JP2019098273A - strainer - Google Patents

Abstract

To provide a strainer which improves a back washing efficiency, and reliably removes sludge even if element opening is fine, and prevents consumption of a scraper part and damage of the element, thereby maintaining filtration performance.SOLUTION: This strainer comprises: a cylindrical strainer body 1 having an inflow port 3; a cylindrical filter element 2 which is provided in the strainer body 1; a rotary shaft 6 having an inflow passage 25 in which sludge is flown, at a middle position of the filter element 2; an outlet port 4 provided in a filter chamber 17 which is provided the strainer body 1 and an outer periphery of the element 2; and an outlet duct 7 which is provided continuously with a lower part of the rotary shaft 6, and is extended to a lower part of strainer body 1. A back washing scraper body 21 is fitted to a suction pipe 26 communicated with the inflow passage 25 of the rotary shaft 6, and a suction back washing position of the back washing scraper body 21 is located in a non-contact state with respect to the element 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a strainer for removing a sludge by filtering a liquid containing sludge (contaminants) with an internal filter element, and in particular, a cylindrical element provided with a liquid flowing from the inside of the cylindrical element to the outside. It relates to a strainer that drains and filters.

  Conventionally, for example, in pipelines such as power generation, steel plants, water for water such as seawater and industrial water, or process lines for refineries, etc., a strainer for removing sludge contained in the liquid and filtering the liquid is used. It is commonly used. Among such strainers, a strainer called a bucket type strainer is known, and this strainer is widely used for horizontal straight piping and offset flow piping.

  In such a strainer, a cylindrical filtering element (screen) is disposed in the main body, and after the liquid is introduced into the inside of the filtering element to capture the sludge, the filtered liquid is collected in the filtering element. It is discharged to the outside and supplied to the secondary side. In this case, sludge adheres to the inside of the filtration element with the passage of filtration time, and this sludge is deposited on the inner periphery of the filtration element and the filtration holes, whereby the pressure loss during filtration becomes large, and the necessary flow rate can not be obtained Problems can occur. As a countermeasure, it is known that a rotatable scraping tool is provided in the filtering element, and the scraping tool forcibly scrapes the sludge and backwashes the inside of the filtering element.

  In this example, the strainer is a scraper (scraper) made of a polymer or metal, or a brush made of a resin, and is a strainer mounted so as to rotate in contact with the filtering element. May be used. In this case, at the time of backwashing, the scraper comes into contact with the inner peripheral surface of the filter element and the sludge is scraped off, and this sludge is called a hopper having a generally U-shaped cross section provided on the primary side of the scraper. In many cases, the gas is discharged to the outside through a communication hole formed in the inside of the rotating shaft via a suction pipe which is guided by the guide and connected to the hopper.

  On the other hand, in the filtration device of Patent Document 1, the scraping body is rotatably mounted on the inner side of the cylindrical filter medium by a rotating shaft, and scraping is carried out with the gap from the inner surface of the filtering medium at the tip of this scraping body. The part is attached. A space is formed inside the tip end side (filter material side) of the scraping portion, and a passage is formed in communication with the scraping body (space portion) and the inside of the rotary shaft, and a suction device is connected to this passage There is. The deposits, which are sludge deposited on the inside of the filter medium, are scraped off by the rotation of the scraping body and move into the space. Furthermore, when removing the deposit in the space, the deposit in the space is discharged to the outside through the passage by operating the suction device.

Japanese Patent Application Laid-Open No. 8-80405

  However, in the case of the strainer using the above-mentioned scraper, the scraper is brought into contact with the inner periphery of the filtering element at the time of backwashing to scrape the sludge, and the scraped sludge is sucked and removed through the hopper. Since it is difficult to scrape the sludge adhering to the filter holes of the filter element with a scraper, it is easy for the sludge to be clogged with the filter holes, especially when the filter holes have fine openings. There is a possibility that sludge may remain in the pores and the inner periphery of the filtering element. In addition to this, contact between the scraper and the filter element accelerates the consumption of the scraper and reduces the sludge removal function, and the filter element is damaged by the scraper and the filtration in the normal state is performed. Performance may be impaired.

