Heat insulation structure for improving heat stability of safety valve under high-temperature working condition

Abstract

The invention discloses a heat insulation structure for improving the heat stability of a safety valve under a high-temperature working condition, a steam safety valve has high requirement on action performance stability under the high-temperature working condition, and the heat insulation structure of the steam safety valve is of an open type and is composed of a rib plate, an inner cavity, an isolating ring and a pressure relief hole; when the safety valve is opened, part of steam enters the inner cavity, the isolating ring prevents the steam from flowing upwards, and the steam is transversely discharged through the pressure relief hole to achieve heat resistance. The rib plates enhance heat convection of steam and air to achieve heat dissipation. The structure has three key technical points: the isolating ring is designed to prevent high-temperature steam from flowing out; the design of double pressure relief holes is matched with the isolating ring to drain steam; the open-type appearance design dissipates heat through heat convection. Through heat resistance and heat dissipation of the heat insulation structure, the influence of steam on the valve can be reduced, the heat stability of the safety valve under the high-temperature working condition is improved, and safe and stable operation of equipment is guaranteed.

Description

Technical Field

[0001] The invention relates to a heat insulation structure for improving the thermal stability of a safety valve under high-temperature working conditions, and belongs to the field of steam safety valves. Background Art

[0002] Steam safety valves are used in steam medium working conditions, mostly for overpressure protection of high temperature and high pressure vessels such as power boilers and ethylene cracking furnaces. In thermal power supercritical units, the temperature of steam medium can reach above 600°C, and the stability of the valve's operating performance under high temperature is very high. If the valve opens in advance before the set pressure point or the valve cannot return to the seat stably and in time after opening, it may cause abnormal shutdown of the device and cause economic losses. This requires that the steam safety valve must also ensure stable operating performance under high temperature conditions, and there must be no inaccurate starting point or failure to return to the seat after starting.

[0003] At present, the commonly used method to improve the thermal stability of safety valves under high temperature conditions is to set a heightening frame between the valve body and the valve cover to raise the position of key parts such as springs. This method has a certain effect when the valve is closed, but when the valve is opened, high-temperature steam will spray upward. Since the height of the heightening frame cannot be too high, otherwise it will affect the valve's neutrality and the strength and stability of the valve stem. Therefore, it is difficult to effectively prevent the impact of steam on parts such as springs, and it is difficult to ensure the long-term thermal stability of the valve under high temperature conditions. Summary of the invention

[0004] The technical problem solved by the present invention is: to overcome the deficiencies of the prior art, to provide an insulation structure for improving the thermal stability of the safety valve under high temperature conditions, to reduce the impact of temperature on the valve, and to improve the stability of the operating performance of the safety valve under high temperature conditions.

[0005] The technical solution of the present invention is: a heat-insulating structure for improving the thermal stability of a safety valve under high-temperature working conditions, wherein the main body of the safety valve comprises: a valve seat, a valve body, a valve cover, a valve disc, a bushing, a guide sleeve, a valve stem, a spring assembly and a valve bonnet, wherein a metal sealing structure is adopted between the sealing surfaces of the valve disc and the valve seat, wherein the valve seat is located at the bottom of the valve body and is tightly connected to the valve body; the valve cover is installed at the top of the valve body, the valve bonnet is located above the valve cover, the valve stem passes through the valve cover, the bushing, and the guide sleeve, and is connected to the valve disc, wherein the guide sleeve is installed at the top opening of the valve body, the bushing is sleeved on the valve stem and is located in the guide sleeve, and the lower end of the bushing cooperates with the valve disc; the spring assembly is located in the valve cover and sleeved on the valve stem;

[0006] The invention is characterized in that: the heat insulation structure is located between the valve body and the valve cover, and includes a rib plate, an upper top plate, a lower bottom plate isolation ring, and an adjustment ring; wherein:

[0007] Three ribs are vertically connected between the upper top plate and the lower bottom plate, and are evenly distributed at 120° in the circumferential direction, forming an open structure with the upper top plate and the lower bottom plate; through holes for the valve stem to pass through are provided at the center positions of the upper top plate and the lower bottom plate; the isolation ring is closely arranged in the through hole of the lower bottom plate, and cooperates with the valve stem for sealing;

[0008] The space between the guide sleeve, bushing, valve stem, isolating ring, and adjusting ring constitutes the internal cavity, which is located between the bottom of the insulation structure and the top of the valve body;

[0009] The first pressure relief hole and the second pressure relief hole are arranged on the side wall of the lower bottom plate of the heat insulation structure, and penetrate through the side wall of the lower bottom plate and the central through hole of the lower bottom plate.

