CN217328640U

CN217328640U - Piston type filtering pressure reducing valve

Info

Publication number: CN217328640U
Application number: CN202221411827.8U
Authority: CN
Inventors: 董西伟
Original assignee: Taizhou Bomiao Water Control Equipment Co ltd
Current assignee: Taizhou Bomiao Water Control Equipment Co ltd
Priority date: 2022-06-07
Filing date: 2022-06-07
Publication date: 2022-08-30
Anticipated expiration: 2032-06-07

Abstract

The utility model provides a piston filters relief pressure valve belongs to valve technical field. It has solved the not good problem that leads to the fact life is short of filter effect. The water filter comprises a valve body with a water inlet and a water outlet, wherein a water passing cavity communicated with the water inlet and the water outlet is formed in the valve body, a piston pressure regulating assembly is arranged in the water passing cavity, a filter channel is arranged between the water inlet and the water passing cavity in the valve body, a round sleeve-shaped filter screen is arranged in the filter channel, the length of the filter screen is smaller than that of the filter channel, a water passing gap is formed between the outer wall of the filter screen and the inner wall of the filter channel, the water inlet is communicated with the water passing gap, and the outlet of the filter channel is communicated with the water passing cavity. It has the advantages of good filtering effect, long service life and the like.

Description

Piston type filtering pressure reducing valve

Technical Field

The utility model belongs to the technical field of the valve, a piston filters relief pressure valve is related to.

Background

The pressure reducing valve is a self-operated pressure difference control device, the working principle of the pressure reducing valve is that the inlet pressure is reduced to a certain required outlet pressure, the outlet pressure is automatically kept stable by means of the energy of a medium, and most of the pressure reducing valves at present rely on a spring arranged inside the pressure reducing valve to achieve the pressure regulating effect. Most relief pressure valve structures for example patent application number is 202121266940.7's a brass forging and pressing double-piston relief pressure valve, it is including the valve body that has the runner, be located the upper cover of valve body top and be located the bottom of valve body below, the valve body right side sets up the water inlet, the left side sets up the delivery port, wear to be equipped with holding screw on covering, holding screw is located one end in the upper cover and is provided with the pressure regulating pad, be provided with the piston in the valve body, be provided with the pressure regulating spring in the upper cover, the pressure regulating spring both ends are supported respectively to lean on and are installed on pressure regulating pad and piston, be provided with down the piston assembly in the bottom, lower piston assembly installs in piston one end, specifically, piston one end is provided with and supplies the pressure regulating spring to support to lean on the installation step of installation, O type sealing washer two has between installation step and the internal perisporium of valve body. When the pressure-reducing valve is used, water flows into the water inlet from the water inlet to the water outlet through the flow passage, water pressure acts on the piston while the water flows through the valve body, and if the water pressure is too high (larger than the elastic force of the pressure-regulating spring), the piston is forced to move to reduce the opening of the flow passage so as to realize pressure reduction.

The leakproofness between installation step and the valve body internal perisporium has very important effect to the life of whole relief pressure valve, finds often that there is particle impurity card between installation step and valve body internal perisporium in the use, leads to O type sealing washer two very easily just to produce serious wearing and tearing along with the in-process that the piston removed. For this reason, someone has proposed a pressure reducing valve of patent application No. 202020674681.0, it has set up filter equipment in the inlet end department of valve body on the foundation structure of original pressure reducing valve, filter equipment is located the radial face of valve body, the radial face of valve body entrance point is equipped with first mounting groove, the opening of first mounting groove is down, be equipped with the internal thread on the open wall of first opening, filter equipment includes the filter screen, first end cap, the filter screen is installed in first mounting groove and is compressed tightly through the first end cap of threaded connection on first opening. The valve body is characterized in that the filter screen is used for filtering water flowing into the valve body from the inlet end, however, the filter screen is vertically arranged with the inlet end, and in actual use, a lot of water directly enters the valve body from a gap between the filter screen and the inner wall of the inlet end without passing through the filter screen, so that the actual filtering effect is poor.

SUMMERY OF THE UTILITY MODEL

The utility model aims at the above-mentioned problem that prior art exists, provide a piston type filtering pressure reducing valve, solved the not good problem that the life that causes of filter effect is short.