  Furthermore, since the sludge scraped off through the hopper is sucked from the suction pipe, it becomes difficult to set the gap on the hopper tip side. That is, if this gap is made small, the pressure difference between the outer peripheral side of the filtering element and the inner side of the hopper is increased to make the flow faster and sludge suction efficiency can be improved, but the rotating hopper tip is for filtration It becomes difficult to adjust so as not to touch the inner circumference of the element. On the other hand, when the gap is increased, the flow of liquid into the hopper is increased, so that the pressure difference between the outer side and the inner side of the filtering element near the hopper tip is reduced, and the sludge suction efficiency is reduced. Thus, it is difficult to remove sludge with high efficiency using a hopper.

  On the other hand, in the case of the filter device of Patent Document 1, a water flow is generated by the gap between the scraping portion and the inner surface of the filter material, and the impetus is scraped off by the momentum of the water flow and the scraped debris is retained in the space portion. There is. However, in this filtration device, since the water flow is unlikely to act in the suction direction, deposits may remain in the filtration holes, particularly if the openings of the elements are fine. Furthermore, by providing a space also on the secondary side in the rotational direction, the extraneous matter leaks from the space, and a pressure difference between this space and the outside of the space is unlikely to occur due to the space inside the scraping portion. As a result, there is a risk that the deposit scraped off by the water flow can not be retained in the space. From these things, the suction device for removing the deposit | attachment collected in the space part is needed, and it also has the problem of leading also to the enlargement of the whole by this suction device.

  The present invention has been developed to solve the above-mentioned problems, and its object is to improve the backwashing efficiency and reliably remove sludge even when the openings of elements are fine. In addition, the present invention is to provide a strainer which maintains the filtration performance by preventing the consumption of the scraper portion and the damage of the element.

  In order to achieve the above object, the invention according to claim 1 relates to a cylindrical strainer main body having an inlet, a cylindrical filter element provided in the strainer main body, and an inner portion at a central position of this filter element. A rotary shaft having an inflow passage into which sludge flows, an outlet provided in a filtration chamber provided between the strainer main body and the element outer periphery, and a lower portion of the rotary shaft, and the strainer main body The backwash scraper body is attached to the suction pipe leading to the inflow passage of the rotation shaft, and the suction backwash position of this backwash scraper body is not in contact with the element. It is a strainer placed in the state.

  The invention according to claim 2 is that the backwashing scraper body is a strainer comprising a nozzle pipe provided at the tip of the suction pipe, and a suction member having a wide surface and a wide surface provided at the tip of the nozzle pipe. .

  The invention according to claim 3 has a backwashing port having a predetermined length on the wide surface of the elongated suction member, and the tip of the backwashing port is thinly provided, and from the backwashing port to the nozzle pipe The strainer is a strainer that is arranged in a wide-angle state to increase the backwash flow velocity to increase the regeneration efficiency of the element.

  The invention according to claim 4 is a strainer in which the scraper body can be biased by the elastic force of a spring mounted in the suction pipe, and the gap between the element and the backwashing scraper body is uniformly maintained.

  The invention according to claim 5 is a strainer provided with a holding member for holding the element annularly.

  According to the invention of claim 1, the backwashing scraper body is attached to the suction pipe communicating with the inflow path of the rotating shaft, and the suction backwashing position of the backwashing scraper body is disposed in noncontact with the element. As a result, the backwashing efficiency of the backwashing scraper body is improved during backwashing, and even when the openings of the element are fine, sludge adhering to the inner surface of the element and filtration holes is reliably removed, and contact is made. The effect of regeneration of the element can be enhanced as compared to the case of scraping. By preventing the backwashing scraper body from coming into contact with the element, the backwashing scraper body is prevented from being exhausted and the element is damaged, and the filtration performance of the sludge by the element is maintained.

