Low pressure safety valve on-line setting automatic switcher

Abstract

This invention discloses an online automatic switching device for low-pressure safety valves, comprising a valve body, an upper valve cover, and a lower valve cover. The valve body has a first air inlet on its left side, a second air inlet on its right side, a central hole in its middle, and an air outlet at its rear. The upper valve cover is fixed to the upper end of the valve body, and an upper diaphragm is sealed between the upper valve cover and the valve body. A first vent hole is located at the upper end of the valve body, and a first air guide hole for connecting the second air inlet and the upper recess is located on the valve body, upper diaphragm, and upper valve cover. The lower valve cover is fixed to the lower end of the valve body, and a lower diaphragm is sealed between the lower valve cover and the valve body. A second vent hole is located at the lower end of the valve body, and a second air guide hole for connecting the first air inlet and the lower recess is located on the valve body, lower diaphragm, and lower valve cover. This invention allows for online setting of the pilot-operated low-pressure safety valve simply by directly inputting a setting air source.

Description

Technical Field

[0001] This invention relates to the field of low-pressure safety valve accessories technology, specifically to an online setting automatic switch for low-pressure safety valves. Background Technology

[0002] A low-pressure safety valve is a type of valve that ensures the storage tank space is isolated from the atmosphere within a certain pressure range, while also allowing it to breathe when the pressure exceeds or falls below this range. Its function is to prevent damage to the storage tank due to overpressure or vacuum, and at the same time reduce the evaporation loss of the stored liquid.

[0003] The low-pressure safety valve is used to maintain the gas pressure balance of the storage tank. When the pressure inside the tank rises to the positive operating pressure of the low-pressure safety valve, the exhalation valve is activated, and gas escapes from the exhalation outlet of the low-pressure safety valve, preventing the pressure inside the tank from continuing to rise. When the pressure inside the tank drops to the negative operating pressure of the low-pressure safety valve, the atmosphere outside the tank pushes open the valve disc assembly of the suction valve, allowing outside gas to enter the tank, preventing the pressure inside the tank from continuing to drop, and maintaining the gas pressure balance between the inside and outside of the tank to protect the storage tank.

[0004] Common low-pressure safety valves (breathing valves) are divided into gravity plate type, spring type and pilot type. Compared with general gravity loading type and spring type breathing valves, pilot type breathing valves have higher sealing performance and can achieve full discharge when the overpressure is less than 10%. Therefore, the operating pressure of pilot type breathing valves can be very close to the maximum design pressure of the storage tank, thereby reducing evaporation loss and improving economic performance.

[0005] However, pilot-operated low-pressure safety valves have a complex structure and require regular calibration. In addition, most of these pilot-operated low-pressure safety valves are installed on the top of large storage tanks, making disassembly and installation inconvenient. Therefore, online setting is the optimal choice for pilot-operated low-pressure safety valves. The common online setting method is to use a three-way ball valve for switching, but there is a risk of operational errors in actual use. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an online automatic switching device for low-pressure safety valves. When setting a pilot-operated low-pressure safety valve, it is only necessary to connect the second connector to the setting air source. The device can automatically select whether the first air inlet or the second air inlet is connected to the air outlet based on the air pressure in the first and second air inlets. This eliminates the need for manual switching and avoids the risks caused by human error.

[0007] The low-pressure safety valve online setting automatic switch of the present invention includes a valve body, an upper valve cover, and a lower valve cover; a first air inlet is provided on the left side of the valve body, which is connected to a pressure tapping pipe through a first connector; a second air inlet is provided on the right side of the valve body, which is connected to a plug cap through a second connector; a vertically penetrating central hole is provided in the middle of the valve body; an air outlet communicating with the central hole is provided on the rear side of the valve body, which is connected to a pilot valve connecting pipe through a third connector; the upper valve cover is fixed to the upper end of the valve body, and an upper diaphragm is sealed between the upper valve cover and the valve body; the lower surface of the upper diaphragm abuts against and seals the outer edge of the upper end of the central hole; the lower end surface of the upper valve cover... The valve body has a concave cavity with an opening at the lower end in the middle. The upper end of the valve body has a first vent hole for connecting the first air inlet and the central hole. The valve body, the upper diaphragm, and the upper valve cover have first air guide holes for connecting the second air inlet and the concave cavity. The lower valve cover is fixed to the lower end of the valve body. The lower diaphragm is sealed between the lower valve cover and the valve body. The upper surface of the lower diaphragm abuts against and seals the outer edge of the lower end of the central hole. The upper end face of the lower valve cover has a concave cavity with an opening at the upper end in the middle. The lower end of the valve body has a second vent hole for connecting the second air inlet and the central hole. The valve body, the lower diaphragm, and the lower valve cover have second air guide holes for connecting the first air inlet and the concave cavity.

