Filter

Abstract

The utility model belongs to the technical field of fluid pipeline systems, and discloses a filter which comprises a valve body, a filter screen, a valve cover and a pollution discharge assembly, an overflowing cavity and a filter cavity which are communicated are arranged in the valve body, the filter screen extends into the overflowing cavity from the filter cavity, and the pollution discharge assembly comprises a valve seat, a valve rod and a valve clack. The valve seat is arranged at the end, close to the valve cover, of the filter screen, a dirt storage bin is formed between the valve seat and the valve cover, a dirt discharging hole communicated with the dirt storage bin is formed in the valve seat, one end of the valve rod extends into the valve body to be connected with the valve clack, the other end of the valve rod extends out of the valve cover, and the valve rod is used for driving the valve clack to move between the position for sealing the dirt discharging hole and the position for opening the dirt discharging hole. A sinking cavity is further formed in the valve body, the sinking cavity and the filtering cavity are formed in the two opposite sides of the overflowing cavity respectively, and the sinking cavity is located on the moving path of the valve clack and can contain the valve clack so that the valve clack can be located in the sinking cavity when in the opening position. The filter can realize online decontamination, is convenient and fast to use, and is not limited in mounting direction.

Description

Technical Field

[0001] This utility model relates to the field of fluid pipeline system technology, and in particular to a filter. Background Technology

[0002] Filters are an indispensable device in fluid media transportation pipelines. They are usually installed at the inlet of pressure reducing valves, pressure relief valves, level control valves, or other equipment to filter solid impurities in the water inside the pipeline, preventing impurities from clogging the pipeline or causing scale buildup, thus ensuring the normal operation of valves and equipment.

[0003] like Figure 1 As shown, the existing filter mainly includes a valve body 10, a filter screen 20, and a valve cover 30. The filter screen 20 is installed inside the valve body 10, and the valve cover 30 is used to seal the filter screen 20 inside the valve body 10. The disadvantages of the existing filter are: First, when cleaning solid impurities inside the filter screen 20, the valve cover 30 needs to be opened, and the medium will flow everywhere, even splashing onto the workers. Therefore, online cleaning is not possible. The medium flow in the pipeline can only be stopped during cleaning, and then the valve cover 30 can be removed for cleaning. The operation is cumbersome, and the pipeline cannot operate continuously, resulting in inconvenience. Second, in order to make solid impurities accumulate at the valve cover 30 under the action of gravity for easy cleaning, the installation direction of the filter is limited. During installation, the filter screen 20 can only face downwards.

[0004] Therefore, there is an urgent need to provide a filter to solve the above problems. Utility Model Content

[0005] The purpose of this utility model is to provide a filter that can achieve online cleaning, is convenient and quick to use, and is not restricted in its installation direction.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A filter includes a valve body, a filter screen, and a valve cover. The valve body has a communicating flow chamber and a filter chamber. The filter screen extends from the filter chamber into the flow chamber. The valve body has a port communicating with the filter chamber and the outside. The valve cover is detachably connected to the port.

[0008] It also includes a drain assembly, which includes a valve seat, a valve stem, and a valve disc. The valve seat is located at one end of the filter screen near the valve cover and forms a sludge storage chamber between the filter screen and the valve cover. The valve seat has a drain hole communicating with the sludge storage chamber. One end of the valve stem extends into the valve body and connects to the valve disc, while the other end extends outside the valve cover. The valve stem is used to drive the valve disc to move between a position that seals the drain hole and a position that opens the drain hole. The valve body also has a recessed cavity, which is located on opposite sides of the flow chamber, along with the filter chamber. The recessed cavity is located on the movement path of the valve disc and can accommodate the valve disc so that the valve disc is located in the recessed cavity when it is in the open position.

[0009] As an alternative, the valve disc, when in the open position, is located at the bottom of the sinking cavity and abuts against the inner wall of the valve body.

[0010] As an alternative, the valve seat has a cylindrical structure.

[0011] As an alternative, the valve seat has a protruding edge on the outer edge of one end near the valve cover, and the filter chamber has a limiting step on the inner wall of one end near the valve cover. The valve seat is housed in the filter chamber, and the protruding edge overlaps the limiting step.

[0012] As an alternative, the drain hole is a circular hole, and the valve disc is a circular plate-shaped structure adapted to the shape of the drain hole.

[0013] As an optional solution, a sealing gasket is provided at one end of the valve seat near the filter screen, the sealing gasket is arranged around the periphery of the drain hole, and the valve disc is pressed against the sealing gasket when in the sealed position.

