阅读说明：本技术 具有稳定输出流量和压力的先导式高压减压阀及其方法 (Pilot-operated high-pressure reducing valve with stable output flow and pressure and method thereof ) 是由 钱锦远 林振浩 赵磊 姚怀宇 金志江 于 2021-08-25 设计创作，主要内容包括：本发明公开了一种具有稳定输出流量和压力的先导式高压减压阀及其方法,减压阀包括阀盖、主阀体和先导阀；其中,先导阀包括先导阀体、先导阀座、先导阀芯和先导弹簧；先导阀芯内部设有气流通道,当第二腔室和第三腔室连通时,从主进口进入先导阀的流体能通过气流通道从主出口流出；先导阀座的第二通孔通过第一先导管与主阀体的出气口连通,第三通孔通过第三先导管与积气腔连通；先导阀芯的侧壁周向开设环形凹槽,当主出口处于关闭状态时,环形凹槽与第二通孔和第三通孔分别连通。本发明利用四通先导阀的减压作用,实现阀芯上下端面的压力差,保证了进口压力降低时阀芯开度增加,从而保持减压阀出口流量和压力的稳定。(The invention discloses a pilot type high-pressure reducing valve with stable output flow and pressure and a method thereof, wherein the reducing valve comprises a valve cover, a main valve body and a pilot valve; the pilot valve comprises a pilot valve body, a pilot valve seat, a pilot valve core and a pilot spring; an airflow channel is arranged in the pilot valve core, and when the second chamber is communicated with the third chamber, fluid entering the pilot valve from the main inlet can flow out from the main outlet through the airflow channel; a second through hole of the pilot valve seat is communicated with the air outlet of the main valve body through a first pilot pipe, and a third through hole is communicated with the air accumulation cavity through a third pilot pipe; and an annular groove is formed in the circumferential direction of the side wall of the pilot valve core, and when the main outlet is in a closed state, the annular groove is respectively communicated with the second through hole and the third through hole. The invention utilizes the pressure reduction function of the four-way pilot valve to realize the pressure difference between the upper end surface and the lower end surface of the valve core, and ensures that the opening degree of the valve core is increased when the inlet pressure is reduced, thereby keeping the flow and the pressure of the outlet of the pressure reducing valve stable.)

1. A pilot-operated high-pressure reducing valve with stable output flow and pressure is characterized by comprising a valve cover, a main valve body (4) and a pilot valve (12); the valve cover is detachably connected with the main valve body (4) in a sealing way, a sealed first chamber is formed inside the main valve body (4), and a main valve core (7) capable of sealing the air inlet of the main valve body (4) in an initial state is arranged in the first chamber; a main valve spring (5) which is always in a compressed state is arranged between the top of the main valve core (7) and the bottom of the valve cover, and the acting direction of the main valve spring (5) is the same as the axial direction of the main valve core (7); the main valve core (7) can slide up and down along the inner wall of the main valve body (4), and the joint of the main valve core and the main valve body is closed; a vertical first through hole is formed in the center of the valve cover; the lower end of the first through hole is communicated with the first cavity, and the upper end of the first through hole is communicated with a main outlet of a pilot valve (12) through a fourth pilot pipe (11); a valve rod connected with the top of the main valve core (7) extends into the first through hole from the lower part, and partial space is always reserved at the upper part of the first through hole and is used as an air accumulation cavity;

the pilot valve (12) comprises a pilot valve body (121), a pilot valve seat (122), a pilot valve core (123) and a pilot spring (124); the pilot valve body (121) and the pilot valve seat (122) are coaxially, sequentially and detachably connected, and a second cavity and a third cavity which are communicated with each other are respectively formed in the centers of the pilot valve body and the pilot valve seat along the axial direction; the air inlet end of the second chamber is used as a main inlet of the pilot valve (12), and the main inlet is communicated with the air inlet of the main valve body (4) through a second pilot pipe (9); the air outlet end of the third chamber is used as a main outlet of a pilot valve (12), and the main outlet is communicated with the gas accumulation chamber through a fourth guide pipe (11); a pilot valve core (123) capable of closing the main outlet by closing the joint of the second chamber and the third chamber in an initial state is arranged in the third chamber, a pilot spring (124) which is always in a compression state is arranged between the pilot valve core (123) and the main outlet, and the action direction of the pilot spring (124) is the same as the axial direction of the pilot valve core (123); the pilot valve core (123) can slide along the inner wall of the pilot valve seat (122) in the third chamber, and the joint of the pilot valve core and the pilot valve seat is closed; an airflow channel is arranged inside the pilot valve core (123), and when the second chamber is communicated with the third chamber, fluid entering the pilot valve (12) from the main inlet can flow out from the main outlet through the airflow channel; a second through hole and a third through hole which are communicated with the third chamber are respectively formed in the side wall of the pilot valve seat (122), the second through hole is communicated with the air outlet of the main valve body (4) through a first pilot pipe (8), and the third through hole is communicated with the gas accumulation chamber through a third pilot pipe (10); an annular groove is formed in the circumferential direction of the side wall of the pilot valve core (123), and when the main outlet is in a closed state, the annular groove is communicated with the second through hole and the third through hole respectively.

