Check valve for liquefied natural gas storage and transportation

Abstract

The utility model relates to a check valve for liquefied natural gas storage and transportation, which comprises a valve body, an opening and closing device, an elastic device, a buffer device and a pipeline connecting device, the valve body comprises a valve body shell and a support frame, the support frame is provided with a support cylinder, and the support cylinder is connected with a connecting table in the support cylinder through a rib plate. The supporting frame is detachably connected with the valve body shell through threads, a bolt hole is formed in the supporting frame, flanges are arranged at an inlet and an outlet of the valve body shell respectively, the pipeline connecting devices are provided with flanges, and the inlet and the outlet of the valve body shell are connected with the pipeline connecting devices through bolts respectively. The opening and closing device comprises a valve seat and a valve clack, the valve seat is connected with the supporting frame through a bolt, the valve clack is connected with a spring guide seat of the elastic device through a taper pin, the spring guide seat is sleeved with a spring, the other end of the spring is installed in a flow guide diffuser installation hole of the buffering device, and a flow guide diffuser installation table is connected with the supporting frame through a bolt. The device is simple and convenient to mount and dismount, and the maintenance cost is saved.

Description

Technical Field

[0001] The utility model relates to a valve used in the field of liquefied natural gas storage and transportation, and specifically relates to a check valve used for liquefied natural gas storage and transportation. Background Art

[0002] In LNG plants, receiving stations, gasification stations, coal gasification and air separation units, coal-to-olefins and other industries, there are many pipeline systems with large pressure differences. Due to the need to protect the safe operation of output pumps and drive motors, large-diameter check valves are widely used. Check valves have smooth operation, no jamming, low pressure drop and excellent dynamic response compared to other valves. There is little research on ultra-low temperature and high-pressure large-diameter check valves in China, and they mainly rely on imports. However, the demand for large-diameter check valves in domestic long-distance oil and natural gas pipeline systems is increasing. Therefore, the research and development, design, processing, manufacturing, inspection and testing of large-diameter check valves need to be continuously innovated and improved.

[0003] When the fluid flows into the inlet of the check valve, the medium pressure of the fluid will push the valve disc and the valve seat to be separated, and the valve will be in forward conduction. When the fluid flows in the reverse direction, the valve disc and the valve seat will be in contact, and the medium pressure of the fluid will push the valve disc to squeeze the valve seat, and the valve will be in reverse cutoff.

[0004] The working process of the check valve needs to be repeatedly opened and closed according to the functional requirements, and the valve disc and the valve seat are prone to vibration when switching under high pressure difference, resulting in poor sealing performance and high noise. When the fluid flows in the opposite direction, the valve disc will squeeze the valve seat, causing deformation and damage to both. The check valve cannot operate stably for a long period of time under ultra-low temperature and high pressure conditions. The types of check valves are relatively complex. In the actual application of check valves, the inside of the valve body will be damaged. This damage is difficult to repair and generally requires replacement of the valve, which is expensive. Summary of the invention

[0005] The utility model aims to provide a check valve for storage and transportation of liquefied natural gas, which is used to solve the problem in the prior art that it is difficult to repair the check valve when the inside is damaged.

[0006] The utility model solves the technical problem by adopting the following technical scheme: the check valve for liquefied natural gas storage and transportation comprises a valve body, an opening and closing device, an elastic device, a buffer device and a pipeline connecting device, the opening and closing device, the elastic device and the buffer device are installed inside the valve body, the valve body comprises a valve body shell and a support frame, the support frame has a support cylinder, the support cylinder is connected with a connecting platform inside the support cylinder through a rib plate, the support frame and the valve body shell are detachably connected together through threads, a latch hole is provided at one end of the support frame at the inlet of the valve body shell, the inlet and outlet of the valve body shell are respectively provided with flanges, the pipeline connecting device is also provided with flanges, the inlet and outlet of the valve body shell are respectively connected to a pipeline connecting device through bolts; the opening and closing device comprises a valve seat and a valve disc, the valve seat is connected to the support frame through bolts, the valve disc is connected to a spring guide seat of the elastic device through a cone pin, a spring is sleeved on the spring guide seat, the other end of the spring is installed in the guide diffuser mounting hole of the buffer device, and the guide diffuser mounting platform is connected to the support frame through bolts.

[0007] In the above scheme, the inner cavity of the valve body is streamlined, trapezoidal annular grooves are arranged at the inlet and outlet of the valve body shell, and an internal thread is arranged at the inlet of the valve body shell; an external thread is arranged on the support tube, and the internal thread of the valve body shell and the external thread of the support frame are matched and connected, an annular boss is arranged on the inner wall of the support frame, and a threaded hole is arranged on the boss, and the connecting platform is stepped, and a sealing groove is arranged on the outer wall of the support tube, and a sealing ring is installed in the sealing groove.

[0008] In the above scheme, the valve seat includes an outer valve seat and an inner valve seat. The inner valve seat is fixed on the support frame connecting platform, and the outer valve seat is fixed on the inner wall of the support tube. The inner valve seat and the outer valve seat are both provided with sealing ring grooves, and a sealing ring is installed in each sealing ring groove. A plurality of mounting holes are arranged circumferentially on the two circular rings of the valve disc, and a plurality of spring guide seat circular holes are arranged on the spring guide seat. The tapered pin is inserted into the mounting hole and the corresponding spring guide seat circular hole to fix the valve disc and the spring guide seat together.

[0009] In the above scheme, the elastic device includes a spring guide seat and a spring. A spring guide seat groove is arranged at one end of the spring guide seat. The spring guide seat groove is provided with a spring guide seat threaded hole axially penetrating the bottom of the groove.

