start switch C1 is operated (OFF) and the treated water supply start command is canceled. Note that when the treated water supply start command is canceled, the treated water on-off valve 71 and the raw water on-off valve 61 are closed.
<Control during backwashing>
As shown in the flowchart of FIG. 5, when the backwash start switch C2 on the external operation panel C is operated (ON) and a backwash start command is given (S30), the control unit B indicates that the treated water on-off valve 71 It is determined whether or not the stopper is opened (S31), and if the treated water on-off valve 71 is opened, an instruction to close the treated water on-off valve 71 is given (S32).

  Next, the control unit confirms the signal from the water amount detection unit 10 and determines whether or not the reference water storage amount is satisfied (S33). When the reference water storage amount is satisfied, the control unit B commands opening of the backwash opening / closing valve 91 and closing of the raw water opening / closing valve 61 (S34). Thereby, the backwashing of the filter medium 5 is started.

  On the other hand, when the reference water storage amount is not satisfied, the control unit B determines whether or not the raw water on-off valve 61 is opened (S35). When the raw water on-off valve 61 is opened, the control unit B checks the signal from the water amount detection unit 10 until the reference water storage amount is satisfied (S33). When the raw water on-off valve 61 is closed, the control unit B commands opening of the raw water on-off valve 61 (S36), and confirms the signal from the water amount detection unit 10 until the reference water storage amount is satisfied (S33). .

  Thereafter, when the reference water storage amount is satisfied, the control unit B commands opening of the backwash opening / closing valve 91 and closing of the raw water opening / closing valve 61 (S34).

  After the start of backwashing, the control unit B confirms the signal from the water amount detection unit 10 and determines whether or not the minimum water storage amount is satisfied (S37).

  When the minimum water storage amount is satisfied, the backwashing is continued as it is. However, when the minimum water storage amount is not satisfied due to the continuation of the backwashing, the control unit B closes the backwash opening / closing valve 91 and the raw water. Command to open the on-off valve 61 (S38).

  Then, the control part B confirms the signal from the water quantity detection part 10, and judges whether the reference | standard water storage amount is satisfy | filled (S39). When the reference water storage amount is satisfied, the control unit B commands to close the raw water on-off valve 61 (S40). As a result, the treated water is again filled in the water storage chamber 3 to prepare for the subsequent supply of treated water and the subsequent backwashing.

  Furthermore, in this embodiment, the backwash start command is given by operating the backwash start switch C2 on the external operation panel C. However, in addition to the operation of the backwash start switch C2, the upper filtration chamber When the pressure detection unit 11 that detects the internal pressure 41 detects a pressure equal to or higher than the set level, a backwash start control and an abnormal value control command are automatically given.

  The backwash control by the pressure detection unit 11 will be described. FIG. 6 is a flowchart showing the pressure detection unit.

  As shown in FIG. 6, the control part B confirms the signal from the 1st pressure sensor 11a, and judges whether the filtration chamber 4 internal pressure has reached the washing | cleaning start pressure P1 (S40). When the cleaning start pressure P1 is reached, the controller B determines whether or not the other machine is backwashing (S41). When the other machine is not backwashing, the control unit B determines that backwashing is necessary, and shifts to the backwashing process (S42). That is, the process proceeds to step 31 shown in FIG. 5 and the backwashing steps (S31) to (S40) are performed. Thereby, when the filter medium 5 needs to be backwashed, the filter medium 5 can be backwashed reliably at an appropriate time.

  When the signal that the internal pressure of the filtration chamber 4 has reached the cleaning start pressure P1 is not detected from the first pressure sensor 11a, and the second pressure sensor 11b detects the abnormal pressure P2 as the internal pressure of the filtration chamber 4 (S43), the control unit B performs abnormal value control such as interlock control (S44). As a result, an abnormality alarm is issued and a warning is given to check the pressure gauge. Thus, when the pressure in the filtration chamber 4 detects the abnormal pressure P2 by the second pressure sensor 11b, the first pressure sensor 11a has failed, and the pressure in the filtration chamber 4 is equal to or higher than the cleaning start pressure P1. This is the case.

  Here, the abnormal value control is to forcibly close the raw water on-off valve 61 for controlling the inflow of seawater to the filtration device, in addition to issuing an abnormality alarm. This makes it possible to prolong the life of the filter medium replacement cycle and prevent damage to the filter device. Moreover, it is also possible to wash the filter medium as in the normal value.

  If the other machine (the previous machine) is being washed, it is preferable that the filter medium washing of this machine waits until the washing process of the other machine is completed. Thus, when a plurality of filtration devices 1 are installed, if a plurality of units are simultaneously transferred to the backwashing process, the amount of drainage discharged outside the filtration tank 2 through the backwash water drain pipe 9 is large, This is because processing becomes difficult.

  In Step 41, when the other machine is being cleaned, the control unit B determines whether or not the internal pressure of the filtration chamber 4 has reached the abnormal pressure P2 based on the signal from the second pressure sensor 11b (S45). . When the second pressure sensor 11b detects the abnormal pressure P2, it is further determined whether or not the other machine is being cleaned (S46). When the control unit B determines that the other machine is being washed, the control unit B closes the raw water on-off valve 61 (S47). Thereby, this unit can be maintained in a standby state without introducing raw water into the upper filtration chamber 41, and an increase in pressure in the filtration tank 2 can be prevented.

