Single-diaphragm type self-operated negative pressure regulating valve and box chamber system

Abstract

The invention discloses a single diaphragm type self-operated negative pressure regulating valve and a box chamber system.The regulating valve comprises a valve body, a valve clack and a driving device, the driving device comprises an upper cylinder body, a lower cylinder body, a diaphragm assembly, a piston, a first connecting piece, a second connecting piece and a balancing weight, an outlet is formed in the top end of the valve body, an inlet is formed in the side face of the valve body, and the upper cylinder body is connected with the bottom end of the valve body; a feedback opening is formed in the upper cylinder body, the lower cylinder body and the upper cylinder body are in butt joint to form a cavity, and an unthreaded hole is formed in the lower cylinder body. The diaphragm assembly is arranged in the cavity and divides the cavity into an upper feedback chamber and a lower feedback chamber, and the piston is arranged in the upper feedback chamber; the first connecting piece is connected with the lower portion of the piston and penetrates through the diaphragm assembly and the lower cylinder body downwards. The balancing weight is arranged at the end, away from the piston, of the second connecting rod. The second connecting piece is connected with the upper portion of the piston and upwards penetrates through the upper cylinder body to extend into the valve body. The valve clack is arranged at the end, away from the piston, of the second connecting rod. According to the invention, automatic adjustment and maintenance of negative pressure within a specified range can be realized.

Description

Technical Field

[0001] This invention belongs to the field of valve design technology, specifically relating to a single-diaphragm self-regulating negative pressure regulating valve and a chamber system. Background Technology

[0002] In various types of nuclear facilities containing radioactive materials, there are typically hot chambers or glove boxes for reprocessing operations, also known as enclosure systems. These enclosure systems require operation under slight negative pressure. Negative pressure regulating valves are installed in the ventilation ducts of these enclosure systems to regulate the pressure inside the enclosure. The opening of these valves controls the flow rate within the enclosure, maintaining the negative pressure within a set range to ensure a stable negative pressure environment and prevent leakage of radioactive materials that could harm operators and the environment. The ventilation system is a crucial component of these enclosure systems. Since operation within the enclosure requires negative pressure, the ventilation system uses negative pressure regulating valves to adjust the pressure inside the enclosure, maintaining it within a set negative pressure range to prevent radioactive material leakage and ensure a stable negative pressure environment.

[0003] The negative pressure value in the chamber is generally designed to be between -200 and -300 Pa, which is a slight negative pressure. Existing mature regulating valve products on the market do not perform well in automatically adjusting this range of slight negative pressure, resulting in large fluctuations in flow rate and failing to meet the functional requirements of the chamber system. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art by providing a single-diaphragm self-regulating negative pressure regulating valve and chamber system, which can realize the automatic adjustment and maintenance of negative pressure within a specified range.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is:

[0006] According to one aspect of the present invention, a single-diaphragm self-regulating negative pressure regulating valve is provided, comprising a valve body, a valve disc, and a drive device. The drive device includes an upper cylinder, a lower cylinder, a diaphragm assembly, a piston, a first connecting member, a second connecting member, and a counterweight, wherein:

[0007] An outlet is opened at the top of the valve body, an inlet is opened on the side of the valve body, the upper cylinder is connected to the bottom of the valve body, a feedback port is provided on the upper cylinder, the lower cylinder is connected to the upper cylinder to form a chamber, and a light hole is provided on the lower cylinder.

[0008] The diaphragm assembly is located in the chamber, dividing the chamber into an upper feedback chamber and a lower feedback chamber, and the piston is located in the upper feedback chamber;

[0009] The first connector is connected to the lower part of the piston and passes downward through the diaphragm assembly and the lower cylinder. The counterweight is located at the end of the second connecting rod away from the piston.

[0010] The second connecting member is connected to the upper part of the piston and extends upward through the upper cylinder body into the valve body, with the valve disc located at the end of the second connecting rod away from the piston.