The purpose of the utility model can be realized by the following technical proposal:

piston filter relief pressure valve, including the valve body that has water inlet and delivery port, the valve body in have the water cavity of crossing that is linked together water inlet and delivery port, cross the intracavity and be equipped with piston pressure regulating subassembly, be equipped with the filtration passageway in the valve body between water inlet and the water cavity of crossing, be equipped with the filter screen of circle cover form in the filtration passageway, its characterized in that, the length of filter screen be less than the length of filtering the passageway, form the water clearance between the outer wall of filter screen and the inner wall of filtering the passageway, the water inlet is linked together with crossing the water clearance, the export and the water cavity of filtering the passageway are linked together.

The central line of the filter screen is arranged along the filter channel, the water inlet is communicated with the water passing gap between the outer wall of the filter screen and the inner wall of the filter channel when the length of the filter screen is smaller than that of the filter channel, so that water can only flow into the water passing cavity after being filtered by the filter screen after entering the water passing gap, and can not directly enter the water passing cavity, thereby greatly improving the filtering effect, avoiding the influence on the sealing performance between the piston pressure regulating assembly and the inner wall of the water passing cavity due to the impurities entering the water passing cavity, and prolonging the service life of the piston type filtering pressure reducing valve.

In the piston type filtering pressure reducing valve, the filtering channel comprises a first channel part and a second channel part which are arranged on the same central line, the filtering net is arranged in the first channel part, and the second channel part is communicated with the water passing cavity.

The filtering channel comprises a first channel part and a second channel part which are arranged at the same center line, and the filtering net is arranged in the first channel part, which means that the length of the filtering channel is greater than that of the filtering net, thus ensuring that water can only completely flow into the water passing cavity after being filtered by the filtering net after entering the water passing gap.

In the above piston type filtering pressure reducing valve, the first passage portion has a larger inner diameter than the second passage portion.

The internal diameter of first passageway portion is greater than second passageway portion, means that the filter screen can set for great, and filter area is just so beaten, has guaranteed the area of overflowing. Meanwhile, the arrangement can also increase the flow speed when the water flows into the second channel part.

In the above piston type filtering pressure reducing valve, a check valve is provided in the second passage.

In the piston type filtering pressure reducing valve, an annular positioning seat is arranged at the joint of the first channel part and the second channel part, and one end of the filter screen abuts against the positioning seat.

In the piston type filtering pressure reducing valve, the inlet of the filtering channel is in threaded connection with the plugging cap, and the other end of the filter screen abuts against the inner side of the plugging cap.

In foretell piston filter relief pressure valve, the valve body in have the baffle that separates the cavity of crossing water for first cavity and second cavity, the export of filtering the passageway is linked together and delivery port and second cavity are linked together, be provided with the water hole on the baffle, piston pressure regulating subassembly is including passing the water hole and can follow axial displacement's core bar, fixed connection is located the seal receptacle of first cavity one end and is used in the pressure regulating spring of core bar position in the second cavity in the seal receptacle of core bar position in one end of first cavity and effect, the outside that the core bar is close to its one end that is located the second cavity has the guide part, be equipped with sealing member one between the guide part outside and the second cavity inner wall.

In foretell piston filter relief pressure valve, the guide part outside still be equipped with sealing member two and sealing member three and sealing member one, sealing member two sets gradually along keeping away from the water hole direction with sealing member three, one side that sealing member two is close to sealing member one has outer edge and the second cavity inner wall supports the sealing member two that leans on, the last notch two that has the notch towards sealing member one of sealing member two, one side that sealing member three is close to sealing member two has outer edge and the second cavity inner wall supports the sealing member three that leans on, the last notch three that has the notch towards sealing member two of sealing member three, sealing member two and sealing member three all have elastic deformation ability and the hardness of sealing member two is greater than sealing member three.