[0014] As an alternative, the valve stem is in a sealing fit with the valve cover, and the valve disc is fixedly connected to the valve stem.

[0015] As an alternative, the valve stem is axially positioned on the valve cover or the valve seat and is rotatable relative to the valve cover or the valve seat, and the valve disc is threaded onto the valve stem and is movable along the valve stem.

[0016] As an alternative, the valve stem is threadedly connected to the valve cover or the valve seat, and the valve stem is fixedly connected to the valve disc.

[0017] As an optional solution, a nut and a handwheel are also included. The nut is threaded onto one end of the valve stem located outside the valve cover, and the handwheel is axially positioned outside the valve cover and fixedly fitted onto the nut. The valve stem is fixedly connected to the valve disc.

[0018] The beneficial effects of this utility model are:

[0019] This utility model provides a filter. When the pipeline is working normally, the valve disc is in the position where the drain hole is open. At this time, the valve disc is in the sinking chamber, which can avoid the medium in the inlet channel, keep the pipeline unobstructed, and reduce the impact of the valve disc on water resistance in the pipeline. At this time, the sludge storage tank is connected to the inside of the filter screen through the drain hole. The medium flows into the filter screen from the inlet channel for filtration and then flows out through the outlet channel. The filtered solid impurities remain inside the filter screen and float in the sludge storage tank through the drain hole under the action of fluid and pipeline pressure. When it is necessary to remove dirt, the valve disc is driven by the valve stem to move along its axis, so that the valve disc moves to the position of sealing the drain hole, cutting off the connection between the sludge storage tank and the inside of the filter screen, so that the solid impurities accumulate in the sludge storage tank. Then, the valve cover is removed, and the solid impurities in the sludge storage tank are cleaned, realizing direct online dirt removal. After completion, the valve cover is fixed, and then the valve disc is moved into the sinking chamber by the valve stem.

[0020] Therefore, the filter provided by this utility model can achieve online cleaning without water interruption or pressure cutoff. It is simple, convenient, and efficient to operate. It avoids the backflow of fluid due to pipeline pressure cutoff, which would bring solid impurities back into the pipeline, resulting in incomplete or ineffective cleaning. At the same time, it can ensure the normal and continuous operation of the pipeline, avoiding economic losses caused by system water interruption or pressure cutoff. In addition, since the impurities are concentrated in the sludge storage bin, the filter is not affected by the opening orientation of the filter screen, so the filter can be installed in any direction. Attached Figure Description

[0021] Figure 1 This is a cross-sectional view of a filter provided by existing technology;

[0022] Figure 2 This is a cross-sectional view of the valve body provided in Embodiment 1 of this utility model;

[0023] Figure 3 This is a first cross-sectional view of the filter provided in Embodiment 1 of this utility model;

[0024] Figure 4 This is a second sectional view of the filter provided in Embodiment 1 of this utility model;

[0025] Figure 5 This is a schematic diagram of the structure of the sewage discharge component provided in Embodiment 1 of this utility model when it is opened;

[0026] Figure 6 This is a first cross-sectional view of the filter provided in Embodiment 2 of this utility model;

[0027] Figure 7 This is a second cross-sectional view of the filter provided in Embodiment 2 of this utility model;

[0028] Figure 8 yes Figure 6 A magnified view of a portion of point A in the middle.

[0029] In the picture:

[0030] 10. Valve body; 20. Filter screen; 30. Valve cover;

[0031] 1. Valve body; 11. Flow chamber; 111. Inlet channel; 112. Outlet channel; 12. Filter chamber; 121. Limiting step; 13. Submerged chamber;

[0032] 2. Filter screen;

[0033] 3. Valve cover; 31. Second limit groove;

[0034] 4. Sewage discharge assembly; 41. Valve seat; 411. Sewage discharge hole; 412. Raised edge; 42. Valve stem; 421. First limit groove; 43. Valve disc; 44. Sewage storage bin; 45. Sealing gasket; 46. Handwheel;

[0035] 5. Retaining ring; 6. Limiting cover. Detailed Implementation

[0036] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0037] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0038] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0039] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0040] Example 1