2. A pilot-operated high-pressure reducing valve according to claim 1, wherein the valve cover is screw-coupled to the main valve body (4) to vary the preload of the main valve spring (5) by adjusting the degree of coupling between the valve cover and the main valve body (4).

3. A pilot operated high pressure reducing valve according to claim 2 wherein the valve cap comprises an upper valve cap (1) and a lower valve cap (2) coaxially connected by a screw thread; the lower valve cover (2) is connected with the main valve body (4) through threads, and a first sealing ring (3) is arranged at the joint.

4. The pilot-operated high-pressure reducing valve according to claim 1, wherein a groove is formed around the boss of the main valve element (7), a second sealing ring is arranged in the groove, and the sealing between the main valve element (7) and the main valve body (4) is realized through the second sealing ring.

5. Piloted high pressure reducing valve as in claim 1, characterized in that said main valve spring (5) is coaxially housed outside the stem.

6. The pilot-operated high-pressure reducing valve according to claim 1, characterized in that the pilot valve body (121), the pilot valve seat (122), the pilot valve core (123) and the pilot spring (124) are all coaxially arranged, preferably, the pilot valve body (121) and the pilot valve seat (122) are connected by a thread.

7. The pilot-operated high-pressure reducing valve according to claim 1, wherein the pilot valve spool (123) comprises a first valve spool and a second valve spool which are sequentially and coaxially connected along the air flow direction, the joint of the second valve spool and the inner wall of the third chamber is closed, and the first valve spool is smaller than the second valve spool and has an air flow chamber with the inner wall of the third chamber; a first flow passage with two ends communicated with the airflow cavity is vertically and axially arranged in the first valve core, and a second flow passage is axially arranged in the second valve core; one end of the second flow passage is communicated with the first flow passage, and the other end of the second flow passage is communicated with the main outlet; when the second chamber is communicated with the third chamber, fluid entering the pilot valve (12) from the main inlet can sequentially pass through the second chamber, the airflow chamber, the first flow passage and the second flow passage, and finally flows out from the main outlet.

8. The pilot-operated high-pressure reducing valve according to claim 7, wherein the end of the first valve core is of a circular truncated cone-shaped structure, and the joint of the second chamber and the third chamber is of a horn-shaped structure which can be matched with the end of the first valve core to realize sealing.

9. The pilot-operated high-pressure relief valve according to claim 1, wherein the annular groove has a groove width equal to the hole diameters of the second through hole and the third through hole, and the annular groove completely coincides with both the second through hole and the third through hole when the main outlet is in the closed state.

10. A method for maintaining the flow rate and pressure at the outlet of a high-pressure gas cylinder stable by using the pilot-operated high-pressure reducing valve as defined in any one of claims 1 to 9, which is characterized by comprising the following steps:

when no gas exists in the high-pressure gas cylinder or a front-section channel of the valve is disconnected, no gas enters a valve inlet of the pilot type high-pressure reducing valve, and a main inlet of the main valve body (4) and a main inlet of the pilot valve (12) are both in a closed state;

