A manually adjustable constant differential pressure blow valve

Abstract

The present application relates to the field of parts of submarine sewage system, and discloses a manually adjusted constant pressure difference blow-off valve. In the state of dynamic balance, the elastic force of the adjusting spring is equal to the elastic force of the auxiliary spring and the pressure of the second piston cavity; the liquid pressure received by the upper part of the first piston is equal to the elastic force of the main spring and the pressure of the piston in the rear cavity of the main valve; and the medium pressure of the second piston cavity and the rear cavity of the main valve is the same. By setting the pilot valve as a sensitive element, the signal of the hand wheel is amplified, thereby expanding the pressure adjustment range of the rear cavity of the main valve; and the outlet pressure of the valve connected with the rear cavity of the main valve is continuously adjustable, so that the blow-off pressure of the valve outlet can be adjusted according to the different diving depth of the submarine, and the appropriate sewage air supply pressure can be selected. By adopting the constant pressure difference blow-off valve, the air supply pressure and blow-off speed of the blow-off sewage are reduced, the amount of compressed air discharged to the outside of the hull is reduced, and the vibration of the sewage pipeline and the sewage transient noise can be effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of components for submarine sewage systems, specifically to a manually adjustable constant pressure differential purging valve. Background Technology

[0002] The submarine's sewage system uses pressure-resistant storage containers to collect black water from the toilets. Once the containers are full, the black water is blown overboard using 3.5 MPa compressed air from the submarine. Currently, the sewage system uses compressed air to blow the filth overboard, resulting in a significant pressure difference between the air and the seawater, causing considerable transient noise. This leads to problems with the sanitation system's ability to function normally due to its concealment. Summary of the Invention

[0003] To address the aforementioned shortcomings of existing technologies, a manually adjustable constant pressure differential purging valve is provided to meet the low-noise sewage discharge requirements of submarines under different diving depth conditions.

[0004] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0005] A manually adjustable constant pressure differential purging valve, characterized in that it includes a main valve, a pilot valve and a connecting pipe, wherein the pilot valve is located above the main valve;

[0006] Both the main valve and the pilot valve have a pre-valve chamber and a post-valve chamber. A first piston chamber is located within the post-valve chamber of the main valve, and this first piston chamber is connected to the post-valve chamber of the pilot valve. A main valve stem is located between the pre-valve chamber and the post-valve chamber of the main valve. The main valve stem, located at one end of the pre-valve chamber, is connected to a compressed main spring, and under the action of the main spring, it cuts off the connection between the pre-valve chamber and the post-valve chamber. A first piston is located within the first piston chamber, and the first piston is fixedly connected to the end of the main valve stem located in the post-valve chamber of the main valve. The first piston moves within the first piston chamber, separating the post-valve chamber of the main valve and the post-valve chamber of the pilot valve. When the piston is pushed to move by the pressure within the post-valve chamber of the pilot valve and overcoming the elastic force of the main spring and the pressure of the medium within the second piston chamber, the main valve stem connects the pre-valve chamber and the post-valve chamber of the main valve.

[0007] The pilot valve also includes a second piston chamber and a secondary valve stem. The second piston chamber, the pilot valve's downstream chamber, and the pilot valve's upstream chamber are connected via a T-shaped pipe. The second piston chamber and the pilot valve's upstream chamber are directly connected via a horizontal section of the T-shaped pipe, while the pilot valve's downstream chamber is connected to the horizontal section via a vertical section. The secondary valve stem is positioned on the horizontal section and cuts off the connection between the second piston chamber and the pilot valve's upstream and downstream chambers. One end of the secondary valve stem in the pilot valve's upstream chamber is connected to a compressed secondary spring. A second piston is located within the second piston chamber. The second piston and the auxiliary valve stem are connected at the end of the pilot valve's rear chamber. The second piston moves within the second piston chamber and seals it. The main valve's front chamber is connected to the pilot valve's front chamber via a connecting pipe, and the main valve's rear chamber is connected to the second piston chamber via a connecting pipe. At the other end of the second piston, there is an adjusting spring assembly whose spring force is adjusted by a handwheel. The adjusting spring assembly acts on the other side of the second piston, causing the second piston to move against the force of the auxiliary spring and push the auxiliary valve stem to connect the pilot valve's front and rear chambers.