[0041] like Figure 2 and Figure 3 As shown, this embodiment provides a filter, including a valve body 1, a filter screen 2, and a valve cover 3. The valve body 1 has a connected flow chamber 11 and a filter chamber 12, wherein... Figure 2 The dotted line at the top is the boundary between the flow chamber 11 and the filter chamber 12. The upper part of the dotted line is the filter chamber 12, and the lower part is the flow chamber 11. The filter screen 2 is cylindrical and extends from the filter chamber 12 into the flow chamber 11. That is, part of the filter screen 2 is located in the filter chamber 12, and the other part is located in the flow chamber 11, dividing the flow chamber 11 into an inlet channel 111 on one side and an outlet channel 112 on the other side. The port of the filter screen 2 faces the inlet channel 111. The valve body 1 has a port connecting the filter chamber 12 to the outside, and the valve cover 3 is detachably connected to this port. In use, as... Figure 2 As shown by the arrow, the medium flows into the filter screen 2 from the inlet channel 111 for filtration, and then flows out from the outlet channel 112. The filtered impurities remain inside the filter screen 2, preventing impurities from clogging the pipe or forming scale inside the pipe, thus ensuring the normal use of the valve equipment.

[0042] Furthermore, combined Figure 3 and Figure 5 The filter also includes a drain assembly 4, which includes a valve seat 41, a valve stem 42, and a valve disc 43. The valve seat 41 is located inside the filter chamber 12 and at the end of the filter screen 2 near the valve cover 3. A sludge storage chamber 44 is formed between the valve seat 41 and the valve cover 3. The valve seat 41 has a drain hole 411 communicating with the sludge storage chamber 44. One end of the valve stem 42 extends into the valve body 1 and is connected to the valve disc 43, while the other end extends outside the valve cover 3. The valve stem 42 is used to drive the valve disc 43 to move axially, so that the valve disc 43 switches between a position that seals the drain hole 411 and a position that opens the drain hole 411. Figure 2 The valve body 1 also includes a recessed cavity 13, which, along with the filter cavity 12, is located on opposite sides of the flow chamber 11. Figure 2The dotted line at the bottom is the boundary line between the flow cavity 11 and the sinking cavity 13. The upper part of the dotted line is the flow cavity 11, and the lower part is the sinking cavity 13. The cross-sectional shape of the sinking cavity 13 is similar to a triangle. The sinking cavity 13 is located on the moving path of the valve disc 43 and can accommodate the valve disc 43 so that the valve disc 43 is located within the sinking cavity 13 when in the open position. Figure 3 As shown, when the pipeline is working normally, valve disc 43 is in the position where the drain hole 411 is open. At this time, valve disc 43 is in the sink chamber 13, and valve disc 43 can avoid the medium in the inlet channel 111, keeping the pipeline unobstructed and reducing the impact of valve disc 43 on water resistance in the pipeline. At this time, the sludge storage tank 44 is connected to the inside of the filter screen 2 through the drain hole 411. The medium flows into the filter screen 2 from the inlet channel 111 for filtration, and then flows out through the outlet channel 112. The filtered solid impurities remain inside the filter screen 2 and float in the sludge storage tank 44 through the drain hole 411 under the action of fluid and pipeline pressure. Figure 4 As shown, when cleaning is required, the valve disc 43 is driven to move axially by the valve stem 42, so that the valve disc 43 moves to the position of sealing the drain hole 411, cutting off the connection between the sludge storage chamber 44 and the inside of the filter screen 2, so that solid impurities accumulate in the sludge storage chamber 44, and the pipeline can work normally. Then, the valve cover 3 is removed, and the solid impurities in the sludge storage chamber 44 are cleaned to achieve direct online cleaning. After completion, the valve cover 3 is fixed, and then the valve disc 43 is moved into the sink chamber 13 by the valve stem 42.

[0043] Therefore, the filter provided in this embodiment can achieve online cleaning without water outage or pressure interruption. It is simple, convenient, and efficient to operate, avoiding the backflow of solid impurities into the pipeline due to pressure interruption, which would cause incomplete or ineffective cleaning. At the same time, it can ensure the normal and continuous operation of the pipeline, avoiding economic losses caused by system water outage or pressure interruption. In addition, since the impurities are concentrated in the sludge storage bin 44, they are not affected by the opening orientation of the filter screen 2, so the filter can be installed in any direction.

[0044] Specifically, such as Figure 3 As shown, when the valve disc 43 is in the open position, it is located at the bottom of the sinking chamber 13 and abuts against the inner wall of the valve body 1. In this way, when the pipeline is working normally, the valve disc 43 can completely avoid the medium in the inlet channel 111, keep the pipeline unobstructed, and prevent the valve disc 43 from affecting the water resistance in the pipeline.

