CN117212501A - Three-way converging regulating valve group for realizing efficient flow proportioning regulation and method thereof - Google Patents

Abstract

The invention discloses a three-way converging regulating valve group and a method for realizing efficient flow proportioning regulation, and belongs to the field of valves. The valve group consists of a three-way main valve and a pilot-operated pressure reducing valve, wherein a main valve core of the three-way main valve is designed into a barrel with a side window, the flow ratio of two inlets can be uniformly regulated and controlled through annular movement, a pilot valve inlet at the upper end of the pilot-operated pressure reducing valve is connected with a side pressure leading port of the three-way main valve, the pressure of the two inlets of the three-way main valve can be kept consistent by pushing a valve rod to move up and down, and the valve group has resistance to inlet pressure fluctuation. The whole valve group adopts an embedded and screw thread fixed assembly method from bottom to top, and is convenient to detach, overhaul and clean.

Description

Three-way converging regulating valve group for realizing efficient flow proportioning regulation and method thereof

Technical Field

The invention belongs to the field of valves, and particularly relates to a three-way converging regulating valve group for realizing efficient flow proportioning regulation and a method thereof.

Background

The three-way regulating valve is used as a pipeline component with strong comprehensiveness, has the functions of converging multiple paths of flow and regulating the flow ratio of each pipeline, and is widely applied to the fields of boric acid regulating systems of nuclear power plants, heating systems, ship host cooling systems and the like, and is in a throat position in a multiple pipeline system. Because different from a common valve with a single inlet and a single outlet, the three-way regulating valve is often faced with more complicated working conditions, and higher regulating accuracy and uniformity are required. At present, the domestic three-way regulating valve is often represented as performance failure when the three-way regulating valve is faced with the following conditions: a large pressure differential between the multiple parallel lines; pressure disturbance at the inlet; the flow rate of the inlet of one path is required to be lower in the converging process, so that the production requirement cannot be met, the flow ratio in the valve core moving process does not show uniform change, and great trouble is brought to parameter calculation and setting of an automatic control system. The three-way regulating valve body is mostly complex in structure and difficult to disassemble and repair.

Disclosure of Invention

The invention discloses a three-way converging regulating valve group for realizing efficient flow proportioning regulation and a method thereof, aiming at overcoming the problems in the prior art. The three-way converging regulating valve group is high in efficiency, can actively adapt to the pressure difference in the inlet pipeline, and realizes uniform and stable flow allocation while resisting the disturbance of the inlet pressure. Meanwhile, the valve group is simple in structure and convenient to assemble and disassemble.

The specific technical scheme adopted by the invention is as follows:

in a first aspect, the invention provides a three-way confluence regulating valve group for realizing efficient flow proportioning regulation, which comprises a three-way main valve, a pilot-operated pressure reducing valve and a pressure guiding port assembly; the side wall of the three-way main valve is provided with a first inlet and a second inlet respectively, the first inlet is used for introducing low-pressure fluid, and the second inlet is communicated with a second outlet of the pilot-operated pressure reducing valve; one side opening of the pressure guiding port assembly is communicated with the first inlet, and the other side opening of the pressure guiding port assembly is communicated with a pilot valve inlet at the upper part of the pilot pressure reducing valve through a pipeline;

the three-way main valve comprises a three-way valve cover, a three-way valve body, a three-way valve rod, a main valve core, an inner sleeve and a main valve seat; the top of the three-way valve body is fixed with a three-way valve cover, and a main valve seat is fixed at a first outlet at the bottom of the three-way valve body; the main valve core is arranged on the main valve seat, the side wall of the main valve core is in sealed rotary connection with the inner wall of the three-way valve body, and the top key is connected with a three-way valve rod; the upper part of the three-way valve rod penetrates through the three-way valve cover, and the three-way valve rod and the three-way valve cover are in sealed rotary connection; the outer side wall of the main valve core is provided with a first window and a second window respectively, the first window is positioned at the inner side of the first inlet, and the second window is positioned at the inner side of the second inlet; the main valve core is driven to rotate by the three-way valve rod, so that the flow areas of the first window and the second window can be adjusted, and the flow ratio of fluid entering the three-way main valve through the first inlet and the second inlet is changed; a diversion cavity is formed in the rear of the inner part of the main valve core, the first window and the second window are respectively communicated with the diversion cavity through a second pressure relief opening, and the top of the diversion cavity is communicated with the upper part of the valve cavity of the three-way valve body through the first pressure relief opening; an inner sleeve is coaxially arranged in the main valve core at intervals, the top of the inner sleeve is sealed with a sealing piece, the bottom of the inner sleeve is fixed on the main valve seat and is communicated with a first outlet of the three-way main valve, and the inner sleeve does not rotate along with the main valve core; the periphery of the upper part of the inner sleeve is axially provided with a spiral guide plate, and the side wall of the inner sleeve positioned at the spiral guide plate is provided with a plurality of third pressure relief openings; the spiral guide plate can completely cover the interval between the main valve core and the inner sleeve, so that fluid at the upper part of the valve cavity of the three-way valve body enters the hollow cavity of the inner sleeve through the third pressure relief opening after being stabilized by the spiral guide plate and flows out from the first outlet of the main valve of the three-way valve;

the pilot-operated pressure reducing valve comprises a pressure reducing valve cover, an upper valve body, a lower valve body, an adjusting rod, a pressure reducing valve rod, an upper valve seat, a lower valve seat and a pressure reducing valve core; the pressure reducing valve cover is fixed at the top of the upper valve body, and an upper isolation plate is clamped and fixed at the joint of the pressure reducing valve cover and the upper valve body; the side wall of the upper valve body is provided with the pilot valve inlet, the bottom of the upper valve body is fixedly connected with the lower valve body, and the lower part of the valve cavity is fixedly provided with an upper valve seat in a sealing way; a lower isolation plate with a pressure relief hole is clamped and fixed at the joint of the upper valve body and the lower valve body, and a lower valve seat is arranged in the middle of a valve cavity of the lower valve body; a first spring capable of providing vertical elastic force is arranged in the decompression valve cover; the upper end of the first spring is connected with the bottom of the adjusting rod through a pressing piece, and the lower end of the first spring is connected with the top of the pressure reducing valve rod through a stress plate; the upper part of the adjusting rod penetrates through the pressure reducing valve cover and is positioned outside the pilot type pressure reducing valve; the pressure reducing valve rod sequentially penetrates through the upper isolation plate and the lower isolation plate from top to bottom, and the bottom of the pressure reducing valve rod is provided with a pressure reducing valve core capable of controlling the opening and closing of the lower valve seat through up-and-down movement; a third inlet for introducing high-pressure fluid is formed in one side of the lower valve body, a second outlet is formed in the other side of the lower valve body and is communicated with the second inlet, and the opening and closing of a flow passage between the third inlet and the second outlet can be controlled through the pressure reducing valve core; a balance plate is fixed on the periphery of the pressure reducing valve rod positioned at the inner cavity of the upper valve seat; the balance plate can completely cover an annular space between the upper valve seat and the pressure reducing valve rod at the position, the inner cavity of the upper valve body is divided into an upper cavity and a lower cavity which are not communicated with each other, and the balance plate can slide up and down along the inner wall of the upper valve seat.