[0010] Preferably, when the steam medium pressure reaches the set pressure point, the lift force generated by the steam medium on the lower surface of the valve disc overcomes the elastic force of the spring assembly, the gravity and friction of the valve disc, so that the valve disc and the valve stem are lifted upward, and the valve disc is separated from the sealing surface of the valve seat to achieve pressure relief. At this time, a part of the steam enters the internal cavity from the gap between the valve disc and the bushing and guide sleeve, and the isolation ring is close to the adjusting ring to block the steam from flowing upward, and the steam is discharged laterally from the first pressure relief hole and the second pressure relief hole.

[0011] Preferably, the open space formed by the ribs of the thermal insulation structure is used to enhance thermal convection between the steam medium and the air, and discharge the escaped steam medium into the surrounding air, and the thickness and height of the ribs are designed according to the heat dissipation requirements of the safety valve to ensure that the overall structural strength of the safety valve is not affected while enhancing thermal convection.

[0012] Preferably, the isolation ring always closely cooperates with the adjustment ring during the opening and closing process of the safety valve to prevent the high-temperature steam medium in the cavity from flowing upward.

[0013] Preferably, when the steam medium pressure drops to approximately 97% of the set pressure, the superimposed force of the pressure in the insulation structure cavity and the spring force is greater than the lift force, pushing the bushing to drive the valve stem and valve disc back to the seat, and the valve disc is pressed against the valve seat sealing surface.

[0014] Preferably, the aperture sizes of the first pressure relief hole and the second pressure relief hole are adapted according to the specifications of the safety valve and the steam flow rate to ensure that the steam can be discharged in a timely and effective manner to achieve the best heat-resistance effect.

[0015] Preferably, the thermal insulation structure is made of high alloy steel with a thermal conductivity ranging from 20 to 30 W / (m·K) to enhance the thermal insulation effect and further improve the thermal stability of the safety valve under high temperature conditions.

[0016] Preferably, the valve seat, valve body, valve cover, guide sleeve and valve cap are stationary parts, and the bushing, valve stem, valve disc and spring assembly are movable parts.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] The present invention adopts the design of the heat-insulating structure. When the steam safety valve is opened, the isolation ring is used to prevent the high-temperature steam medium from flowing upward, and the internal double pressure relief hole design is used to drain the steam medium laterally to achieve heat insulation. The open rib plate design discharges steam to the surroundings to achieve heat dissipation. Finally, the heat-insulating structure reduces the influence of steam on the valve through the dual effects of heat insulation and heat dissipation, thereby improving the long-term thermal stability of the safety valve under high-temperature conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the appearance diagram of the thermal insulation structure;

[0020] Figure 2 It is a schematic diagram of the overall structure section of the steam safety valve;

[0021] Figure 3 Schematic diagram of the cross section of the thermal insulation structure.

[0022] The accompanying drawings are marked as: 1-valve seat, 2-valve body, 3-valve cover, 4-valve disc, 5-bushing, 6-guide sleeve, 7-valve stem, 8-valve bonnet, 9-spring, 10-thermal insulation structure, 11-rib plate, 12-internal cavity, 13-isolating ring, 14-adjusting ring, 15-pressure relief hole 1, 16-pressure relief hole 2, 17-upper spring seat, 18-lower spring seat. DETAILED DESCRIPTION

[0023] The overall structure of the safety valve in which the structure of the present invention is located is shown in the attached Figure 2 As shown, it is composed of a valve seat 1, a valve body 2, an insulation structure 10, a valve cover 3, a valve disc 4, a bushing 5, a guide sleeve 6, a valve stem 7, a spring assembly, a valve cap 8, etc. The spring assembly includes a spring 9, an upper spring seat 17 and a lower spring seat 18.