[0008] By adopting the above-described structure, when adjusting the pilot-operated low-pressure safety valve, this invention only requires connecting the second connector to the adjusting air source. The invention can automatically select whether the first air inlet or the second air inlet is connected to the outlet, or vice versa, based on the air pressure in the first and second air inlets. This eliminates the need for manual switching, thus avoiding risks caused by human error. Furthermore, this invention only requires direct input of the adjusting air source to achieve online adjustment of the pilot-operated low-pressure safety valve, providing convenience for operators.

[0009] The low-pressure safety valve online setting automatic switch of the present invention includes a first annular recess on the upper surface of the valve body, the upper end of the first vent hole communicating with the first annular recess, and the lower surface of the upper diaphragm abutting and sealing against the upper ends of both sides of the first annular recess. By setting the first annular recess on the upper surface of the valve body, when the plug is removed from the second connector and the second connector is connected to the setting air source, if the air pressure from the pressure tapping pipe is greater than the air pressure of the setting air source, the gas from the pressure tapping pipe can more reliably act on the lower surface of the upper diaphragm (acting on the lower surface of the upper diaphragm in a circumferential manner) through the first vent hole and the first annular recess, thereby making it easier to push the middle part of the upper diaphragm upward, so that the gas from the pressure tapping pipe enters the central hole and enters the third connector and the pilot valve connecting pipe through the air outlet.

[0010] The low-pressure safety valve online setting automatic switch of the present invention includes a second annular recess on the lower end face of the valve body, the lower end of the second vent hole communicating with the second annular recess, and the upper surface of the lower diaphragm abutting and sealing against the lower ends of both sides of the second annular recess. By setting the second annular recess on the lower end face of the valve body, when the plug is removed from the second connector and the second connector is connected to the setting gas source, if the gas pressure from the pressure tapping pipe is less than the gas pressure of the setting gas source, the gas from the setting gas source can more reliably act on the upper surface of the lower diaphragm (acting on the upper surface of the lower diaphragm in a circumferential manner) through the second vent hole and the second annular recess. This makes it easier to push the middle part of the lower diaphragm downward, so that the gas from the setting gas source can enter the central hole and enter the third connector and the pilot valve connecting pipe through the vent hole.

[0011] The low-pressure safety valve online setting automatic switch of the present invention has a first annular bend edge provided at the outer edge of the upper diaphragm, and the first annular bend edge is press-fitted and fixed between the upper valve cover and the upper end of the valve body; by adopting this structure, the upper diaphragm can be reliably and sealingly fixed between the upper valve cover and the upper end of the valve body.

[0012] The low-pressure safety valve online setting automatic switch of the present invention has a second annular bend at the outer edge of the lower diaphragm, which is press-fitted and fixed between the lower valve cover and the lower end of the valve body; by adopting this structure, the lower diaphragm can be reliably and sealingly fixed between the lower valve cover and the lower end of the valve body.

[0013] The low-pressure safety valve online setting automatic switch of the present invention, wherein the upper diaphragm and the lower diaphragm are both made of polytetrafluoroethylene (PTFE); by using PTFE to make the upper and lower diaphragms, freezing between the upper and lower diaphragms and the valve body can be avoided at low temperatures. Attached Figure Description

[0014] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0015] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0016] Figure 2 This is a three-dimensional cross-sectional view of the present invention;

[0017] Figure 3 for Figure 2 A magnified structural diagram of point A in the middle;

[0018] Figure 4 for Figure 2 A magnified structural diagram of point B in the middle;

[0019] Figure 5 This is a schematic diagram of the normal operation of the present invention;

[0020] Figure 6 This is a schematic diagram of the online tuning process of the present invention. Detailed Implementation

[0021] The following drawings disclose several embodiments of the present invention. For clarity, many practical details will be described in the following description. However, it should be understood that these practical details are not intended to limit the invention. That is, in some embodiments of the invention, these practical details are not essential. Furthermore, for the sake of simplicity, some conventional structures and components will be shown in the drawings in a simple schematic manner.

[0022] Furthermore, in this invention, the use of terms such as "first" and "second" is for descriptive purposes only and does not specifically refer to any order or sequence, nor is it intended to limit the invention. They are merely used to distinguish components or operations described using the same technical terms, and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but only if they are feasible for those skilled in the art. If a combination of technical solutions is contradictory or impossible to implement, such a combination should be considered nonexistent and not within the scope of protection claimed by this invention.