[0008] According to the above technical solution, the adjusting spring assembly includes a pilot valve cover fixed outside the second piston chamber of the pilot valve, and a lower spring seat, an upper spring seat, a limiting screw, an adjusting screw, and a handwheel located on the pilot valve cover; a chamber for installing the adjusting spring is provided inside the valve cover, and a guide groove with the same compression direction as the adjusting spring is provided on the side wall of the chamber, the length of which is determined according to the compression range of the spring; the lower spring seat is located between the adjusting spring and the second piston, and the upper valve seat is located at the other end of the adjusting spring; a threaded hole is provided at the end of the chamber away from the second piston, and the adjusting screw passes through the threaded hole and abuts against the upper spring seat; a limiting screw hole is provided at the position where the upper spring seat matches the guide groove, and the limiting screw is fixed in the limiting screw hole and placed in the guide groove.

[0009] According to the above technical solution, a pressure scale dial for the main valve's downstream chamber is provided at the handwheel, and the handwheel is rotated with reference to the pointer on the scale dial.

[0010] According to the above technical solution, the handwheel is replaced with a polygonal sleeve driven by a motor, and a polygonal post matching the polygonal sleeve is provided on the outside of the adjusting screw.

[0011] According to the above technical solution, the pilot valve includes a pilot valve body, which has two chambers serving as a second piston chamber and a pilot valve front chamber. The front and rear chambers are connected by a horizontal section of a T-shaped pipe. A vertical section is located in the middle of the horizontal section, extending downwards to communicate with the first piston chamber of the main valve and serving as the pilot valve rear chamber. The horizontal section, located on one side of the second piston chamber, has the same dimensions as the auxiliary valve stem and cuts off the communication between the second piston chamber and the pilot valve's front and rear chambers. The horizontal section, located on one side of the pilot valve front chamber, has a larger cross-sectional dimension than the auxiliary valve stem. When the pilot valve disc opens, the medium enters the pilot valve rear chamber from the pilot valve front chamber. A pilot valve cap and a secondary spring assembly are provided on the pilot valve front chamber. Under the action of the secondary spring, the end of the auxiliary valve stem located in the pilot valve front chamber blocks the horizontal section, and its opening is controlled by an adjusting spring.

[0012] According to the above technical solution, the main valve includes a main valve body, a main valve front chamber and a main valve rear chamber are located on the left and right sides of the main valve body, a first piston chamber is located at the upper part of the main valve body and communicates with the vertical section; a valve disc chamber is provided at the lower part of the first piston chamber, and the main valve stem is connected between the valve disc chamber and the first piston chamber, and controls the connection and disconnection between the two; the main valve front chamber and the valve disc chamber are in a normally connected state, and the main valve rear chamber and the first piston chamber are in a normally connected state.

[0013] According to the above technical solution, piston rings for sealing are provided on both the first piston and the second piston; and sealing rings are provided between the valve cover and the pilot valve, between the screw cover and the pilot valve, and between the main valve and the lower end cover.

[0014] The present invention has the following beneficial effects:

[0015] 1. By rotating the handwheel, the spring force of the adjusting spring is controlled. When the spring force is greater than the spring force of the auxiliary spring and the pressure exerted on the second piston by the medium in the second piston chamber, the second piston is driven to open the auxiliary valve stem, thus connecting the pre-valve chamber and the post-valve chamber of the pilot valve. After the pre-valve chamber and the post-valve chamber of the pilot valve are connected, the medium pressure in the post-valve chamber of the pilot valve increases, acting on the top of the main piston. When the force exerted by the medium on the top of the main piston is greater than the spring force of the main spring and the pressure exerted on the first piston by the medium in the first piston chamber (i.e., the pressure exerted on the first piston by the post-valve chamber of the main valve), the first piston is driven to open the main valve stem, thus connecting the pre-valve chamber and the post-valve chamber of the main valve. Subsequently, the pressure after the main valve changes and is fed back to the second piston chamber of the pilot valve, causing the pilot valve opening to decrease and the pressure on the upper part of the first piston to decrease. This process repeats until dynamic equilibrium is reached.

