Automatic washing system for strainer for filtration

Abstract

To provide an automatic washing system and an automatic cleaning method for a strainer for filtration capable of always automatically washing a filtration element in a filtration treatment operation without discharging a liquid to the outside of a machine.SOLUTION: An automatic washing system comprises: a filter element 2 having a backwash function in a strainer body 1 having an inflow port into which a raw liquid flows and an outflow port from which a filtered liquid flows out; a backwash liquid discharge pipe 10 for discharging a backwash liquid containing sludge to a discharge port provided in the filter element 2; and a cyclone separator 20 connected to the backwash liquid discharge pipe 10 and configured to separate the sludge from the liquid; a suction pipe 25 for sucking and discharging the liquid, disposed above the cyclone separator 20; and an ejector 30 connected to a raw liquid supply pipe positioned in the vicinity of the inflow port and having a suction supply function. The automatic washing system is configured to form a circulation circuit in which the backwash liquid is sucked by the ejector 30 and circulates in the strainer body 1 without being discharged to an outside of the machine, and always exhibits the backwash function during operation of the strainer body 1.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a filtration strainer that filters water containing various solids and the like to be treated to remove the solids and the like, and more particularly to an automatic cleaning system and method for a filtration strainer that can reduce liquid loss in the raw liquid and can constantly perform filtration treatment and cleaning of the filtration strainer without intermittent operation. [Background technology]

[0002] In order to remove various foreign objects, solids, sludge, etc. contained in raw water (treated water, seawater, wastewater, water, etc.), a filtration strainer (filtration device) with a built-in screen (filtration element) with a certain mesh size is used as a prefilter.

[0003] This type of strainer has a filtration element installed inside the strainer body through which the water to be treated flows. This filtration element allows the water to pass through while capturing solid matter in the water to be treated, and filtered water that has been filtered by the filtration element is supplied to the downstream side of the strainer.

[0004] If the filtration process using the strainer continues, solid matter will adhere to and accumulate on the surface of the filtration element, causing the pressure inside the strainer body to increase and reducing the filtration capacity, so a cleaning process (maintenance work) must be carried out to remove the solid matter that has adhered to the surface of the filtration element.

[0005] In Patent Document 1, when the difference in pressure measured by a pressure gauge installed at the inlet and outlet of the strainer reaches a predetermined value or at predetermined intervals, the rotating shaft of the backwash mechanism is rotated via a drive source such as a motor to clean the filtration element.

[0006] In this device, in order to remove sludge that does not sink to the bottom of the equipment under its own weight, the sludge is sucked in by a suction pipe having a backwash scraper body on the inner periphery of the filter element and discharged outside the machine. During the cleaning operation, the drive unit is operated and the discharge valve is opened to the atmosphere, connecting the secondary side of the discharge pipe to the flow path of the rotating shaft. This allows atmospheric pressure to reach the backwash port of the backwash scraper body, creating a pressure difference inside the strainer body. As the rotating shaft rotates, suction is drawn through the suction portion of the wide surface of the scraper body, sucking in sludge adhering to the inner surface and filter holes of the filter element and cleaning the filter element. The sucked in sludge and other materials are then discharged outside the strainer together with the liquid through the discharge pipe. Next, the drain valve is opened to the atmosphere to generate a pressure difference, and the sludge that has sunk under its own weight and accumulated at the bottom is discharged outside the machine through a drain passage.

[0007] In this way, the filter element is opened to the atmosphere intermittently to perform a cleaning operation (discharging sludge from the discharge pipe by backwashing) and a discharge operation of sludge from the drain valve, thereby recovering the filtering ability of the filter element. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 7080465 Summary of the Invention [Problem to be solved by the invention]

[0009] Here, the solid matter contained in the raw water includes fine particles, and in order to remove fine particles of, for example, about 10 to 50 μm, it is necessary to use a screen (filter element) with fine openings.

[0010] However, this fine-mesh screen has the problem of clogging in a short time. Even if the clogging is cleared to restore the filtering capacity and the filtering operation is resumed, the filter holes of the filter element are soon clogged with fine particles, causing the internal pressure to rise. For this reason, in order to remove the fine particles, the filtering operation must be stopped and maintenance work must be frequently repeated, which not only makes the cleaning work more time-consuming, but also makes it impossible to perform continuous filtering, resulting in a poor operating rate.

[0011] As described above, in conventional devices, clogging occurs quickly when filtering fine particles, and it is necessary to frequently clean the filter elements to restore filtering capacity. This makes it difficult to perform stable, continuous filtering without intermittent operation.

[0012] In addition, the liquid discharged from the machine during the cleaning operation contains the undiluted product, and there is a need to reduce the amount of liquid wasted and increase the product yield. If the liquid discharged from the strainer is returned to the tank, there is also the problem that the concentration of solids and fine particles increases in the returned tank.

[0013] Therefore, there has been a demand for the development of a filtration device that does not require intermittent operation, but allows for constant automatic cleaning even during filtering, thereby maintaining stable filtering capacity and reducing liquid loss of the raw liquid.