On the basis of the first sealing element, a second sealing element and a third sealing element are additionally arranged between the guide part and the inner wall of the second cavity, and the first sealing element, the second sealing element and the third sealing element are in a contact state with the inner wall of the second cavity in a normal state. However, when the first sealing part is not worn to a failure state, water does not contact with the second sealing part of the second sealing part, meanwhile, the second sealing part is worn to a lesser extent than the first sealing part due to the existence of the second groove, and meanwhile, the third sealing part is worn to a lesser extent than the second sealing part due to hardness being smaller than the second sealing part. When the first sealing piece fails in the long-term action of the piston pressure regulating assembly, water enters a space between the first sealing piece and the second sealing part from a gap between the first sealing piece and the inner wall of the second cavity and starts to act on the second sealing part. When water enters the second groove of the second sealing part, water pressure exerts acting force on the second sealing part from the groove walls on the two sides of the second groove, and the second sealing part deforms to enable the outer edge of the second sealing part to be tightly abutted against the inner wall of the second cavity, so that effective sealing between the guide part and the inner wall of the second cavity is guaranteed in the state that the first sealing part fails. When the second sealing part of the sealing element fails due to abrasion, water enters a space between the second sealing part and the third sealing part from a gap between the second sealing part and the inner wall of the second cavity and starts to act on the third sealing part. When water enters the third groove of the third sealing part, the water pressure exerts acting force on the third sealing part from the groove walls on the two sides of the third groove, and the third sealing part deforms to enable the outer edge of the third sealing part to be tightly abutted against the inner wall of the second cavity, so that effective sealing between the guide part and the inner wall of the second cavity is guaranteed in the state that the second sealing part is small. Through the arrangement, the sealing service life between the guide part and the inner wall of the second cavity is greatly prolonged, so that the service life of the whole piston type filtering pressure reducing valve is prolonged.

In foretell piston relief pressure valve, the guide part be cylindricly, the guide part outside is equipped with annular mounting groove one, annular mounting groove two and annular mounting groove three in proper order, sealing member one is located annular mounting groove one, sealing member two is located in annular mounting groove two and sealing member three is located annular mounting groove three.

The guide portion is provided in a cylindrical shape, so that the guide portion has a sufficient length to mount the first seal, the second seal, and the third seal.

In the piston type pressure reducing valve, the guide part is in clearance fit with the inner wall of the second cavity, a second positioning step is arranged between the groove wall of one side, close to the first sealing element, of the second annular mounting groove and the bottom wall of the second annular mounting groove, a third positioning step is arranged between the groove wall of one side, close to the second sealing element, of the third annular mounting groove and the bottom wall of the second annular mounting groove, the position, close to the inner edge, of the second sealing part abuts against the second positioning step, and the position, close to the inner edge, of the third sealing part abuts against the third positioning step.

The piston pressure regulating assembly needs to move, so that the guide part and the inner wall of the second cavity need to be in clearance fit in order to avoid eccentric wear, the clearance between the outer wall of the guide part and the inner wall of the second cavity is very small, the second groove or the third groove can hardly extend out of the outer side of the guide part, and the water pressure is not easy to enter the second groove or the third groove.

Therefore, a second positioning step is arranged between the groove wall of one side, close to the first sealing element, of the second annular mounting groove and the bottom wall of the second annular mounting groove, the position, close to the inner edge, of the second sealing part abuts against the second positioning step, the position of the second groove is raised, a gap through which water can flow is formed between the second sealing part and the groove wall of one side, close to the first sealing element, of the second annular mounting groove, and therefore water can smoothly enter the second groove and the second sealing part is forced to deform through water pressure. A third positioning step is arranged between the groove wall on one side, close to the second sealing element, of the third annular mounting groove and the bottom wall of the third annular mounting groove, the position, close to the inner edge, of the third sealing part abuts against the third positioning step, the position of the third groove is raised, a gap through which water can flow is formed between the third sealing part and the groove wall on one side, close to the second sealing element, of the third annular mounting groove, and therefore water can smoothly enter the third groove and is forced to deform through water pressure.

In the piston type pressure reducing valve, the bottom of the guide part is provided with a weight reducing groove, and a reinforcing rib is integrally and fixedly connected between the core rod and the inner side groove wall of the weight reducing groove.

The arrangement of the weight reduction groove can reduce the moving resistance to the core rod caused by the cylindrical arrangement of the guide part, and meanwhile, the arrangement of the reinforcing ribs ensures the overall structural strength of the core rod.

