JP2005288311A - Strainer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a strainer which facilitates back washing of whole of a filter element, permits continuous filtration operation and is capable of performing the manufacturing assembly by using low-cost constitutional components. <P>SOLUTION: A medium filtration passage 21 formed in a container 25 is divided into an upstream side passage 21a and a downstream side passage 21b across the filter element 26, an opening/closing switching valve 27 is disposed on an inlet pipe 23 of the upstream side passage 21a and an opening/closing blow valve 29 is disposed on a blow pipe 28 for discharging material to be filtered of the same upstream side passage 21a. The medium filtration passage 21 and a medium filtration passage 22 having the similar structure are communicated with common medium supply pipe 31 and medium collection pipe 32 in parallel, medium is allowed to flow backward from the downstream side passage 21b to the upstream side passage 21a by selectively closing one side switching valve 27 and opening the blow valve 29 and, thereby, the filter element 26 is subjected to back washing. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a strainer that removes solid matter (subject to be filtered) contained in a medium such as seawater or fresh water by filtering with a filter element.

  In the case of a plate heat exchanger using seawater as a cooling medium, marine organisms such as shellfish and solids such as wood chips contained in the seawater are removed by a strainer, and seawater is taken as a cooling medium for the heat exchanger. This strainer passes the seawater through the filter element in a predetermined forward direction to filter solids, and when the filter element is clogged with solids and the filtration capacity is reduced, the seawater is passed through the filter element in the forward direction. A device having a reverse flow cleaning (back cleaning) function of flowing in the reverse direction to wash off solid matter adhering to the filter element is known (for example, see Patent Document 1).

  A strainer having a backwashing function will be described with reference to FIGS. The strainer 1 shown in FIG. 3A is a medium filtration flow in which a seawater medium flows from the inlet pipe 3 toward the outlet pipe 4 inside a cylindrical container 2 having an inlet pipe 3 and an outlet pipe 4 on both the left and right sides. A path 5 is formed. A cylindrical filtration element 6 is installed concentrically in the container 2. In FIG. 3A of the filter element 6, the right side opening communicates with the inlet pipe 3, the filtration outlet discharge blow pipe 7 is connected to the left side opening, and the pipe open / close blow valve 8 is installed in the blow pipe 7. The The blow tube 7 is led out through the bottom of the container 2. The medium filtration flow path 5 is divided into an upstream flow path 5a and a downstream flow path 5b by a medium flow with the filter element 6 as a boundary, and the inside of the filtration element 6 constituting a part of the upstream flow path 5a. The backwash switching valve 9 is disposed in a substantially central portion of the container so as to be opened and closed in the left-right direction, and a motor 10 for opening and closing the backwash switching valve 9 is installed outside the container 2. An injection nozzle 11 is installed in the inlet pipe 3 toward the inner periphery of the filter element 6.

  FIG. 3A shows a state during the medium filtering operation. With the backwash switching valve 9 opened and the blow valve 8 closed, the medium (seawater) that has flowed into the medium filtration channel 5 from the inlet pipe 3 passes from the inner periphery to the outer periphery of the filter element 6 and is filtered. Then, the filtered solid matter adheres to the inner periphery of the filter element 6. The medium that has passed through the filter element 6 enters the downstream flow path 5b, and is sent out as a cooling medium from the outlet pipe 4 to a plate heat exchanger (not shown).

  When the medium filtering operation is continuously performed in the state of FIG. 3 (A) and the filter element 6 is clogged with solid matter accumulated on the inner periphery, the backwash switching valve 9 is turned on as shown in FIG. 3 (B). Close and open blow valve 8. Then, the medium that has flowed from the inlet pipe 3 into the right half element portion 6a in FIG. 3B of the filtration element 6 passes through the element portion 6a from the inner peripheral side to the outer peripheral side and flows into the downstream flow path 5b. , A part of which flows out to the outlet pipe 4, and another part moves the element portion 6b of the left half of the filter element 6 from the outer peripheral side to the inner peripheral side as indicated by the broken line arrow in FIG. The solid flow (subject to be filtered) adhering to the inner periphery of the filter element 6 is peeled off due to the reverse flow, and flows into the blow tube 7 together with the reverse flow medium to be discharged.

