Pilot operated safety valve

Abstract

The pilot operated safety valve comprises a pilot valve, the pilot valve comprises a base assembly and a valve clack assembly, and the base assembly is provided with a pilot valve lower cavity, a pilot valve upper cavity and a communication opening; the valve clack assembly comprises a valve shaft and a valve clack main body, the valve shaft is provided with a sealing body and a shaft body, the sealing body is movably arranged in the pilot valve lower cavity and can form hard sealing with an inlet of the pilot valve lower cavity and an outlet of the pilot valve lower cavity respectively, one end of the shaft body is connected with the sealing body, and the other end of the shaft body extends towards the valve clack main body. The valve clack body is movably arranged in the pilot valve upper cavity, and the valve clack body and an inlet of the pilot valve upper cavity can form hard sealing. According to the pilot valve, hard sealing is formed through direct contact among the valve shaft, the valve clack body and the base assembly, the defect that an existing pilot valve sealed through an O-shaped ring cannot be used under the working condition of a high-pressure corrosive medium is overcome, and the application occasion of the pilot valve is further expanded.

Description

Technical Field

[0001] The utility model relates to the technical field of valves, in particular to a pilot-operated safety valve. Background Art

[0002] Pilot-operated safety valves are mainly used in the oil refining, chemical and other industries. They have advantages that spring-loaded safety valves do not have, such as: pilot-operated safety valves can achieve high sealing performance; can meet the working conditions where the difference between the working pressure and the set pressure is very small; can be used in large-caliber and high-set pressure occasions; can be used in high back pressure occasions, etc. Pilot-operated safety valves are generally composed of a main valve and a pilot valve, and the action of the main valve is controlled by the opening and closing of the pilot valve. However, the pilot valve structure in the traditional pilot-operated safety valve uses an O-ring for sealing design.

[0003] The design uses the valve seat and the valve seat cover to fix the sealing O-ring, and the airflow pushes the valve shaft up and down to realize the opening and return sealing of the pilot valve. The use of O-ring sealing has advantages and disadvantages. The advantage is reliable sealing and can achieve zero leakage under sealing pressure; but the disadvantages are also obvious. The material and hardness of the O-ring limit the use conditions of the pilot valve. Under the working conditions where the O-ring is not applicable (the medium is not applicable, the temperature is too high, the set pressure is too high, etc.), the O-ring will be corroded, deformed or even damaged. In severe cases, it will cause the pilot valve seal to fail completely, putting the entire pressure pipeline in a dangerous condition. Summary of the invention

[0004] The utility model aims to provide a pilot-operated safety valve with simplified internal parts and a metal hard seal design, which is suitable for ultra-high pressure and highly corrosive medium working conditions.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0006] A pilot-operated safety valve comprises a main valve and a pilot valve, wherein the pilot valve comprises:

[0007] Base assembly: the base assembly has a pilot valve lower chamber, a pilot valve upper chamber and a connecting port, the pilot valve lower chamber has a pilot valve lower chamber inlet and a pilot valve lower chamber outlet, and the pilot valve upper chamber has a pilot valve upper chamber inlet and a pilot valve upper chamber outlet;

[0008] Valve flap assembly: The valve flap assembly includes a valve shaft and a valve flap body. The valve shaft has a sealing body and a shaft body. The sealing body is movably arranged in the lower chamber of the pilot valve, and can form hard seals with the inlet and outlet of the lower chamber of the pilot valve respectively. One end of the shaft body is connected to the sealing body, and the other end of the shaft body extends toward the valve flap body. The valve flap body is movably arranged in the upper chamber of the pilot valve, and can form a hard seal with the inlet of the upper chamber of the pilot valve.

[0009] In the above technical solution, the pilot valve has a first state, a second state and a third state.

[0010] When the pilot valve is in the first state, the sealing body forms a hard seal with the inlet of the lower chamber of the pilot valve, and the valve disc body forms a hard seal with the inlet of the upper chamber of the pilot valve;

[0011] When the pilot valve is in the second state, the pilot valve lower chamber inlet, the pilot valve lower chamber outlet and the communication port are connected, and the valve disc body forms a hard seal with the pilot valve upper chamber inlet;

[0012] When in the third state, the sealing body forms a hard seal with the outlet of the lower chamber of the pilot valve, and the communication port, the inlet of the upper chamber of the pilot valve, and the outlet of the upper chamber of the pilot valve are connected.