[0011] Optionally, the diaphragm assembly includes a diaphragm and a diaphragm pressure plate, with the edge of the diaphragm sealed to the inner wall of the chamber, dividing the chamber into an upper feedback chamber and a lower feedback chamber, and the diaphragm pressure plate located at the bottom of the diaphragm.

[0012] Optionally, the diaphragm is a rolling diaphragm, and the material of the rolling diaphragm is EPDM rubber.

[0013] Optionally, the first connecting member includes a lower piston rod and a screw. The lower piston rod passes through the diaphragm assembly and the lower cylinder. Its top end is detachably connected to the middle position of the lower part of the piston, and its bottom end is connected to the screw. The configuration block is mounted on the screw.

[0014] Optionally, the first connecting member also includes a lever plate, which is located on the lower piston rod and outside the chamber, or on the screw but above the counterweight; the regulating valve also includes a bracket, the lower cylinder is mounted on the bracket, the bracket is provided with a limit switch, and the lever plate can touch the limit switch to achieve position feedback.

[0015] Optionally, the second connecting member includes an upper piston rod and a valve rod. The upper piston rod passes through the upper cylinder body, and its bottom end is detachably connected to the middle position of the upper part of the piston. Its top end is connected to one end of the valve rod, and the valve disc is located at the other end of the valve rod.

[0016] Optionally, the valve disc has a spherical cone shape.

[0017] Optionally, the valve disc and valve stem are connected by a ball joint.

[0018] Optionally, the second connecting component also includes a bushing and a bellows. The bushing is fitted over the upper piston rod and is located outside the upper cylinder body. The bellows is also fitted over the upper piston rod, with one end connected to the top of the bushing and the other end connected to the bottom of the valve stem.

[0019] Optionally, a valve seat is provided at the outlet of the valve body, and a snap ring groove is provided in the valve body near the outlet, with a snap ring inside the snap ring groove, and the valve seat is located between the snap ring and the valve disc.

[0020] According to another aspect of the present invention, a chamber system is provided, comprising a chamber and a ventilation duct, wherein the ventilation duct is provided with the single-diaphragm self-regulating negative pressure regulating valve described above.

[0021] Beneficial effects:

[0022] (1) The present invention can activate the drive device by the pressure difference generated by the pressure change in the chamber, thereby driving the valve disc to move up and down, adjusting the opening of the valve body outlet, and changing the flow rate of the ventilation and exhaust pipes in the chamber system, thereby realizing automatic adjustment of the pressure in the chamber.

[0023] (2) By setting a rolling diaphragm, the overall size and weight of the regulating valve of the present invention can be reduced.

[0024] (3) By using a valve with a ball-cone structure, the flow rate through the ventilation and exhaust pipe can be stabilized and the fluctuation range is small.

[0025] (4) By using a ball joint connection between the valve disc and the valve stem, the valve disc and the valve seat can have an automatic alignment function, which avoids the valve disc from failing to reset when the valve is opened and closed, thus preventing the valve from opening and closing normally.

[0026] (5) By setting the snap ring groove and snap ring, this regulating valve can have the advantages of simple maintenance, and the structure of the valve seat and valve disc can be changed according to the requirements of different flow characteristic curves.

[0027] (6) Position feedback can be achieved by setting up a toggle switch and a limit switch. Attached Figure Description

[0028] Figure 1 This is a cross-sectional view of the single-diaphragm self-regulating negative pressure regulating valve in an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the drive device in an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the overall structure of the single-diaphragm self-regulating negative pressure regulating valve in an embodiment of the present invention;

[0031] Figure 4 This is a bottom view of the single-diaphragm self-regulating negative pressure regulating valve in an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the connection between the valve body and the valve seat in an embodiment of the present invention;

[0033] Figure 6 This is a schematic diagram of the connection between the valve disc and the valve stem in an embodiment of the present invention;

[0034] Figure 7 This is a schematic diagram illustrating the control principle of negative pressure regulation and maintenance in the chamber system of this invention.