  Furthermore, if the control part B judges that the washing | cleaning of other machines was complete | finished (S48), it will transfer-control to a backwashing process (S42).

  It is desirable not to open the raw water on-off valve 61 and the treated water on-off valve 71 until the filter media cleaning of this machine is completed. As a result, the life of the filter medium replacement cycle can be extended, and damage to the filter device can be prevented. Although it is conceivable that the filtered water supply stops, the problem of the filtered water supply stopping by providing a plurality of filtering devices can be avoided.

  In the present embodiment, two (a plurality of) pressure sensors of different types (different detection temperatures) (first pressure sensor 11a and second pressure sensor 11b) are used, but the same type (equivalent set pressure). Can also be adopted. A combination of a single pressure sensor 11c, a timer, and a counter (not shown) may be used. FIG. 7 is a flowchart showing another pressure detection unit. That is, as shown in FIG. 7, when the pressure sensor 11 has not reached the predetermined pressure in the filtration chamber 4 (S50), when the predetermined time T has elapsed by the timer (S51), the process proceeds to the back washing process ( S52). That is, the process proceeds to step 31 shown in FIG. 5 and the backwashing steps (S31) to (S40) are performed. For example, when the predetermined time T is set to 24 hours, backwashing is performed every 24 hours.

  If the pressure sensor 11 detects that the inside of the filtration chamber 4 has reached a predetermined pressure before the predetermined time T has elapsed (between the previous backwashing process and the subsequent backwashing process) (S50), the number of times is counted. (S53). When the count reaches the set number (S54), abnormal value control such as interlock control is performed (S55). Thus, after the count reaches a predetermined number, it can be determined that it is time to replace the filter medium. For example, when the set number of times is set to 1, the abnormal value control is performed by one count.

  In the present embodiment, when the raw water on-off valve 61 is opened / closed, the control unit B controls the operation / stop of the pump P, but is transmitted from the water amount detection unit 10. Based on the signal, the control unit B may control the increase or decrease in the pumping amount of the pump P. In addition, increase / decrease in the pumping amount of the pump P can be easily performed by using an inverter etc., for example.

  The filtration device 1 of the present invention is not limited to the above embodiment. For example, as shown in FIG. 8A, the filtering device 1 may be of an overflow type. That is, the filtration device 1 does not include the treated water supply pipe 7 and the treated water on-off valve 71 for supplying treated water from the lower filtration chamber 42, and employs the overflow pipe 31 as the treated water supply pipe. The water amount detection unit 10 includes a low water level detection unit 10L.

  As shown in FIG. 8B, the filtration device 1 is of a pumping type. That is, the inside of the filtration tank 2 is sealed, and the treated water supply pipe 7 </ b> A is connected to the upper surface or upper side surface of the filtration tank 2 so as to communicate with the water storage chamber 3. The water amount detection unit 10 includes a low water level detection unit 10L.

  Moreover, although the thing provided with the water storage chamber 3 which stores treated water as the filtration tank 2 was illustrated, the filtration tank 2 is not provided with the water storage chamber 3, but the tank which stores backwash water is provided via piping. It may be configured to be connected.

DESCRIPTION OF SYMBOLS 1 Filtration apparatus 2 Filtration tank 21 Bulkhead 3 Water storage chamber 4 Filtration chamber 41 Upper filtration chamber 42 Lower filtration chamber 5 Filter medium 6 Raw water intake pipe 61 Raw water on-off valve 7 Treated water supply pipe 71 Treated water on-off valve 8 Collecting pipe 9 Backwash water drainage Pipe 91 Backwash on-off valve 10 Water volume detection unit 11 Pressure detection unit 11a First pressure sensor 11b Second pressure sensor A Filtration device body B Control unit C External operation panel P Pump P1 Cleaning start pressure P2 Abnormal pressure T Predetermined time

Claims (2)

A filtration tank having a filtration chamber;
A filter bed that divides the filtration chamber into an upper filtration chamber on the upper side and a lower filtration chamber on the lower side;
A filter medium layer composed of a filter medium provided on the upper surface of the filter bed,
Water filtered through the raw water introduced into the upper filtration chamber through the filter medium is introduced into the lower filtration chamber and discharged from the filtration tank,
In the filtration device that guides the water in the lower filtration chamber to the upper filtration chamber opposite to the time of the filtration to wash the filter medium and discharges the washed water from the filtration tank,
A pressure detection unit for detecting the internal pressure of the upper filtration chamber, a raw water opening / closing valve for introducing raw water into the upper filtration chamber by being opened, and a backwash start control or an abnormal value based on a signal from the pressure detection unit A control unit that performs control,
The pressure detection unit includes a first pressure sensor that detects a predetermined pressure, and a second pressure sensor that detects an abnormal pressure higher than the predetermined pressure ,
The control unit can determine whether another filtration tank is backwashing,
When the first pressure sensor detects the predetermined pressure and the second pressure sensor does not detect the abnormal pressure, if the other filtration tank is backwashed, the other filtration tank Until the backwashing of the filter medium is finished,
When the first pressure sensor detects the predetermined pressure and the second pressure sensor detects the abnormal pressure, if the other filtration tank is backwashing, the abnormal value control is performed. The filtration apparatus is characterized in that the raw water on-off valve is closed and the back filtration of the filter medium is waited until the back washing of the other filtration tank is completed . The filtration device according to claim 1 ,
At least one of the first pressure sensor and the second pressure sensor is a semiconductor pressure gauge.

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