[0013] Further preferably, when the pilot valve is transformed from the first state to the second state, the other end of the shaft body presses against the valve disc body;

[0014] The shaft lifts the valve disc body to transform the pilot valve from the second state to the third state.

[0015] Preferably, the above technical solution is that the base assembly includes a base, a valve seat and a valve body, the valve seat is connected to the base, the valve body is connected to the valve seat, the base and the valve seat together form the lower chamber of the pilot valve, and the inlet of the lower chamber of the pilot valve is opened on the base, the outlet of the lower chamber of the pilot valve is opened on the valve seat, the connecting port is opened on the valve seat, the valve seat and the valve body together form the upper chamber of the pilot valve, and the inlet of the upper chamber of the pilot valve is opened on the valve seat, the inlet of the upper chamber of the pilot valve is opened on the valve seat, and the outlet of the upper chamber of the pilot valve is opened on the valve body.

[0016] Further preferably, the base, valve seat, valve body, valve shaft and valve flap body are made of metal, and the bottom surface of the sealing body and the inlet of the lower chamber of the pilot valve, the top surface of the sealing body and the outlet of the lower chamber of the pilot valve, and the valve flap body and the inlet of the upper chamber of the pilot valve are in direct contact to form a hard seal.

[0017] Further preferably, the bottom surface of the valve flap body and / or the top surface of the inlet of the upper chamber of the pilot valve has an annular convex portion, and the valve flap body and the inlet of the upper chamber of the pilot valve are sealed by the convex portion.

[0018] Preferably, the above technical solution is such that the axes of the pilot valve lower chamber inlet, the pilot valve lower chamber outlet, and the pilot valve upper chamber inlet coincide with each other, the axes of the pilot valve upper chamber outlet and the connecting port coincide with each other and are perpendicular to the axis of the pilot valve lower chamber inlet, and the connecting port is located between the pilot valve lower chamber outlet and the pilot valve upper chamber inlet.

[0019] Preferably, the above technical solution is such that the pilot valve further comprises a cover assembly, which comprises a valve cover, a valve stem and an elastic assembly, the valve cover is arranged on the base assembly, the valve stem is arranged in the valve cover, and the bottom of the valve stem is abutted against the top of the valve disc, and the elastic assembly is arranged on the valve stem to give the valve disc body an elastic force to close the entrance of the upper chamber of the pilot valve.

[0020] Further preferably, the cover assembly also includes a protective cover and an adjusting screw. The protective cover is arranged on the valve cover. The adjusting screw is adjustably arranged in the protective cover and is offset against the elastic component to adjust the compression amount of the elastic component.

[0021] Preferably, in the above technical solution, the main valve comprises a main valve lower chamber and a main valve upper chamber, the inlet of the pilot valve lower chamber is communicated with the main valve lower chamber, and the communication port is communicated with the main valve upper chamber.

[0022] Due to the application of the above technical solution, the utility model has the following advantages compared with the prior art:

[0023] The utility model abandons the traditional O-ring seal and forms a hard seal through direct contact between the valve shaft, the valve disc body and the inlet, outlet and inlet of the lower chamber of the pilot valve, thereby overcoming the disadvantage that the existing O-ring sealed pilot valve cannot be used under high-pressure corrosive medium working conditions, thereby further expanding the application occasions of the pilot valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Attached Figure 1 is a cross-sectional schematic diagram of the pilot valve in this embodiment;

[0025] Attached Figure 2 is a cross-sectional schematic diagram of the pilot valve in this embodiment;

[0026] Attached Figure 3a , 3b 3c is a cross-sectional schematic diagram of the working state of the pilot valve in this embodiment.