Compared with the prior art, the piston type filtering pressure reducing valve has the advantages that the filtering channel is obliquely arranged to enable the inlet of the filtering channel to be closer to the water inlet than the outlet of the filtering channel, the length of the filtering screen is smaller than that of the filtering channel, meanwhile, the water inlet is communicated with the water passing gap between the outer wall of the filtering screen and the inner wall of the filtering channel, so that water can only flow into the water passing cavity after being filtered by the filtering screen after entering the water passing gap, and can not directly enter the water passing cavity, the filtering effect is greatly improved, the influence on the sealing performance between the piston pressure regulating assembly and the inner wall of the water passing cavity due to the fact that impurities enter the water passing cavity is avoided, and the service life of the piston type filtering pressure reducing valve is prolonged.

On the basis of the first sealing element, a second sealing element and a third sealing element are additionally arranged, the second sealing element can be used for sealing when the first sealing element fails due to abrasion, and the third sealing element can be used for sealing when the second sealing element fails due to abrasion, so that the sealing service life between the guide part and the inner wall of the valve body is greatly prolonged, and the service life of the whole piston type pressure reducing valve is prolonged.

Drawings

FIG. 1 is a cross-sectional view of a first embodiment of the present piston-type filter and pressure relief valve.

Fig. 2 is a partially enlarged view of a portion a in fig. 1.

FIG. 3 is a schematic view of a core rod of the present pistonic filter and pressure relief valve.

FIG. 4 is a cross-sectional view of a third embodiment of the present piston-type filter relief valve.

In the figure, 1, a valve body; 1a, a water inlet; 1b, a water outlet; 1c, a water passing cavity; 1c1, a first cavity; 1c2, second cavity; 1d, a filtering channel; 1d1, a first channel part; 1d11, positioning seat; 1d2, a second channel part; 1e, a partition plate; 1e1, water passing hole; 2. a piston pressure regulating assembly; 2a, a core rod; 2a1, a guide; 2a11, a first annular mounting groove; 2a12 and a second annular mounting groove; 2a13 and a third annular mounting groove; 2a14 and a positioning step II; 2a15 and a positioning step III; 2a16, weight-reduction grooves; 2a2, reinforcing ribs; 2b, a sealing seat; 2c, a pressure regulating spring; 3. a filter screen; 4. a water passing gap; 5. a plugging cap; 6. a pressure stabilizing spring; 7. a first sealing element; 8. a second sealing element; 8a and a second sealing part; 8a1 and a second groove; 9. a third sealing element; 9a, a third sealing part; 9a1 and a groove III; 10. a check valve.

Detailed Description

The following are specific embodiments of the present invention and the accompanying drawings are used to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

Example one

As shown in fig. 1, the piston type filtering pressure reducing valve includes a valve body 1 having a water inlet 1a and a water outlet 1b, a water passing cavity 1c communicating the water inlet 1a with the water outlet 1b is provided in the valve body 1, and a piston pressure regulating assembly 2 is provided in the water passing cavity 1 c. Be equipped with filtration passageway 1d in valve body 1 between water inlet 1a and the water cavity 1c of crossing, be equipped with the filter screen 3 of circle cover form in the filtration passageway 1d, the import that filtration passageway 1d slope set up and filtration passageway 1d is compared and will be closer to water inlet 1a in the export, filter screen 3 sets up along the inclination of filtration passageway 1d, the length of filter screen 3 is less than the length of filtration passageway 1d, form water clearance 4 between the outer wall of filter screen 3 and the inner wall of filtration passageway 1d, water inlet 1a is linked together with water clearance 4, the export of filtration passageway 1d is linked together with the water cavity 1c of crossing. The filtering channel 1d comprises a first channel part 1d1 and a second channel part 1d2 which are arranged on the same center line, the inner diameter of the first channel part 1d1 is larger than that of the second channel part 1d2, the filtering net 3 is arranged in the first channel part 1d1, and the second channel part 1d2 is communicated with the water passing cavity 1 c.

The filter channel 1d is inclined, the inlet of the filter channel is closer to the water inlet 1a than the outlet, the length of the filter screen 3 is smaller than that of the filter channel 1d, the water inlet 1a is communicated with the water passing gap 4 between the outer wall of the filter screen 3 and the inner wall of the filter channel 1d, and therefore water can only completely flow into the water passing cavity 1c after being filtered by the filter screen 3 after entering the water passing gap 4 and can not directly enter the water passing cavity 1c, the filtering effect is greatly improved, the influence of impurities entering the water passing cavity 1c on the sealing performance between the piston pressure regulating assembly 2 and the inner wall of the water passing cavity 1c is avoided, and the service life of the piston type filtering pressure reducing valve is prolonged.