[0014] The present invention was developed to solve the above-mentioned problems, and its purpose is to provide an automatic cleaning system and method for a filtration strainer that enables automatic cleaning of the filtration element at all times during filtration processing operation without discharging liquid outside the machine. [Means for solving the problem]

[0015] In order to achieve the above object, the invention of claim 1 is an automatic cleaning system for a filtration strainer, comprising a filtration element having a backwash function within a strainer body having an inlet through which raw liquid flows in and an outlet through which filtrate flows out, a backwash liquid discharge pipe for discharging backwash liquid containing sludge to an outlet provided in the filtration element, a cyclone separator connected to the backwash liquid discharge pipe for separating sludge and liquid, a suction pipe through which liquid is sucked in and discharged above the cyclone separator, and an ejector having a suction supply function connected to a raw liquid supply pipe located near the inlet, forming a circulation circuit in which the backwash liquid is sucked in by the ejector and circulated within the strainer body without being discharged outside the machine, and configured to constantly perform the backwash function while the strainer body is in operation.

[0016] The invention according to claim 2 is an automatic cleaning system for a filter strainer, in which a cylindrical filtering element is provided inside a cylindrical strainer body, a rotating shaft tube is constantly rotated inside the filtering element, and sludge clogged in the filtering element is scraped off and sucked up by a backwash scraper provided in the radial direction of the rotating shaft tube, and discharged from the backwash liquid discharge pipe, while the backwash liquid is circulated through a circulation circuit.

[0017] The invention according to claim 3 is an automatic cleaning system for a filtration strainer, which has a sludge pot or bag filter with an observation window for collecting sludge disposed below a cyclone separator.

[0018] The invention of claim 4 is an automatic cleaning method for a filtering strainer, comprising: a filtration step in which raw liquid is supplied through a raw liquid supply pipe, flows into the inlet of the strainer body, and is filtered by the filtering element in the strainer body; a backwash step in which the inner and outer periphery of the filtering element are backwashed simultaneously with the filtration step; a separation step in which the backwash liquid containing sludge after the backwash step is separated into sludge and liquid by a cyclone separator; and a suction supply step in which the liquid is sucked in by an ejector provided in the raw liquid supply pipe, and by circulating the separated liquid in the strainer body through suction supply, the backwash liquid is not discharged outside the machine, and the backwash step is simultaneously performed while the strainer body is in operation, thereby performing circulation operation. Effect of the Invention

[0019] According to the invention of claim 1, the backwash liquid discharge pipe provided at the discharge port for discharging the backwash liquid containing sludge used to clean the filter element is connected to the cyclone separator, and a suction pipe for sucking the separated backwash liquid is provided above the cyclone separator, and this liquid is caused to flow into the raw liquid supply pipe by an ejector and supplied to the strainer body, forming a circulation circuit in which the backwash liquid circulates within the strainer body. Therefore, only the backwash liquid separated by the cyclone separator circulates through this circulation circuit at all times, and is not discharged outside the machine.

[0020] Therefore, by circulating the backwash liquid in the circulation circuit without discarding it, the loss of the backwash liquid discharged outside the machine can be reduced, and as a result, the loss of the liquid contained in the raw liquid can be reduced and the recovery amount and yield of the filtrate can be improved. In addition, since the liquid containing sludge is not returned to the tank that stores the raw liquid, there is no problem of the concentration of sludge and foreign matter increasing in the raw liquid tank.

[0021] In addition, the backwash liquid constantly circulates within the circulation circuit when the strainer body is in operation (filtering operation), so the filter element within the strainer body can be automatically cleaned. Therefore, even if the sludge in the raw liquid contains fine particles, the backwash function is exerted during filtering operation, eliminating clogging of the filter element, and the filtering capacity is not reduced, allowing continuous operation with stable filtering performance, and no maintenance work is required, improving the value of the device.

[0022] In addition, since the liquid is supplied to the strainer body at an increased flow rate by an ejector installed in the raw liquid supply pipe near the inlet of the strainer body, a swirling flow is easily generated within the strainer body, thereby improving filtration performance and cleaning performance (backwash function).

[0023] According to the invention of claim 2, within the strainer body, for example, the rotating shaft tube in the filtration element is constantly rotated without power by a rotating water wheel provided in the strainer body due to the driving force of a motor or the water flow of the raw liquid flowing into the strainer body, and the backwash scraper formed in the radial direction of the rotating shaft tube operates along the inner surface of the filtration element, so that the backwash scraper scrapes off sludge that has clogged the filter holes of the filtration element, sucks it up, and discharges it from the backwash liquid discharge pipe, thereby improving the cleaning efficiency. In addition, because the rotating shaft tube rotates due to the water flow, the filtration element can be constantly cleaned without the need for a power source (motor, handle, etc.) to operate the backwash function, significantly reducing the cost of the equipment.

[0024] According to the invention of claim 3, a sludge pot or bag filter with a viewing window for collecting sludge is provided below the cyclone separator, so that the backwash liquid containing sludge is separated into sludge and liquid by the cyclone separator, and the sludge discharged from the cyclone separator can be collected by the sludge pot or bag filter, so that the sludge can be collected without stopping the filtration operation.

[0025] According to the invention of claim 4, the raw liquid is supplied through the raw liquid supply pipe and flows into the strainer body, and the raw liquid is filtered by the filter element in the strainer body in a filtration step, and a backwash step is performed to wash the filter element with a water flow. Next, the backwash liquid containing sludge after the backwash step is sent to a cyclone separator to separate the sludge and liquid in a separation step, and a suction supply step is performed in which only the separated liquid is sucked in by an ejector provided in the raw liquid supply pipe.