[0027] In the above attached figure:

[0028] 1. Main valve; 10. Valve body; 100. Main valve lower chamber; 101. Main valve upper chamber; 102. Main valve outlet; 11. Valve disc;

[0029] 2. Pilot valve; 200. Pilot valve lower chamber; 2000. Pilot valve lower chamber inlet; 2001. Pilot valve lower chamber outlet; 201. Pilot valve upper chamber; 2010. Pilot valve upper chamber inlet; 2011. Pilot valve upper chamber outlet; 202. Connecting port; 210. Base; 211. Valve seat; 212. Valve body; 220. Sealing body; 221. Shaft body; 222. Valve disc body; 223. Protrusion; 230. Valve cover; 231. Valve stem; 232. Elastic component; 233. Protective cover; 234. Adjusting screw;

[0030] 3. Connecting pipe. DETAILED DESCRIPTION

[0031] The technical solution of the utility model will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0032] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0033] like Figure 1 The pilot-operated safety valve shown in the figure comprises a main valve 1 and a pilot valve 2. Among them:

[0034] The main valve 1 includes a valve body 10 and a valve disc 11. The valve body 10 has a main valve lower chamber 100, a main valve upper chamber 101 and a main valve outlet 102. The main valve lower chamber 100 and the main valve upper chamber 101 are respectively located on the upper and lower sides of the valve disc 11. The medium entering the main valve lower chamber 100 can push the valve disc 11 to open, so that the medium flows out from the main valve outlet 102. The medium entering the main valve upper chamber 101 can push the valve disc 11 to close or keep it closed.

[0035] like Figure 2 As shown: the pilot valve 2 includes a base assembly, a valve disc assembly and a cover assembly, and each assembly is introduced in detail below.

[0036] The base assembly has a pilot valve lower chamber 200, a pilot valve upper chamber 201 and a communication port 202. The pilot valve lower chamber 200 has a pilot valve lower chamber inlet 2000 and a pilot valve lower chamber outlet 2001, and the pilot valve upper chamber 201 has a pilot valve upper chamber inlet 2010 and a pilot valve upper chamber outlet 2011. The pilot valve lower chamber 2000 inlet is connected to the main valve lower chamber 100 through a connecting pipe 3, and the communication port 202 is connected to the main valve upper chamber 101 through a connecting pipe 3.

[0037] In this embodiment, the base assembly specifically includes a base 210, a valve seat 211 and a valve body 212. The valve seat 211 is connected to the base 210, and the valve body 212 is connected to the valve seat 211. The connection is sealed by a sealing ring. The base 210 and the valve seat 211 together form a pilot valve lower chamber 200, and the pilot valve lower chamber inlet 2000 is provided on the base 210, and the pilot valve lower chamber outlet 2001 is provided on the valve seat 211; the communication port 202 is provided on the valve body 212, and the valve seat 211 and the valve body 212 together form a pilot valve upper chamber 201, and the pilot valve upper chamber inlet 2010 is provided on the valve seat 211, and the pilot valve upper chamber outlet 2011 is provided on the valve body 212.

[0038] In this embodiment: the axes of the pilot valve lower chamber inlet 2000, the pilot valve lower chamber outlet 2001, and the pilot valve upper chamber inlet 2010 coincide, and are all in the vertical direction as shown in the figure; the axes of the pilot valve upper chamber outlet 2011 and the connecting port 202 coincide, and are all in the horizontal direction as shown in the figure, perpendicular to the axis of the pilot valve lower chamber inlet 2001, and the connecting port 202 is located between the pilot valve lower chamber outlet 2001 and the pilot valve upper chamber inlet 2010.

[0039] The valve flap assembly includes a valve shaft and a valve flap body 222. The valve shaft has a sealing body 220 and a shaft body 221. The cross section of the entire valve shaft is an inverted T-shape as shown in the figure. The sealing body 222 is movably arranged in the lower chamber 200 of the pilot valve, and can form hard seals with the inlet 2000 of the lower chamber of the pilot valve and the outlet 2001 of the lower chamber of the pilot valve, respectively. The lower end of the shaft body 221 is connected to the sealing body 220, and the upper end of the shaft body 221 extends toward the valve flap body 222. The valve flap body 222 is movably arranged in the upper chamber 201 of the pilot valve, and can form a hard seal with the inlet of the upper chamber 201 of the pilot valve.

[0040] In this embodiment: the base 210, the valve seat 211, the valve body 212, the valve shaft and the valve flap body 222 are all made of metal, and the bottom surface of the sealing body 220 and the pilot valve lower chamber inlet 2000 on the base 210, the top surface of the sealing body 220 and the pilot valve lower chamber outlet 2001 on the valve seat 211, and the valve flap body 222 and the pilot valve upper chamber inlet 2010 on the valve seat 211 are in direct contact to form a hard seal. In this way, the sealing is ensured while the O-ring is omitted, and it can be applied under the working conditions of high-pressure corrosive media.