when gas is contained in the high-pressure gas cylinder and the channel at the front section of the valve is opened, the gas is divided into two paths to circulate; the first path of gas enters the pilot valve (12) through the second pilot conduit (9), when the gas inlet pressure is larger than the elastic force applied to the pilot valve core (121) by the pilot spring (124), the pilot valve core (121) is in a fully open state, the second through hole and the third through hole are gradually closed in the opening process of the pilot valve core (123), and the gas is decompressed by the pilot valve core (121) and then enters the gas accumulation cavity through the fourth pilot conduit (11); the second path of gas acts on the bottom of the main valve core (7), when the gas inlet pressure is greater than the sum of the elastic force applied to the main valve core (7) by the main valve spring (5) and the gas pressure applied to the main valve core (7) by the gas in the gas accumulation cavity through the valve rod, the main valve core (7) is opened, and the gas flows out from the gas outlet of the valve body (4) after the pressure reduction action of the main valve core (7);

when the gas pressure in the high-pressure gas cylinder is gradually reduced, the gas inlet pressure is reduced; the gas pressure is decompressed by the pilot valve core (121) and then enters the gas accumulation cavity through the fourth pilot pipe (11); when the pressure of a gas inlet in the pilot valve (12) is smaller than the elastic force applied to the pilot valve core (121) by the pilot spring (124), the pilot valve core (121) is gradually closed, the second through hole and the third through hole are gradually opened in the closing process of the pilot valve core (123), the gas in the gas accumulation cavity enters the pilot valve (12) through the third pilot pipe (10) to be decompressed, and then flows out of a gas outlet of the valve body (4) through the first pilot pipe (8); due to the multiple pressure reduction effect of the gas, the pressure and the flow of the gas flowing out of the gas outlet of the valve body (4) through the first guide pipe (8) can be ignored;

meanwhile, the pressure of the gas entering the gas accumulation cavity is gradually reduced along with the reduction of the pressure of the gas inlet; along with the outflow of the gas in the gas accumulation cavity and the reduction of the pressure, the gas pressure exerted on the main valve core (7) by the gas in the gas accumulation cavity through the valve rod is reduced, and the gas pressure in the gas accumulation cavity is smaller than the gas inlet pressure; under the condition that the area of the upper surface of the main valve core (7) is not changed, the opening degree of the main valve core (7) is increased; therefore, when the gas pressure in the high-pressure gas cylinder is reduced, the flow and the pressure of the gas flowing out of the gas outlet of the valve body (4) can be kept stable;

when the gas pressure in the high-pressure gas cylinder is reduced to be smaller than the elastic force exerted on the main valve core (7) by the main valve spring (5), the air inlet of the main valve body (4) and the main inlet of the pilot valve (12) are in a closed state.

Technical Field

The invention belongs to the field of valve devices, and particularly relates to a pilot type high-pressure reducing valve with stable output flow and pressure and a method thereof.

Background

Hydrogen is used as clean energy, generates water vapor during combustion, is safe and nontoxic renewable clean energy, has the advantages of rich resources, high combustion value, cleanness, renewability and the like, and is increasingly concerned by countries in the world. In daily transportation, hydrogen is often compressed in high-pressure hydrogen storage bottles, and is widely applied to automobiles with hydrogen fuel cells. In a hydrogen fuel cell vehicle, hydrogen is generally stored in a gas cylinder in the form of high-pressure gaseous hydrogen, and is required to be reduced in pressure to a prescribed pressure by a pressure reducing valve when supplied to the fuel cell for use. The pressure reducing valve is used as a main component of the vehicle-mounted high-pressure hydrogen storage bottle and is responsible for reducing the pressure of high-pressure hydrogen into low-pressure hydrogen. The safety, stability and efficiency of the pressure reducing valve during pressure reduction are essential conditions for the proper operation of the entire hydrogen supply system, especially for maintaining the pressure and flow at the outlet of the pressure reducing valve stable.

The hydrogen fuel cell vehicle continuously consumes hydrogen during running, and the pressure of the hydrogen in the hydrogen storage cylinder is reduced accordingly. The flow of the traditional pressure reducing valve is reduced along with the reduction of the inlet pressure, the flow and the pressure of outlet gas cannot be kept stable, and when the pressure of introduced hydrogen is changed, the gas pressure and the flow at the outlet are changed along with the change of the pressure of the introduced hydrogen. This may affect the stability of the fuel supply of the fuel cell, shortening the life. Therefore, it is of great significance to research a pilot-operated high-pressure hydrogen cylinder pressure reducing valve with functions of maintaining outlet flow and pressure stability.