[0026] Therefore, only the separated liquid is sucked into the ejector and supplied to the strainer body again, so the backwash liquid is reused and circulated, and is not discharged outside the machine. This reduces the amount of backwash liquid to be discarded, reduces the loss of liquid contained in the raw liquid, and improves the recovery amount and yield of the filtrate. In addition, since the liquid containing sludge is not returned to the tank that stores the raw liquid, there is no problem of the concentration of sludge and foreign matter increasing in the raw liquid tank.

[0027] In addition, since the filtration step and the backwash step are performed simultaneously within the strainer body while the backwash liquid is circulating, clogging of the filtration element within the strainer body during the filtration step is suppressed, making automatic cleaning possible and eliminating the need for intermittent operation to clean the filtration element. Since the filtering capacity during the filtering operation is stable, it is also suitable for filtering processes that remove sludge of fine particles. [Brief description of the drawings]

[0028] [Figure 1] FIG. 2 is a schematic circuit diagram of an automatic cleaning system for a filtration strainer according to the present invention. [Diagram 2] 1 is a schematic cross-sectional view showing an automatic cleaning system for a filtration strainer according to a first embodiment of the present invention. [Diagram 3] FIG. 11 is a schematic cross-sectional view showing an automatic cleaning system for a filtration strainer according to a second embodiment. [Figure 4] FIG. 1 is a schematic cross-sectional view showing an example in which the present invention is applied to a Y-type strainer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the automatic cleaning system for a filtration strainer and the automatic cleaning method for a filtration strainer according to the present invention will be described in detail with reference to the drawings.

[0030] Fig. 1 is a schematic circuit diagram of an automatic cleaning system for a filtration strainer in the present invention, and Fig. 2 is a schematic cross-sectional view showing an automatic cleaning system for a filtration strainer in a first embodiment of the present invention.

[0031] As shown in Figures 1 and 2, the automatic cleaning system for a filtration strainer according to the present invention comprises a filtration element 2 with a backwash function within a strainer body 1 having an inlet 3 through which raw liquid flows in and an outlet 4 through which filtrate flows out, a backwash liquid discharge pipe 10 for discharging backwash liquid containing sludge to an outlet 14 provided in the filtration element 2, a cyclone separator 20 connected to the backwash liquid discharge pipe 10 for separating sludge and liquid, a suction pipe 25 through which liquid is sucked and discharged above the cyclone separator 20, and an ejector 30 with a suction supply function connected to a raw liquid supply pipe 26 located in the vicinity of the inlet 3. In this manner, a circulation circuit is formed between the ejector 30, the strainer body 1, and the cyclone separator 20 (hereinafter, abbreviated as "cyclone"), through which the backwash liquid circulates.

[0032] The automatic cleaning system is an automatic cleaning system that combines an ejector, a cyclone, and a strainer to form a circulation circuit, allowing the backwash liquid to flow within the circulation circuit, making it possible to automatically clean the filtration element at all times without discharging the backwash liquid.

[0033] <Strainer> The cylindrical strainer body 1 has an inlet 3 through which the raw liquid flows in, a filtration chamber 12 that houses a roughly cylindrical filtration element 2 that filters the raw liquid that flows in from the inlet 3, an outlet 4 through which the filtrate (filtered water) filtered by the filtration element 2 flows out of the strainer body 1, a discharge chamber 13 provided at the bottom of the filtration chamber 12, a drain piping 9 connected to the discharge chamber 13, and a backwash liquid discharge pipe 10 connected to the discharge port 14. The filter element 2 of the strainer body 1 is provided with a backwash scraper 5 and a suction nozzle 6 that perform a backwash function.

[0034] <Filter element> The filtration element 2 is provided in a vertical cylindrical shape with openings at the top and bottom, is fixed and held by a holding member 7, and is built into the filtration chamber 12 of the strainer body 1. The filtration element 2 is configured to pass the raw liquid that flows into the inside from the opening at the top toward the filtration chamber 12 on the outside, removing sludge (particles, solids, foreign matter, etc.) in the raw liquid. In this manner, in this embodiment, a filtration strainer is configured in which the fluid flows from the inside to the outside of the filtration element for filtering.

[0035] In this example, a fine mesh metal filter (sintered filter) is used as the filtration element to enable removal of fine solid matter (particles). Since fine mesh metal filters (filtration filters) are prone to tearing, multiple filters such as reinforcing layers, protective layers, and dispersion layers are laminated in addition to the filtration filter to provide a desired strength and durability. For example, when removing fine particles of about 10 to 50 μm contained in the raw solution, a filtration filter with mesh size of about 10 to 50 μm can be used, but can be appropriately selected depending on the object to be filtered and the purpose.

[0036] <Backwashing means> A backwash scraper 5 for removing clogging of the filtration element 2 is provided on the inner peripheral side of the filtration element 2. A plurality of backwash scrapers 5 are provided in the radial direction of the rotary shaft tube 8 and are configured to be rotatable integrally with the rotary shaft tube 8. A suction nozzle 6 extends from the rotary shaft tube 8 toward the inner peripheral surface of the filtration element 2 and is provided so as to be able to suck in sludge that has clogged and accumulated in the filter holes of the filtration element 2 and sludge that is floating in the air. In this example, the backwash scrapers 5 are installed above and below at intervals of 180 degrees, but they may also be installed at intervals of 90 degrees, and the number, positions, spacing, etc. can be set appropriately depending on the embodiment.