Preferably, the plugging piece is a hexagonal screw plug, the top of the inner sleeve is provided with internal threads, and the plugging piece is in sealing connection with the threads of the inner sleeve through the internal threads.

Preferably, a first inner cavity for installing an inner sleeve is axially formed in the main valve core, a plurality of wedge-shaped limit grooves are formed in the main valve core along the periphery of the top of the first inner cavity, and a plurality of protrusions which can be embedded into the limit grooves are circumferentially arranged at the bottom of the three-way valve rod, so that the three-way valve rod is connected with the main valve core through keys.

Preferably, the adjusting rod is in threaded connection with the pressure reducing valve cover, and can move up and down through circumferential rotation; the bottom of the adjusting rod is fixed with a pressing piece, and the pressing piece is pressed at the upper end of the first spring.

Preferably, the pressure guiding port assembly comprises a first shell and a second shell; the first shell is of a cube structure with an inner cavity, a threaded hole is formed in the outer wall of one side of the first shell, the threaded hole is fixed to the outer portion of the three-way main valve through the threaded hole, a third window communicated with the hollow inner cavity is formed in the outer wall of the other side of the first shell, and the third window is communicated with the first inlet through a pipeline; the second shell is of a cylindrical structure and is fixed at the top of the first shell, the bottom of the second shell is communicated with the inner cavity of the first shell through a communication port, and a top pressure leading port is communicated with a pilot valve inlet at the upper part of the pilot pressure reducing valve through a pipeline; the cross-sectional area of the communication port is smaller than that of the inner cavity of the first shell.

Preferably, the bottom of the inner sleeve is circumferentially provided with a plurality of positioning grooves, and the top of the main valve seat is provided with a plurality of protrusions which can be embedded and matched with the positioning grooves, so that the inner sleeve is connected with the main valve seat through keys.

Preferably, the top of the pressure reducing valve core is in threaded connection with the bottom of the pressure reducing valve rod, and a second spring capable of providing vertical elastic force is fixed at the bottom of the pressure reducing valve core; the bottom of the pressure reducing valve core and the second spring are jointly arranged in a groove at the bottom of the lower valve seat, so that the pressure reducing valve core can only move up and down along the axial direction.

Preferably, a third sealing ring is arranged on the inner wall of the upper valve seat, and the balance plate can vertically slide up and down along the third sealing ring; a fourth sealing ring is arranged at the joint of the three-way valve rod and the three-way valve cover, and the three-way valve rod can rotate along the circumferential direction of the fourth sealing ring; the upper part and the lower part of the outer wall of the main valve core are respectively provided with a first sealing ring and a second sealing ring which are used for realizing sealing with the inner wall of the three-way valve body.

Preferably, the upper valve seat is located below the pilot valve inlet.

In a second aspect, the present invention provides a flow regulating method for realizing efficient flow proportioning regulation by using the three-way confluence regulating valve set in any one of the first aspects, which specifically includes the following steps:

rotating the three-way valve rod to change the positions of the first window and the second window, and adjusting the flow areas of the two windows to change the flow ratio of the first inlet and the second inlet; after the fluid of the first inlet and the second inlet is throttled from the corresponding windows, the fluid enters a diversion cavity behind the main valve core through the second pressure relief opening, then enters the upper area of the valve cavity of the three-way valve body through the first pressure relief opening and is fully mixed at the upper area, then enters the inside of the main valve core through a gap between the three-way valve rod and the main valve core under the action of gravity, and flows downwards along the spiral diversion plate; the spiral guide plate can stabilize the fluid motion state, reduce the turbulence degree and throw out impurities possibly existing by virtue of centrifugal force; then fluid enters the hollow interior of the inner sleeve through the third pressure relief opening, and one path of fluid downwards finally flows out of the first outlet of the three-way main valve;

because one side opening of the pressure leading port assembly is communicated with the first inlet, in the process, low-pressure fluid enters an upper chamber of an upper valve body in the pilot reducing valve from the pilot valve inlet through the pressure leading port assembly; meanwhile, the high-pressure port fluid entering from the third inlet of the pilot-operated pressure reducing valve enters the lower chamber of the upper valve body through the pressure relief hole of the lower isolation plate;

when the internal static pressure of the first inlet for introducing low-pressure fluid is increased, the pressure of the upper chamber of the pilot-operated pressure reducing valve is increased as the internal static pressure of the upper chamber is equal to the internal pressure of the first inlet; at the moment, the pressure on the upper surface of the balance plate is increased, the balance plate drives the pressure reducing valve rod to move downwards, and the pressure reducing valve rod drives the pressure reducing valve core at the bottom to move downwards, so that the opening of the lower valve seat is increased; the flow area between the pressure reducing valve core and the lower valve seat is increased, the flow resistance coefficient is reduced, and the pressure drop between the third inlet and the second outlet of the pilot pressure reducing valve is reduced, so that the pressure of high-pressure fluid entering the three-way main valve through the second outlet is also increased, and the pressure of the first inlet and the second inlet of the three-way main valve is kept consistent;

when the internal static pressure of a first inlet for introducing low-pressure fluid is reduced, the pressure of the upper chamber is reduced, the pressure of the upper surface of the balance plate is reduced, the balance plate drives the pressure reducing valve rod to move upwards, and the pressure reducing valve rod drives the pressure reducing valve core at the bottom to move upwards, so that the opening of the lower valve seat is reduced; the flow area between the pressure reducing valve core and the lower valve seat is reduced, the flow resistance coefficient is increased, and the pressure drop between the third inlet and the second outlet of the pilot pressure reducing valve is increased, so that the pressure of high-pressure fluid entering the three-way main valve through the second outlet is also reduced, and the pressure of the first inlet and the second inlet of the three-way main valve is kept consistent;