Disclosure of Invention

The present invention is directed to overcoming the disadvantages of the prior art and providing a pilot operated high pressure relief valve having stable output flow and pressure and a method thereof. The invention realizes different stresses on the upper end surface and the lower end surface of the main valve by means of the pilot valve structure, thereby realizing the increase of the opening of the valve core of the main valve when the pressure of the gas inlet is reduced, and keeping the stability of the gas pressure and the flow at the outlet of the main valve. The pilot-operated high-pressure reducing valve and the method thereof can be applied to high-pressure hydrogen cylinders and other high-pressure gas cylinders, and have wide application scenes.

The invention adopts the following specific technical scheme:

in a first aspect, the present invention provides a pilot-operated high-pressure reducing valve with stable output flow and pressure, which is characterized by comprising a valve cover, a main valve body and a pilot valve; the valve cover is detachably connected with the main valve body in a sealing manner, a sealed first chamber is formed in the main valve body, and a main valve core capable of sealing the air inlet of the main valve body in an initial state is arranged in the first chamber; a main valve spring which is always in a compressed state is arranged between the top of the main valve core and the bottom of the valve cover, and the acting direction of the main valve spring is the same as the axial direction of the main valve core; the main valve core can slide up and down along the inner wall of the main valve body, and the joint of the main valve core and the main valve body is closed; a vertical first through hole is formed in the center of the valve cover; the lower end of the first through hole is communicated with the first cavity, and the upper end of the first through hole is communicated with the main outlet of the pilot valve through a fourth pilot tube; a valve rod connected with the top of the main valve core extends into the first through hole from the lower part, and partial space is always reserved at the upper part of the first through hole and is used as an air accumulation cavity;

the pilot valve comprises a pilot valve body, a pilot valve seat, a pilot valve core and a pilot spring; the pilot valve body and the pilot valve seat are coaxially, sequentially and detachably connected, and a second cavity and a third cavity which are mutually communicated are respectively formed in the centers of the pilot valve body and the pilot valve seat along the axial direction; the air inlet end of the second chamber is used as a main inlet of the pilot valve, and the main inlet is communicated with the air inlet of the main valve body through a second pilot pipe; the air outlet end of the third chamber is used as a main outlet of the pilot valve, and the main outlet is communicated with the air accumulation chamber through a fourth pilot pipe; a pilot valve core which can close the main outlet by closing the joint of the second chamber and the third chamber in an initial state is arranged in the third chamber, a pilot spring which is always in a compressed state is arranged between the pilot valve core and the main outlet, and the action direction of the pilot spring is the same as the axis direction of the pilot valve core; the pilot valve core can slide along the inner wall of the pilot valve seat in the third chamber, and the joint of the pilot valve core and the pilot valve seat is closed; an airflow channel is arranged in the pilot valve core, and when the second chamber is communicated with the third chamber, fluid entering the pilot valve from the main inlet can flow out from the main outlet through the airflow channel; a second through hole and a third through hole which are communicated with the third chamber are respectively formed in the side wall of the pilot valve seat, the second through hole is communicated with the air outlet of the main valve body through the first pilot pipe, and the third through hole is communicated with the air accumulation chamber through the third pilot pipe; and an annular groove is formed in the circumferential direction of the side wall of the pilot valve core, and when the main outlet is in a closed state, the annular groove is respectively communicated with the second through hole and the third through hole.

Preferably, the valve cover is in threaded connection with the main valve body, and the pretightening force of the main valve spring is changed by adjusting the connection degree between the valve cover and the main valve body.

Further, the valve cover comprises an upper valve cover and a lower valve cover which are coaxially connected through threads; the lower valve cover is connected with the main valve body through threads, and a first sealing ring is arranged at the joint of the lower valve cover and the main valve body.

Preferably, a groove is formed in the peripheral side of the boss of the main valve element, a second sealing ring is arranged in the groove, and the main valve element and the main valve body are sealed through the second sealing ring.

Preferably, the main valve spring is coaxially sleeved outside the valve rod.

Preferably, the pilot valve body, the pilot valve seat, the pilot valve core and the pilot spring are coaxially arranged, and preferably, the pilot valve body and the pilot valve seat are connected through threads.