[0045] In this embodiment, as Figure 2 As shown, the filter chamber 12 is inclined relative to the flow chamber 11, that is, the filter is a Y-shaped filter. In other alternative embodiments, the filter chamber 12 may also be arranged perpendicular to the flow chamber 11, that is, the filter is a T-shaped filter.

[0046] In this embodiment, to facilitate the disassembly and assembly of the valve cover 3 and ensure a good sealing effect, the valve cover 3 is fixed to the port connecting the filter chamber 12 to the outside using multiple bolts and nuts. In other optional embodiments, the valve cover 3 can also be fixed to the port connecting the filter chamber 12 to the outside using a threaded connection.

[0047] In this embodiment, as Figure 3 and Figure 5 As shown, the valve seat 41 has a cylindrical structure, and the cylindrical structure extends axially to the valve cover 3. That is to say, the valve seat 41 has a sludge storage chamber 44 with a certain volume, which can store the impurities filtered in the pipeline and facilitate cleaning. In another optional embodiment, the valve seat 41 can also be a flat plate structure, and the valve seat 41, the valve cover 3, and the inner wall of the filter chamber 12 together form a closed sludge storage chamber 44.

[0048] Combination Figure 3 The inner wall of the valve body 1 is provided with a step. After the filter screen 2 extends into the flow cavity 11, its bottom end abuts against the step for limiting. The valve seat 41 is housed in the filter cavity 12, and the bottom of the valve seat 41 abuts against the top of the filter screen 2, sealing the filter screen 2 in the filter cavity 12.

[0049] Furthermore, the valve seat 41 has a protruding edge 412 on its outer edge near the valve cover 3, and the filter chamber 12 has a limiting step 121 on its inner wall near the valve cover 3. After the valve seat 41 is housed in the filter chamber 12, the protruding edge 412 overlaps the limiting step 121. The limiting step 121 can support and limit the valve seat 41 to prevent the entire weight of the valve seat 41 from acting on the filter screen 2.

[0050] like Figure 5 As shown, the drain hole 411 is a circular hole that almost covers the entire bottom of the valve seat 41. The valve disc 43 is a circular plate-shaped structure that matches the shape of the drain hole 411. This allows the bottom of the valve seat 41 to have a sufficiently large drain hole 411, ensuring that filtered impurities can fully enter the sludge storage chamber 44 under the pressure of the pipeline and the force of the fluid, resulting in more thorough cleaning. Furthermore, the valve disc 43 is a circular plate-shaped structure with an outer diameter slightly smaller than the inner diameter of the filter screen 2. During cleaning, the valve disc 43 is driven to move by the valve stem 42, moving from one end of the filter screen 2 to the other end and sealing the drain hole 411. Some impurities attached to the inner wall of the filter screen 2 are also carried into the sludge storage chamber 44 when the valve disc 43 moves, resulting in more thorough cleaning.

[0051] Of course, in another optional embodiment, the valve seat 41 can also have an inner ring added to the bottom inner circle of the cylindrical structure. The inner ring is sealed and fitted outside the valve stem 42. The cylindrical structure and the inner ring are connected by at least two connecting ribs. In this case, the drain hole 411 is a fan-shaped annulus.

[0052] Furthermore, such as Figure 3 and Figure 5 As shown, a sealing gasket 45 is provided at the end of the valve seat 41 near the filter screen 2, and the sealing gasket 45 is arranged around the periphery of the drain hole 411. When the valve disc 43 seals the drain hole 411, the valve disc 43 can press against the sealing gasket 45, thereby achieving a reliable seal for the drain hole 411, so as to facilitate online cleaning.

[0053] like Figure 3 and Figure 4 As shown, in this embodiment, in order to achieve the up-and-down movement of the valve disc 43, the valve stem 42 and the valve cover 3 are in a sealing and movable fit. Specifically, the valve stem 42 can slide relative to the valve cover 3, the valve disc 43 and the valve stem 42 are fixedly connected, and the two are coaxially arranged. Figure 4 As shown, when cleaning is required, pull the handle of valve stem 42 protruding from valve cover 3 upwards, causing valve disc 43 to move upwards, thereby sealing the drain hole 411. Then, remove valve cover 3 and remove solid impurities from the storage compartment. At this time, valve disc 43 can completely self-seal due to the pressure of the pipeline fluid. After cleaning, push valve stem 42 to lower valve disc 43 into the sink chamber 13. Since valve disc 43 completely avoids the medium in the inlet channel 111 at this time, valve disc 43 will not be forced to seal the drain hole 411 under the pressure of the pipeline fluid during normal pipeline operation, thus affecting the collection of solid impurities.