[0035] In the diagram: 1-Valve body; 2-Valve disc; 3-Valve stem; 4-Upper piston rod; 5-Upper cylinder; 6-Piston; 7-Diaphragm; 8-Diaphragm pressure plate; 9-Lower cylinder; 10-Bracket; 11-Pulley; 12-Counterweight; 13-Screw; 14-Limit switch; 15-Valve seat; 16-Snap ring; 17-Bellows; 18-Bushing; 19-Feedback port; 20-Lower piston rod; 21-Snap ring groove. Detailed Implementation

[0036] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0037] In the description of this invention, it should be noted that the terms "above" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience and simplification of the description and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0038] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0039] To address the problem that negative pressure regulating valves in traditional enclosure systems' ventilation ducts cannot automatically adjust for slight negative pressure, this invention discloses a single-diaphragm self-regulating negative pressure regulating valve, comprising a valve body, a valve disc, and a driving device. The driving device includes an upper cylinder, a lower cylinder, a diaphragm assembly, a piston, a first connecting member, a second connecting member, and a counterweight, wherein:

[0040] An outlet is opened at the top of the valve body, an inlet is opened on the side of the valve body, the upper cylinder is connected to the bottom of the valve body, a feedback port is provided on the upper cylinder, the lower cylinder is connected to the upper cylinder to form a chamber, and a light hole is provided on the lower cylinder.

[0041] The diaphragm assembly is located in the chamber, dividing the chamber into an upper feedback chamber and a lower feedback chamber, and the piston is located in the upper feedback chamber;

[0042] The first connector is connected to the lower part of the piston and passes downward through the diaphragm assembly and the lower cylinder. The counterweight is located at the end of the second connecting rod away from the piston.

[0043] The second connecting member is connected to the upper part of the piston and extends upward through the upper cylinder body into the valve body, with the valve disc located at the end of the second connecting rod away from the piston.

[0044] Furthermore, the present invention also discloses a chamber system, including a chamber and a ventilation duct communicating with the chamber, wherein the ventilation duct is provided with the single diaphragm self-regulating negative pressure regulating valve described above.

[0045] The working principle of the regulating valve of this invention is as follows: In use, the regulating valve is installed on the ventilation duct of the chamber in the chamber system. The inlet end of the regulating valve is connected to the outlet end of the chamber, and the outlet end of the regulating valve is connected to the inlet end of the ventilation duct. The feedback port of the regulating valve is connected to the pressure tapping pipe led out from the chamber, so that the pressure in the upper feedback chamber is equal to the pressure in the chamber. The aperture is connected to the external environment, so that the pressure in the lower feedback chamber is equal to atmospheric pressure. When the negative pressure in the chamber changes, the pressure in the upper feedback chamber also changes accordingly. The counterweight makes the regulating valve partially open, so that the negative pressure in the chamber reaches the set value. When the negative pressure inside the chamber rises and deviates from the set value, the pressure causes the diaphragm in the upper feedback chamber to roll upward, which in turn moves the valve disc upward, reducing the valve opening and decreasing the flow rate through the ventilation duct, thus lowering the negative pressure inside the chamber back to the set range. When the negative pressure inside the chamber decreases and deviates from the set range, the pressure causes the diaphragm in the upper feedback chamber to roll downward, which in turn moves the valve disc downward, increasing the valve opening and increasing the flow rate through the ventilation duct, thus raising the negative pressure inside the chamber back to the set range.

[0046] This invention can activate the drive device by the pressure difference generated by the pressure change in the chamber, thereby driving the valve disc to move up and down, adjusting the opening of the valve body outlet, and changing the flow rate of the ventilation and exhaust pipes in the chamber system, thus achieving automatic adjustment of the pressure in the chamber.