Preferably, the pilot valve core comprises a first valve core and a second valve core which are sequentially and coaxially connected along the airflow direction, the joint of the second valve core and the inner wall of the third chamber is closed, and the first valve core is smaller than the second valve core and has an airflow chamber with the inner wall of the third chamber; a first flow passage with two ends communicated with the airflow cavity is vertically and axially arranged in the first valve core, and a second flow passage is axially arranged in the second valve core; one end of the second flow passage is communicated with the first flow passage, and the other end of the second flow passage is communicated with the main outlet; when the second chamber is communicated with the third chamber, fluid entering the pilot valve from the main inlet can sequentially pass through the second chamber, the airflow chamber, the first flow passage and the second flow passage and finally flows out from the main outlet.

Furthermore, the end part of the first valve core is of a circular truncated cone-shaped structure, and the joint of the second chamber and the third chamber is of a horn-shaped structure which can be matched with the end part of the first valve core to realize sealing.

Preferably, the groove width of the annular groove is the same as the aperture of the second through hole and the aperture of the third through hole, and when the main outlet is in a closed state, the annular groove is completely overlapped with the second through hole and the third through hole.

In a second aspect, the present invention provides a method for maintaining the outlet flow and pressure of a high-pressure gas cylinder stable by using any one of the pilot-operated high-pressure reducing valves in the first aspect, which includes:

when no gas exists in the high-pressure gas cylinder or the front-section channel of the valve is disconnected, no gas enters the valve inlet of the pilot type high-pressure reducing valve, and the main valve body gas inlet and the main inlet of the pilot valve are both in a closed state;

when gas is contained in the high-pressure gas cylinder and the channel at the front section of the valve is opened, the gas is divided into two paths to circulate; the first path of gas enters the pilot valve through the second pilot pipe, when the pressure of a gas inlet is greater than the elastic force applied to the pilot valve core by the pilot spring, the pilot valve core is in a full-open state, the second through hole and the third through hole are gradually closed in the opening process of the pilot valve core, and the gas enters the gas accumulation cavity through the fourth pilot pipe after being decompressed by the pilot valve core; the second path of gas acts on the bottom of the main valve core, when the pressure of a gas inlet is greater than the sum of the elastic force applied to the main valve core by the main valve spring and the gas pressure applied to the main valve core by the gas in the gas accumulation cavity through the valve rod, the main valve core is opened, and the gas flows out of the gas outlet of the valve body after the pressure of the main valve core is reduced;

when the gas pressure in the high-pressure gas cylinder is gradually reduced, the gas inlet pressure is reduced; the gas pressure is reduced by the pilot valve core and then enters the gas accumulation cavity through the fourth pilot pipe; when the pressure of a gas inlet in the pilot valve is smaller than the elastic force applied to the pilot valve core by the pilot spring, the pilot valve core is gradually closed, the second through hole and the third through hole are gradually opened in the closing process of the pilot valve core, and the gas in the gas accumulation cavity enters the pilot valve through the third pilot pipe to be decompressed and then flows out of the gas outlet of the valve body through the first pilot pipe; due to the multiple pressure reduction effect of the gas, the pressure and the flow of the gas flowing out of the gas outlet of the valve body through the first pilot pipe can be ignored;

meanwhile, the pressure of the gas entering the gas accumulation cavity is gradually reduced along with the reduction of the pressure of the gas inlet; along with the outflow of the gas in the gas accumulation cavity and the reduction of the pressure, the gas pressure of the gas in the gas accumulation cavity, which is applied to the main valve core through the valve rod, is reduced, and the gas pressure in the gas accumulation cavity is smaller than the gas inlet pressure; under the condition that the area of the upper surface of the main valve element is not changed, the opening degree of the main valve element is increased to some extent; therefore, when the gas pressure in the high-pressure gas cylinder is reduced, the flow and the pressure of the gas flowing out of the gas outlet of the valve body can be kept stable;

when the gas pressure in the high-pressure gas cylinder is reduced to be smaller than the elastic force exerted on the main valve core by the main valve spring, the main valve body gas inlet and the main inlet of the pilot valve are in a closed state.

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

1) the invention utilizes the pressure reduction function of the four-way pilot valve to realize the pressure difference between the upper end surface and the lower end surface of the main valve core, thereby ensuring that the opening degree of the main valve core is increased when the pressure of the gas inlet is reduced, and further keeping the flow and the pressure of the outlet of the pressure reducing valve stable.