  According to the second aspect of the present invention, the backwashing scraper body has the nozzle pipe and the suction member having a wide surface, so that the backwashing scraper body is extremely effective on the surface of the suction member and the inner circumferential surface of the element at the time of backwashing. It is possible to increase the suction effect by providing a narrow gap. As a result, even in the case of an element with fine openings, loss of backwashing performance is suppressed, and fine sludge adhering to the inner circumferential surface of the element and filtration holes can be reliably sucked and filtered through a wide surface. .

  According to the invention of claim 3, the suction member has a backwashing opening on the wide surface of the suction member, the tip of the backwashing opening is provided thin, and the backwashing opening is continuously connected in a wide angle toward the nozzle pipe Since the cleaning flow rate is increased to increase the regeneration efficiency of the element, it is possible to carry out a wide range of backwashing with high efficiency through a wide surface while suppressing the loss of backwashing performance, and improve the suction flow rate to make fine openings. Even in the case of an element, minute sludge can be reliably removed.

  According to the invention of claim 4, the backwashing scraper body can be biased by the elastic force of the spring, and the gap between the element and the backwashing scraper body is uniformly maintained, whereby the backwashing can be rotated by the pivot shaft. The suction force of the scraper body can be kept constant. As a result, the sludge on the element side opposite to the backwashing scraper body can be reliably removed, and the contact between the backwashing scraper body and the element can be prevented, and the consumption of the backwashing scraper body and the damage to the element can be prevented.

  According to the invention of claim 5, the element is held in a substantially perfect circular shape by the holding member provided on the element, and at the time of backwashing, the clearance between the backwashing scraper body and the element inner circumferential surface is secured approximately constant. The backwashing function can be worked uniformly.

It is a sectional view showing one embodiment of a strainer in the present invention. It is a partially expanded sectional view which shows element vicinity of FIG. FIG. 2A is a schematic plan view of FIG. (B) is a front view of a backwashing scraper body. It is the A section enlarged sectional view of Drawing 3 (a). It is a longitudinal cross-sectional view which shows the other example of an element.

Hereinafter, an embodiment of a strainer in the present invention will be described in detail based on the drawings.
FIG. 1 is a cross-sectional view showing an embodiment of a strainer of the present invention, and FIG. 2 is a partially enlarged cross-sectional view showing the vicinity of an element in FIG.

  In the figure, the strainer of the present invention is, for example, a bucket type, and a cylindrical filtration element 2 is provided in a cylindrical strainer main body 1 disposed vertically, and an inlet 3 for filtration liquid (stock solution) And the outlet 4 of the liquid after filtration are piped in the horizontal direction to the strainer body 1, and these are arranged in an offset state. In addition to the strainer main body 1 and the element 2, the strainer of the present invention is provided with a lid 5, a rotating shaft 6, and a discharge pipe 7.

  A lid 5 is detachably attached to the upper end opening 1 a of the cylindrical strainer main body 1 by a bolt and nut 10, and the upper end opening 1 a is covered with the lid 5. A drain passage 11 is connected to the lower portion of the strainer body 1 in communication with the inside thereof, and a drain valve 12 is provided in the drain passage 11 so as to be able to open and close. Leg portions 13 are provided at a plurality of locations on the bottom side of the strainer main body 1, and are arranged upright via the leg portions 13. In the present example, some of the legs 13 are omitted.

  The filter element 2 is formed in a cylindrical shape, for example, by a wire called a so-called wedge wire, and filter holes 14 communicating the inside and the outside are provided between the respective wires by fine openings. The element 2 is detachably fixed by the fixing bolt 16 in a state of being held between the disk-shaped holding portions 15 attached to the upper and lower portions of the inside of the strainer main body 1, and is rotated inside the element 2. A shaft 6 is provided. By mounting the element 2 in the strainer main body 1, a filtration chamber 17 is provided between the strainer main body 1 and the outer periphery of the element 2, and the outlet 4 is communicated with the filtration chamber 17 from the outside. Provided.