[0047] Example 1

[0048] like Figures 1-4 As shown, this embodiment discloses a single-diaphragm self-regulating negative pressure regulating valve for installation on the ventilation duct of a chamber in a chamber system. It includes a valve body 1, a valve disc 2, and a driving device. The driving device includes an upper cylinder 5, a lower cylinder 9, a diaphragm assembly, a piston 6, a first connecting member, a second connecting member, and a counterweight 12.

[0049] The valve body 1 has an outlet at the top and an inlet on the side. The upper cylinder 5 is detachably connected to the bottom of the valve body 1 by bolts or other means. The upper cylinder 5 has a feedback port 19 on one side of its top, which is used to connect to the chamber. The lower cylinder 9 is detachably located below the upper cylinder 5 by bolts or other means and is connected to the upper cylinder 5 to form a chamber. The bottom of the lower cylinder 9 has several evenly distributed light holes, which are used to connect to the external environment outside the chamber.

[0050] The diaphragm assembly is located in the chamber, dividing the chamber into an upper feedback chamber and a lower feedback chamber, and the piston 6 is located in the upper feedback chamber;

[0051] The first connecting piece is connected to the lower part of the piston 6 and passes downward through the diaphragm assembly and the lower cylinder 9. The counterweight 12 is detachably mounted on the end of the second connecting rod away from the piston 6 (i.e., the bottom end) by means of bolts or other means. The number or weight of the counterweight 12 is adjusted according to the negative pressure range that needs to be set in the chamber.

[0052] The second connecting piece is connected to the upper part of the piston 6 and extends upward through the upper cylinder 5 into the valve body 1. The valve disc 2 is located at the end of the second connecting rod away from the piston 6 (i.e. the top end). The valve disc moves up and down through the action of the driving device, thereby adjusting the opening of the valve body outlet.

[0053] In some implementations, such as Figure 5 As shown, a valve seat 15 is provided at the outlet of the valve body 1, and the valve seat 15 and the valve disc 2 form a sealing pair. The valve seat 15 is connected to the valve body 1 by a detachable means such as threads, so as to facilitate online maintenance and replacement. In addition, a retaining ring groove 21 is provided in the valve body 1 near the outlet, and a retaining ring 16 is provided in the retaining ring groove 21. The valve seat 15 is located between the retaining ring 16 and the valve disc 2.

[0054] Compared to the structure where the valve seat 15 and valve body 1 are integrally formed, this regulating valve has advantages such as simple maintenance by setting a snap ring groove and snap ring. Furthermore, the structure of the valve seat 15 and valve disc 2 can be replaced according to the requirements of different flow characteristic curves.

[0055] In some embodiments, the top end of the upper cylinder 5 and the bottom end of the valve body 1 are respectively provided with matching bosses and grooves to serve as guides during installation.

[0056] In some embodiments, the diaphragm assembly includes a diaphragm 7 and a diaphragm pressure plate 8. The edge of the diaphragm 7 is sealed to the inner wall of the chamber. The diaphragm 7 divides the chamber into an upper feedback chamber and a lower feedback chamber. The diaphragm pressure plate 8 is located at the bottom of the diaphragm 7. The diaphragm 7 can be compressed by the diaphragm pressure plate 8 and the piston 6, thereby achieving a seal.

[0057] In some more specific embodiments, the top of the lower cylinder 9 and the bottom of the diaphragm 7 are respectively provided with matching sealing grooves and sealing ribs. By snapping the sealing ribs into the sealing grooves, the edge of the diaphragm is sealed to the inner wall of the cavity. During installation and use, the sealing grooves and sealing ribs cooperate to achieve a sealing effect and prevent leakage.

[0058] In some embodiments, the diaphragm 7 is a rolling diaphragm, such as... Figure 2As shown, the rolling diaphragm, in its free state, has a "top hat" shape and a wave-like structure that can undulate up and down, responding to pressure changes through elastic deformation. The edges of this diaphragm are pressed and fixed by the upper cylinder 5 and the lower cylinder 9, while the center is connected to the valve stem 3 for axial displacement. This special structure enables a relatively large stroke, which helps to reduce the overall size and weight of the regulating valve.