[0037] The suction nozzle 6 is connected to an inlet passage 8a formed in the rotating shaft tube 8, and the backwash port of the backwash scraper 5 connected to the suction nozzle 6 is arranged to face the inner surface of the filter element 2, so that the sludge sucked into the suction nozzle 6 from this backwash port flows into the inlet passage 8a together with the liquid.

[0038] A coil spring is attached inside the suction nozzle 6, and the resilient force of the spring urges the backwash scraper 5 toward the filter element 2. The urging of the backwash scraper 5 by the spring presses the backwash scraper 5 against the inner surface of the filter element 2 so that no gap is created between the backwash scraper 5 and the inner surface of the filter element 2.

[0039] In this example, the backwash scraper provided inside the filter element has been described, but the invention also includes a case where a scraper is provided outside the element, or where backwash is performed by a swirling flow inside the strainer body.

[0040] The backwash scraper 5 has a wide surface, and a backwash port having a predetermined length is provided on this wide surface, and this backwash port is formed to be narrow. A flow path from this backwash port to the suction nozzle 6 is provided in a wide angle shape, and the backwash port increases the backwash flow rate to improve the cleaning efficiency of the filter element 2. The backwash scraper 5 may be configured integrally with a scraping part and a cleaning brush or may be configured separately. The scraping part and the cleaning brush scrape off sludge that has clogged the filter holes of the filter element 2, and the sludge is sucked up by the suction nozzle 6 and the backwash liquid containing the sludge is discharged from the backwash liquid discharge pipe 10.

[0041] <Rotor shaft tube> The rotating shaft tube 8 is rotatably provided within the filter element 2, and during filtering operation, the rotating shaft tube within the filter element is constantly rotatable by the water flow within the strainer body 1. The rotating shaft tube 8 is also connected to a connecting member 11 via a transmission fitting, and the connecting member 11 is provided with a speed reducing mechanism (not shown) or the like, making the rotation speed of the rotating shaft tube 8 adjustable, and making the rotation speed of the backwash scraper 5 provided on the rotating shaft tube 8 adjustable. The connecting member 11 may be configured to be connected to a drive unit 17, or may be connected to a drive machine such as a motor so that an external driving force is used as a power source to rotate the rotating shaft tube 8 and perform the backwash function. Also, a manual device such as a handle may be attached to the connecting member 11 so that the handle can be rotated to manually perform the backwash function and perform maintenance work as necessary.

[0042] As shown in a second embodiment in FIG. 3, which will be described later, a water wheel 18 may be provided in the strainer body 1 without being connected to a drive unit, so that the rotating shaft tube in the filter element is always rotatable.

[0043] The rotating shaft tube 8 is provided with an inlet passage 8a through which the backwash liquid containing sludge sucked in by the suction nozzle 6 flows. This inlet passage 8a is connected to an outlet 14 below the strainer body 1, and the backwash liquid discharged from the outlet 14 to the outside of the strainer body 1 flows into the backwash liquid discharge pipe 10.

[0044] <Drain piping> The drain pipe 9 is arranged to extend below the strainer body 1 and is connected to a discharge chamber 13 at the bottom of the strainer body 1. A valve 15 provided on the drain pipe 9 is controlled to open and close so that sludge accumulated at the bottom can be discharged.

[0045] <Backwash liquid discharge pipe> One end of the backwash liquid discharge pipe 10 communicates with the inlet passage 8a of the rotating shaft pipe 8, and is configured so that the backwash liquid containing sludge from the filter element 2 flows toward the discharge port 14. The other end of the backwash liquid discharge pipe 10 is connected to the inlet 21 of the cyclone 20, and therefore, the backwash liquid flowing through the backwash liquid discharge pipe 10 is discharged from the strainer body 1, and then the backwash liquid containing sludge (solids) is sent to the cyclone 20. In addition, the backwash liquid discharge pipe 10 is provided with a valve 16 which can be manually or automatically opened and closed to control communication with the cyclone 20. In order to increase the capacity of supplying water to the cyclone 20, a water supply pump, an ejector, etc. may be provided.

[0046] <Cyclone separator> The inlet 21 of the cyclone 20 is provided so that the backwash liquid containing sludge sent from the strainer body 1 can flow in. The liquid outlet 22 at the top of the cyclone 20 is connected to a suction pipe 25 and is provided so as to communicate with the suction port 35 of the ejector 30, and the solid outlet 23 at the bottom of the cyclone 20 is configured to be connected to a sludge pod 40 via a valve 24.

[0047] The backwash liquid containing sludge that flows into cyclone 20 has its solid components (sludge) collected toward the outer periphery of the inverted cone-shaped (cone-like) cone due to the centrifugal force, while the liquid components of the backwash liquid flow toward the inner cylindrical part, where the solid and liquid components are separated. The separated liquid backwash liquid flows out from the liquid outlet 22, and the separated solids (sludge) flow out from the solid outlet 23.

[0048] The backwash liquid separated in the cyclone 20 and flowing out from the liquid outlet 22 flows into the flow path in the raw liquid supply pipe 26 through the suction port 35 of the ejector 30, and is supplied to the inlet 3 of the strainer body 1 via the ejector 30.

[0049] Moreover, the sludge separated in the cyclone 20 flows out from the solid outlet 23 and accumulates in the sludge pod 40. In this example, the sludge pod 40 has an observation window 40a, which makes it possible to check the state of the sludge accumulating in the sludge pod 40, and allows the sludge to be collected at a predetermined timing without stopping the filtering operation.