when the internal pressure of the third inlet for introducing high-pressure fluid is increased, the pressure of the lower chamber of the pilot-operated pressure reducing valve is increased as the static pressure of the lower chamber is equal to the internal pressure of the third inlet; at the moment, the pressure on the lower surface of the balance plate is increased, the balance plate drives the pressure reducing valve rod to move upwards, and the pressure reducing valve rod drives the pressure reducing valve core at the bottom to move upwards, so that the opening of the lower valve seat is reduced; the flow area between the pressure reducing valve core and the lower valve seat is reduced, the flow resistance coefficient is increased, and the pressure drop between the third inlet and the second outlet of the pilot pressure reducing valve is increased, so that the pressure of the high-pressure fluid entering the three-way main valve through the second outlet is unchanged;

when the internal pressure of a third inlet for introducing high-pressure fluid is reduced, the pressure of the lower chamber is reduced, the pressure of the lower surface of the balance plate is reduced, the balance plate drives the pressure reducing valve rod to move downwards, and the pressure reducing valve rod drives the pressure reducing valve core at the bottom to move downwards, so that the opening of the lower valve seat is increased; the flow area between the pressure reducing valve core and the lower valve seat is increased, the flow resistance coefficient is reduced, and the pressure drop between the third inlet and the second outlet of the pilot pressure reducing valve is reduced, so that the pressure of the high-pressure fluid entering the three-way main valve through the second outlet is unchanged.

Compared with the prior art, the invention has the following beneficial effects:

1. the conventional converging three-way regulating valve can generate the problem that the regulating performance such as small regulating area, low pressure inlet pipeline backflow and the like is invalid when the pressures in the inlet pipelines at two sides are unequal. In order to overcome the problems, the three-way converging regulating valve group provided by the invention balances the pressure of a high-pressure inlet by means of an integrated pilot reducing valve. And the three-way main valve is in an oblique longitudinal section symmetrical type, so that the inlet pressures at two sides are ensured to be equal, and stable distribution and adjustment of flow are realized.

2. Pressure fluctuation in the inlet pipeline causes fluctuation and change of the flow ratio of the three-way regulating valve. When the pressure at any inlet of the pilot reducing valve is changed, the pressure at the high-pressure inlet can be reversely compensated, so that the flow ratio is kept unchanged.

3. The three-way main valve is designed into a cylinder shape, and the movement mode of the valve core is a circular direction. The mode can enable the flow proportioning change to be more uniform, reduce unbalanced moment born by the valve core to a certain extent, and reduce the possibility of clamping stagnation.

4. The fluid from the two inlets is fully mixed in the upper area of the three-way main valve and reaches the outlet pipeline through the central spiral flow passage, so that the fluid flowing state is stabilized, impurities are removed, and the uniformity and stability of the fluid at the outlet of the three-way main valve are ensured.

5. The valve group provided by the invention adopts an embedded and screw thread fixed assembly method from bottom to top, and is convenient to detach, overhaul and clean.

Drawings

FIG. 1 is a three-dimensional perspective view of a three-way converging valve group;

FIG. 2 is a three-dimensional cross-sectional view of a three-way junction flow regulating valve set;

fig. 3 is a three-dimensional perspective view (a) and a cross-sectional view (b) of the main spool;

FIG. 4 is a three-dimensional perspective view (a) and cross-sectional view (b) of the inner sleeve;

FIG. 5 is a three-dimensional perspective view (a) and a cross-sectional view (b) of the nip assembly;

FIG. 6 is a cross-sectional view of the connection between the pilot port assembly and the three-way main valve;

FIG. 7 is a plan engineering view of a three-way main valve;

FIG. 8 is a plan engineering view of a pilot operated pressure relief valve;

in the figure: 1. a three-way valve rod; 2. a three-way valve cover; 3. a blocking member; 4. an inner sleeve; 401. a spiral deflector; 402. a positioning groove; 403. an internal thread; 404. a third pressure relief vent; 5. a main spool; 501. a first pressure relief vent; 5021. a first window; 5022. a second window; 503. a limit groove; 504. a second pressure relief vent; 505. a first lumen; 6. a three-way valve body; 7. an adjusting rod; 8. a relief valve cover; 9. a pressing member; 10. a first spring; 11. a force-bearing plate; 12. an upper isolation plate; 13. an upper valve body; 14. an upper valve seat; 15. a balance plate; 16. a lower partition plate; 17. a lower valve body; 18. a pressure reducing valve rod; 19. a pressure relief valve spool; 20. a second spring; 21. a lower valve seat; 22. a fixing member; 23. a pressure port assembly; 231. a third window; 232. a threaded hole; 233. a communication port; 241. a first seal ring; 242. a second seal ring; 243. a third seal ring; 244. a fourth seal ring; 25. a main valve seat.

Detailed Description

The invention is further illustrated and described below with reference to the drawings and detailed description. The technical features of the embodiments of the invention can be combined correspondingly on the premise of no mutual conflict.

As shown in fig. 1 and 2, the three-way confluence regulating valve group for realizing efficient flow proportioning regulation mainly comprises a three-way main valve, a pilot-operated pressure reducing valve and a pressure guiding port assembly 23. The side wall of the three-way main valve is provided with a first inlet and a second inlet respectively, and the lower pipeline is a fluid outlet. The first inlet is used for introducing low-pressure fluid, and the second inlet is communicated with the second outlet of the pilot-operated pressure reducing valve. One side opening of the pressure leading port assembly 23 is communicated with the first inlet, and the other side opening is communicated with a pilot valve inlet at the upper part of the pilot pressure reducing valve through a pipeline. A third inlet for high-pressure fluid is formed in the main valve of the pilot-operated pressure reducing valve, and a second outlet is formed in the other side of the main valve.

In actual construction, as shown in fig. 1, the internal pressure conditions of two pipelines to be joined are first evaluated, and the three-way valve body 6 is vertically placed in the process pipeline system. One side of the three-way valve body 6 is connected with a low-pressure pipeline outlet through a lateral inlet flange, the other side of the three-way valve body is connected with an outlet of the lower valve body 17 through a lateral inlet bolt, and the lower outlet flange is connected with a pipeline inlet which needs to be converged.

The structure and connection of the components will be described in detail.