[0041] Preferably, the bottom surface of the valve flap body 222 and the top surface of the pilot valve upper chamber inlet 2010 on the valve seat 211 have an annular convex portion 223 , and the bottom surface of the valve flap body 222 and the top surface of the pilot valve upper chamber inlet 2010 on the valve seat 211 are sealed by the convex portion 223 .

[0042] The cover assembly includes a valve cover 230, a valve stem 231, an elastic component 232, a protective cover 233, and an adjusting screw 234. The valve cover 230 is covered on the valve body 212, the valve stem 231 is arranged in the valve cover 230, and the bottom of the valve stem 231 is against the top of the valve flap 222. The elastic component 232 is arranged on the valve stem 231 to give the valve flap body 222 an elastic force to close the inlet 2010 of the upper chamber of the pilot valve. The protective cover 233 is covered on the valve cover 230, and the adjusting screw 234 is adjustably arranged in the protective cover 233 and against the elastic component 232. By adjusting the up and down movement of the screw 234, the compression amount of the elastic component 232 is increased or decreased, thereby increasing or decreasing the magnitude of the elastic force, thereby changing the magnitude of the set pressure.

[0043] The following is a detailed description of the working process of the pilot valve:

[0044] like Figure 3a As shown: This is the state of the pilot valve 2 when the valve is not pressurized;

[0045] like Figure 3b As shown: after the valve inlet is pressurized, the medium pressure enters the pilot valve 2 from the lower chamber 100 of the main valve through the connecting pipe 3. When the opening pressure of the pilot valve 2 is not reached, the valve shaft rises under the influence of the airflow, and presses against the valve disc body 222. The airflow enters the upper chamber 101 of the main valve through the inlet 2000 of the upper chamber of the pilot valve, the outlet 2001 of the lower chamber of the pilot valve, and the connecting port 202. The valve inlet pressure is connected with the upper chamber 101 of the main valve. When the pressure is equal, the main valve 1 and the pilot valve 2 are not opened.

[0046] like Figure 3c As shown: when the valve inlet continues to increase pressure and the inlet pressure exceeds the valve set pressure, the valve shaft pushes the valve disc body 222 to rise, the pilot valve 2 opens, and the valve shaft continues to rise under the influence of the airflow until the top surface of the sealing body 220 fits with the sealing surface of the pilot valve lower chamber outlet 2001 of the valve seat 211, and the pressure entering the pilot valve 2 is cut off, and the pressure of the main valve upper chamber 101 enters the connecting port 202 of the pilot valve 2, the pilot valve upper chamber inlet 2010, and the pilot valve upper chamber outlet 2011 from the connecting pipe 3. The pressure of the main valve upper chamber 101 is less than the inlet pressure, and the main valve 1 opens;

[0047] like Figure 3bAs shown: as the main valve 1 is opened, the inlet pressure drops rapidly until it is lower than the set pressure of the pilot valve 2, the valve disc 11 of the main valve 1 and the valve disc body 222 of the pilot valve 2 return to their original positions, pushing the valve shaft down, and the top surface of the sealing body 220 separates from the sealing surface of the outlet 2001 of the pilot valve lower chamber of the valve seat 211, and the medium pressure is connected to the upper chamber 101 of the main valve again, completing a pressure discharge.

[0048] Finally, the valve returns to Figure 3a Initial state shown.

[0049] The above embodiments are only for illustrating the technical concept and features of the utility model, and their purpose is to enable people familiar with the technology to understand the content of the utility model and implement it accordingly, and they cannot be used to limit the protection scope of the utility model. Any equivalent changes or modifications made according to the spirit of the utility model should be included in the protection scope of the utility model.