[0050] In addition, a valve 27 is provided below the sludge pod and is configured to be able to recover sludge (solids) by controlling its opening and closing. By configuring the valve 27 as an automatic valve, it is possible to automatically recover the sludge (solids) by controlling its opening and closing at a predetermined time or interval. In addition, a bag filter may be placed at the solid outlet 23 below the cyclone 20 to enable sludge recovery.

[0051] <Ejector> The ejector 30 is provided with a nozzle section 31 and a diffuser section 32 in the ejector body. The ejector 30 is driven by the raw liquid flowing in from an inlet 33, and is disposed near the inlet 3 of the strainer body 1 of the raw liquid supply pipe 26 so that the fluid (liquid) sucked in from a suction port 35 can be pressurized within the ejector body and supplied at an increased flow rate.

[0052] The discharge port 34 of the ejector 30 is connected to the inlet 3 of the strainer body 1 , and the suction port 35 of the ejector 30 is connected to the liquid outlet 22 of the cyclone 20 via a suction pipe 25 . When the raw liquid is sent to the raw liquid supply pipe 26 by a pump (not shown) or the like provided on the inlet 33 side of the ejector 30, the nozzle section 31 sprays the liquid at high speed, and a low-pressure space is generated inside the ejector body. The backwash liquid is sucked in through the suction port 35 connected to the suction pipe 25 and flows into the raw liquid supply pipe 26. The liquid and the raw liquid are pressurized by the diffuser section 32 of the ejector 30 to increase the flow rate, and the raw liquid and the backwash liquid are then supplied to the inlet 3 of the strainer body 1.

[0053] In this way, a circulation circuit is formed between the strainer body 1, the cyclone 20, and the ejector 30, and when the strainer body 1 is operated to perform filtering, the backwash liquid constantly circulates within the circulation circuit, and is not discharged outside the machine.

[0054] <Actions and Effects> Next, the operation and effect of the automatic cleaning system for a filtration strainer of the present invention will be described.

[0055] By sending the raw liquid to the raw material supply pipe 26 by a pump or the like, the raw liquid flows into the inlet 33 of the ejector 30 and is discharged from the outlet 34 at an increased flow rate. The outlet 34 is connected to the inlet 3 of the strainer body 1, and the raw liquid is supplied into the strainer body 1, where a swirling flow is generated by the inflow of the fluid with a high flow rate.

[0056] The raw liquid flows in through an opening at the top of the filter element 2, and the raw liquid that passes through the filter element 2 passes through the filtration chamber 12, where sludge is removed, and the liquid is discharged as filtrate from the outlet 4 outside the strainer body 1, thereby supplying the filtrate and carrying out the filtering operation.

[0057] When the strainer body 1 is operated for filtering, part of the liquid in the strainer body 1 is sucked into the backwash nozzle 6 connected to the backwash scraper 5 and flows into the inlet passage 8a of the rotating shaft tube 8. The flow direction of this liquid is the same as the flow direction when cleaning the filtering element 2 in the strainer body 1, so it functions as a backwash liquid.

[0058] In other words, as the liquid flows in the direction of the backwash liquid within the strainer body 1, the sludge adhering to the filter holes and surfaces of the filter element 2 is also sucked into the suction nozzle 6, thereby providing a backwash function that unclogs the filter element 2.

[0059] In addition, the rotating shaft tube 8 is rotatably provided within the filter element 2, and during filtering operation it is constantly rotating due to the water flow within the strainer body 1. Therefore, the backwash scraper 5 provided on the rotating shaft tube 8 operates along the inner surface of the filter element 2 to scrape off sludge that has clogged the filter holes of the filter element 2 or adhered to the surface, and then sucks it up with the suction nozzle 6, thereby constantly performing the backwash function and eliminating clogging of the filter element 2.

[0060] In this way, a cleaning operation can be performed simultaneously with the filtering operation to remove clogging of the filtering element 2. Furthermore, during filtering operation, the backwash function can be performed without power by the water flow inside the strainer body 1, so no external power source is required to drive the backwash function, and the filtering element 2 can be cleaned automatically.

[0061] The backwash liquid containing sludge sucked from the suction nozzle 6 flows into the inlet passage 8a of the rotating shaft tube 8 and flows into the backwash liquid discharge pipe 10 connected to this inlet passage 8a. The backwash liquid containing sludge is discharged outside the strainer body 1 and then sent to the cyclone separator 20 connected to the backwash liquid discharge pipe 10.

[0062] The cyclone separator 20 separates the backwash liquid containing sludge into liquid and sludge (solid), and the separated liquid of the backwash liquid is discharged from the liquid outlet 22 and is also sucked through the suction port 35 of the ejector connected to the suction pipe 25, and flows into the flow path of the raw liquid supply pipe 26.

[0063] On the other hand, the sludge separated from the backwash liquid is discharged from the solid discharge outlet 23 of the cyclone 20 and deposited in the sludge pod 40. The sludge deposited in the sludge pod 40 can be collected at a predetermined time as needed.

[0064] Here, only the backwash liquid separated by the cyclone 20 is again supplied to the inlet 3 of the strainer body 1 together with the raw liquid, allowing the backwash liquid to constantly circulate within the circulation circuit formed by the strainer body 1, the cyclone 20, and the ejector 30. In this way, the backwash liquid is constantly circulated within the system without being discharged outside the apparatus, so that the backwash liquid is not discharged outside the apparatus and discarded.