[0016] In a state of dynamic equilibrium, the elastic force of the adjusting spring equals the elastic force of the secondary spring plus the pressure in the second piston chamber (this pressure is not greater than the pressure in the main valve's pre-valve chamber); the liquid pressure received by the upper part of the first piston equals the elastic force of the main spring plus the pressure at the piston in the main valve's post-valve chamber (i.e., the liquid pressure borne by the lower part of the first piston); since the main valve's post-valve chamber is connected to the second piston chamber through a connecting pipe, the medium pressure in the second piston chamber and the main valve's post-valve chamber is the same.

[0017] Based on the above measures, by setting a pilot valve as a sensitive element to amplify the signal from the handwheel, the pressure regulation range of the main valve's downstream chamber is expanded. Furthermore, the outlet pressure of the valve connected to the downstream chamber of the main valve is continuously adjustable, allowing for adjustment of the outlet purging pressure according to the submarine's diving depth, thus selecting a suitable sludge supply pressure. By employing a constant pressure differential purging valve, the supply pressure and purging speed of the sludge are reduced, decreasing the amount of compressed air discharged overboard, effectively reducing sludge pipeline vibration and transient sludge noise.

[0018] 2. Flexible adjustment and convenient installation. The purging valve is equipped with a dial marked with the outlet pressure value. The outlet pressure value can be easily adjusted by turning the handwheel of the valve and referring to the dial. Attached Figure Description

[0019] Figure 1 This is a front sectional view of an embodiment provided by the present invention;

[0020] Figure 2 This is a partial lateral sectional view of an embodiment provided by the present invention;

[0021] Figure 3 This is a cross-sectional view of the pilot valve provided in an embodiment of the present invention.

[0022] In the diagram, 1. Main valve; 1-1. Main valve inlet chamber; 1-2. Main valve outlet chamber; 1-3. First piston chamber; 1-4. Main valve stem; 1-5. Main spring; 1-6. Main valve disc; 1-7. First piston; 1-8. Main valve body; 1-9. Valve disc chamber; 1-10. Lower end cap; 2. Pilot valve; 2-1. Pilot valve inlet chamber; 2-2. Pilot valve outlet chamber; 2-3. Second piston chamber; 2-4. Secondary valve stem; 2-5. 1. T-shaped pipe; 2-51. Horizontal section; 2-52. Vertical section; 2-6. Secondary spring; 2-7. Second piston; 2-8. Valve cover; 2-81. Guide groove; 2-9. Pilot valve body; 2-10. Screw cap; 2-11. Pilot valve disc; 3. Connecting pipe; 4. Adjusting spring assembly; 4-1. Handwheel; 4-2. Lower spring seat; 4-3. Upper spring seat; 4-4. Limit screw; 4-5. Adjusting screw; 4-6. Adjusting spring. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0024] Reference Figures 1-3 As shown, the present invention provides a manually adjustable constant pressure differential purging valve.

[0025] Example 1

[0026] It includes a main valve 1, a pilot valve 2, and a connecting pipe 3. The pilot valve is located above the main valve. The pilot valve is fixed to the main valve by bolts and a sealing gasket.

[0027] Both the main valve and the pilot valve are provided with a pre-valve cavity and a post-valve cavity (see figure: main valve pre-valve cavity 1-1, main valve post-valve cavity 1-2, pilot valve pre-valve cavity 2-1, pilot valve post-valve cavity 2-2). A first piston cavity 1-3 is provided in the post-valve cavity of the main valve, and the first piston cavity is connected to the post-valve cavity of the pilot valve. A main valve stem 1-4 is provided between the pre-valve cavity and the post-valve cavity of the main valve. The main valve stem is located at one end of the pre-valve cavity of the main valve and is connected to a main spring 1-5 in a compressed state. Under the action of the main spring, it cuts off the pre-valve cavity of the main valve. The main valve stem is connected to the main valve cavity and the valve rear cavity (the end of the main valve stem is provided with a main valve disc 1-6); a first piston 1-7 is provided in the first piston cavity, and the first piston is fixedly connected to the end of the main valve stem located in the valve rear cavity of the main valve. The first piston moves in the first piston cavity and separates the valve rear cavity of the main valve and the valve rear cavity of the pilot valve; when the piston is pushed to move by the pressure in the valve rear cavity of the pilot valve and overcomes the elastic force of the main spring and the pressure of the medium in the second piston cavity, the main valve stem connects the valve front cavity and the valve rear cavity of the main valve.