[0024] The main body of the safety valve comprises a valve seat 1, a valve body 2, a valve cover 3, a valve disc 4, a valve stem 7, a spring assembly and a valve bonnet 8. A metal sealing structure is adopted between the sealing surfaces of the valve disc 4 and the valve seat 1. The valve seat 1 is located at the bottom of the valve body 2 and is tightly connected with the valve body 2. The valve cover 3 is installed at the top of the valve body 2. The valve bonnet 8 is located above the valve cover 3. The valve stem 7 passes through the valve cover 3, a bushing 5 and a guide sleeve 6 and is connected with the valve disc 4. The guide sleeve 6 is installed at the top opening of the valve body 2. The bushing 5 is sleeved on the valve stem 7 and is located in the guide sleeve 6. The lower end of the bushing (5) cooperates with the valve disc 4. The spring assembly is located in the valve cover 3 and sleeved on the valve stem 7. The valve seat 1, valve body 2, valve cover 3, guide sleeve 6 and valve bonnet 8 are stationary parts, and the bushing 5, valve stem 7, valve disc 4 and spring assembly are movable parts. The spring assembly is sleeved on the valve stem 7. One end of the spring 9 contacts with the upper spring seat 17, and the other end contacts with the lower spring seat 18. The elastic coefficient of the spring 9 is optimized and temperature-corrected according to the working pressure range and temperature range of the safety valve to ensure the sensitive action and stable performance of the safety valve under high temperature conditions.

[0025] The heat insulation structure 10 is located between the valve body 2 and the valve cover 3, and includes a rib plate 11, an upper top plate, a lower bottom plate isolation ring 13, and an adjustment ring 14; wherein:

[0026] Three ribs 11 are vertically connected between the upper top plate and the lower bottom plate, and are evenly distributed at 120° between each other in the circumferential direction, forming an open structure with the upper top plate and the lower bottom plate; a through hole for the valve stem 7 to pass through is provided at the center of the upper top plate and the lower bottom plate; an isolation ring 13 is tightly arranged in the through hole of the lower bottom plate against the adjustment ring 14, and cooperates with the valve stem 7 for sealing;

[0027] The space between the guide sleeve 6, the bushing 5, the valve stem 7, the isolation ring 13, and the adjustment ring 14 forms an internal cavity 12, and the internal cavity 12 is located between the bottom of the thermal insulation structure 10 and the top of the valve body 2;

[0028] The first pressure relief hole 15 and the second pressure relief hole 16 are formed on the side wall of the lower bottom plate of the heat insulation structure 10 and penetrate through the side wall of the lower bottom plate and the central through hole of the lower bottom plate.

[0029] When the steam medium pressure reaches the set pressure point, the lift force generated by the steam medium on the lower surface of the valve disc overcomes the spring force, the gravity of the valve disc and the friction force of the valve disc, so that the valve disc and the valve stem are lifted upward, and the valve disc is separated from the sealing surface of the valve seat to achieve pressure relief. At this time, a part of the steam enters the internal cavity from the gap between the valve disc and the bushing and guide sleeve, and the isolation ring is close to the adjusting ring to block the steam from flowing upward, and the steam is discharged horizontally from the first pressure relief hole and the second pressure relief hole.

[0030] The open space formed by the ribs of the thermal insulation structure is used to enhance the thermal convection between the steam medium and the air, and discharge the escaped steam medium into the surrounding air. The thickness and height of the ribs are designed according to the heat dissipation requirements of the safety valve to ensure that the overall structural strength of the safety valve is not affected while enhancing the thermal convection.

[0031] The isolation ring always cooperates closely with the adjustment ring during the opening and closing process of the safety valve to prevent the high-temperature steam medium in the cavity from flowing upward.

[0032] When the steam medium pressure drops to nearly 97% of the set pressure, the superimposed force of the pressure in the insulation structure cavity and the spring force is greater than the lift force, pushing the bushing to drive the valve stem and valve disc back to the seat, and the valve disc is pressed against the valve seat sealing surface.