In the above-described backflow cleaning operation, there is no backflow of the medium in the element portion 6a on the right half of the filter element 6, and this element portion 6a cannot be backwashed, so the filtration function of the strainer 1 is lowered. In order to prevent this functional deterioration, the injection nozzle 11 is installed in the inlet pipe 3. 3B, the fluid in the cylindrical container 2 is discharged, the backwash switching valve 9 is opened, and the medium is moved from the injection nozzle 11 toward the entire inner periphery of the filter element 6 at high speed. Spray. By this medium jetting, the solid matter remaining on the inner periphery of the filter element 6 without being backwashed is peeled off and discharged from the blow tube 7 together with the jetted medium.
JP-A-11-90125 (FIGS. 1 and 4)

  The strainer having the backwashing function as described above is a complicated structure that is difficult to manufacture and assemble, because the backwash switching valve installed in the filter element is designed for the specific filter element, and the manufacturing cost is high. The strainer is expensive. In addition, since an injection nozzle for cleaning the entire filter element is incorporated, a high-pressure pipe and a high-pressure pump for supplying a medium to the injection nozzle at a high pressure are required, which increases the manufacturing cost of the strainer. Further, in order to use the injection nozzle, it is necessary to temporarily interrupt the medium filtering operation and discharge the fluid in the cylindrical container to the outside, and there is a problem that the medium filtering operation cannot always be performed.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a strainer that facilitates back-flow cleaning of the entire filtration element, enables continuous medium filtration operation, and can be manufactured and assembled at low cost. .

  The present invention relates to a strainer having a medium filtration flow path that filters a medium flowing from an inlet pipe into an upstream flow path with a filter element and flows from the downstream flow path to the outlet pipe, and is used for opening and closing the inlet disposed in the inlet pipe. Provided with a switching valve and a blow valve for discharging an object to be filtered disposed in the upstream flow path, the downstream flow path is determined by a medium pressure difference between the downstream flow path and the upstream flow path generated by closing the switching valve and opening the blow valve. Then, the filter element is back-washed by allowing the medium to flow back through the filter element to the upstream flow path.

  Here, as the medium, seawater or fresh water liquid used in a heat exchanger, a sprinkler, or the like can be applied. As the filtration element for removing the object to be filtered contained in this medium, for example, a metal mesh such as a bowl or cylinder can be applied. This filtration element is arranged in the medium filtration flow path, and the medium filtration flow path is divided into a flow path on the upstream side and a flow path on the downstream side with respect to the medium flow with the filter element as a boundary, and an inlet pipe is provided in the upstream flow path. The outlet pipe is connected to the downstream flow path, the fluid flows from the inlet pipe into the medium filtration flow path, passes through the entire filter element, and is filtered, and the filtered medium flows out from the outlet pipe. Two types of valves are provided to open and close the inlet pipe with the switching valve, and open and close the blow pipe for discharging the filtration object connected to the bottom of the upstream flow path with the blow valve. Then, the medium is flowed in the forward direction through the medium filtration flow path to perform the medium filtration operation, the switching valve is closed, the blow valve is opened, the medium is caused to flow back to the filter element, and the backwashing operation of the filter element is performed. The object to be filtered (solid matter) peeled off from the filter element by the backwashing is discharged to the outside through the blow valve in the open state together with the backflowed medium. Since the medium flowing back through the filter element is performed in the forward direction and the reverse direction in which the medium passes through the entire filter element during the medium filtering operation, the entire filter element is flowed back, and the backwashing can be performed over the entire filter element. In addition, as the switching valve for opening and closing the inlet pipe, an inexpensive commercially available general-purpose valve used for general-purpose size piping can be applied. Similarly, an inexpensive general-purpose valve can be applied to the blow valve.

  In the present invention, a pressure sensor that detects a medium pressure difference between the upstream flow path and the downstream flow path can be provided in the medium filtration flow path.

  The medium filtration operation for flowing the medium in the forward direction through the medium filtration flow path and the backflow washing operation for washing the filter element by causing the medium to flow backward are manually switched at any time based on the experience of the worker, or manually performed periodically. If the medium pressure difference between the upstream flow path and the downstream flow path is detected and displayed by the pressure sensor at the time of the operation switching, the operator can determine the operation switching timing by viewing the display. It is possible to always switch appropriately. Further, by using the detection signal of the pressure sensor, appropriate switching between the medium filtration operation and the backwashing operation can be automatically performed.

  Further, in the present invention, a plurality of medium filtration channels each equipped with a set of an inlet tube, an outlet tube, a filtration element, a blow valve, and the like, and a switching valve is connected to each of the inlet tubes of the plurality of medium filtration channels. A common medium supply pipe that communicates with each other and a common medium collecting pipe that communicates with each of the outlet pipes of the plurality of medium flow paths can be provided.