In the three-way confluence regulating valve group, as shown in fig. 7, a three-way main valve mainly comprises a three-way valve cover 2, a three-way valve body 6, a three-way valve rod 1, a main valve core 5, an inner sleeve 4 and a main valve seat 25. The top of the three-way valve body 6 is fixed with a three-way valve cover 2, the first outlet of the bottom is fixed with a main valve seat 25, and the valve seat 25 and the three-way valve body 6 can be in embedded fit and fixed. In the embodiment, the three-way valve body 6 is connected with the three-way valve cover 2 through bolts. The main valve core 5 is arranged on the main valve seat 25, the side wall is in sealing connection with the inner wall of the three-way valve body 6, and the main valve core 5 can rotate along the inner wall of the three-way valve body 6 in the circumferential direction. In this embodiment, in order to ensure the tightness between the main valve core 5 and the inner wall of the three-way valve body 6, a first seal ring 241 and a second seal ring 242 for sealing with the inner wall of the three-way valve body 6 may be provided at the upper portion and the lower portion of the outer wall of the main valve core 5, respectively. The top key of the main valve core 5 is connected with the three-way valve rod 1, that is, the main valve core 5 can rotate along with the three-way valve rod 1 in the circumferential direction. In this embodiment, a first inner cavity 505 for installing the inner sleeve 4 is axially provided in the main valve core 5, a plurality of wedge-shaped limiting grooves 503 are provided on the main valve core 5 along the periphery of the top of the first inner cavity 505, and a plurality of protrusions capable of being in embedded fit with the limiting grooves 503 are circumferentially provided at the bottom of the three-way valve rod 1, so that the three-way valve rod 1 is in key connection with the main valve core 5. The upper part of the three-way valve rod 1 penetrates through the three-way valve cover 2, and the three-way valve rod and the three-way valve cover are in sealed rotary connection. In this embodiment, in order to ensure tightness between the three-way valve rod 1 and the three-way valve cover 2, a fourth sealing ring 244 may be disposed at a joint between the two, and the three-way valve rod 1 may rotate along the circumferential direction of the fourth sealing ring 244.

In the three-way confluence regulating valve group, as shown in fig. 3, a first window 5021 and a second window 5022 are respectively arranged on the outer side wall of a main valve core 5, the first window 5021 is positioned at the inner side of a first inlet, and the second window 5022 is positioned at the inner side of a second inlet. The main valve core 5 is driven to rotate through the three-way valve rod 1, the flow areas of the first window 5021 and the second window 5022 can be adjusted, and then the flow ratio of fluid entering the three-way main valve through the first inlet and the second inlet is changed. In practical application, the shape, size and angle of the first window 5021 and the second window 5022 can be further adjusted according to the requirement of the practical flow distribution. A diversion cavity is arranged behind the main valve core 5 and is positioned inside the main valve core 5. The first window 5021 and the second window 5022 are respectively communicated with the diversion cavity through the second pressure relief opening 504, and the top of the diversion cavity is communicated with the upper part of the valve cavity of the three-way valve body 6 through the first pressure relief opening 501.

In the three-way confluence regulating valve group, an inner sleeve 4 is coaxially arranged in a main valve core 5 at intervals, a sealing piece 3 is sealed at the top of the inner sleeve 4, the bottom of the inner sleeve is fixed on a main valve seat 25 and is communicated with a first outlet of a three-way main valve, and the inner sleeve 4 does not rotate along with the main valve core 5. That is, the inner sleeve 4 is disposed inside the main valve core 5 and above the main valve seat 25, and the inner sleeve 4 and the main valve seat 25 are fixed in a fitting manner.

In this embodiment, the plugging member 3 may be a hexagonal screw plug, the top of the inner sleeve 4 is provided with an internal thread 403, and the plugging member 3 is in threaded sealing connection with the inner sleeve 4 through the internal thread 403. A plurality of positioning grooves 402 are circumferentially formed in the bottom of the inner sleeve 4, a plurality of protrusions are formed in the top of the main valve seat 25, and the protrusions can be matched with the positioning grooves 402 in an embedded mode, so that key connection between the inner sleeve 4 and the main valve seat 25 is achieved.

In the three-way confluence regulating valve group, as shown in fig. 4, a spiral guide plate 401 is axially arranged on the outer periphery of the upper part of an inner sleeve 4, and a plurality of third pressure relief openings 404 are formed in the side wall of the inner sleeve 4 positioned at the spiral guide plate 401. The spiral guide plate 401 can completely cover the interval between the main valve core 5 and the inner sleeve 4, so that the fluid at the upper part of the valve cavity of the three-way valve body 6 completely flows through the spiral guide plate 401 to be stabilized, then enters the hollow cavity of the inner sleeve 4 through the third pressure relief port 404, and flows out from the first outlet of the three-way main valve.

In practical use, the three-way valve stem 1, the main valve core 5 and the inner sleeve 4 are preferably coaxially arranged.

In actual construction, as shown in fig. 2 and 7, the main valve seat 25 is disposed at the bottom of the three-way valve body 6, and the positioning boss at the bottom of the three-way valve body 6 is embedded in the positioning groove of the main valve seat 25 to prevent the circumferential movement of the main valve seat 25. The first sealing ring 241 and the second sealing ring 242 are respectively arranged on the upper part and the lower part of the main valve core 5, and then the main valve core 5 is arranged in the three-way valve body 6, wherein the main valve core 5, the three-way valve body 6 and the main valve seat 25 are in clearance fit, and the first sealing ring 241 and the second sealing ring 242 are tightly attached to the three-way valve body 6 and the main valve core 5, so that the sealing performance of the valve is ensured. The inner sleeve 4 is arranged at the center of the inner part of the main valve core 5 and is arranged on the main valve seat 25, the inner sleeve positioning groove 402 is aligned with and embedded in the positioning boss of the main valve seat 25, the circumferential movement of the inner sleeve 4 is prevented, the inner sleeve 4 and the main valve core 5 are in clearance fit, and lubrication is carried out to reduce friction. The lower end of the three-way valve rod 1 is embedded in a groove of the main valve core 5, and can drive the main valve core 5 to move in the circumferential direction. The three-way valve cover 2 is covered, and the three-way valve cover 2 is fixed on the three-way valve body 6 by using screws.

In the three-way confluence regulating valve group of the present invention, as shown in fig. 8, the pilot type pressure reducing valve mainly includes a pressure reducing valve cover 8, an upper valve body 13, a lower valve body 17, an adjusting lever 7, a pressure reducing valve stem 18, an upper valve seat 14, a lower valve seat 21, and a pressure reducing valve core 19. The decompression valve cover 8 is fixed on the top of the upper valve body 13, and an upper isolation plate 12 is clamped and fixed at the joint of the decompression valve cover 8 and the upper valve body. The side wall of the upper valve body 13 is provided with a pilot valve inlet, the bottom is fixedly connected with the lower valve body 17, and the lower part of the valve cavity is fixedly sealed with an upper valve seat 14. The lower isolation plate 16 with a pressure relief hole is clamped and fixed at the joint of the upper valve body 13 and the lower valve body 17, and a lower valve seat 21 is arranged in the middle of the valve cavity of the lower valve body 17. The decompression valve cover 8 is internally provided with a first spring 10 which can provide vertical elastic force, and the first spring 10 has pretightening force. The upper end of the first spring 10 is connected with the bottom of the adjusting rod 7 through the pressing piece 9, and the lower end is connected with the top of the pressure reducing valve rod 18 through the stress plate 11. The upper part of the adjusting rod 7 penetrates through the pressure reducing valve cover 8 and is positioned outside the pilot type pressure reducing valve.