[0033] The aperture sizes of the first pressure relief hole and the second pressure relief hole are adapted according to the specifications of the safety valve and the steam flow rate to ensure that the steam can be discharged in a timely and effective manner to achieve the best heat-resistance effect.

[0034] The material of the thermal insulation structure is high alloy steel with low thermal conductivity, ranging from 20 to 30 W / (m·K), to enhance the thermal insulation effect and further improve the thermal stability of the safety valve under high temperature conditions.

[0035] A metal sealing structure is used between the valve disc 4 and the valve seat 1, which can ensure good sealing under high-temperature and high-pressure steam conditions. When the steam medium pressure reaches the set pressure point, the lift force generated by the steam medium on the lower surface of the valve disc 4 overcomes the gravity and friction of the spring 9 force, the valve disc 4 and other parts, so that the movable parts move upward, the valve disc 4 and the valve stem 7 are lifted, and the valve disc 4 is separated from the sealing surface of the valve seat 1, and the steam medium is discharged to achieve the pressure relief protection function. Among them, part of the steam is discharged from the outlet of the valve body 2, and the other part of the steam enters the cavity 12 inside the thermal insulation structure 10 from the gap between the valve disc 4 and the bushing 5 and the guide sleeve 6. The thermal insulation structure 10 discharges the high-temperature steam from the first pressure relief hole 15 and the second pressure relief hole 16 inside it and the open part of the rib plate 11 structure, increasing the degree of temperature attenuation. When the steam medium pressure drops to about 97% of the set pressure, the superposition force of the pressure in the cavity of the thermal insulation structure 10 and the spring force is greater than the lift force, pushing the bushing 5 to drive the valve stem 7 and the valve disc 4 to start returning to the seat, and finally the valve disc 4 is pressed tightly to the sealing surface of the valve seat 1. In the above process, the isolation ring 13 inside the insulation structure 10 is always tightly matched with the adjustment ring 14 to block the upward movement of high-temperature steam. The steam is discharged from the two pressure relief holes 15 and 16 of the insulation structure 10. At the same time, the open design of the rib plate 11 of the insulation structure 10 discharges the escaping steam medium into the surrounding air. Through air convection, the influence of high temperature on the valve is reduced, thereby ensuring the stability of the valve action performance.

[0036] The patent of this invention has the following obvious features:

[0037] The heat-insulating structure 10 is designed to be composed of a rib plate 11, an isolation ring 13 and two pressure relief holes (15, 16). The three rib plates 11 are evenly distributed at 120° to form an open structure. The internal cavity 12 is located between the bottom of the heat-insulating structure 10 and the top of the valve body 2, and is composed of the space between the guide sleeve 6, the bushing 5, the valve stem 7, the isolation ring 13 and the adjustment ring 14. When the safety valve is opened, a part of the steam enters the internal cavity from the gap between the valve disc 4 and the bushing 5 and the guide sleeve 6. The isolation ring 13 is close to the adjustment ring 14 to block the steam from flowing upward, and the steam medium is drained horizontally through the first pressure relief hole 15 and the second pressure relief hole 16, which plays a heat-insulating role; the open space formed by the rib plate 11 enhances the heat convection between the steam medium and the air, which plays a heat-dissipating role. The heat-insulating structure reduces the influence of high temperature on the valve through the heat-insulating effect of the isolation ring and the pressure relief hole and the heat-dissipating effect of the open structure.

[0038] The thermal insulation structure has three key technical points:

[0039] 1. Isolation ring design: During the opening and closing process of the safety valve, the isolation ring 13 and the adjustment ring 14 are always in a coordinated state to prevent the high-temperature steam medium in the cavity from flowing upward and prevent the high temperature from affecting the valve performance.

[0040] 2. Double pressure relief hole design: The interior adopts a double pressure relief hole design, through which the steam medium accumulated in the cavity is drained horizontally, and the isolation ring is used to prevent the steam from escaping upward.

[0041] 3. Open shape design: The open shape design discharges steam into the atmosphere and dissipates heat to the surroundings in the form of heat convection, thereby increasing the degree of temperature attenuation, reducing the impact of steam on the valve, and improving the thermal stability of the valve's operating performance under high temperature conditions.