[0028] The pilot valve also includes a second piston chamber 2-3 and a secondary valve stem 2-4. The second piston chamber, the pilot valve's downstream chamber, and the pilot valve's upstream chamber are connected via a T-shaped pipe 2-5. The second piston chamber and the pilot valve's upstream chamber are directly connected via a horizontal section 2-51 of the T-shaped pipe, while the pilot valve's downstream chamber is connected to the horizontal section via a vertical section 2-52. The secondary valve stem is positioned on the horizontal section and cuts off the connection between the second piston chamber and the pilot valve's upstream and downstream chambers. One end of the secondary valve stem in the pilot valve's upstream chamber is connected to a compressed secondary spring 2-6. The second piston chamber contains... The second piston 2-7 is connected to the end of the auxiliary valve stem located in the rear chamber of the pilot valve. The second piston moves within the second piston chamber and seals the second piston chamber. The front chamber of the main valve is connected to the front chamber of the pilot valve through a connecting pipe, and the rear chamber of the main valve is connected to the second piston chamber through a connecting pipe. At the other end of the second piston, there is an adjusting spring assembly 4 whose spring force is adjusted by a handwheel 4-1. The adjusting spring assembly acts on the other side of the second piston, causing the second piston to move against the spring force of the auxiliary spring and push the auxiliary valve stem to connect the front and rear chambers of the pilot valve.

[0029] In this embodiment, by rotating the handwheel, the elastic force of the adjusting springs 4-6 is controlled. When the elastic force of the adjusting springs is greater than the elastic force of the auxiliary spring and the pressure exerted on the second piston by the medium in the second piston cavity, the second piston is driven to open the auxiliary valve stem, thus connecting the pre-valve cavity and the post-valve cavity of the pilot valve. After the pre-valve cavity and the post-valve cavity of the pilot valve are connected, the medium pressure in the post-valve cavity of the pilot valve increases, acting on the top of the main piston. When the force exerted by the medium on the top of the main piston is greater than the elastic force of the main spring and the pressure exerted on the first piston by the medium in the first piston cavity (i.e., the pressure exerted on the first piston by the post-valve cavity of the main valve), the first piston is driven to open the main valve stem, thus connecting the pre-valve cavity and the post-valve cavity of the main valve. Subsequently, the pressure after the main valve changes and is fed back to the second piston cavity of the pilot valve, causing the pilot valve opening to decrease and the pressure on the upper part of the first piston to decrease. This process repeats until dynamic equilibrium is reached.

[0030] In a state of dynamic equilibrium, the elastic force of the adjusting spring equals the elastic force of the secondary spring plus the pressure in the second piston chamber (this pressure is not greater than the pressure in the main valve's pre-valve chamber); the liquid pressure received by the upper part of the first piston equals the elastic force of the main spring plus the pressure at the piston in the main valve's post-valve chamber (i.e., the liquid pressure borne by the lower part of the first piston); since the main valve's post-valve chamber is connected to the second piston chamber through a connecting pipe, the medium pressure in the second piston chamber and the main valve's post-valve chamber is the same.

[0031] Based on the above measures, with the pressure in the main valve's upstream chamber remaining constant, the pressure in the downstream chamber of the main valve is controlled by adjusting the spring force via a handwheel. Furthermore, the pilot valve, controlled by the adjusting spring assembly, indirectly controls the opening of the main valve. Compared to directly controlling the main valve opening via the adjusting spring assembly, this increases the adjustment range of the pressure in the downstream chamber of the main valve. This allows for continuous and precise adjustment of the valve outlet pressure over a wider pressure range, meeting the low-noise wastewater discharge requirements of submarines at different diving depths.