In the embodiment, the decompression valve cover (8) and the upper valve body (13) are fixedly connected through bolts. The adjusting rod 7 is connected with the decompression valve cover 8 through threads, and the adjusting rod 7 can move up and down through circumferential rotation to adjust the initial elasticity of the first spring 10. The bottom of the adjusting rod 7 is fixed with a pressing piece 9, and the pressing piece 9 is pressed on the upper end of the first spring 10.

In the three-way confluence regulating valve group, a pressure reducing valve rod 18 sequentially penetrates through an upper isolation plate 12 and a lower isolation plate 16 from top to bottom, and a pressure reducing valve core 19 capable of controlling the opening and closing of a lower valve seat 21 through up-and-down movement is arranged at the bottom. The top of the decompression valve rod 18 is positioned in the decompression valve cover (8), and is fixedly connected with a stress plate 11 through threads, and the stress plate (11) and the first spring (10) are tightly pressed. A third inlet for introducing high-pressure fluid is formed in one side of the lower valve body 17, a second outlet is formed in the other side of the lower valve body and is communicated with the second inlet, and the opening and closing of a flow passage between the third inlet and the second outlet can be controlled through the pressure reducing valve core 19.

In this embodiment, the top of the pressure reducing valve core 19 is in threaded connection with the bottom of the pressure reducing valve rod 18, and a second spring 20 capable of providing vertical elastic force is fixed at the bottom of the pressure reducing valve core 19, and the second spring 20 has pretightening force. In the initial state, the top of the pressure reducing valve core 19 blocks the outlet of the lower valve seat upwards under the action of the elastic force of the second spring 20, and the passage between the second outlet and the second inlet is disconnected. The bottom of the pressure reducing valve core 19 is placed in a groove at the bottom of the lower valve seat 21 together with the second spring 20, so that the pressure reducing valve core 19 can only move up and down in the axial direction. The second spring (20) and the pressure reducing valve core (19) are fixed by welding.

In the three-way converging regulating valve group, a balance plate 15 is fixed on the periphery of a decompression valve rod 18 positioned at the inner cavity of an upper valve seat 14. The balance plate 15 can completely cover the annular space between the upper valve seat 14 and the pressure reducing valve rod 18, the inner cavity of the upper valve body 13 is divided into an upper cavity and a lower cavity which are not communicated with each other, and the balance plate 15 can slide up and down along the inner wall of the upper valve seat 14. Specifically, a low pressure chamber (i.e., an upper chamber) is formed on the upper side of the balance plate (15) in the upper valve body (13), and a high pressure chamber (i.e., a lower chamber) is formed on the lower side of the balance plate (15) in the upper valve body (13).

In this embodiment, the inner wall of the upper valve seat 14 is provided with a third sealing ring 243, and the balance plate 15 can vertically slide up and down along the third sealing ring 243. The upper valve seat 14 is located at a step below the pilot valve inlet. The balance plate (15) and the relief valve stem 18 are fixed by lateral screws.

In practical use, it is preferable to coaxially arrange the adjusting lever 7, the relief valve cap 8, the pressing member 9, the first spring 10, the force receiving plate 11, the upper partition plate 12, the relief valve stem 18, the upper valve seat 14, the balance plate 15, the lower partition plate 16, the relief valve element 19, and the second spring 20.

In actual construction, as shown in fig. 2 and 8, an inlet of one end of the lower valve body 17, which is not connected to the three-way valve body 6, is flange-connected to a high-pressure fluid outlet pipe. The second spring 20 is placed in a groove of the base of the lower valve body 17 of the pilot-operated relief valve, and the relief valve core 19 is placed on the second spring 20 and props against the second spring 20, so that the second spring 20 has a certain compression degree. The lower valve seat 21 is placed in the central restriction of the lower valve body 17. The lower end of the pressure reducing valve rod 18 is threaded through the lower valve seat 21 and connected with the internal threaded hole of the pressure reducing valve core 19. The lower isolation center hole penetrates through the decompression valve rod 18 to be arranged at the upper opening of the lower valve body 17, the upper valve body 13 is connected with the lower valve body 17 through bolts, and the lower isolation plate 16 is pressed by bolt pretightening force. The upper valve seat 14 is arranged inside the upper valve body 13, and a layer of third sealing ring 243 is tightly arranged inside the upper valve seat 14. The balance plate 15 is arranged in the middle of the pressure reducing valve rod 18 by using a lateral screw, the side edge of the balance plate 15 is tightly attached to the sealing layer in the upper valve seat 14, and the upper and lower areas of the balance plate 15 are mutually independent. An upper partition plate 12 is placed through a relief valve stem 18 to the upper mouth of the upper valve body 13. The stress plate 11 is screwed and fixed on the top end of the pressure reducing valve rod 18, and the first spring 10 is placed on the stress plate 11 and is positioned in the center of the stress plate 11. The pressing member 9 is placed on the upper end of the first spring 10, and the ring on the upper end thereof is concentric with the first spring 10. The relief valve cap 8 is mounted over the upper valve body 13 using bolts. The adjusting rod 7 is screwed in a threaded hole at the top end of the pressure reducing valve cover 8, and the lower end of the adjusting rod 7 abuts against the pressing piece 9. A pipe is used to connect the pilot port with the inlet pipe of the upper valve body 13. Before the unit is started, air in the valve is required to be injected and discharged, so that the performance of the three-way regulating valve group is not influenced by bubbles. The disassembly process is the reverse of the assembly process described above.

In the present embodiment, as shown in fig. 5 and 6, the pressure port assembly 23 mainly includes a first housing and a second housing. The first shell is of a cube structure with an inner cavity, the outer wall of one side is provided with a threaded hole 232, the threaded hole 232 is fixed outside the three-way main valve through a threaded hole 23222, the outer wall of the other side is provided with a third window 231 communicated with the hollow inner cavity, and the third window 231 is communicated with the first inlet through a pipeline. The second shell is of a cylindrical structure and is fixed at the top of the first shell, the bottom of the second shell is communicated with the inner cavity of the first shell through a communication port 233, and a top pressure leading port is communicated with a pilot valve inlet at the upper part of the pilot-operated pressure reducing valve through a pipeline. The communication port 233 has a smaller cross-sectional flow area than the first housing cavity.