[0059] The rolling diaphragm is made of EPDM rubber, which has good temperature resistance, excellent fatigue performance, and a good fatigue life.

[0060] Compared to traditional butterfly diaphragms and flat diaphragms, the rolling diaphragm in this embodiment can generate greater thrust under the same pressure and size. At the same time, EPDM rubber has good airtightness, which can ensure its sealing performance with a small thickness, thereby reducing the overall size and weight of this control valve.

[0061] In some embodiments, the first connector includes a lower piston rod 20 and a screw 13. The lower piston rod 20 passes through the diaphragm assembly and the lower cylinder 9. Its top end is detachably connected to the lower middle position of the piston 6 by means of a thread (e.g., thread), and its bottom end is connected to the screw 13. The mounting block 12 is mounted on the screw 13.

[0062] In some embodiments, the first connecting member further includes a lever 11, which is disposed between the lower piston rod 20 and the screw 13. More precisely, the lever 11 is disposed on the lower piston rod 20 and outside the chamber, or on the screw 13 but above the counterweight 12. Furthermore, the regulating valve also includes a bracket 10, on which the lower cylinder 9 is mounted. A limit switch 14 is provided at the middle position of the bracket 10, which can cooperate with the lever to achieve position feedback.

[0063] Specifically, when the drive unit is activated, the dial moves up and down accordingly, and position feedback is achieved by the dial touching the limit switch.

[0064] In this embodiment, the number of brackets 10 is three, but not limited to this, and the three brackets are evenly distributed below the lower cylinder 9.

[0065] In some embodiments, the second connector includes an upper piston rod 4 and a valve rod 3. The upper piston rod 4 passes through the upper cylinder 5, and its bottom end is detachably connected to the middle position of the upper part of the piston 6 by means of a thread. Together with the first connector, it locks and fixes the diaphragm assembly. Its top end is connected to one end of the valve rod 3, and the valve disc 2 is located at the other end of the valve rod 3 away from the piston.

[0066] In some implementations, such as Figure 6As shown, valve disc 2 has a spherical cone structure. The flow characteristic curve of this type of valve is linear, meaning that when the valve stroke changes, the corresponding flow change is the same, thus making the flow change through the ventilation duct stable and with a small fluctuation range.

[0067] In some implementations, such as Figure 6 As shown, valve disc 2 and valve stem 3 are connected by a ball joint or a ball-shaped connection structure. This structure enables the valve disc and valve seat to automatically align, preventing the valve disc from failing to reset when the valve is opened or closed, thus preventing the valve from opening or closing normally.

[0068] In some embodiments, the second connector also includes a bushing 18 and a bellows 17, which can achieve a seal between the valve stem and the rolling diaphragm, ensuring that the atmosphere exists only in the upper cylinder and preventing internal atmosphere leakage.

[0069] Specifically, the bushing 18 is fitted outside the upper piston rod 4 and is located outside the upper cylinder 5; the bellows 17 is also fitted outside the upper piston rod 4, with one end connected to the top of the bushing 18 and the other end connected to the bottom of the valve stem 3.

[0070] The single-diaphragm self-regulating negative pressure regulating valve of this embodiment has the following effects:

[0071] (1) The present invention can activate the drive device by the pressure difference generated by the pressure change in the chamber, thereby driving the valve disc to move up and down, adjusting the opening of the valve body outlet, and changing the flow rate of the ventilation and exhaust pipes in the chamber system, thereby realizing automatic adjustment of the pressure in the chamber.

[0072] (2) By setting a rolling diaphragm, the overall size and weight of the regulating valve of the present invention can be reduced.

[0073] (3) By using a valve with a ball-cone structure, the flow rate through the ventilation and exhaust pipe can be stabilized and the fluctuation range is small.