[0065] Therefore, by circulating the backwash liquid in the circulation circuit without discarding it, the loss of the backwash liquid discharged outside the machine can be reduced, and as a result, the loss of the liquid contained in the raw liquid can be reduced and the recovery amount and yield of the filtrate can be improved. In addition, since the liquid containing sludge is not returned to the tank that stores the raw liquid, there is no problem of the concentration of sludge and foreign matter increasing in the raw liquid tank.

[0066] Furthermore, since the backwash liquid circulates constantly within the circulation circuit when the strainer body 1 is in operation (filtering operation), a flow of liquid that backwashes the filter element 2 is generated within the strainer body 1, making it possible to automatically clean the filter element 2 within the strainer body 1. Therefore, even if the sludge in the raw liquid contains fine particles, the backwash function is constantly performed during filtering operation, eliminating clogging of the filter element 2 and preventing a decrease in filtering capacity.

[0067] Therefore, the filter element 2 of the strainer body 1 maintains stable filtering performance, enabling continuous operation. Moreover, since the filter element 2 can be automatically washed, maintenance work is no longer necessary, thereby increasing the value of the product.

[0068] During filtering operation, the backwash scraper 5 formed in the radial direction of the rotating shaft tube 8 operates along the inner peripheral surface of the filter element 2 to scrape off sludge clogging the filter holes of the filter element 2, suck it up, and discharge it through the backwash liquid discharge pipe 10, thereby improving cleaning efficiency.

[0069] In addition, a sludge pot or bag filter with a sight glass for collecting sludge is provided below the cyclone 20. Therefore, the backwash liquid containing sludge is separated into sludge and liquid by the cyclone 20, and the sludge discharged from the cyclone 20 can be collected by the sludge pot or bag filter. Therefore, only the sludge can be collected without stopping the filtering operation.

[0070] <Second embodiment> Next, a second embodiment will be described. The second embodiment is an example of an embodiment in which the rotating shaft tube 8 is configured to be rotatable without power in the automatic cleaning system for a filtration strainer of the present invention. The same components as those in the first embodiment described above are given the same reference numerals and detailed description thereof will be omitted.

[0071] In the embodiment shown in FIG. 3, the rotating shaft tube 8 is rotatably provided within the filter element 2, and during filtering operation, the rotating shaft tube 8 within the filter element 2 is constantly rotatable by a roughly bowl-shaped rotating water wheel 18 provided on the strainer body 1 due to the water flow of the raw liquid flowing into the strainer body 1. That is, in this embodiment, the raw liquid flows in at an increased flow rate by the ejector 30 and collides with the rotating water wheel 18, causing the rotating shaft tube 8 to rotate via the rotating water wheel 18, so that the rotating shaft tube 8 rotates without the need for an external driving force.

[0072] In this example, a plurality of bowl-shaped rotary water wheels 18 are provided on the rotating shaft tube 8, but the shape of the water wheels may be other shapes, etc. In addition, the method of applying the automatic cleaning system in this example to drive the system in a non-powered state is not limited to rotary water wheels, and other means may be used, and is optional depending on the implementation.

[0073] In the second embodiment, in addition to the effects and advantages of the first embodiment described above, when raw liquid flows into the strainer body 1 during filtering operation, the rotating water wheel 18 provided in the strainer body 1 rotates due to the water flow of the raw liquid flowing into the strainer body, and the rotating shaft tube 8 rotates via the rotation of the rotating water wheel 18. Therefore, no external power is required, and the rotating shaft tube 8 in the filtration element 2 rotates constantly during filtering without power, making it possible to operate the backwash function.

[0074] In addition, during filtration operation, the backwash function operates without power, eliminating the need for a separate power source. The filtration element 2 can be automatically cleaned at all times, unmanned, and this allows for significant reductions in equipment costs and maintenance work.

[0075] In addition, since the rotating water wheel 18 is bowl-shaped, the momentum of the raw liquid that flows in can be easily received by the water wheel 18 and rotated efficiently, so that the energy that rotates the rotating shaft tube 8 can be transmitted efficiently.

[0076] <Automatic cleaning method for filtration strainers> Next, the automatic cleaning method for a filter strainer of the present invention will be described. The automatic cleaning method for a filter strainer of the present invention can be carried out based on the automatic cleaning system for a filter strainer of the above embodiment, but is not limited thereto.

[0077] The automatic cleaning method for a filtration strainer of the present invention includes a filtration step in which raw liquid is supplied through a raw liquid supply pipe, flows into the inlet of the strainer body, and is filtered by the filtration element in the strainer body, a backwash step in which the inner and outer periphery of the filtration element are backwashed simultaneously with the filtration step, a separation step in which the backwash liquid containing sludge after the backwash step is separated into sludge and liquid using a cyclone separator, and a suction supply step in which the liquid is sucked in by an ejector provided in the raw liquid supply pipe.

[0078] By suctioning and supplying the separated liquid and circulating it within the strainer body, the backwash liquid is not discharged outside the machine, and the circulation operation is performed through a backwash step at the same time as the strainer body is operating.