In the present embodiment, as shown in fig. 1, the joint of the first channel portion 1d1 and the second channel portion 1d2 has an annular positioning seat 1d11, and one end of the filter screen 3 abuts against the positioning seat 1d 11. The inlet of the filtering channel 1d is connected with a blocking cap 5 by screw thread, and the other end of the filter screen 3 is propped against the inner side of the blocking cap 5.

Specifically, as shown in fig. 1, a partition plate 1e is provided in the valve body 1 to divide the water passing cavity 1c into a first cavity 1c1 and a second cavity 1c2, an outlet of the filter passage 1d is communicated with the first cavity 1c1, a water outlet 1b is communicated with the second cavity 1c2, a water passing hole 1e1 is provided in the partition plate 1e, the piston pressure regulating assembly 2 comprises a core rod 2a which passes through the water passing hole 1e1 and can move along the axial direction, the sealing seat 2b is fixedly connected to one end of the core rod 2a, which is located in the first cavity 1c1, and the pressure regulating spring 2c acts on one end of the core rod 2a, which is located in the second cavity 1c2, when the core rod 2a moves in the axial direction, the sealing seat 2b can control the inlet end of the water through hole 1e1 to be opened or closed, and the elastic force direction of the pressure regulating spring 2c acting on the core rod 2a is opposite to the direction that the sealing seat 2b moves to close the inlet end of the water through hole 1e 1. A pressure stabilizing spring 6 acting on the sealing seat 2b is also arranged in the first cavity 1c1, and the acting direction of the pressure stabilizing spring 6 is opposite to the acting direction of the pressure regulating spring 2 c.

As shown in fig. 1, 2 and 3, the core rod 2a has a guide part 2a1 near the outer side of one end of the core rod located in the second cavity 1c2, and a first sealing element 7 is arranged between the outer side of the guide part 2a1 and the inner wall of the second cavity 1c 2. The outer side of the guide part 2a1 is further provided with a second sealing element 8 and a third sealing element 9, the first sealing element 7 and the second sealing element 8 and the third sealing element 9 are sequentially arranged along the direction far away from the water through hole 1e1, one side of the second sealing element 8 close to the first sealing element 7 is provided with a second sealing part 8a with an outer edge abutting against the inner wall of the second cavity 1c2, the second sealing part 8a is provided with a second groove 8a1 with a notch facing the first sealing element 7, one side of the third sealing element 9 close to the second sealing element 8 is provided with a third sealing part 9a with an outer edge abutting against the inner wall of the second cavity 1c2, the third sealing part 9a is provided with a third groove 9a1 with a notch facing the second sealing element 8, the second sealing part 8a and the third sealing part 9a both have elastic deformation capacity, and the hardness of the second sealing part 8a is greater than that of the third sealing part 9 a.

On the basis of the first sealing element 7, a second sealing element 8 and a third sealing element 9 are additionally arranged between the guide part 2a1 and the inner wall of the second cavity 1c2, and the first sealing element 7, the second sealing element 8 and the third sealing element 9 are in a contact state with the inner wall of the second cavity 1c2 in a normal state. However, when the first seal 7 is not worn to a failure state, water does not contact the second seal portion 8a of the second seal 8, and the second seal portion 8a is worn less than the first seal portion 7 due to the second groove 8a1, and the third seal portion 9a is worn less than the second seal portion 8a due to the hardness being less than the second seal portion 8 a. When the first sealing member 7 fails in the long-term movement of the piston pressure regulating assembly 2, water enters into the space between the first sealing member 7 and the second sealing portion 8a from the gap between the first sealing member 7 and the inner wall of the second chamber 1c2 and starts to act on the second sealing portion 8 a. When water enters the second groove 8a1 of the second sealing portion 8a, water pressure exerts force on the second sealing portion 8a from the groove walls on both sides of the second groove 8a1, and the second sealing portion 8a deforms accordingly such that the outer edge of the second sealing portion forms a tight abutment with the inner wall of the second cavity 1c2, thereby ensuring effective sealing between the guiding portion 2a1 and the inner wall of the second cavity 1c2 in a state where the first sealing portion 7 fails. When the second seal portion 8a of the seal is failed by abrasion, water enters into a space between the second seal portion 8a and the third seal portion 9a from a gap between the second seal portion 8a and the inner wall of the second cavity 1c2 and starts to act on the third seal portion 9 a. When water enters the groove III 9a1 of the sealing part III 9a, water pressure exerts force on the sealing part III 9a from the groove walls on the two sides of the groove III 9a1, and the sealing part III 9a deforms accordingly so that the outer edge of the sealing part III forms close abutment with the inner wall of the second cavity 1c2, thereby ensuring effective sealing between the guide part 2a1 and the inner wall of the second cavity 1c2 in a small state of the sealing part II 8 a. Through the arrangement, the sealing life between the guide part 2a1 and the inner wall of the second cavity 1c2 is greatly prolonged, so that the service life of the whole piston type filtering pressure reducing valve is prolonged.