  This structure is a composite strainer structure in which a plurality of strainers are connected in parallel by a medium supply pipe and a medium collecting pipe, and the number of strainers connected in parallel can be two or more. To do. The pair of strainers can be arranged in a line by directly connecting the respective outlet pipes, or in parallel in the left and right direction or in parallel in the vertical direction. Further, each of the plurality of medium filtration channels opens a corresponding switching valve, closes the blow valve, and performs a medium filtering operation in which the medium flows in the forward direction from the upstream channel to the downstream channel, and the corresponding switching valve. One of the back-flow cleaning operation that closes the valve and opens the blow valve, and the operation that stops the switching valve and blow valve that correspond to each other are performed. In this case, when a plurality of medium filtration channels are divided into a group for medium filtration operation and a group for backflow cleaning operation, and each of them is operated simultaneously, a part of the medium in the outlet pipe of the medium filtration passage for medium filtration operation is backwashed. It is used as a backflow medium for the outlet pipe of the medium filtration passage to be operated, and the medium strainer system and the backwashing operation are performed simultaneously and continuously as the entire composite strainer system.

  Further, in the present invention, the medium collecting pipe is communicated with an external medium using device so that the medium can flow back, and the medium is returned from the medium using device to the medium filtration passage for performing the reverse flow cleaning operation, thereby continuing the back washing operation. it can. In this case, a plate heat exchanger using seawater as a cooling medium can be applied to the medium using device.

  According to the strainer of the present invention, the outlet valve switching valve in the upstream channel of the medium filtration channel is closed, the blow valve in the same upstream channel is opened, and the upstream channel and the downstream channel are opened. Since the fluid in the downstream flow path is caused to flow backward to the upstream flow path by the fluid pressure difference and the filtration element is backwashed, the filtration element can be efficiently backwashed with the backflow medium. In addition, by connecting multiple media filtration channels in parallel and selectively switching between media filtration operation and backwashing operation, continuous media filtration operation can be continued, and plate heat exchange It is possible to provide a strainer with excellent practical value that can continuously feed the filtered medium to a vessel. Furthermore, as the switching valve and the blow valve arranged in the fluid filtration channel, an inexpensive commercially available general-purpose valve can be used, and it becomes easy to reduce the manufacturing cost of the strainer.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  The strainer shown in FIGS. 1 (A) and 1 (B) has two first medium filtration channels 21 and second medium filtration channels 22 connected in parallel, and both medium filtration channels 21 and 22 are arranged in parallel. A medium supply pipe 31 and a medium collecting pipe 32 communicating with each other.

  The first medium filtration channel 21 is formed inside a cylindrical container 25 having an inlet pipe 23 and an outlet pipe 24, and a cylindrical filtration element 26 is installed concentrically inside the container 25. One opening end of the filter element 26 communicates with the inlet pipe 23 and is fixed to the container 25, and a flange extending radially outward from the other opening is fixed to the entire inner surface of the container 25. 25 is divided into two flow paths 21a and 21b with the filter element 26 as a boundary. One flow path 21 a is a flow path on the upstream side in the medium flow direction until the medium flowing in from the inlet pipe 23 passes through the entire filtration element 26, and the other flow path 21 b passes through the entire filtration element 26. Hereinafter, the two flow paths 21a and 21b are referred to as an upstream flow path 21a and a downstream flow path 21b as necessary.

  Further, the first medium filtration channel 21 includes a pressure sensor 30 for detecting a pressure (water pressure) difference between the medium in the upstream channel 21a and the downstream channel 21b when necessary. It is installed between 21a and 21b. A switching valve 27 for opening and closing is installed in a part of the inlet pipe 23, and a blow valve 29 for switching the filtered object discharge is installed in a blown pipe 28 for discharging the filtered substance connected to the bottom of the upstream passage 21a. The pressure sensor 30 may be installed between the medium supply pipe 31 and the external communication pipe 33 connected to the medium collecting pipe 32 as in the pressure sensor 30 ′ of FIG.

  The second medium filtration flow path 22 may have the same structure as the first medium filtration flow path 21, and the same parts as the first medium filtration flow path 21 are denoted by the same reference numerals and description thereof is omitted. Further, the second medium filtration channel 22 is formed by the filtration element 26 in the same manner as the first medium filtration channel 21 is divided into the upstream channel 21a and the downstream channel 21b with the filtration element 26 as a boundary. It is divided into an upstream channel 22a and a downstream channel 22b.