[0023] like Figure 1-4As shown, the low-pressure safety valve online setting automatic switch of the present invention includes a valve body 1, an upper valve cover 2, and a lower valve cover 3. A first air inlet 11 is provided on the left side of the valve body 1, and the first air inlet 11 is connected to a pressure tapping pipe 42 via a first connector 41. A second air inlet 12 is provided on the right side of the valve body 1, and the second air inlet 12 is connected to a plug cap 52 via a second connector 51. A vertically penetrating central hole 13 is provided in the middle of the valve body 1. An air outlet 14 communicating with the central hole 13 is provided on the rear side of the valve body 1, and the air outlet 14 is connected to a pilot valve connecting pipe 62 via a third connector 61. The upper valve cover 2 is fixed to the upper end of the valve body 1. An upper diaphragm 7 is sealed between the upper valve cover 2 and the valve body 1. The lower surface of the upper diaphragm 7 abuts against and seals the outer edge of the upper end of the central hole 13. The lower end of the upper valve cover 2... A concave cavity 21 with an opening at the lower end is provided in the middle of the valve body 1. A first vent 15 for connecting the first air inlet 11 and the central hole 13 is provided at the upper end of the valve body 1. A first air guide hole 16 for connecting the second air inlet 12 and the concave cavity 21 is provided on the valve body 1, the upper diaphragm 7 and the upper valve cover 2. The lower valve cover 3 is fixed to the lower end of the valve body 1. A lower diaphragm 8 is sealed between the lower valve cover 3 and the valve body 1. The upper surface of the lower diaphragm 8 abuts against and seals the outer edge of the lower end of the central hole 13. A concave cavity 31 with an opening at the upper end is provided in the middle of the upper end of the lower valve cover 3. A second vent 17 for connecting the second air inlet 12 and the central hole 13 is provided at the lower end of the valve body 1. A second air guide hole 18 for connecting the first air inlet 11 and the concave cavity 31 is provided on the valve body 1, the lower diaphragm 8 and the lower valve cover 3.

[0024] A first annular recess 191 is provided on the upper end face of the valve body 1. The upper end of the first vent hole 15 is connected to the first annular recess 191. The lower surface of the upper diaphragm 7 abuts against and seals the upper ends of both sides of the first annular recess 191. After the first annular recess is provided on the upper end face of the valve body, when the plug is removed from the second connector and the second connector is connected to the setting gas source, if the gas pressure from the pressure tapping pipe is greater than the gas pressure of the setting gas source, the gas from the pressure tapping pipe can more reliably act on the lower surface of the upper diaphragm (acting on the lower surface of the upper diaphragm in a circumferential manner) through the first vent hole and the first annular recess. This makes it easier to push the middle part of the upper diaphragm upward, so that the gas from the pressure tapping pipe can enter the central hole and enter the third connector and the pilot valve connecting pipe through the vent hole.

[0025] A second annular recess 192 is provided on the lower end face of the valve body 1. The lower end of the second vent hole 17 is connected to the second annular recess 192. The upper surface of the lower diaphragm 8 abuts against and seals the lower ends on both sides of the second annular recess 192. After the second annular recess is provided on the lower end face of the valve body, when the plug is removed from the second connector and the second connector is connected to the setting air source, if the air pressure from the pressure tapping pipe is less than the air pressure of the setting air source, the gas from the setting air source can more reliably act on the upper surface of the lower diaphragm (acting on the upper surface of the lower diaphragm in a circumferential manner) through the second vent hole and the second annular recess. This makes it easier to push the middle part of the lower diaphragm downward, so that the gas from the setting air source can enter the central hole and enter the third connector and the pilot valve connecting pipe through the air outlet.

[0026] The outer edge of the upper diaphragm 7 is provided with a first annular bend 71, which is press-fitted and fixed between the upper valve cover 2 and the upper end of the valve body 1. With this structure, the upper diaphragm can be reliably and sealingly fixed between the upper valve cover and the upper end of the valve body.

[0027] A second annular bend 81 is provided at the outer edge of the lower diaphragm 8. The second annular bend 81 is press-fitted and fixed between the lower valve cover 3 and the lower end of the valve body 1. With this structure, the lower diaphragm can be reliably and sealingly fixed between the lower valve cover and the lower end of the valve body.

[0028] Both the upper diaphragm 7 and the lower diaphragm 8 are made of polytetrafluoroethylene (PTFE). By using PTFE to make the upper and lower diaphragms, freezing between the upper and lower diaphragms and the valve body can be avoided at low temperatures.

[0029] like Figure 5 As shown, the low-pressure safety valve online setting automatic switch is a high-pressure selector that sends the higher-pressure gas from the first and second air inlets to the outlet. Its principle is as follows: When the pressure P1 in the first air inlet is greater than the pressure P0 in the second air inlet, the pressure at the bottom of the upper diaphragm is P1, and the pressure at the top of the upper diaphragm is P0. The upper diaphragm opens due to an upward force, and the pressure difference is ΔP = P1 - P0, with the entire upper diaphragm acting on it. Similarly, the pressure at the bottom of the lower diaphragm is P1, and the pressure at the top of the lower diaphragm is P0. The pressure in the central hole is P1, and the lower diaphragm closes due to an upward force, with the pressure difference being ΔP = P1 - P0, and the acting area being the outer annular area of ​​the lower diaphragm. In this way, the outlet receives pressure P1 without leaking into the setting gas source.