[0079] <Filtration step> The filtration step, in which the raw liquid is supplied through a raw liquid supply pipe, flows into the inlet of the strainer body, and is filtered by the filtering element inside the strainer body, supplies the raw liquid to be supplied to the strainer body at an increased flow rate and volume by an ejector or the like provided near the inlet of the strainer body, causes the raw liquid to be filtered to flow into the filtering element, and filters the raw liquid through the filtering element while a water flow is generated inside the strainer body. In addition, when the strainer body is cylindrical, the water flows along the inner peripheral surface of the cylindrical body, so that a swirling flow is likely to occur within the strainer body.

[0080] <Backwash step> In the backwashing step, which is performed simultaneously with the filtering step and in which the inner and outer periphery of the filtering element are backwashed, backwashing is performed to remove clogging of the filtering element by a backwashing means using a water flow within the strainer body. As long as the filtering step and the backwashing step can be performed simultaneously, the backwashing means is not particularly limited, but it is sufficient that it has a mechanism for removing sludge using a water flow and can discharge the sludge outside the strainer. Note that the backwashing means can be used in combination with multiple means such as a backwashing scraper and a backwashing brush to increase the cleaning efficiency.

[0081] <Separation step> In the separation step, the backwash liquid containing sludge after the backwash step is separated into sludge and liquid using a cyclone separator. The backwash liquid containing sludge that was sucked in and discharged from the strainer body in the backwash step is sent to the cyclone separator, and the cyclone separator separates the sludge of the backwash liquid from the liquid of the backwash liquid. The cyclone separator is not particularly limited as long as it can separate sludge from the backwash liquid, but it is preferable to implement it based on the system of the first or second embodiment described above.

[0082] <Suction supply step> The suction supply step, in which the liquid is sucked in by an ejector installed in the raw liquid supply pipe, uses the ejector to suck in only the backwash liquid separated by the above-mentioned separation step, causes this liquid to flow into the flow path of the raw liquid supply pipe, and supplies the backwash liquid to the strainer body through the raw liquid supply pipe.

[0083] By having all of the above steps, a flow of backwash liquid circulates in the strainer body during filtration, and the backwash liquid is not discharged outside the machine. In addition, the strainer body performs filtering and backwashing simultaneously while the backwash liquid circulates.

[0084] Therefore, this automatic cleaning method for a filtration strainer includes a filtration step in which the raw liquid is supplied through a raw liquid supply pipe and allowed to flow into the inlet of the strainer body, and the raw liquid is filtered by the filter element in the strainer body, as well as a backwash step in which the filter element is cleaned by the water flow within the strainer body.Next, after the backwash step, the backwash liquid containing sludge is sent to a cyclone separator to separate it into sludge and liquid, and a suction supply step is performed in which only the separated liquid is sucked in by an ejector provided in the raw liquid supply pipe.

[0085] As a result, only the liquid separated by the cyclone separator is sucked into the ejector and supplied again to the strainer body, so the backwash liquid is reused and circulated, and is not discharged outside the machine. This reduces the amount of backwash liquid to be disposed of, reduces the loss of liquid contained in the raw liquid, and improves the recovery amount and yield of filtrate. In addition, because the liquid containing sludge is not returned to the tank that contains the raw liquid, there is no problem of the concentration of sludge or foreign matter increasing in the raw liquid tank.

[0086] Furthermore, within the strainer body, during the filtration process, a flow is generated in which the backwash liquid circulates within the strainer body, and since the backwash liquid circulates, it is possible to carry out the filtration step and the backwash step simultaneously within the strainer body.During the filtration step, clogging of the filtration elements within the strainer body is suppressed, making automatic cleaning possible and eliminating the need for intermittent operation to clean the filtration elements.

[0087] Therefore, the filtering ability of the filtering element during filtering is stable, so that even in filtering to remove sludge of fine particles, the problem of reduced filtering ability due to clogging of the filtering element does not occur, and the filtering can be preferably carried out.

[0088] In addition, since the sludge can be discharged outside the system without being exposed to the atmosphere and only the sludge can be collected, it can also be applied to, for example, Y-type strainers and T-type strainers.

[0089] <Other examples> Next, an example in which the automatic cleaning system for a filtration strainer of the present invention is applied to a Y-strainer will be described. Fig. 4 is a schematic cross-sectional view showing an automatic cleaning system in which the present invention is applied to a Y-strainer. The same components as those in the first embodiment described above are given the same reference numerals and detailed descriptions thereof will be omitted.

[0090] As shown in FIG. 4 , an ejector 30 is provided near the inlet 53 of the Y-strainer body 50, and the outlet 56 of the Y-strainer body 50 is connected to the cyclone 20 via the backwash liquid discharge pipe 10, and the liquid outlet 22 of the cyclone 20 is connected to the suction port 35 of the ejector 30. As in the above embodiment, a circulation circuit is formed between the strainer body 50, the cyclone 20, and the ejector 30, and the backwash liquid is configured to be able to circulate within this circuit.

[0091] The Y-strainer body 50 houses the filtration element 2 and a backwash brush 55 for removing clogging of the filtration element 2. The backwash brush 55 is rotatably mounted on the rotary shaft 52, and the backwash brush 55 of the Y-strainer body 50 rotates to clean the inner surface of the filtration element 2. The rotating shaft 52 is connected to an operating handle 51 so that the backwash brush 55 rotates when the handle 51 is manually operated.

[0092] During the filtering operation, the raw liquid is supplied to the inlet 53 of the Y-strainer body 50 at an increased flow rate by the ejector 30 provided in the raw material supply piping 26, and the supplied raw liquid flows into the filtering element 2 built into the Y-strainer body 50, where sludge and the like are removed. The filtrate is then supplied from the outlet 54 of the Y-strainer body 50 and can be filtered.