  One common medium supply pipe 31 is used for both medium filtration flow paths 21 and 22, and is connected upstream of the switching valves 27 and 27 of the inlet pipes 23 and 23 of both medium filtration flow paths 21 and 22, The same medium is supplied to the inlet pipes 23 and 23 of both medium filtration channels 21 and 22. The medium collecting pipe 32 is also one common to both the medium filtration channels 21, 22, and both ends communicate with the outlet pipes 24, 24 of both the medium filtration channels 21, 22. The filtered media flowing out from the outlet pipes 24 and 24 are merged and sent to the external communication pipe 33 connected to the center. The external communication pipe 33 communicates with an external medium using device, for example, a plate heat exchanger 40, and the medium from the outlet pipes 24 and 24 of both medium filtration channels 21 and 22 is used as a cooling medium in the heat exchanger 40. Send it out.

  FIG. 1A shows a state in which the switching valves 27 and 27 of both the medium filtration channels 21 and 22 are opened, the blow valves 29 and 29 are closed, and both the medium filtration channels 21 and 22 are operated as a medium filtration. Is shown. In the first medium filtration channel 21, the medium flowing into the inlet tube 23 from the medium supply pipe 31 flows through the upstream channel 21 a and passes through the filtration element 26 as a whole, and the solid matter contained in the medium is filtered. The whole is filtered. The medium that has passed through the filtration element 26 flows into the outlet pipe 24 from the downstream side flow path 21b, enters the medium collecting pipe 32, merges with the medium from the second medium filtration flow path 22, and passes through the external communication pipe 33 to plate-type heat. It is sent to the exchanger 40 and used as a cooling medium in the heat exchanger 40. A similar medium filtration operation is performed simultaneously in the second medium filtration flow path 22.

  When the cooling medium sent to the plate heat exchanger 40 is seawater, solid matter of marine organisms such as shellfish contained in the seawater can be filtered and removed by the both medium filtration channels 21 and 22. For example, the flow path interval through which the cooling medium of the plate heat exchanger 40 flows is approximately 3 to 10 mm, and the size of solid matter such as marine organisms that can flow into the heat exchanger cannot be more than the flow path interval. Therefore, the filter size (opening size) of the filtration elements 26 and 26 of both the medium filtration channels 21 and 22 is desirably 2 to 8 mm which is smaller than the channel interval of the heat exchanger 40.

  By performing the medium filtration operation on both medium filtration channels 21 and 22 simultaneously, a sufficient amount of the filtered cooling medium is continuously sent to the heat exchanger 40, and the heat exchanger 40 is continuously operated. During this continuous operation, the pressure difference between the fluid pressures in the medium filtration channels 21 and 22 is detected by the pressure sensors 30 and 30, respectively. Further, for example, when one of the first medium filtration channels 21 is manually or automatically switched from the medium filtration operation to the backwashing operation as necessary during the continuous operation, the following operation is performed.

  As shown in FIG. 1B, the switching valve 27 of the first medium filtration channel 21 to be switched is closed and the blow valve 29 is opened. Then, the medium inflow to the inlet pipe 23 is blocked, and the medium from the medium supply pipe 31 flows only toward the second medium filtration flow path 22, and the medium filtration operation in the second medium filtration flow path 22 continues. Done. In the first medium filtration flow path 21, when the blow valve 29 in the upstream flow path 21 a is opened, the medium filtration fluid pressure by the second medium filtration flow path 22 is increased between the external communication pipe 33 and the first medium filtration flow path 21. Since it acts on the outlet pipe 24 in the downstream channel 21b, the fluid pressure of the downstream channel 21b is higher than that of the upstream channel 21a. Due to the fluid pressure difference between the two flow paths 21a and 21b, the fluid in the downstream flow path 21b flows into the upstream flow path 21a as shown by the broken line arrow in FIG. Reversely flows through the filter element 26 to peel off the solid matter adhering to the filter element 26. The solid matter separated from the filter element 26 flows into the blow pipe 28 together with the medium flowing backward through the filter element 26 and is discharged. This backflow cleaning operation is continuously performed together with the medium filtration operation of the second medium filtration flow path 22. A part of the filtered medium from the second medium filtering channel 22 that performs the medium filtering operation is used as the medium that flows back to the first medium filtering channel 21.