[0032] Example 2

[0033] The structure and principle of Example 2 are similar to those of Example 1, except that a preferred structural form of the adjusting spring assembly is provided.

[0034] The adjusting spring assembly includes a pilot valve cover 2-8 fixed outside the second piston chamber of the pilot valve, and a lower spring seat 4-2, an upper spring seat 4-3, a limit screw 4-4, an adjusting screw 4-5, and a handwheel located on the pilot valve cover. A chamber for installing the adjusting spring is provided inside the valve cover. A guide groove 2-81 with the same compression direction as the adjusting spring is provided on the side wall of the chamber. The length of the guide groove is determined according to the spring compression range. The lower spring seat is located between the adjusting spring and the second piston, and the upper valve seat is located at the other end of the adjusting spring. A threaded hole is provided at the end of the chamber away from the second piston. The adjusting screw passes through the threaded hole and abuts against the upper spring seat. A limit screw hole is provided at the position where the upper spring seat matches the guide groove. The limit screw is fixed in the limit screw hole and placed inside the guide groove.

[0035] In this embodiment, the adjusting spring is located between the upper spring seat and the lower spring seat, and the lower spring seat is located between the second piston adjusting spring, so as to evenly transmit the elastic force of the adjusting spring to the second piston; the movement direction of the upper spring seat is limited by the limiting screws fixed on both sides of the upper spring seat and the guide groove on the valve cover of the pilot valve; by rotating the handwheel to drive the adjustment screw to rotate, the upper spring seat is driven to move forward or backward, thereby controlling the elastic force applied by the adjusting spring to the second piston.

[0036] In embodiment 2, preferably, a pressure scale for the main valve's downstream chamber is provided at the handwheel. The handwheel is rotated with reference to the pointer on the scale, thereby precisely adjusting the valve outlet pressure.

[0037] Example 3

[0038] The structure and principle of Example 3 are similar to those of Example 2, except that the handwheel is replaced with a motor-driven polygonal sleeve, and a polygonal post matching the polygonal sleeve is provided on the outside of the adjusting screw. In this example, the rotation of the adjusting screw is driven by an electric sleeve, which increases the degree of electrification and reduces the intensity of operation for the worker.

[0039] A preferred structure of the pilot valve is given in Examples 1-3. Specifically, the pilot valve includes a pilot valve body 2-9, which has two chambers serving as a second piston chamber and a pilot valve front chamber. The front and rear chambers are connected by a horizontal section of a T-shaped pipe. A vertical section is located in the middle of the horizontal section, extending downwards to communicate with the first piston chamber of the main valve and serving as the pilot valve rear chamber. The horizontal section, located on one side of the second piston chamber, has the same dimensions as the auxiliary valve stem and cuts off the communication between the second piston chamber and the pilot valve's front and rear chambers. The horizontal section, located on one side of the pilot valve front chamber, has a larger cross-sectional dimension than the auxiliary valve stem. When the pilot valve disc 2-11 is opened, the medium enters the pilot valve rear chamber from the pilot valve front chamber. The pilot valve front chamber has a pilot valve cap 2-10 and a secondary spring assembly located on the cap. Under the action of the secondary spring, the end of the auxiliary valve stem located in the pilot valve front chamber blocks the horizontal section, and its opening is controlled by an adjusting spring.

[0040] In this embodiment, when the spring force is insufficient to open the valve disc at the end of the valve stem, the valve disc cuts off the connection between the front and rear chambers of the pilot valve. When the spring force continues to increase and can open the valve disc at the end of the valve stem, the auxiliary valve stem moves along the horizontal section, connecting the front and rear chambers of the pilot valve, and increasing the pressure in the rear chamber. During this process, since the auxiliary valve stem and the horizontal section have the same dimensions, the second piston chamber is not connected to the front and rear chambers of the pilot valve. In this embodiment, the separate rear chamber of the pilot valve is omitted, and the vertical section of the T-shaped pipe is used as the rear chamber of the pilot valve.