A holding member 20 made of a thin plate-like metal material is mounted on the outer periphery of the element 2, and reinforcement of the holding member 20 holds the element 2 in an annular shape.
The holding member 20 may be disposed, for example, in a spiral shape or a mesh shape with respect to the element 2, and in the present embodiment, the holding member 20 is attached in a spiral shape with respect to the element inner circumferential surface 2a. Thus, the element 2 is held in a substantially perfect circular cylindrical shape.

  Although not shown, an annular member provided with a cross-shaped reinforcing member is mounted on the upper and lower opening sides of the element 2, respectively, and the upper and lower sides of the element 2 are perfect circles without obstructing the flow of liquid by this annular member. It is reinforced in shape.

  As shown in FIGS. 2 and 3, the pivot shaft 6 is provided at the central position of the element 2, and the pivot shaft 6 is provided in a hollow shape so that the inflow passage 25 into which sludge (contaminants) is introduced. Is provided. Then, on the rotation shaft 6, suction pipes 26 are provided at a plurality of places, in the present embodiment, at an interval of 180 ° at a plurality of places, in the present embodiment, communicating with the inflow path 25.

  A discharge pipe 7 is connected to a lower portion of the pivot shaft 6, and the discharge pipe 7 is extended to a lower portion of the strainer main body 1. A discharge valve 27 is attached to the discharge pipe 7, and the suction side of the backwashing scraper body 21 communicating with the inner peripheral side of the element 2 is opened and closed through the rotary shaft 6 and the discharge pipe 7 by opening and closing the discharge valve 27. It is provided in communication with the downstream side of the discharge pipe 7. The downstream side of the discharge pipe 7 is provided at atmospheric pressure.

In FIG. 4, the backwashing scraper body 21 includes a nozzle pipe 30 and a suction member 31, and is attached to the tip end side of the suction pipe 26.
The nozzle pipe 30 is attached to the tip end of the suction pipe 26 so that the rear end side is inserted, and between the nozzle pipe 30 and the suction pipe 26, a spring 32 formed of a coil spring is attached. The backwash scraper body 21 is biased in the direction of the element 2 by the elastic force of the spring 32 mounted in the suction pipe 26.

  By urging of the backwashing scraper body 21 by the spring 32, a gap S having a predetermined width shown in FIG. 4 is formed between the suction backwashing position of the backwashing scraper body 21 and the element 2. The backwash scraper body 21 is disposed in non-contact with the element 2 via the gap S. The gap S is held substantially uniformly by the resilient force of the spring 32.

  The suction member 31 is provided, for example, by a resin material with a width of about 30 to 50 mm and a predetermined length, and is provided on the tip end side of the nozzle pipe 30. In this embodiment, the suction member 31 (backwash scraper body 21) is divided into four for the entire length of the element 2, and when each backwash scraper body 21 is attached to the suction pipe 26, the interval of 180 ° Are alternately arranged in the axial direction of the rotation shaft 6.

  At that time, each suction member 31 is provided so that the upper and lower end sides overlap in the length direction, and when the rotation shaft 6 rotates, the entire length of the suction member 31 opposes the length direction of the element inner circumferential surface 2a. It has become. The suction member 31 is easy to manufacture by cutting and the like, and is provided so as to be easily replaceable to the nozzle pipe 30 in accordance with wear and tear and the like.