[0054] It should be noted that the valve disc 43 and the valve stem 42 can be fixed together by means of screwing, clamping, etc., and no specific limitation is made here.

[0055] To prevent leakage, a sealing ring is provided between the valve stem 42 and the valve cover 3 to ensure the sealing performance between the valve stem 42 and the valve cover 3.

[0056] Example 2

[0057] The filter provided in this embodiment has a basically the same structure as that in Embodiment 1 above, and the similarities will not be repeated here. The main difference is that, Figures 6 to 8 As shown, in order to realize the up and down movement of valve disc 43, valve stem 42 can also be axially positioned inside valve cover 3 or valve seat 41 and can rotate relative to valve cover 3 or valve seat 41. The valve stem 42 is provided with external thread, and valve disc 43 is threadedly connected to valve stem 42 and can move along valve stem 42.

[0058] In other words, the valve stem 42 can only rotate and cannot move axially. By rotating the valve stem 42, the valve disc 43 moves up and down along the thread of the valve stem 42, so that the valve disc 43 can switch between the open position and the sealed position. However, the speed of the valve stem 42 sliding method in the first embodiment is slower.

[0059] In this embodiment, to prevent the valve disc 43 from rotating when the valve stem 42 is rotated, one of the protrusions or grooves needs to be provided on the circumference of the valve disc 43, and the other of the protrusions or grooves needs to be provided on the moving path of the valve disc 43 (the inner wall of the valve body 1 and the inner wall of the filter screen 2). In this way, the valve disc 43 can be circumferentially limited by the cooperation of the protrusions and grooves, preventing the valve disc 43 from rotating when the valve stem 42 is rotated.

[0060] like Figure 6 As shown, in this embodiment, the sewage discharge assembly 4 also includes a handwheel 46, which is detachably connected to the end of the valve stem 42 located outside the valve cover 3. By rotating the handwheel 46, the valve stem 42 can be driven to rotate, thereby causing the valve disc 43 to move up and down along the valve stem 42, which is convenient to operate and saves time and effort.

[0061] In this embodiment, in order to limit the axial movement of the valve stem 42, such as Figure 6 and Figure 8 As shown, the filter also includes a retaining ring 5 and a limiting cover 6. A first limiting groove 421 is provided on the outer wall of the valve stem 42, and a second limiting groove 31 is provided on the outer end face of the valve cover 3. The second limiting groove 31 is arranged around the outer periphery of the first limiting groove 421. The retaining ring 5 is simultaneously housed within the first limiting groove 421 and the second limiting groove 31. The limiting cover 6 is fitted onto the valve stem 42 and fixedly connected to the outer end face of the valve cover 3 by multiple screws. The limiting cover 6 presses against the retaining ring 5. By restricting the retaining ring 5 with the limiting cover 6, the valve stem 42 can only rotate and cannot move axially. During decontamination, the handwheel 46 is first removed, then the limiting cover 6 is removed to release the restriction on the retaining ring 5. Then, the valve cover 3 is removed, causing the valve cover 3 to move the retaining ring 5 away from the valve stem 42. Finally, the solid impurities in the sludge storage bin 44 are cleaned, achieving direct online decontamination.

[0062] In another optional embodiment, if the valve seat 41 has an inner ring portion that seals with the valve stem 42, the axial fixed connection between the valve stem 42 and the inner ring portion of the valve seat 41 is the same as the axial fixed connection between the valve stem 42 and the valve cover 3 described above, and will not be repeated here.

[0063] Example 3

[0064] The filter provided in this embodiment has a structure that is basically the same as that in Embodiment 1 above, and the similarities will not be repeated here. The main difference is that, in order to realize the up-and-down movement of the valve disc 43, the valve stem 42 is threadedly connected to the valve cover 3 or the valve seat 41, and the valve stem 42 is fixedly connected to the valve disc 43. That is to say, the valve stem 42 both rotates and moves. By rotating the valve stem 42, the valve stem 42 moves up and down at the same time, thereby driving the valve disc 43 to move up and down together, so that the valve disc 43 switches between the open position and the sealed position.