As shown in fig. 2 and 3, the guide portion 2a1 is cylindrical, the bottom of the guide portion 2a1 is provided with a lightening groove 2a16, and the reinforcing rib 2a2 is integrally connected between the core bar 2a and the inner groove wall of the lightening groove 2a 16. The outer side of the guide part 2a1 is sequentially provided with a first annular mounting groove 2a11, a second annular mounting groove 2a12 and a third annular mounting groove 2a13, a first sealing element 7 is arranged in the first annular mounting groove 2a11, a second sealing element 8 is arranged in the second annular mounting groove 2a12, and a third sealing element 9 is arranged in the third annular mounting groove 2a 13. The guide part 2a1 is in clearance fit with the inner wall of the second cavity 1c2, a positioning step two 2a14 is arranged between the groove wall of one side, close to the first sealing element 7, of the annular mounting groove two 2a12 and the bottom wall of the annular mounting groove two 2a, a positioning step three 2a15 is arranged between the groove wall of one side, close to the second sealing element 8, of the annular mounting groove three 2a13 and the bottom wall of the annular mounting groove three 2a, the position, close to the inner edge, of the second sealing part 8a abuts against the positioning step two 2a14, and the position, close to the inner edge, of the third sealing part 9a abuts against the positioning step three 2a 15. In this embodiment, the first sealing element 7 is an O-ring, and the second sealing element 8 and the third sealing element 9 are both Y-shaped frameless oil seals.

Example two

The structure and principle of this embodiment are basically the same as those of the first embodiment, except that: in the present embodiment, the first sealing element 7 is a frameless oil seal, one side of the first sealing element 7, which faces away from the second sealing element 8, is provided with a first sealing part, the outer edge of which abuts against the inner wall of the second cavity 1c2, and the first sealing part is provided with a first groove, the groove opening of which faces away from the second sealing element 8. A first positioning step is arranged between the groove wall of one side, far away from the second sealing element 8, of the first annular sealing groove and the bottom wall of the first annular sealing groove, and the position, close to the inner edge, of the first sealing part abuts against the first positioning step.

EXAMPLE III

The structure and principle of this embodiment are basically the same as those of the first embodiment, except that: in the present embodiment, as shown in fig. 4, the check valve 10 is provided in the second passage portion 1d 2.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications, additions and substitutions for the specific embodiments described herein may be made by those skilled in the art without departing from the spirit of the invention or exceeding the scope of the invention as defined in the accompanying claims.

Claims

1. A piston type filtering pressure reducing valve comprises a valve body (1) with a water inlet (1a) and a water outlet (1b), the valve body (1) is internally provided with a water passing cavity (1c) which is used for communicating the water inlet (1a) with the water outlet (1b), a piston pressure regulating assembly (2) is arranged in the water passing cavity (1c), a filtering channel (1d) is arranged between the water inlet (1a) and the water passing cavity (1c) in the valve body (1), a round sleeve-shaped filtering net (3) is arranged in the filtering channel (1d), the water filter is characterized in that the length of the filter screen (3) is smaller than that of the filter channel (1d), a water passing gap (4) is formed between the outer wall of the filter screen (3) and the inner wall of the filter channel (1d), the water inlet (1a) is communicated with the water passing gap (4), and the outlet of the filter channel (1d) is communicated with the water passing cavity (1 c).