[0074] (4) By using a ball joint connection between the valve disc and the valve stem, the valve disc and the valve seat can have an automatic alignment function, which avoids the valve disc from failing to reset when the valve is opened and closed, thus preventing the valve from opening and closing normally.

[0075] (5) By setting the snap ring groove and snap ring, this regulating valve can have the advantages of simple maintenance, and the structure of the valve seat and valve disc can be changed according to the requirements of different flow characteristic curves.

[0076] (6) Position feedback can be achieved by setting up a toggle switch and a limit switch.

[0077] Example 2

[0078] This embodiment discloses a chamber system, including a chamber and a ventilation duct. The ventilation duct is connected to the chamber and is equipped with the single-diaphragm self-regulating negative pressure regulating valve described above.

[0079] When setting the negative pressure inside the chamber, the valve is partially opened by adjusting the number or weight of the counterweight 12, thereby bringing the negative pressure inside the chamber to the required range. When the negative pressure inside the chamber changes, the pressure difference generated by the change in pressure inside the chamber can activate the drive device, thereby driving the valve disc to move up and down, adjusting the opening of the valve body outlet, and changing the flow rate of the ventilation ducts in the chamber system, thus achieving automatic adjustment of the pressure inside the chamber.

[0080] Specifically, the overall structure of the chamber system in this embodiment is as follows: Figure 7 As shown, the control principle for achieving negative pressure regulation and maintenance is as follows:

[0081] Taking box #1 (i.e., chamber) as an example, the air inlet pipe in the ventilation duct is connected to the air inlet of box #1. An electric ball valve for air intake control, a filter, and an air volume transmitter are installed on the air inlet pipe. The fan in the exhaust system is connected to the exhaust port of box #1 through the exhaust pipe in the ventilation duct. Necessary filters (such as filters #2, #3, #4, and #5), sensors (such as displacement sensor #1, air volume transmitter #2, #3, and #6), negative pressure measuring instruments (such as pressure tapping pipe #1), and the aforementioned single-diaphragm self-operated negative pressure regulating valve (i.e., negative pressure regulating valve #1) are connected in series in the exhaust pipe. A negative pressure feedback valve, a solenoid valve, and an electric ball valve for emergency operation control are installed on box #1.

[0082] First, adjust the negative pressure inside the No. 1 box to the set range by adjusting the ball valves at both ends of the air inlet and exhaust outlet (such as the No. 1 recent control electric ball valve).

[0083] Under normal operating conditions, the negative pressure inside chamber #1 is regulated within the specified range. The self-regulating negative pressure regulating valve automatically adjusts and maintains the negative pressure inside chamber #1 through feedback from negative pressure inside chamber #1 (such as feedback from negative pressure inside chamber #2 and negative pressure inside chamber #3). Specifically, the upper end of the rolling diaphragm of the single-diaphragm self-regulating negative pressure regulating valve reflects the measured negative pressure inside the chamber, while the lower end reflects the atmospheric pressure of the surrounding space. By calculating and configuring a suitable counterweight at the lower end of the single-diaphragm self-regulating negative pressure regulating valve, the valve can automatically adapt to changes in the negative pressure inside chamber #1, keeping the negative pressure inside chamber #1 within the set range, with fluctuations not exceeding 10% of the set negative pressure.

[0084] When the seal of box #1 is damaged, the flow rate of the exhaust pipe will be at its maximum, while the single-diaphragm self-regulating negative pressure regulating valve will be at its maximum flow rate. At the same time, the feedback will cause the emergency control electric ball valve #1 to open, increasing the exhaust of box #1 and keeping box #1 under negative pressure to prevent internal atmosphere from leaking out.

[0085] The chamber system of this embodiment has all the effects of the single diaphragm self-regulating negative pressure regulating valve described in Embodiment 1, which will not be described in detail here.