  A wide surface 33 having a wide width is provided on the tip end side (element 2 side) of the suction member 31, and the above-described surface of the suction member 31 is provided between the tip side of the suction member 31 and the element inner circumferential surface 2 a via the wide surface 33. The gap S is set to be extremely narrow. The wide surface 33 is formed in a rounded shape, and the curved wide surface 33 is formed with a radius smaller than the radius of the element inner circumferential surface 2a, whereby the gap S is directed to both ends of the suction member 31. It is getting wider gradually as

A backwash port 34 having a predetermined length is provided on the wide surface 33 of the suction member 31, and the backwash port 34 has a narrow portion 35 and a wide angle portion 36.
The narrow portion 35 is thinly provided from the front end side of the backwashing opening 34, and the wide angle portion 36 is provided continuously to the nozzle pipe 30 following the narrow portion 35. The wide-angle portion 36 is provided in a wide-angle shape in which the flow path widens toward the nozzle tube 30, and the backwashing opening 34 by the narrow portion 35 and the wide-angle portion 36 accelerates the backwashing flow velocity to reproduce the element. I'm raising.

  The narrow portion 35 is formed in an elongated shape along the length direction of the element 2 with a substantially constant width in the length direction, for example, a width of about 3 mm. On the other hand, the wide-angle portion 36 is formed so as to be hollowed out in a substantially triangular prism shape in the suction member 31 following the narrow-width portion 35, and the flow channel width on the wide angle side is approximately the same as the flow channel in the nozzle tube 30. It has become.

In FIG. 1, an I-shaped locking member 40 is attached to the top end side of the rotating shaft 6, and the locking member 40 is provided so as to be interlocked with a drive mechanism 41 for transmitting a driving force.
The drive mechanism 41 includes a locking tool 42, a drive shaft 43, and a drive unit 44. The locking tool 42 is formed in a substantially U-shape, and is attached to the lower end side of the drive shaft 43 with the opening side facing downward, and the locking member 40 is locked to the locking tool 42. The drive shaft 43 receives the rotation from the drive unit 44 which is an electric motor. With these configurations, the rotation of the drive shaft 43 by the drive unit 44 is transmitted to the locking member 40 via the locking member 41, the rotation shaft 6 integral with the locking member 40 rotates, and the rotation shaft The backwashing scraper body 21 is rotated relative to the element 2 by the rotation of 6.

  The drive mechanism 41 is attached to the lid 5 by the fixing bolt 46 in a state where the drive shaft 43 can rotate via the bearing member 45. The locking member 42 on the drive unit 44 side and the locking member 40 on the rotating shaft 6 side (strainer main body 1 side) are previously positioned at their heights (drive The length of each of the shaft 43 and the rotation shaft 6 is set.

  With the above configuration, when the bolt nut 10 is loosened and the lid 5 is lifted, the locking of the locking member 42 to the locking member 40 is released, and the drive mechanism 41 can be removed from the strainer main body 1 together with the lid 5 It becomes. By loosening the fixing bolt 16 in this state, the element 2 can be attached to and detached from the strainer main body 10.

  In the present embodiment, the backwashing scraper body 21 is provided in a mode in which the backwash scraper body 21 is divided into four in the longitudinal direction of the element 2, but the number of divisions may be other than this, or over the entire length of the element 2 It may be provided integrally, and the intervals may also be provided at a plurality of locations of the pivot shaft 6 at an arbitrary interval other than 180 °.

Further, the element 2 may be in a form other than a wedge wire, and for example, various types such as a punching plate (perforated plate) and a wire mesh (mesh) type can be used, and the size of the opening is not limited minutely. For example, it may be a relatively large opening for coarse filtration.
The holding member is provided on the outer periphery of the element 2, but may be provided on the inner peripheral side of the element 2.

  The drive unit 44 may be other than an electric motor. For example, the drive shaft 43 may be rotated by an air motor or a manual handle, and this rotation may be transmitted to the suction pipe 26 side.