2. The piston type filtering pressure reducing valve according to claim 1, characterized in that the filtering passage (1d) comprises a first passage part (1d1) and a second passage part (1d2) which are arranged in the same center line, the filtering net (3) is arranged in the first passage part (1d1), and the second passage part (1d2) is communicated with the water passing cavity (1 c).

3. The piston-type filtering and pressure-reducing valve as claimed in claim 2, wherein the first passage portion (1d1) has a larger inner diameter than the second passage portion (1d 2).

4. The piston-type filter and pressure relief valve as claimed in claim 3, characterized in that a check valve (10) is provided in said second passage portion (1d 2).

5. The piston type filtering and pressure reducing valve as claimed in claim 3, characterized in that the joint of the first channel part (1d1) and the second channel part (1d2) is provided with an annular positioning seat (1d11), and one end of the filter screen (3) abuts against the positioning seat (1d 11).

6. A piston type filtering and pressure reducing valve according to claim 1 or 2 or 3 or 4 or 5, characterized in that a plugging cap (5) is screwed at the inlet of the filtering channel (1d), and the other end of the filtering net (3) is abutted against the inner side of the plugging cap (5).

7. The piston type filtering and pressure reducing valve according to claim 1, characterized in that the valve body (1) is provided with a partition plate (1e) which divides the water passing cavity (1c) into a first cavity (1c1) and a second cavity (1c2), the outlet of the filtering channel (1d) is communicated with the first cavity (1c1), the water outlet (1b) is communicated with the second cavity (1c2), the partition plate (1e) is provided with a water passing hole (1e1), the piston pressure regulating assembly (2) comprises a core rod (2a) which passes through the water passing hole (1e1) and can move along the axial direction, a sealing seat (2b) which is fixedly connected with the core rod (2a) and is positioned at one end of the first cavity (1c1), and a pressure regulating spring (2c) which is used at one end of the core rod (2a) and is positioned in the second cavity (1c2), and the guide part (2a1) is arranged at the outer side of the core rod (2a) close to one end of the core rod (2a) and is positioned in the second cavity (1c2), a first sealing element (7) is arranged between the outer side of the guide part (2a1) and the inner wall of the second cavity (1c 2).

8. The piston type filtering and pressure reducing valve as claimed in claim 7, characterized in that a second sealing element (8) and a third sealing element (9) are further arranged outside the guide part (2a1), the first sealing element (7) and the second sealing element (8) and the third sealing element (9) are sequentially arranged along the direction far away from the water through hole (1e1), one side of the second sealing element (8) close to the first sealing element (7) is provided with a second sealing part (8a) with an outer edge abutting against the inner wall of the second cavity (1c2), the second sealing part (8a) is provided with a second groove (8a1) with a notch facing towards the first sealing element (7), one side of the third sealing element (9) close to the second sealing element (8) is provided with a third sealing part (9a) with an outer edge abutting against the inner wall of the second cavity (1c2), the third sealing part (9a) is provided with a third groove (9a1) with a notch facing towards the second sealing element (8), and the second sealing part (8a) and the third sealing part (9a) and have elastic deformation capacity and the second sealing part (8a) Is greater than the third seal portion (9 a).

9. The piston type filtering and pressure reducing valve according to claim 8, characterized in that the guide part (2a1) is cylindrical, a first annular mounting groove (2a11), a second annular mounting groove (2a12) and a third annular mounting groove (2a13) are sequentially arranged on the outer side of the guide part (2a1), the first sealing element (7) is arranged in the first annular mounting groove (2a11), the second sealing element (8) is arranged in the second annular mounting groove (2a12) and the third sealing element (9) is arranged in the third annular mounting groove (2a 13).

10. The piston type filtering and pressure reducing valve as claimed in claim 9, characterized in that the guide part (2a1) is in clearance fit with the inner wall of the second cavity (1c2), a positioning step II (2a14) is arranged between the groove wall of one side of the annular mounting groove II (2a12) close to the sealing element I (7) and the bottom wall of the annular mounting groove II, a positioning step III (2a15) is arranged between the groove wall of one side of the annular mounting groove III (2a13) close to the sealing element II (8) and the bottom wall of the annular mounting groove II, the sealing part II (8a) abuts against the positioning step II (2a14) close to the inner edge position, and the sealing part III (9a) abuts against the positioning step III (2a15) close to the inner edge position.