[0065] Example 4

[0066] The filter provided in this embodiment has a structure that is basically the same as that in the first embodiment above. The similarities will not be repeated here. The main difference is that, in order to realize the up and down movement of the valve disc 43, the filter also includes a nut and a handwheel. The nut is threaded on the end of the valve stem 42 located outside the valve cover 3, so that the valve stem 42 is threadedly connected to the nut. The handwheel is axially positioned outside the valve cover 3 and fixedly fitted outside the nut. The valve stem 42 and the valve disc 43 are fixedly connected.

[0067] In other words, both the handwheel and the nut can only rotate and cannot move axially. A support seat is provided on the valve cover 3, and the handwheel is rotatably connected to this support seat to be axially positioned outside the valve cover 3. The valve stem 42 can only move axially. The handwheel drives the nut to rotate, causing the valve stem 42 to move axially relative to the nut. Simultaneously, the valve stem 42 drives the valve disc 43 to move up and down, thus switching the valve disc 43 between the open and sealed positions. It should be noted that this structure for driving the valve stem 42 is similar to the setup of a rising stem gate valve in the prior art, and will not be elaborated further here.

[0068] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make various obvious changes, readjustments, and substitutions without departing from the protection scope of this utility model. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A filter comprising a valve body (1), a filter screen (2), and a valve cover (3), wherein the valve body (1) has a communicating flow chamber (11) and a filter chamber (12), the filter screen (2) extends from the filter chamber (12) into the flow chamber (11), the valve body (1) has a port communicating with the filter chamber (12) and the outside, and the valve cover (3) is detachably connected to the port, characterized in that: It also includes a drain assembly (4), which includes a valve seat (41), a valve stem (42), and a valve disc (43). The valve seat (41) is located at one end of the filter screen (2) near the valve cover (3) and forms a sludge storage chamber (44) between the filter screen (2) and the valve cover (3). The valve seat (41) has a drain hole (411) communicating with the sludge storage chamber (44). One end of the valve stem (42) extends into the valve body (1) and connects to the valve disc (43), while the other end extends to the outside of the valve cover (3). The rod (42) is used to drive the valve disc (43) to move between the position of sealing the drain hole (411) and the position of opening the drain hole (411). The valve body (1) is also provided with a sinking cavity (13). The sinking cavity (13) and the filter cavity (12) are respectively located on opposite sides of the flow cavity (11). The sinking cavity (13) is located on the moving path of the valve disc (43) and can accommodate the valve disc (43) so that the valve disc (43) is located in the sinking cavity (13) when it is in the open position.

2. The filter of claim 1, wherein, When in the open position, the valve disc (43) is located at the bottom of the sinking cavity (13) and abuts against the inner wall of the valve body (1).

3. The filter according to claim 1, characterized in that, The valve seat (41) has a cylindrical structure.

4. The filter according to claim 3, characterized in that, The valve seat (41) has a raised edge (412) on the outer edge of one end near the valve cover (3), and the filter cavity (12) has a limiting step (121) on the inner wall of one end near the valve cover (3). The valve seat (41) is housed in the filter cavity (12), and the raised edge (412) overlaps the limiting step (121).

5. The filter according to claim 3, characterized in that, The drain hole (411) is a circular hole, and the valve disc (43) is a circular plate-shaped structure adapted to the shape of the drain hole (411).

6. The filter of claim 1, wherein, A sealing gasket (45) is provided at one end of the valve seat (41) near the filter screen (2). The sealing gasket (45) is arranged around the periphery of the drain hole (411). The valve disc (43) is pressed against the sealing gasket (45) when in the sealed position.

7. The filter according to any one of claims 1 to 6, wherein The valve stem (42) is in a sealing and movable fit with the valve cover (3), and the valve disc (43) is fixedly connected to the valve stem (42).

8. The filter according to any one of claims 1-6, characterized in that, The valve stem (42) is axially positioned on the valve cover (3) or the valve seat (41) and can rotate relative to the valve cover (3) or the valve seat (41). The valve disc (43) is threaded onto the valve stem (42) and can move along the valve stem (42).

9. The filter according to any one of claims 1-6, characterized in that, The valve stem (42) is threadedly connected to the valve cover (3) or the valve seat (41), and the valve stem (42) is fixedly connected to the valve disc (43).

10. The filter according to any one of claims 1-6, characterized in that, It also includes a nut and a handwheel. The nut is threaded onto one end of the valve stem (42) outside the valve cover (3). The handwheel is axially positioned outside the valve cover (3) and fixedly fitted onto the nut. The valve stem (42) is fixedly connected to the valve disc (43).

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