  Since the medium flows back through the filtration element 26 of the first medium filtration channel 21, the entire medium is efficiently backwashed collectively. Switching from the medium filtration operation to the backwashing operation in the first medium filtration channel 21 can be performed manually or automatically at an appropriate timing by using the detection signal of the pressure sensor 30. In addition, when the pressure sensor 30 'shown in FIG. 1B is used, the fluid differential pressure before and after the medium filtration process can be checked at once, and various conditions such as the backflow cleaning interval can be planned.

  When the first medium filtration channel 21 is switched from the backwash operation to the medium filtration operation, the blow valve 29 in the open state is closed and the switch valve 27 in the closed state is fully opened. Switching between the backwashing operation and the medium filtration operation in the second medium filtration channel 22 is also performed in the same manner as the first medium filtration channel 21.

  The operation of both the medium filtration channels 21 and 22 is stopped by closing both the switching valves 27 and 27. Further, the first medium filtration flow path 21 and the second medium filtration flow path 22 are alternately subjected to medium filtration operation, and the cooling medium is alternately and continuously supplied from both medium filtration flow paths 21 and 22 to the heat exchanger 40. I can do this. The switching valve 27 that switches between the medium filtration operation, the reverse flow operation, and the operation stop of the both medium filtration flow paths 21 and 22 is a commercially available general purpose one that opens and closes a general purpose pipe such as the inlet pipe 23. The same applies to the blow valve 29.

  The pair of medium filtration channels 21 and 22 shown in FIGS. 1A and 1B have a parallel arrangement structure in which the inlet pipes 23 and 23 are directly connected to each other. The arrangement state of the channels 21 and 22 is arbitrary, and for example, as shown in FIG. 2, the pair of medium filtration channels 21 and 22 can be arranged left and right or up and down. In the case of the arrangement shown in FIG. 2, since the containers forming both medium filtration channels approach, both the blow pipes 28 and 28 may be connected to one discharge pipe 28 '. In the above embodiment, a strainer is configured by communicating a pair of medium filtration channels, but it is also possible to communicate two or more medium filtration channels in parallel, and a single medium. It is also possible to configure a strainer with a filtration channel. In the case of using a single medium filtration channel, the medium is communicated with an external medium using device so that the medium can flow backward from the outlet pipe of the medium filtration channel if necessary.

  Furthermore, the strainer of the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

  The strainer of the present invention can be applied to a strainer other than the plate heat exchanger, for example, a strainer for filtering fresh water or groundwater from a river to a snow melting water sprinkler and sending it.

(A) is a flowchart at the time of the medium filtration operation which shows the outline | summary of the strainer which is embodiment of this invention, (B) is a flowchart at the time of backflow washing operation. It is a flowchart which shows other embodiment. (A) is a flowchart at the time of the medium filtration operation which shows the outline | summary of the conventional strainer, (B) is a flowchart at the time of backflow washing operation.

Explanation of symbols

21 (first) medium filtration flow path 21a upstream flow path 21b downstream flow path 22 (second) medium filtration flow path 22a upstream flow path 22b downstream flow path 23 inlet pipe 24 outlet pipe 25 container 26 filtration element 27 Switching valve 28 Blow pipe 29 Blow valve 30 Pressure sensor 30 'Pressure sensor 31 Medium supply pipe 32 Medium collecting pipe 33 External communication pipe 40 Medium use equipment, plate type heat exchanger

Claims (5)

In a strainer having a medium filtration flow path that filters the medium flowing into the upstream flow path from the inlet pipe through the filtration element and flows out from the downstream flow path to the outlet pipe,
The downstream flow path, which includes an inlet open / close switching valve disposed in the inlet pipe and a filtration object discharge blow valve disposed in the upstream flow path, and is generated by closing the switching valve and opening the blow valve And a reverse flow cleaning of the filtration element by causing the medium to flow backward from the downstream flow path through the filtration element to the upstream flow path due to a medium pressure difference between the upstream flow path and the upstream flow path.   The strainer according to claim 1, further comprising a pressure sensor that detects a medium pressure difference between the upstream flow path and the downstream flow path of the medium filtration flow path.   A plurality of medium filtration channels, a medium supply pipe communicating with each of inlet pipes of the plurality of medium filtration channels via a switching valve, and a medium collecting pipe communicating with each of the outlet pipes of the plurality of medium channels The strainer according to claim 1, comprising:   The strainer according to claim 3, wherein the medium collecting pipe communicates with an external medium using device so that the medium can flow back to the outlet pipe. The strainer according to claim 4, wherein the medium using device is a plate heat exchanger.