[0042] The thermal insulation structure of the present invention is further described below in conjunction with the accompanying drawings.

[0043] The thermal insulation structure is a component of the steam safety valve and is located between the valve body and the valve cover. Figure 2 As shown in the figure, it is mainly composed of valve seat 1, valve body 2, heat insulation structure 10, valve cover 3, valve disc 4, bushing 5, guide sleeve 6, valve stem 7, valve bonnet 8, spring 9 and other parts. Among them, valve seat 1, valve body 2, valve cover 3, valve bonnet 8 and other parts are stationary parts, and bushing 5, guide sleeve 6, valve stem 7, valve disc 4 and spring 9 are movable parts. There is a metal seal between valve disc 4 and valve seat 1, and valve stem 7 is connected to valve disc 4.

[0044] like Figure 1 and Figure 3As shown, the heat insulation structure described in the present invention is shaped like an open hollow cylinder, which is composed of a rib plate 11, an isolation ring 13 and two pressure relief holes (15, 16). The three rib plates 11 are evenly distributed at 120 degrees to form an open structure. The internal cavity 12 is located between the bottom of the heat insulation structure 10 and the top of the valve body 2, and is composed of the space between the guide sleeve 6, the bushing 5, the valve stem 7, the isolation ring 13, and the adjustment ring 14. The isolation ring 13 and the pressure relief holes (15, 16) can block the upward flow of steam and drain the steam medium horizontally to play a heat-blocking role; the open space formed by the rib plate 11 enhances the heat convection between the steam medium and the air, and plays a heat dissipation role. Under the combined effect of heat resistance and heat dissipation of the heat insulation structure, the influence of high-temperature steam on the valve is reduced.

[0045] When the steam medium pressure in the protected device reaches the set pressure, the safety valve begins to open, the valve disc 4 and the valve stem 7 are pushed upward by the steam medium pressure, and the steam medium begins to be discharged through the sealing surface between the valve disc 4 and the valve seat 1. During the discharge process, part of the steam medium leaks out from the outlet flange of the valve body 2, and the other part of the steam flows into the internal cavity 12 of the thermal insulation structure 10 from the gap between the valve disc 4 and the bushing 5 and the guide sleeve 6. The isolation ring 13 and the adjustment ring 14 fit tightly to block the upward movement of high-temperature steam. The steam is discharged from the first pressure relief hole 15 and the second pressure relief hole 16 of the thermal insulation structure 10 to achieve heat insulation; part of the steam escapes from the gap at the adjustment ring 14, and the open space formed by the rib plate discharges steam to the surroundings, and the steam and air conduct heat convection to achieve heat dissipation. Through heat insulation and heat dissipation, the purpose of reducing the impact of high-temperature steam and improving the thermal stability of the safety valve is achieved. When a certain amount of steam medium is released and the medium pressure decreases, the superimposed force of the medium pressure and the spring force in the cavity is greater than the medium force, pushing the bushing 5 to drive the valve disc 4 and valve stem 7 to move downward at an accelerated speed until the valve disc 4 is pressed tightly against the sealing surface of the valve seat 1, tightly closed, and the valve is closed.

[0046] The contents not described in detail in the specification of the present invention belong to the prior art known to the professional and technical personnel in this field.