In actual construction, the pressure guiding port assembly 23 is fixed at the hole opening on the side surface of the valve body, one side of the third window 231 is tightly attached to the wall surface of the valve body, the pressure guiding port assembly 23 is connected with the fixing piece 22 through screws, and the fixing piece 22 is connected with the valve body through screws.

Based on the three-way converging regulating valve group for realizing efficient flow proportioning regulation, the invention also provides a flow regulating method, which comprises the following steps:

when the three-way valve rod 1 is rotated, the three-way valve rod 1 only drives the main valve core 5 to move in the circumferential direction, and the inner sleeve 4 and the valve seat 25 do not move together with the main valve core 5 due to the existence of the positioning groove below.

Fluid at the first inlet and the second inlet of the three-way main valve enters the interior of the valve body through the first window 5021 and the second window 5022. When the three-way valve rod 1 is rotated, the flow area of an inlet at one side is reduced and the flow is reduced due to the change of the position of the window; the flow area of the inlet at one side is increased, and the flow is increased, so that the flow ratio of the two inlets is changed. After being throttled from the corresponding window, the fluid of the first inlet and the second inlet enters the diversion cavity behind the main valve core 5 through the second pressure relief port 504, then enters the upper area of the valve cavity of the three-way valve body 6 through the first pressure relief port 501 and is fully mixed therein, then enters the interior of the main valve core through the gap between the three-way valve rod 1 and the main valve core 5 under the action of gravity, and flows downwards along the spiral diversion plate 401. The spiral flow guide plate 401 can stabilize the fluid motion state, reduce turbulence and throw away impurities possibly existing by centrifugal force. The fluid then enters the hollow interior of the inner sleeve 4 through the third pressure relief port 404, and one way down and finally out the first outlet of the three-way main valve.

Since one side opening of the pilot port assembly 23 communicates with the first inlet, in the process, low pressure fluid enters the upper chamber of the upper valve body 13 of the pilot relief valve from the pilot valve inlet via the pilot port assembly 23. At the same time, the high-pressure port fluid entering from the third inlet of the pilot-operated pressure reducing valve enters the lower chamber of the upper valve body 13 through the pressure relief hole of the lower partition plate 16.

When the first inlet internal static pressure of the low pressure fluid is raised, the upper chamber pressure is raised because the upper chamber static pressure of the pilot operated relief valve and the first inlet internal pressure are equal. At this time, the pressure on the upper surface of the balance plate 15 is increased, the balance plate 15 drives the pressure reducing valve rod 18 to move downwards, and the pressure reducing valve rod 18 drives the pressure reducing valve core 19 at the bottom to move downwards, so that the opening of the lower valve seat 21 is increased. The flow area between the relief valve element 19 and the lower valve seat 21 increases, the flow resistance coefficient decreases, and the pressure drop between the third inlet and the second outlet of the pilot relief valve decreases, so that the pressure of the high-pressure fluid entering the three-way main valve through the second outlet also increases, and the pressures of the first inlet and the second inlet of the three-way main valve remain consistent.

When the internal static pressure of the first inlet for introducing low-pressure fluid is reduced, the pressure of the upper chamber is reduced, the pressure of the upper surface of the balance plate 15 is reduced, the balance plate 15 drives the pressure reducing valve rod 18 to move upwards, and the pressure reducing valve rod 18 drives the pressure reducing valve core 19 at the bottom to move upwards, so that the opening of the lower valve seat 21 is reduced. The flow area between the relief valve element 19 and the lower valve seat 21 is reduced, the flow resistance coefficient is increased, and the pressure drop between the third inlet and the second outlet of the pilot relief valve is increased, so that the pressure of the high-pressure fluid entering the three-way main valve through the second outlet is also reduced, and the pressure of the first inlet and the second inlet of the three-way main valve is kept consistent.

When the third inlet internal pressure that is fed with the high-pressure fluid increases, the lower chamber pressure increases because the lower chamber static pressure of the pilot-operated relief valve and the third inlet internal pressure are equal. At this time, the pressure on the lower surface of the balance plate 15 is increased, the balance plate 15 drives the pressure reducing valve rod 18 to move upwards, and the pressure reducing valve rod 18 drives the pressure reducing valve core 19 at the bottom to move upwards, so that the opening of the lower valve seat 21 is reduced. The flow area between the relief valve element 19 and the lower valve seat 21 decreases, the flow resistance coefficient increases, and the pressure drop between the third inlet and the second outlet of the pilot relief valve increases, so that the pressure of the high-pressure fluid entering the three-way main valve through the second outlet is unchanged.

When the internal pressure of the third inlet for introducing high-pressure fluid is reduced, the pressure of the lower chamber is reduced, the pressure of the lower surface of the balance plate 15 is reduced, the balance plate 15 drives the pressure reducing valve rod 18 to move downwards, and the pressure reducing valve rod 18 drives the pressure reducing valve core 19 at the bottom to move downwards, so that the opening of the lower valve seat 21 is increased. The flow area between the relief valve element 19 and the lower valve seat 21 increases, the flow resistance coefficient decreases, and the pressure drop between the third inlet and the second outlet of the pilot relief valve decreases, so that the pressure of the high-pressure fluid entering the three-way main valve through the second outlet is unchanged.

The three-way confluence regulating valve can uniformly regulate and control the flow ratio of two paths of inlets through circumferential movement, the inlet of the pilot valve at the upper end of the pilot pressure reducing valve is connected with the side pressure leading port of the three-way main valve, and the two paths of inlet pressures of the three-way main valve can be kept consistent by pushing the valve rod to move up and down and have resistance to inlet pressure fluctuation. The whole valve group adopts an embedded and screw thread fixed assembly method from bottom to top, and is convenient to detach, overhaul and clean.

The above embodiment is only a preferred embodiment of the present invention, but it is not intended to limit the present invention. Various changes and modifications may be made by one of ordinary skill in the pertinent art without departing from the spirit and scope of the present invention. Therefore, all the technical schemes obtained by adopting the equivalent substitution or equivalent transformation are within the protection scope of the invention.