2) The device designed by the invention has the advantages of compact structure, convenient manufacture and low cost, and can keep the flow and the pressure of the outlet of the pressure reducing valve stable in a positive mode.

3) The pilot-operated high-pressure reducing valve and the method thereof can be applied to high-pressure hydrogen cylinders and other high-pressure gas cylinders, and have wide application scenes.

Drawings

FIG. 1 is a schematic diagram of a pilot-operated high-pressure relief valve;

FIG. 2 is a schematic view of a main valve;

FIG. 3 is a schematic structural diagram of a pilot valve;

FIG. 4 is a schematic medium flow diagram of a pilot operated high pressure relief valve in use;

in the figure: 1. an upper valve cover; 2. a lower valve cover; 3. a first seal ring; 4. a main valve body; 5. a main valve spring; 6. a second seal ring; 7. a main valve element; 8. a first catheter; 9. a second catheter; 10. a third catheter; 11. a fourth catheter; 12. a pilot valve; 121. a pilot valve body; 122. a pilot valve seat; 123. a pilot valve spool; 124. a pilot spring.

Detailed Description

The invention will be further elucidated and described with reference to the drawings and the detailed description. The technical features of the embodiments of the present invention can be combined correspondingly without mutual conflict.

As shown in fig. 1, the present invention provides a pilot type high pressure reducing valve with stable output flow and pressure, which mainly comprises a main valve and a pilot valve 12. The main valve mainly includes a valve cover, a main valve body 4, a main valve spring 5 and a main valve core 7, and the pilot valve 12 mainly includes a pilot valve body 121, a pilot valve seat 122, a pilot valve core 123 and a pilot spring 124. The structure and connection of the respective components will be specifically described below.

As shown in fig. 2, is a main valve of the pilot type high pressure reducing valve. The valve cover is detachably connected with the main valve body 4, and the joint of the valve cover and the main valve body is closed. After the valve cover and the main valve body 4 are connected and assembled, a closed first chamber is formed in the main valve body 4, the lower portion of the first chamber is communicated with an air inlet of the main valve body 4, and a main valve core 7 and a main valve spring 5 are arranged in the first chamber. The main valve core 7 is located below the first chamber, and can seal the air inlet of the main valve body 4 in an initial state, i.e. the joint between the first chamber and the air inlet of the main valve body 4 is sealed, so that air cannot enter the main valve body 4 through the air inlet. A main valve spring 5 is provided between the top of the main valve element 7 and the bottom of the valve cover in a compressed state at all times, and the main valve spring 5 acts in the same direction as the axial direction of the main valve element 7. The main valve core 7 can slide up and down along the inner wall of the main valve body 4 in the first chamber, and the joint of the main valve core and the main valve body is always in a closed state in the sliding process. A vertical first through hole is formed in the center of the valve cover along the central axis direction. The lower end of the first through hole is communicated with the first chamber, and the upper end is communicated with the main outlet of the pilot valve 12 through a fourth pilot pipe 11. The top of main valve core 7 is connected with vertical valve rod, and the valve rod stretches into first through-hole from the below of first through-hole after passing main valve spring 5, and the length of valve rod is less than the length of first through-hole for partial space is left all the time on the upper portion of first through-hole, and this partial space is as the gas accumulation chamber.

In the present embodiment, the valve cap may be provided in a two-part structure including an upper valve cap 1 and a lower valve cap 2. The upper valve cover 1 and the lower valve cover 2 are coaxially connected through threads, the lower valve cover 2 and the main valve body 4 are connected through threads, and a first sealing ring 3 is arranged at the joint. By adjusting the degree of connection between the valve cover and the main valve body 4, the initial pretension of the main valve spring 5 can be changed. Specifically, the upper valve cover 1 can be in a hexagonal bolt type structure, and a small hole is formed in the upper part of the upper valve cover, so that the top of the gas accumulation cavity is connected with the fourth guide pipe 11; the side surface of the upper valve cover 1 is provided with a small hole, so that the gas accumulation cavity is connected with the third guide pipe 10; the lower part of the upper valve cover 1 extends into the center of the upper part of the lower valve cover 2 and is connected with the lower valve cover 2 through threads. In practical application, the medium entering through the fourth pilot conduit 11 is accumulated in the gas accumulation cavity, and medium pressure is applied to the upper end face of the valve core 7 to realize the adjustment of the acting force on the upper part of the main valve core 7. In addition, a groove is formed in the periphery of the boss of the main valve element 7, a second sealing ring is arranged in the groove, and the sealing between the main valve element 7 and the main valve body 4 is realized through the second sealing ring. The main valve spring 5 is coaxially sleeved outside the valve rod.