[0041] To facilitate the application of pressure from the medium from the pilot valve to the first piston, which then acts on the valve disc of the main valve stem, a valve disc cavity is provided at the bottom of the first piston cavity. In a sense, the valve disc cavity is an extension of the main valve's front cavity. A preferred structure of the main valve is given in embodiments 1-3. Specifically, the main valve includes a main valve body 1-8, with a main valve front cavity and a valve rear cavity located on the left and right sides of the main valve body. The first piston cavity is located at the upper part of the main valve body and communicates with the vertical section. A valve disc cavity 1-9 is provided at the lower part of the first piston cavity. The main valve stem connects the valve disc cavity and the first piston cavity, controlling their connection and disconnection. The main valve front cavity and the valve disc cavity are in a normally connected state, and the main valve rear cavity and the first piston cavity are in a normally connected state. A lower end cap 1-10 is provided at the bottom of the valve disc cavity for easy maintenance of the main valve.

[0042] In embodiments 1-3, piston rings for sealing are provided on both the first piston and the second piston; and sealing rings are provided between the valve cover and the pilot valve, between the screw cap and the pilot valve, and between the main valve and the lower end cover.

[0043] In one embodiment of the present invention, the working principle of the present invention is as follows:

[0044] The valve employs a pilot-operated structure. Changes in outlet pressure are amplified by the pilot valve to control the main valve's operation. Rotating the pilot valve handwheel opens the secondary valve stem assembly valve disc, allowing the medium to flow from the pilot valve's inlet chamber into its outlet chamber (above the piston). This pushes the piston downwards, opening the main valve and allowing the medium to flow into its outlet chamber. The pressure in the main valve's outlet chamber is transmitted through a connecting pipe to the pilot valve's second piston chamber. The force of the adjusting spring in the second piston chamber balances the pilot valve's opening, thus altering the pressure above the first piston and controlling the opening of the main valve stem assembly valve disc, maintaining a constant pressure downstream of the valve.

[0045] The first piston and the first piston chamber are sensitive elements of the purge valve actuator, driving the valve disc to make adjustment movements; the second piston, the second piston chamber, and the auxiliary valve stem are the actuators of the pilot valve. The second piston of the pilot valve isolates the medium in the pilot valve chamber from the regulating spring chamber, ensuring that the medium pressure in the pilot valve chamber balances the force of the regulating spring, keeping the downstream pressure constant; the auxiliary spring in the pilot valve supports the pilot valve disc and also balances the regulating spring in the pilot valve.

[0046] The above are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent changes made in accordance with the claims of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A manually adjusted constant differential pressure blow off valve member characterized by: It includes a main valve, a pilot valve, and connecting pipes, with the pilot valve located above the main valve; Both the main valve and the pilot valve have a pre-valve chamber and a post-valve chamber. A first piston chamber is located within the post-valve chamber of the main valve, and this first piston chamber is connected to the post-valve chamber of the pilot valve. A main valve stem is located between the pre-valve chamber and the post-valve chamber of the main valve. The main valve stem, located at one end of the pre-valve chamber, is connected to a compressed main spring, and under the action of the main spring, it cuts off the connection between the pre-valve chamber and the post-valve chamber. A first piston is located within the first piston chamber, and the first piston is fixedly connected to the end of the main valve stem located in the post-valve chamber of the main valve. The first piston moves within the first piston chamber, separating the post-valve chamber of the main valve and the post-valve chamber of the pilot valve. When the piston is pushed to move by the pressure within the post-valve chamber of the pilot valve and overcoming the elastic force of the main spring and the pressure of the medium within the second piston chamber, the main valve stem connects the pre-valve chamber and the post-valve chamber of the main valve. The pilot valve also includes a second piston chamber and a secondary valve stem. The second piston chamber, the pilot valve's downstream chamber, and the pilot valve's upstream chamber are connected via a T-shaped pipe. The second piston chamber and the pilot valve's upstream chamber are directly connected via a horizontal section of the T-shaped pipe, while the pilot valve's downstream chamber is connected to the horizontal section via a vertical section. The secondary valve stem is positioned on the horizontal section and cuts off the connection between the second piston chamber and the pilot valve's upstream and downstream chambers. One end of the secondary valve stem in the pilot valve's upstream chamber is connected to a compressed secondary spring. A second piston is located within the second piston chamber. The second piston and the auxiliary valve stem are connected at the end of the pilot valve's rear chamber. The second piston moves within the second piston chamber and seals it. The main valve's front chamber is connected to the pilot valve's front chamber via a connecting pipe, and the main valve's rear chamber is connected to the second piston chamber via a connecting pipe. At the other end of the second piston, there is an adjusting spring assembly whose spring force is adjusted by a handwheel. The adjusting spring assembly acts on the other side of the second piston, causing the second piston to move against the force of the auxiliary spring and push the auxiliary valve stem to connect the pilot valve's front and rear chambers.