Claims

1. A pilot-operated safety valve, comprising a main valve and a pilot valve, characterized in that: The pilot valve comprises: Base assembly: the base assembly comprises a pilot valve lower chamber, a pilot valve upper chamber and a communication port, the pilot valve lower chamber comprises a pilot valve lower chamber inlet and a pilot valve lower chamber outlet, and the pilot valve upper chamber comprises a pilot valve upper chamber inlet and a pilot valve upper chamber outlet; valve flap assembly: the valve flap assembly comprises a valve shaft and a valve flap body, the valve shaft comprises a sealing body and a shaft body, the sealing body is movably arranged in the pilot valve lower chamber, and can form hard seals with the pilot valve lower chamber inlet and the pilot valve lower chamber outlet respectively, one end of the shaft body is connected to the sealing body, and the other end of the shaft body extends toward the valve flap body, the valve flap body is movably arranged in the pilot valve upper chamber, and can form a hard seal with the pilot valve upper chamber inlet; Cover assembly: The cover assembly includes a valve cover, a valve stem, an elastic component, a protective cover, and an adjusting screw. The valve cover is arranged on the base assembly, the valve stem is arranged in the valve cover, and the bottom of the valve stem is against the top of the valve disc. The elastic component is arranged on the valve stem to give the valve disc body an elastic force to close the entrance of the upper chamber of the pilot valve. The protective cover is arranged on the valve cover. The adjusting screw is adjustably arranged in the protective cover and is against the elastic component to adjust the compression amount of the elastic component.

2. The pilot operated safety valve according to claim 1, characterized in that: The pilot valve has a first state, a second state and a third state. When the pilot valve is in the first state, the sealing body forms a hard seal with the inlet of the lower chamber of the pilot valve, and the valve disc body forms a hard seal with the inlet of the upper chamber of the pilot valve; When the pilot valve is in the second state, the pilot valve lower chamber inlet, the pilot valve lower chamber outlet and the communication port are connected, and the valve disc body forms a hard seal with the pilot valve upper chamber inlet; When in the third state, the sealing body forms a hard seal with the outlet of the lower chamber of the pilot valve, and the communication port, the inlet of the upper chamber of the pilot valve, and the outlet of the upper chamber of the pilot valve are connected.

3. The pilot operated safety valve according to claim 2, characterized in that: When the pilot valve is transformed from the first state to the second state, the other end of the shaft body presses against the valve disc body; The shaft lifts the valve disc body to transform the pilot valve from the second state to the third state.

4. The pilot operated safety valve according to claim 1, characterized in that: The base assembly includes a base, a valve seat and a valve body, the valve seat is connected to the base, the valve body is connected to the valve seat, the base and the valve seat together form the lower chamber of the pilot valve, and the inlet of the lower chamber of the pilot valve is opened on the base, the outlet of the lower chamber of the pilot valve is opened on the valve seat, the connecting port is opened on the valve seat, the valve seat and the valve body together form the upper chamber of the pilot valve, and the inlet of the upper chamber of the pilot valve is opened on the valve seat, the inlet of the upper chamber of the pilot valve is opened on the valve seat, and the outlet of the upper chamber of the pilot valve is opened on the valve body.

5. The pilot operated safety valve according to claim 4, characterized in that: The base, valve seat, valve body, valve shaft and valve disc body are made of metal. The bottom surface of the sealing body and the inlet of the lower chamber of the pilot valve, the top surface of the sealing body and the outlet of the lower chamber of the pilot valve, and the valve disc body and the inlet of the upper chamber of the pilot valve are in direct contact to form a hard seal.

6. The pilot operated safety valve according to claim 4, characterized in that: The bottom surface of the valve flap body and / or the top surface of the inlet of the upper chamber of the pilot valve has an annular convex portion, and the valve flap body and the inlet of the upper chamber of the pilot valve are sealed by the convex portion.

7. The pilot operated safety valve according to claim 1, characterized in that: The axes of the pilot valve lower chamber inlet, the pilot valve lower chamber outlet, and the pilot valve upper chamber inlet coincide with each other; the axes of the pilot valve upper chamber outlet and the connecting port coincide with each other and are perpendicular to the axis of the pilot valve lower chamber inlet; the connecting port is located between the pilot valve lower chamber outlet and the pilot valve upper chamber inlet.

8. The pilot operated safety valve according to claim 1, characterized in that: The main valve comprises a main valve lower chamber and a main valve upper chamber. The inlet of the pilot valve lower chamber is communicated with the main valve lower chamber, and the communication port is communicated with the main valve upper chamber.

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