Claims

1. A heat insulation structure for improving the thermal stability of a safety valve under high temperature conditions, the main body of the safety valve comprising: A valve seat (1), a valve body (2), a valve cover (3), a valve disc (4), a bushing (5), a guide sleeve (6), a valve stem (7), a spring assembly and a valve bonnet (8); a metal sealing structure is adopted between the sealing surfaces of the valve disc (4) and the valve seat (1); the valve seat (1) is located at the bottom of the valve body (2) and is tightly connected to the valve body (2); the valve cover (3) is installed at the top of the valve body (2); the valve bonnet (8) is located above the valve cover (3); the valve stem (7) passes through the valve cover (3), the bushing (5) and the guide sleeve (6) and is connected to the valve disc (4); the guide sleeve (6) is installed at the top opening of the valve body (2); the bushing (5) is sleeved on the valve stem (7) and is located in the guide sleeve (6); the lower end of the bushing (5) cooperates with the valve disc (4); the spring assembly is located in the valve cover (3) and is sleeved on the valve stem (7); The invention is characterized in that: the heat insulation structure (10) is located between the valve body (2) and the valve cover (3), and comprises a rib plate (11), an upper top plate, a lower bottom plate isolation ring (13), and an adjustment ring (14); wherein: Three ribs (11) are vertically connected between the upper top plate and the lower bottom plate, and are evenly distributed at 120 degrees in the circumferential direction, forming an open structure with the upper top plate and the lower bottom plate; a through hole for the valve stem (7) to pass through is provided at the center position of each of the upper top plate and the lower bottom plate; an isolation ring (13) is tightly arranged in the through hole of the lower bottom plate against the adjustment ring (14), and cooperates with the valve stem (7) to seal; The space between the guide sleeve (6), the bushing (5), the valve stem (7), the isolation ring (13) and the adjustment ring (14) forms an internal cavity (12) which is located between the bottom of the thermal insulation structure (10) and the top of the valve body (2); The first pressure relief hole (15) and the second pressure relief hole (16) are provided on the side wall of the lower base plate of the heat insulation structure (10), and penetrate the side wall of the lower base plate and the central through hole of the lower base plate.

2. The heat insulation structure for improving the thermal stability of a safety valve under high temperature conditions according to claim 1, characterized in that: When the steam medium pressure reaches the set pressure point, the lift force generated by the steam medium on the lower surface of the valve disc (4) overcomes the elastic force of the spring assembly, the gravity of the valve disc (4) and the friction force, so that the valve disc (4) and the valve stem (7) are lifted upward, and the valve disc (4) and the valve seat (1) sealing surface are separated to achieve pressure relief. At this time, a part of the steam enters the internal cavity (12) from the gap between the valve disc (4) and the bushing (5) and the guide sleeve (6), and the isolation ring (13) is tightly attached to the adjustment ring (14) to block the steam from flowing upward, and the steam is discharged laterally from the first pressure relief hole (15) and the second pressure relief hole (16).

3. The heat insulation structure for improving the thermal stability of a safety valve under high temperature conditions according to claim 1, characterized in that: The open space formed by the ribs (11) of the thermal insulation structure (10) is used to enhance the thermal convection between the steam medium and the air, and discharge the escaped steam medium into the surrounding air. The thickness and height of the ribs (11) are designed according to the heat dissipation requirements of the safety valve, ensuring that the overall structural strength of the safety valve is not affected while enhancing the thermal convection.

4. The heat insulation structure for improving the thermal stability of a safety valve under high temperature conditions according to claim 1, characterized in that: The isolation ring (13) is always in close cooperation with the adjustment ring (14) during the opening and closing process of the safety valve, thereby preventing the high-temperature steam medium in the cavity from flowing upward.

5. The heat insulation structure for improving the thermal stability of a safety valve under high temperature conditions according to claim 2, characterized in that: When the steam medium pressure drops to approximately 97% of the set pressure, the combined force of the pressure in the cavity of the heat insulation structure (10) and the spring force is greater than the lifting force, pushing the bushing (5) to drive the valve stem (7) and the valve disc (4) to return to the seat downward, and the valve disc (4) is pressed tightly against the sealing surface of the valve seat (1).

6. The heat insulation structure for improving the thermal stability of a safety valve under high temperature conditions according to claim 1, characterized in that: The aperture sizes of the first pressure relief hole (15) and the second pressure relief hole (16) are adapted according to the specifications of the safety valve and the steam flow rate to ensure that the steam can be discharged in a timely and effective manner, thereby achieving the best heat-resistance effect.

7. The heat insulation structure for improving the thermal stability of a safety valve under high temperature conditions according to claim 1, characterized in that: The thermal insulation structure (10) is made of high alloy steel with a thermal conductivity ranging from 20 to 30 W / (m·K).

8. The heat insulation structure for improving the thermal stability of a safety valve under high temperature conditions according to claim 1, characterized in that: The valve seat (1), valve body (2), valve cover (3), guide sleeve (6) and valve cap (8) are stationary parts, and the bushing (5), valve stem (7), valve disc (4) and spring assembly are movable parts.

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