[0086] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A single-diaphragm self-regulating negative pressure regulating valve, characterized in that, It includes a valve body (1), a valve disc (2) and a drive device. The drive device includes an upper cylinder (5), a lower cylinder (9), a diaphragm assembly, a piston (6), a first connector, a second connector and a counterweight (12). An outlet is opened at the top of the valve body, an inlet is opened on the side of the valve body, the upper cylinder is connected to the bottom of the valve body, a feedback port (19) is provided on the upper cylinder, the lower cylinder is connected to the upper cylinder to form a chamber, and a light hole is provided on the lower cylinder. The diaphragm assembly is located in the chamber, dividing the chamber into an upper feedback chamber and a lower feedback chamber, and the piston is located in the upper feedback chamber; The first connector is connected to the lower part of the piston and passes downward through the diaphragm assembly and the lower cylinder. The counterweight is located at the end of the second connecting rod away from the piston. The second connecting member is connected to the upper part of the piston and extends upward through the upper cylinder body into the valve body, with the valve disc located at the end of the second connecting rod away from the piston.

2. The single-diaphragm self-regulating negative pressure regulating valve according to claim 1, characterized in that, The diaphragm assembly includes a diaphragm (7) and a diaphragm pressure plate (8). The edge of the diaphragm is sealed to the inner wall of the chamber, dividing the chamber into an upper feedback chamber and a lower feedback chamber. The diaphragm pressure plate is located at the bottom of the diaphragm.

3. The single-diaphragm self-regulating negative pressure regulating valve according to claim 2, characterized in that, The diaphragm is a rolling diaphragm, and the rolling diaphragm is made of EPDM rubber.

4. The single-diaphragm self-regulating negative pressure regulating valve according to claim 1, characterized in that, The first connecting member includes a lower piston rod (20) and a screw (13). The lower piston rod passes through the diaphragm assembly and the lower cylinder. Its top end is detachably connected to the middle of the lower part of the piston, and its bottom end is connected to the screw. The mounting block is installed on the screw.

5. The single-diaphragm self-regulating negative pressure regulating valve according to claim 4, characterized in that, The first connecting member also includes a lever (11), which is located on the lower piston rod and outside the chamber, or on the screw but above the counterweight. The regulating valve also includes a bracket (10), the lower cylinder is mounted on the bracket, and a limit switch (14) is provided on the bracket. The lever can touch the limit switch to realize position feedback.

6. The single-diaphragm self-regulating negative pressure regulating valve according to claim 1, characterized in that, The second connecting component includes an upper piston rod (4) and a valve rod (3). The upper piston rod passes through the upper cylinder body, and its bottom end is detachably connected to the middle position of the upper part of the piston. Its top end is connected to one end of the valve rod, and the valve disc is located at the other end of the valve rod.

7. The single-diaphragm self-regulating negative pressure regulating valve according to claim 6, characterized in that, The valve disc has a spherical cone shape.

8. The single-diaphragm self-regulating negative pressure regulating valve according to claim 6, characterized in that, The valve disc and valve stem are connected by a ball joint.

9. The single-diaphragm self-regulating negative pressure regulating valve according to claim 6, characterized in that, The second connector also includes a bushing (18) and a bellows (17). The bushing is fitted outside the upper piston rod and is located outside the upper cylinder body; The bellows is also fitted over the upper piston rod, with one end connected to the top of the bushing and the other end connected to the bottom of the valve stem.

10. The single-diaphragm self-regulating negative pressure regulating valve according to any one of claims 1 to 9, characterized in that, A valve seat (15) is provided on the outlet of the valve body, and a snap ring groove (21) is provided in the valve body near the outlet. A snap ring (16) is provided in the snap ring groove, and the valve seat is located between the snap ring and the valve disc.

11. A compartment system, comprising a compartment and ventilation ducts, characterized in that, The ventilation duct is equipped with a single-diaphragm self-regulating negative pressure regulating valve as described in any one of claims 1 to 10.

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