As shown in fig. 3, is a pilot valve 12 of a pilot type high pressure reducing valve. The pilot valve body 121 and the pilot valve seat 122 are connected in sequence, the axes of the two are the same, and the pilot valve body 121 and the pilot valve seat 122 are detachably connected, for example, by a screw connection. A second chamber with two through ends is formed in the inner center of the pilot valve body 121 along the axial direction, a third chamber with two through ends is formed in the inner center of the pilot valve seat 122 along the axial direction, and the second chamber and the third chamber are communicated with each other. In practical applications, the pilot valve body 121, the pilot valve seat 122, the second chamber, and the third chamber may be coaxially disposed.

The inlet end of the second chamber serves as the primary inlet of the pilot valve 12, which communicates with the inlet of the main valve body 4 via the second pilot conduit 9. The outlet end of the third chamber is used as the main outlet of the pilot valve 12, and the main outlet is communicated with the gas accumulation chamber through a fourth pilot pipe 11. In the third chamber, a pilot spool 123 and a pilot spring 124 are provided in this order in the direction of the gas flow. The pilot spool 123 in the initial state can achieve main outlet closure by closing the junction of the second and third chambers. A pilot spring 124 that is always in a compressed state is provided between the pilot valve spool 123 and the main outlet, and the direction of action of the pilot spring 124 is the same as the axial direction of the pilot valve spool 123. The pilot valve core 123 can slide along the inner wall of the pilot valve seat 122 in the third chamber, and in the sliding process, the connection between the pilot valve core and the pilot valve seat is always in a closed state. The pilot spool 123 is opened and closed by a difference between the elastic force of the pilot spring 124 and the gas hydraulic pressure in the second pilot conduit 9.

An airflow passage is provided inside the pilot valve spool 123, and when the second chamber and the third chamber are communicated (i.e., the pilot valve spool 123 moves from the initial state to the airflow outlet direction), the fluid entering the pilot valve 12 from the primary inlet can flow out from the primary outlet through the airflow passage. A second through hole and a third through hole which are communicated with the third chamber are respectively formed in the side wall of the pilot valve seat 122, the second through hole is communicated with the air outlet of the main valve body 4 through the first pilot pipe 8, and the third through hole is communicated with the gas accumulation chamber through the third pilot pipe 10. An annular groove is formed in the circumferential direction of the side wall of the pilot valve element 123, and when the main outlet is in a closed state, the annular groove is communicated with the second through hole and the third through hole respectively.

In practical applications, the pilot valve core 123 may be provided as a two-part structure, including a first valve core and a second valve core connected in sequence along the airflow direction, and the axes of the first valve core and the second valve core are the same. The joint of the second valve core and the inner wall of the third chamber is closed, and the first valve core is smaller than the second valve core and is provided with an airflow chamber between the first valve core and the inner wall of the third chamber. A first flow passage with two ends communicated with the airflow cavity is vertically and axially arranged in the first valve core, and a second flow passage is axially arranged in the second valve core. One end of the second flow passage is communicated with the first flow passage, and the other end of the second flow passage is communicated with the main outlet. That is to say, in the sliding process of the pilot valve core 123 in the third chamber, the second valve core is always in a sealed state with the inner wall of the third chamber, and after the pilot valve core 123 leaves the initial state, because the first valve core is smaller than the second valve core, the second chamber and the third chamber can present a communicated state, at this moment, the fluid entering the pilot valve 12 from the main inlet can sequentially pass through the second chamber, the airflow chamber, the first flow passage and the second flow passage, and finally flows out from the main outlet. Meanwhile, the end part of the first valve core can be set to be a round table-shaped structure, and the joint of the second cavity and the third cavity is set to be a horn-shaped structure which can be matched with the end part of the first valve core to realize sealing. The groove width of annular groove is the same with the aperture of second through-hole and third through-hole, and when the main export was in the closed condition, the annular groove all coincided with second through-hole and third through-hole completely, and at this moment, the gaseous ability of long-pending intracavity gets into the annular groove through third through-hole through third pipe 10 first, flows out from the gas outlet of main valve through first pipe 8 through the second through-hole afterwards.