[0093] In addition, the backwash liquid containing sludge discharged from the discharge outlet 56 of the strainer body 50 is sent to the cyclone 20 via the backwash liquid discharge piping 10, the backwash liquid containing sludge is separated into sludge and liquid, and only the sludge is discharged from the solid discharge outlet 23. The separated liquid is sucked from the suction port 35 of the ejector, flows into the flow path of the raw liquid supply pipe 26, and is supplied to the inlet 53 of the strainer body 50, and only the backwash liquid circulates in the circulation circuit. Therefore, the backwash liquid circulates without being discharged outside the machine, so that the amount of backwash liquid to be discarded can be reduced, and the loss of raw liquid can be reduced.

[0094] Therefore, even if a suction pump is arranged on the secondary side of the Y-type strainer, the liquid containing sludge can be sent to the cyclone 20 without being released to the atmosphere, and the sludge separated by the cyclone 20 can be discharged from the solid discharge outlet 23, allowing the sludge to be collected even in a negative pressure environment. Moreover, since accumulation of sludge inside the Y-strainer body 50 can be suppressed, there is no decrease in filtering capacity. Furthermore, without stopping the filtering operation, the handle 51 can be appropriately operated to rotate the backwash brush 55 of the Y-strainer body 50, thereby cleaning the inner surface of the filter element 2 and restoring filtering capacity.

[0095] In this way, the automatic cleaning system in which the present invention is applied to a Y-strainer allows the backwash liquid to circulate at all times without stopping the filtering operation, and sends the backwash liquid containing sludge to the cyclone 20, making it possible to discharge only the sludge using the cyclone 20. Even if the inside of the Y-type strainer 50 is in a negative pressure environment, sludge can be collected, eliminating the need for cleaning work to remove the sludge, and preventing sludge from accumulating inside the Y-type strainer body 50, eliminating the problem of reduced filtering capacity of the filter element 2.

[0096] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention as described in the claims of the present invention.

[0097] The filtering element built into the strainer in the above embodiment filters from the inside to the outside, but may filter from the outside to the inside.

[0098] A pressure gauge or a flow-adjustable pump may be provided at the inlet and outlet of the backwash liquid discharge piping or the strainer to monitor the pressure and flow rate within the automatic cleaning system, and the flow rate and flow speed of the water supplied may be adjusted by an external control device. [Explanation of symbols]

[0099] 1 Strainer body 2 Filter element 3 Inlet 4 Outlet 5 Backwash scraper 6 Suction nozzle 7 Retaining member 8 Rotating shaft tube 8a Inlet channel 9 Drain piping 10 Backwash liquid drain pipe 11 Connecting members 12 Filtration chamber 13 Discharge chamber 14 Outlet 15 Valve 16 Valve 17 Drive unit 18 Rotating Waterwheel 20 Cyclone separator (cyclone) 21 Intake 22 Liquid outlet 23 Solids outlet 24 Valve 25 Suction tube 26 Stock solution supply pipe 27 Valve 30 Ejector 31 Nozzle section 32 Diffuser section 33 Introduction 34 Discharge port 35 Suction port 40 Sludgepod 40a Viewing window 50 Y-type strainer body 51 Handle 52 Rotating shaft 53 Inlet 54 Outlet 55 Backwash brush 56 Outlet

Claims

1. An automatic cleaning system for a filtration strainer comprising: a filtration element having a backwash function within a strainer body having an inlet through which raw liquid flows in and an outlet through which filtrate flows out; a backwash liquid discharge pipe for discharging backwash liquid containing sludge to an outlet provided in the filtration element; a cyclone separator connected to the backwash liquid discharge pipe for separating sludge and liquid; a suction pipe through which liquid is sucked and discharged above the cyclone separator; and an ejector having a suction supply function connected to a raw liquid supply pipe located in the vicinity of the inlet, wherein the backwash liquid is sucked into the ejector and circulated within the strainer body without being discharged outside the machine, and the backwash function is constantly performed while the strainer body is in operation.

2. 2. The automatic cleaning system for a filter strainer as described in claim 1, wherein a cylindrical filtering element is provided within the cylindrical strainer body, a rotating shaft tube is constantly rotated within the filtering element, and a backwash scraper provided in the radial direction of the rotating shaft tube scrapes off and sucks up sludge clogged in the filtering element, and the sludge is discharged from the backwash liquid discharge pipe, while the backwash liquid is circulated through the circulation circuit.

3. 3. The automatic cleaning system for a filtration strainer according to claim 1 or 2, wherein a sludge pot or bag filter with an observation window for collecting sludge is disposed below the cyclone separator.

4. An automatic cleaning method for a filtration strainer, comprising: a filtration step in which raw liquid is supplied through a raw liquid supply pipe, flows into the inlet of the strainer body, and is filtered by a filtration element in the strainer body; a backwash step in which the inner and outer periphery of the filtration element are backwashed simultaneously with the filtration step; a separation step in which the backwash liquid containing sludge after the backwash step is separated into sludge and liquid using a cyclone separator; and a suction supply step in which the liquid is sucked in by an ejector provided in the raw liquid supply pipe, wherein the liquid separated by suction supply is circulated within the strainer body, so that the backwash liquid is not discharged outside the machine, and circulation operation is performed through the backwash step simultaneously while the strainer body is in operation.

Images