Next, the operation and action of the above-described embodiment of the strainer of the present invention will be described.
When filtering liquid for filtration (stock solution) by the strainer, when the stock solution flows into the strainer main body 1 sealed by the lid 5 from the inflow port 3, this stock solution flows into the inside of the element 2. The sludge contained in the stock solution is removed and filtered by flowing from the inner circumferential side to the filtration chamber 17 through the filtration holes 14. At that time, the filtered sludge remains inside the element 2 or adheres to the element inner circumferential surface 2 a and the filter hole 14. The filtered liquid is allowed to flow from the filtration chamber 17 through the outlet 4 to the outside of the strainer body 1.

  The sludge filtered from the stock solution and left inside the element 2 falls to the bottom of the strainer body 1 and accumulates. In the case of removing the sludge, if the drain valve 12 is operated in the open state so that the liquid flows from the inflow port 3, it can be discharged to the outside through the drain channel 11.

  When the sludge adheres to the element inner circumferential surface 2a and the filter holes 14 by filtration of the strainer, the pressure loss increases and the filtration efficiency decreases. In this case, particularly when it is the element 2 of the fine-pored filter hole 14, the sludge tends to be particularly easily deposited, so it is necessary to remove the sludge.

  In this case, the drive unit 44 is operated, and the discharge valve 27 is operated to open the secondary side atmospheric pressure of the discharge pipe 7 and the inflow passage 25 of the rotary shaft 6 in communication. At this time, the drain valve 12 is closed.

  When the drive unit 44 is operated, the drive shaft 43 is rotated, and the locking member 40 engaged with the locking tool 42 provided at the tip of the drive shaft 43 interlocks, and as a result, the rotation shaft 6 is rotated. When the rotary shaft 6 rotates, the tip end side of the narrow portion 35 of the backwashing port 34, which is the suction backwashing position of the backwashing scraper body 21, has a substantially constant gap S with the element inner circumferential surface 2a. Rotate in contact.

  At this time, since the inflow path 25 of the rotation shaft 6 and the discharge pipe 7 communicate with each other, the atmospheric pressure reaches the backwash port 34 of the backwash scraper body 21, and the backwash port 34 side and the liquid There is a pressure difference between the inside of the strainer body 1 and the inside of which is in a high pressure state by being introduced.

  Thus, in the non-contact state between the element inner circumferential surface 2a and the backwashing scraper body 21, the backwashing port 34 side and the strainer main body 1 inner side (the flow path side through which liquid flows) are relatively low pressure and high pressure. As a result, a water flow that flows into (is sucked into) the backwash port 34 from the outer peripheral side of the element 2 via the gap S is generated, and the element 2 is backwashed by this water flow.

  In this case, since the backwashing scraper body 21 is composed of the nozzle pipe 30 and the suction member 31 having the wide wide surface 33, the pressure in the gap S between the wide wide surface 33 and the element inner circumferential surface 2a side. The flow velocity rises while the pressure drops, and the suction efficiency increases. As a result, a strong suction force is exerted in a wide range on the element inner circumferential surface 2a side opposed by the suction member 31. At this time, sludge adhering to the element inner circumferential surface 2a by the flow velocity improvement is The accumulated sludge can be reliably sucked from the wide surface 33 into the backwash port 34 and removed.

  Moreover, the wide surface 33 is formed in a rounded shape, and the gap S is widened toward both ends of the suction member 31 so that the amount of the sludge increases as the backwash port 34 is sucked from the end side of the wide surface 33. There is no possibility that clogging will be prevented and the suction function by the backwash port 34 will be reduced.

  Furthermore, since the backwash port 34 has the narrow portion 35 provided with a narrow end on the front end side, and the wide angle portion 36 continuously arranged in a wide angle form from the narrow portion 35 toward the nozzle pipe 30, The flow rate is increased by the width portion 35 to efficiently absorb sludge, and the pressure is increased by the wide angle portion 36 spreading from the narrow portion 35 to be supplied to the inflow path 25 of the rotating shaft 6. As a result, the backwash flow rate can be increased by the backwash port 34 to improve the regeneration efficiency of the element 2, and the maintenance span can be extended.