[0030] like Figure 6As shown, when the low-pressure safety valve online setting automatic switch is set online, the second connector is connected to the setting air source, and the air pressure P2 of the setting air source is greater than the air pressure P1 in the first air inlet. The principle at this time is as follows: when the air pressure P2 of the setting air source is greater than the air pressure P1 in the first air inlet, the air pressure at the bottom of the lower diaphragm is P1, and the air pressure at the top of the lower diaphragm is P2. The lower diaphragm is opened by a downward force, and the air pressure difference is ΔP = P2 - P1, with the effective area being the entire lower diaphragm. The air pressure at the top of the upper diaphragm is P2, the air pressure at the outer ring area at the bottom of the upper diaphragm is P1, and the air pressure in the central hole is P2. The upper diaphragm is closed by a downward force, and the air pressure difference is ΔP = P2 - P1, with the effective area being the outer ring area of ​​the upper diaphragm. In this way, the air outlet can obtain air pressure P2 without leakage into the pressure tapping pipe.

[0031] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. An online setting automatic switch for low-pressure safety valves, characterized in that: The valve body includes a valve body (1), an upper valve cover (2), and a lower valve cover (3). A first air inlet (11) is provided on the left side of the valve body (1), and the first air inlet (11) is connected to a pressure tapping pipe (42) via a first connector (41). A second air inlet (12) is provided on the right side of the valve body (1), and the second air inlet (12) is connected to a plug cap (52) via a second connector (51). A vertically penetrating central hole (13) is provided in the middle of the valve body (1). A vent (14) communicating with a central hole (13) is provided on the rear side of the valve body (1). The vent (14) is connected to the pilot valve connecting pipe (62) through a third connector (61). The upper valve cover (2) is fixed to the upper end of the valve body (1). An upper diaphragm (7) is sealed between the upper valve cover (2) and the valve body (1). The lower surface of the upper diaphragm (7) abuts against and seals the outer edge of the upper end of the central hole (13). A lower end is provided in the middle of the lower end face of the upper valve cover (2). The valve body (1) has an open upper concave cavity (21). The upper end of the valve body (1) is provided with a first vent (15) for connecting the first air inlet (11) and the central hole (13). The valve body (1), upper diaphragm (7), and upper valve cover (2) are provided with a first air guide hole (16) for connecting the second air inlet (12) and the upper concave cavity (21). The lower valve cover (3) is fixed to the lower end of the valve body (1), and a lower diaphragm (8) is sealed between the lower valve cover (3) and the valve body (1). The upper surface of the lower diaphragm (8) abuts against and seals the outer edge of the lower end of the central hole (13). The upper end face of the lower valve cover (3) is provided with a recessed cavity (31) with an upper opening. The lower end of the valve body (1) is provided with a second vent (17) for connecting the second air inlet (12) and the central hole (13). The valve body (1), the lower diaphragm (8) and the lower valve cover (3) are provided with a second air guide hole (18) for connecting the first air inlet (11) and the recessed cavity (31).

2. The low-pressure safety valve online setting automatic switcher according to claim 1, characterized in that, The valve body (1) has a first annular recess (191) on its upper surface. The upper end of the first vent (15) is connected to the first annular recess (191). The lower surface of the upper diaphragm (7) abuts against and seals the upper ends of both sides of the first annular recess (191).

3. The low-pressure safety valve online setting automatic switcher according to claim 1, characterized in that, The lower end face of the valve body (1) is provided with a second annular recess (192), the lower end of the second vent (17) is connected to the second annular recess (192), and the upper surface of the lower diaphragm (8) abuts against and seals the lower ends on both sides of the second annular recess (192).

4. The low-pressure safety valve online setting automatic switcher according to any one of claims 1-3, characterized in that, The upper diaphragm (7) has a first annular bend (71) at its outer edge, and the first annular bend (71) is press-fitted between the upper valve cover (2) and the upper end of the valve body (1).

5. The low-pressure safety valve online setting automatic switcher according to any one of claims 1-3, characterized in that, The lower diaphragm (8) has a second annular bend (81) at its outer edge, and the second annular bend (81) is press-fitted between the lower valve cover (3) and the lower end of the valve body (1).

6. The low-pressure safety valve online setting automatic switcher according to any one of claims 1-3, characterized in that, Both the upper diaphragm (7) and the lower diaphragm (8) are made of polytetrafluoroethylene.

Images