Claims (10)

1. The three-way converging regulating valve group for realizing efficient flow proportioning regulation is characterized by comprising a three-way main valve, a pilot-operated pressure reducing valve and a pressure guiding port assembly (23); the side wall of the three-way main valve is provided with a first inlet and a second inlet respectively, the first inlet is used for introducing low-pressure fluid, and the second inlet is communicated with a second outlet of the pilot-operated pressure reducing valve; one side opening of the pressure guiding port assembly (23) is communicated with the first inlet, and the other side opening of the pressure guiding port assembly is communicated with a pilot valve inlet at the upper part of the pilot type pressure reducing valve through a pipeline;

the three-way main valve comprises a three-way valve cover (2), a three-way valve body (6), a three-way valve rod (1), a main valve core (5), an inner sleeve (4) and a main valve seat (25); the top of the three-way valve body (6) is fixedly provided with a three-way valve cover (2), and a main valve seat (25) is fixedly arranged at a first outlet at the bottom; the main valve core (5) is arranged on the main valve seat (25), the side wall is in sealing and rotating connection with the inner wall of the three-way valve body (6), and the top key is connected with the three-way valve rod (1); the upper part of the three-way valve rod (1) penetrates through the three-way valve cover (2), and the three-way valve rod and the three-way valve cover are in sealed rotary connection; a first window (5021) and a second window (5022) are respectively arranged on the outer side wall of the main valve core (5), the first window (5021) is positioned at the inner side of the first inlet, and the second window (5022) is positioned at the inner side of the second inlet; the main valve core (5) is driven to rotate through the three-way valve rod (1), the flow areas of the first window (5021) and the second window (5022) can be adjusted, and then the flow ratio of fluid entering the three-way main valve through the first inlet and the second inlet is changed; a diversion cavity is formed in the rear of the inside of the main valve core (5), a first window (5021) and a second window (5022) are respectively communicated with the diversion cavity through a second pressure relief opening (504), and the top of the diversion cavity is communicated with the upper part of a valve cavity of the three-way valve body (6) through a first pressure relief opening (501); an inner sleeve (4) is coaxially arranged in the main valve core (5) at intervals, a sealing piece (3) is sealed at the top of the inner sleeve (4), the bottom of the inner sleeve is fixed on a main valve seat (25) and is communicated with a first outlet of the three-way main valve, and the inner sleeve (4) does not rotate along with the main valve core (5); a spiral guide plate (401) is axially arranged on the periphery of the upper part of the inner sleeve (4), and a plurality of third pressure relief openings (404) are formed in the side wall of the inner sleeve (4) positioned at the spiral guide plate (401); the spiral guide plate (401) can completely cover the interval between the main valve core (5) and the inner sleeve (4) so that fluid at the upper part of the valve cavity of the three-way valve body (6) enters the hollow cavity of the inner sleeve (4) through the third pressure relief opening (404) after being stabilized by the spiral guide plate (401) and flows out from the first outlet of the three-way main valve;

the pilot-operated pressure reducing valve comprises a pressure reducing valve cover (8), an upper valve body (13), a lower valve body (17), an adjusting rod (7), a pressure reducing valve rod (18), an upper valve seat (14), a lower valve seat (21) and a pressure reducing valve core (19); the decompression valve cover (8) is fixed at the top of the upper valve body (13), and an upper isolation plate (12) is clamped and fixed at the joint of the decompression valve cover and the upper valve body; the side wall of the upper valve body (13) is provided with the pilot valve inlet, the bottom of the upper valve body is fixedly connected with the lower valve body (17), and the lower part of the valve cavity is fixedly provided with an upper valve seat (14) in a sealing way; a lower isolation plate (16) with a pressure relief hole is clamped and fixed at the joint of the upper valve body (13) and the lower valve body (17), and a lower valve seat (21) is arranged in the middle of a valve cavity of the lower valve body (17); a first spring (10) capable of providing vertical elastic force is arranged in the decompression valve cover (8); the upper end of the first spring (10) is connected with the bottom of the adjusting rod (7) through the pressing piece (9), and the lower end of the first spring is connected with the top of the pressure reducing valve rod (18) through the stress plate (11); the upper part of the adjusting rod (7) penetrates through the pressure reducing valve cover (8) and is positioned outside the pilot type pressure reducing valve; the pressure reducing valve rod (18) sequentially penetrates through the upper isolation plate (12) and the lower isolation plate (16) from top to bottom, and the bottom of the pressure reducing valve rod is provided with a pressure reducing valve core (19) capable of controlling the opening and closing of the lower valve seat (21) through up-and-down movement; a third inlet for introducing high-pressure fluid is formed in one side of the lower valve body (17), a second outlet is formed in the other side of the lower valve body and is communicated with the second inlet, and the opening and closing of a flow passage between the third inlet and the second outlet can be controlled through a pressure reducing valve core (19); a balance plate (15) is fixed on the periphery of a decompression valve rod (18) positioned at the inner cavity of the upper valve seat (14); the balance plate (15) can completely cover an annular space between the upper valve seat (14) and the pressure reducing valve rod (18), the inner cavity of the upper valve body (13) is divided into an upper cavity and a lower cavity which are not communicated with each other, and the balance plate (15) can slide up and down along the inner wall of the upper valve seat (14).

2. The three-way confluence regulating valve group for realizing efficient flow proportioning regulation according to claim 1, wherein the plugging piece (3) is a hexagonal screw plug, an internal thread (403) is arranged at the top of the inner sleeve (4), and the plugging piece (3) is in threaded sealing connection with the inner sleeve (4) through the internal thread (403).

3. The three-way confluence regulating valve group for realizing efficient flow proportioning regulation according to claim 1, wherein a first inner cavity (505) for installing an inner sleeve (4) is axially formed in the main valve core (5), a plurality of wedge-shaped limit grooves (503) are formed in the main valve core (5) along the periphery of the top of the first inner cavity (505), and a plurality of protrusions which can be in embedded fit with the limit grooves (503) are circumferentially formed in the bottom of the three-way valve rod (1), so that the three-way valve rod (1) is in key connection with the main valve core (5).

4. The three-way confluence regulating valve group for realizing efficient flow proportioning regulation according to claim 1, wherein the regulating rod (7) is in threaded connection with the pressure reducing valve cover (8) and can move up and down through circumferential rotation; the bottom of the adjusting rod (7) is fixed with a pressing piece (9), and the pressing piece (9) is pressed at the upper end of the first spring (10).

5. The three-way confluence regulating valve group for realizing efficient flow proportioning regulation according to claim 1, wherein the pressure guiding port assembly (23) comprises a first shell and a second shell; the first shell is of a cube structure with an inner cavity, a threaded hole (232) is formed in the outer wall of one side of the first shell, the threaded hole (232) is fixed to the outer portion of the three-way main valve through the threaded holes (232) (22), a third window (231) communicated with the hollow inner cavity is formed in the outer wall of the other side of the first shell, and the third window (231) is communicated with the first inlet through a pipeline; the second shell is of a cylindrical structure and is fixed at the top of the first shell, the bottom of the second shell is communicated with the inner cavity of the first shell through a communication port (233), and the top pressure leading port is communicated with the pilot valve inlet at the upper part of the pilot pressure reducing valve through a pipeline; the communication port (233) has a cross-sectional flow area smaller than the cross-sectional flow area of the first housing interior.