2. The manually adjusted constant differential pressure blowdown valve member of claim 1, wherein: The adjusting spring assembly includes a pilot valve cover fixed outside the second piston chamber of the pilot valve, and a lower spring seat, an upper spring seat, a limit screw, an adjusting screw, and a handwheel located on the pilot valve cover. A chamber for installing the adjusting spring is provided inside the valve cover. A guide groove with the same compression direction as the adjusting spring is provided on the side wall of the chamber, and the length of the guide groove is determined according to the spring compression range. The lower spring seat is located between the adjusting spring and the second piston, and the upper valve seat is located at the other end of the adjusting spring. A threaded hole is provided at the end of the chamber away from the second piston, through which the adjusting screw passes and abuts against the upper spring seat. A limit screw hole is provided at the position where the upper spring seat matches the guide groove, and the limit screw is fixed in the limit screw hole and placed within the guide groove.

3. The manually adjusted constant differential pressure blow valve of claim 2, wherein: The handwheel is equipped with a pressure dial for the main valve's downstream chamber. Rotate the handwheel according to the pointer on the dial.

4. The manually adjusted constant differential pressure blow valve of claim 2, wherein: Replace the handwheel with a motor-driven polygonal sleeve, with a polygonal post on the outside of the adjusting screw that matches the polygonal sleeve.

5. A manually adjusted constant differential pressure blow off valve according to any one of claims 2-4, characterized in that: The pilot valve includes a pilot valve body with two chambers serving as a second piston chamber and a pilot valve front chamber. The front and rear chambers are connected by a horizontal section of a T-shaped pipe. A vertical section is located in the middle of the horizontal section, extending downwards to communicate with the first piston chamber of the main valve and serving as the pilot valve rear chamber. The horizontal section, located on one side of the second piston chamber, has the same dimensions as the auxiliary valve stem and cuts off the communication between the second piston chamber and the pilot valve's front and rear chambers. The horizontal section, located on the side of the pilot valve front chamber, has a larger cross-sectional dimension than the auxiliary valve stem. When the pilot valve disc opens, the medium enters the pilot valve rear chamber from the pilot valve front chamber. The pilot valve front chamber has a pilot valve cap and a secondary spring assembly located on the cap. Under the action of the secondary spring, the end of the auxiliary valve stem located in the pilot valve front chamber blocks the horizontal section, and its opening is controlled by an adjusting spring.

6. The manually adjusted constant differential pressure blow valve of claim 5, wherein: The main valve includes a main valve body, a main valve front chamber and a main valve rear chamber located on the left and right sides of the main valve body, a first piston chamber located on the upper part of the main valve body and connected to the vertical section; a valve disc chamber is located at the lower part of the first piston chamber, and the main valve stem is connected between the valve disc chamber and the first piston chamber, controlling the connection and disconnection between the two; the main valve front chamber and the valve disc chamber are in a normally connected state, and the main valve rear chamber and the first piston chamber are in a normally connected state.

7. The manually adjustable constant pressure differential purging valve according to claim 5, characterized in that: Both the first and second pistons are provided with piston rings for sealing; and sealing rings are provided between the valve cover and the pilot valve, between the screw cap and the pilot valve, and between the main valve and the lower end cover.

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