As shown in fig. 4, the method for maintaining the flow rate and pressure at the outlet of the high-pressure gas cylinder stable by using the pilot-operated high-pressure reducing valve specifically comprises the following steps:

when no gas exists in the high-pressure gas cylinder or the front-section channel of the valve is disconnected, no gas enters the valve inlet of the pilot type high-pressure reducing valve, and the gas inlet of the main valve body 4 and the main inlet of the pilot valve 12 are both in a closed state. I.e. main spool 7 is lowermost in the first chamber and pilot spool 121 is leftmost in the third chamber.

When gas is contained in the high-pressure gas cylinder and the channel at the front section of the valve is opened, the gas entering from the gas inlet is divided into two paths for circulation: the first path of gas enters the pilot valve 12 through the second pilot conduit 9 when the gas inlet pressure P is₁When the elastic force applied to the pilot valve core 121 by the pilot spring 124 is greater than the elastic force applied to the pilot valve core 121, the pilot valve core 121 leaves the initial position and is in a fully open state, the second through hole and the third through hole are gradually closed in the opening process of the pilot valve core 123, and the gas pressure is reduced to P by the pilot valve core 121₃Then enters the gas cavity through the fourth guide pipe 11, and the gas pressure in the gas cavity is P₃(ii) a The second path of gas enters the main valve from the gas inlet and acts on the bottom of the main valve core 7 when the pressure P of the gas inlet₁The valve rod is larger than the elastic force exerted by the main valve spring 5 on the main valve core 7 and the gas in the gas accumulation cavityGas pressure P exerted on main valve element 7₃When the sum is over, the main valve core 7 is opened, the gas pressure is reduced to P through the main valve core 7₂Then, the gas flows out from the gas outlet of the valve body 4, and the flow rate Q of the gas flowing out from the gas outlet at the time_outAnd pressure P₂。

When the gas pressure in the high-pressure gas cylinder is gradually reduced, the gas inlet pressure P is gradually reduced₁And is reduced accordingly. When the gas inlet pressure P in the pilot valve 12₁When the elastic force applied to the pilot valve core 121 by the pilot spring 124 is smaller, the pilot valve core 121 is gradually closed, and the gas pressure is reduced to P by the pilot valve core 121₃And then into the plenum chamber through the fourth pilot tube 11. Meanwhile, the second through hole and the third through hole are gradually opened in the closing process of the pilot valve element 123, and gas P in the gas accumulation cavity₃Enters the pilot valve 12 through the third pilot conduit 10 and is depressurized to P₄And then flows out of the outlet port of the valve body 4 through the first pilot conduit 8. The pressure P of the gas flowing out of the outlet of the valve body 4 through the first pre-conduit 8 due to the multiple decompression of the gas₄And the flow rate can be ignored.

At the inlet pressure P of the main valve during the gradual reduction of the gas pressure in the high-pressure gas cylinder₁While decreasing, P₃Is also decreasing, and P₃<P₁. As the gas in the gas accumulation chamber flows out and the pressure decreases, the gas pressure applied to main spool 7 by the valve stem becomes smaller. Under the condition that the surface area of the upper surface of the main valve element 7 is not changed, the opening degree of the main valve element 7 is increased. Therefore, when the gas pressure in the high-pressure gas cylinder is reduced, the flow rate and pressure of the gas flowing out from the gas outlet of the valve body 4 can be kept stable.

When the gas pressure in the high-pressure gas cylinder is reduced to be smaller than the elastic force exerted on the main valve spool 7 by the main valve spring 5, the main valve body 4 gas inlet and the main inlet of the pilot valve 12 are both in a closed state.

The invention utilizes the pressure reduction function of the four-way pilot valve to realize the pressure difference between the upper end surface and the lower end surface of the valve core, and ensures that the opening degree of the valve core is increased when the inlet pressure is reduced, thereby keeping the flow and the pressure of the outlet of the pressure reducing valve stable.

The above-described embodiments are merely preferred embodiments of the present invention, which should not be construed as limiting the 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, the technical scheme obtained by adopting the mode of equivalent replacement or equivalent transformation is within the protection scope of the invention.