  At that time, the backwash scraper body 21 is resiliently springed by the spring 32, and the tip end side of the suction member 31 is urged toward the element inner circumferential surface 2a, and the gap S between the element 2 and the tip end side of the suction member 31 is uniformly maintained, The suction force by the narrow portion 35 is exerted over the entire wide surface 33 through the gap S, and the sludge adhering to the element inner circumferential surface 2a opposite to the wide surface 33 and the filtration hole 14 is reliably sucked and removed Do. As described above, the contact between the suction member 31 and the element 2 is prevented to prevent the wear and damage of the suction member 31 and the element 2.

  Since the holding member 20 is provided on the outer periphery of the element 2, while holding the element 2 annularly by the holding member 20, the tip end side of the suction member 31 is brought close to a position extremely close to the element inner circumferential surface 2 a. It becomes possible to carry out backwashing in the state which pressed equally.

  When backwashing the element 2 described above, the differential pressure between the inflow port 3 and the outflow port 4 is measured by a pressure gauge (not shown), and if it is visually recognized that the difference is less than the specified value, the element inner periphery It is possible to confirm that the filtration performance has recovered by reliably removing the sludge adhering to the surface 2 a and the filter holes 14. In this case, by stopping the operation of the drive unit 44 and operating the discharge valve 27 in the closed state, the backwashing operation of the element 2 is completed, and the filtration operation of the stock solution by the strainer can be resumed.

FIG. 5 shows another example of the element. In this example, the same parts as the elements described above are denoted by the same reference numerals, and the description thereof is omitted.
In the element 50, a holding member 51 is provided in a mesh shape on the inner peripheral side, and the cylindrical element 50 is held in a substantially perfect circular state by the holding member 51.

  In this case, the holding member 51 is disposed to be inclined at an angle of about 45 ° with respect to the rotation direction of the pivot shaft 6 of FIG. Thereby, the holding force by the holding member 51 is uniformly exerted on the element 50, and the strength can be enhanced.

  As mentioned above, although the embodiment of the present invention has been described in detail, the present invention is not limited to the description of the above embodiment, and the scope does not deviate from the spirit of the invention described in the claims of the present invention. And various changes can be made.

Reference Signs List 1 strainer main body 2 filter element 3 inlet 4 outlet 6 rotary shaft 7 discharge pipe 17 filter chamber 20, 51 holding member 21 backwash scraper body 25 inflow path 26 suction pipe 30 nozzle pipe 31 suction member 32 spring 33 wide surface 34 backwash 35 width detail 36 wide angle section S gap

Claims (5)

  A cylindrical strainer body having an inlet, a cylindrical filter element provided in the strainer body, a pivot shaft having an inflow path into which sludge flows in at a central position of the filter element, An outlet provided in a filtration chamber provided between the strainer main body and the element outer periphery, and a discharge pipe provided continuously with the lower portion of the pivot shaft and extended in the lower portion of the strainer main body; The backwashing scraper body is attached to a suction pipe communicating with the inflow path of the rotation shaft, and a suction backwashing position of the backwashing scraper body is disposed in a noncontact state with respect to the element. Strainer.   The strainer according to claim 1, wherein the backwashing scraper body comprises a nozzle pipe provided at the tip of the suction pipe, and a suction member having a wide surface provided at the tip of the nozzle pipe.   A long back surface of the suction member has a backwashing port having a predetermined length, and a tip of the backwashing port is thinly provided, and the backwashing port continues in a wide angle state toward the nozzle pipe. The strainer according to claim 1 or 2, wherein the flow rate of backwashing is increased to increase the regeneration efficiency of the element.   4. The backwashing scraper body can be biased by the elastic force of a spring mounted in the suction pipe, and the gap between the element and the backwashing scraper body is uniformly maintained. Strainer described in Section.   The strainer according to any one of claims 1 to 4, wherein the element is provided with a holding member for holding the element annularly.

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