6. The three-way confluence regulating valve group for realizing efficient flow proportioning regulation according to claim 1, wherein a plurality of positioning grooves (402) are circumferentially formed in the bottom of the inner sleeve (4), and a plurality of protrusions which can be embedded and matched with the positioning grooves (402) are arranged on the top of the main valve seat (25) so that the inner sleeve (4) is in key connection with the main valve seat (25).

7. The three-way confluence regulating valve group for realizing efficient flow proportioning regulation according to claim 1, wherein the top of the pressure reducing valve core (19) is in threaded connection with the bottom of the pressure reducing valve rod (18), and a second spring (20) capable of providing vertical elastic force is fixed at the bottom; the bottom of the pressure reducing valve core (19) and the second spring (20) are jointly arranged in a groove at the bottom of the lower valve seat (21), so that the pressure reducing valve core (19) can only move up and down along the axial direction.

8. The three-way confluence regulating valve group for realizing efficient flow proportioning regulation according to claim 1, wherein a third sealing ring (243) is arranged on the inner wall of the upper valve seat (14), and the balance plate (15) can vertically slide up and down along the third sealing ring (243); a fourth sealing ring (244) is arranged at the joint of the three-way valve rod (1) and the three-way valve cover (2), and the three-way valve rod (1) can rotate along the circumferential direction of the fourth sealing ring (244); the upper part and the lower part of the outer wall of the main valve core (5) are respectively provided with a first sealing ring (241) and a second sealing ring (242) which are used for realizing sealing with the inner wall of the three-way valve body (6).

9. A three-way junction valve set for achieving efficient flow proportioning adjustment as claimed in claim 1 wherein said upper valve seat (14) is located below said pilot valve inlet.

10. A flow regulating method of a three-way confluence regulating valve group for realizing efficient flow proportioning regulation by using the method of any one of claims 1 to 9, which is characterized by comprising the following specific steps:

the three-way valve rod (1) is rotated to change the positions of the first window (5021) and the second window (5022), and the flow areas of the two windows are adjusted to change the flow ratio of the first inlet and the second inlet; after the fluid of the first inlet and the second inlet is throttled from the corresponding windows, the fluid enters a diversion cavity behind the main valve core (5) through the second pressure relief opening (504), then enters the upper area of the valve cavity of the three-way valve body (6) through the first pressure relief opening (501) and is fully mixed therein, then enters the inside of the main valve core through a gap between the three-way valve rod (1) and the main valve core (5) under the action of gravity, and flows downwards along the spiral diversion plate (401); the spiral guide plate (401) can stabilize the fluid motion state, reduce the turbulence and throw out impurities possibly existing by virtue of centrifugal force; then fluid enters the hollow interior of the inner sleeve (4) through the third pressure relief opening (404), and one path of fluid downwards finally flows out of the first outlet of the three-way main valve;

since the opening at one side of the pressure leading port assembly (23) is communicated with the first inlet, in the process, low-pressure fluid enters an upper chamber of an upper valve body (13) in the pilot relief valve from the pilot valve inlet through the pressure leading port assembly (23); meanwhile, high-pressure port fluid entering from a third inlet of the pilot-operated pressure reducing valve enters a lower chamber of the upper valve body (13) through a pressure relief hole of the lower isolation plate (16);

when the internal static pressure of the first inlet for introducing low-pressure fluid is increased, the pressure of the upper chamber of the pilot-operated pressure reducing valve is increased as the internal static pressure of the upper chamber is equal to the internal pressure of the first inlet; at the moment, the pressure on the upper surface of the balance plate (15) is increased, the balance plate (15) drives the pressure reducing valve rod (18) to move downwards, and the pressure reducing valve rod (18) drives the pressure reducing valve core (19) at the bottom to move downwards, so that the opening of the lower valve seat (21) is increased; the flow area between the pressure reducing valve core (19) and the lower valve seat (21) is increased, the flow resistance coefficient is reduced, and the pressure drop between the third inlet and the second outlet of the pilot pressure reducing valve is reduced, so that the pressure of high-pressure fluid entering the three-way main valve through the second outlet is also increased, and the pressure of the first inlet and the second inlet of the three-way main valve is kept consistent;

when the internal static pressure of a first inlet for introducing low-pressure fluid is reduced, the pressure of an upper chamber is reduced, the pressure of the upper surface of a balance plate (15) is reduced, the balance plate (15) drives a pressure reducing valve rod (18) to move upwards, and the pressure reducing valve rod (18) drives a pressure reducing valve core (19) at the bottom to move upwards, so that the opening of a lower valve seat (21) is reduced; the flow area between the pressure reducing valve core (19) and the lower valve seat (21) is reduced, the flow resistance coefficient is increased, and the pressure drop between the third inlet and the second outlet of the pilot pressure reducing valve is increased, so that the pressure of high-pressure fluid entering the three-way main valve through the second outlet is also reduced, and the pressure of the first inlet and the second inlet of the three-way main valve is kept consistent;

when the internal pressure of the third inlet for introducing high-pressure fluid is increased, the pressure of the lower chamber of the pilot-operated pressure reducing valve is increased as the static pressure of the lower chamber is equal to the internal pressure of the third inlet; at the moment, the pressure on the lower surface of the balance plate (15) is increased, the balance plate (15) drives the pressure reducing valve rod (18) to move upwards, and the pressure reducing valve rod (18) drives the pressure reducing valve core (19) at the bottom to move upwards, so that the opening of the lower valve seat (21) is reduced; the flow area between the pressure reducing valve core (19) and the lower valve seat (21) is reduced, the flow resistance coefficient is increased, the pressure drop between the third inlet and the second outlet of the pilot pressure reducing valve is increased, and the pressure of high-pressure fluid entering the three-way main valve through the second outlet is unchanged;

when the internal pressure of a third inlet for introducing high-pressure fluid is reduced, the pressure of the lower chamber is reduced, the pressure of the lower surface of the balance plate (15) is reduced, the balance plate (15) drives the pressure reducing valve rod (18) to move downwards, and the pressure reducing valve rod (18) drives the pressure reducing valve core (19) at the bottom to move downwards, so that the opening of the lower valve seat (21) is increased; the flow area between the relief valve element (19) and the lower valve seat (21) increases, the flow resistance coefficient decreases, and the pressure drop between the third inlet and the second outlet of the pilot relief valve decreases, so that the pressure of the high-pressure fluid entering the three-way main valve through the second outlet is unchanged.