[0010] In the above scheme, the buffer device includes a guide diffuser and a leaf spring. The guide diffuser is a multi-groove body with a bottom. A cylindrical guide diffuser mounting platform is arranged in the center of the guide diffuser. The annular cavity between the guide diffuser mounting platform and the outer wall of the guide diffuser is divided into an inner ring groove and an outer ring groove by an intermediate cylinder. The guide diffuser mounting hole and the guide diffuser boss are arranged at intervals in the outer ring groove. Two threaded holes are arranged on the guide diffuser boss, and a threaded hole is arranged on the guide diffuser mounting platform. One end of the leaf spring is connected to the axial threaded hole of the spring guide seat by a bolt assembly. The other end of the leaf spring is connected to the guide diffuser boss by a bolt assembly.

[0011] In the above scheme, the flange of the pipeline connecting device is provided with a trapezoidal ring groove, and a sealing ring is installed between the trapezoidal ring groove of the flange and the trapezoidal ring groove on the valve body shell.

[0012] The utility model has the following beneficial effects:

[0013] The valve body of the utility model comprises a valve body shell and a support frame. The support frame has a support tube. The support tube is connected to the connecting platform inside the support tube by a cylindrical rib plate. The support frame and the valve body shell are detachably connected together by threads. One end of the support frame located at the inlet of the valve body shell is arranged at a latch hole. Since the support frame and the valve body shell are detachably connected, when the opening and closing device and other components in the valve body are damaged, the pin is inserted into the latch hole of the support frame and rotated, and the support frame is separated from the valve body shell. The support frame is a straight tube and its length is only one-third of the valve body shell. It is only located at the inlet of the valve body, and the opening and closing device and other components are relatively simple to disassemble, repair or replace. The component that has a problem can be replaced, thereby saving maintenance costs.

[0014] The inlet and outlet of the valve body shell of the utility model are respectively provided with flanges, and the pipeline connecting device is also provided with flanges. The inlet and outlet of the valve body shell are respectively connected to a pipeline connecting device by bolts. Since the pipeline connecting device is provided, the connection between the check valve and the pipeline is time-saving and labor-saving, and the check valve is easy to install and easy to operate.

[0015] 3. The utility model is easy and convenient to install and disassemble, the check valve has a simple structure and has a rapid closing function, and the safety is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the utility model.

[0017] Figure 2 It is a three-dimensional diagram of the utility model.

[0018] Figure 3 It is a structural schematic diagram of the valve body shell in the utility model.

[0019] Figure 4 It is a structural schematic diagram of the support frame in the utility model.

[0020] Figure 5 It is a schematic diagram of the structure of the opening and closing device in the utility model.

[0021] Figure 6 It is a structural schematic diagram of the elastic device in the utility model.

[0022] Figure 7 It is a structural schematic diagram of the spring guide seat in the utility model.

[0023] Figure 8It is a structural schematic diagram of the buffer device in the utility model.

[0024] In the figure: 1-valve body, 11-valve body shell, 12-support frame, 13-inlet, 14-outlet, 111-trapezoidal ring groove, 121-support frame boss, 122-boss threaded hole, 123-rib plate, 124-connecting platform, 125-threaded hole at the maximum diameter of the connecting platform, 126-threaded hole at the minimum diameter of the connecting platform, 127-support frame sealing groove, 128-pin hole;

[0025] 2-opening and closing device, 21-inner valve seat, 22-outer valve seat, 23-valve disc, 24 sealing ring;

[0026] 3-elastic device, 31-spring guide seat, 311-spring guide seat circular hole, 312-spring guide seat groove, 313-spring guide seat threaded hole, 32-taper pin, 33-spring;

[0027] 4-buffer device, 41-flow guide diffuser, 411-flow guide diffuser mounting hole, 412-flow guide diffuser boss, 413-flow guide diffuser mounting platform, 42-gasket, 43-leaf spring;

[0028] 5-Pipeline connection device. DETAILED DESCRIPTION

[0029] The utility model is further described below in conjunction with the accompanying drawings:

[0030] Combination Figure 1-Figure 8 As shown, the check valve for liquefied natural gas storage and transportation includes a valve body 1, an opening and closing device 2, an elastic device 3 and a buffer device 4, the opening and closing device 2, the elastic device 3 and the buffer device 4 are installed inside the valve body 1, the valve body includes a valve body shell 11, a support frame 12, the support frame 12 has a support cylinder, the support frame 12 and the valve body shell 11 are detachably connected together by threads, the support frame 12 is provided with a pin hole at one end of the inlet of the valve body shell 11, the inlet and outlet of the valve body shell are respectively provided with flanges, the pipeline connecting device 5 is also provided with flanges, and the inlet and outlet of the valve body shell are respectively connected to a pipeline connecting device 5 by bolts. For this large-diameter check valve, when the fluid flows into the inlet of the check valve, the medium pressure of the fluid will push the opening and closing device to open, the valve disc and the valve seat are in a separated state, and the valve is in a forward conduction state. When the fluid flows in the reverse direction, the opening and closing device is closed, the valve disc and the valve seat are in a contact state, the medium pressure of the fluid pushes the valve disc to squeeze the valve seat, and the valve will be in a reverse cutoff state.

[0031] The inner cavity of the valve body 1 is streamlined. Figure 1-3As shown, the inner cavity of the valve body 1 is the main channel for fluid flow. The inner cavity of the valve body 1 is streamlined, which reduces the impact caused by sudden changes in the fluid flow direction, channel shape and cross-sectional area, so that the valve has better flow capacity and smaller flow resistance when it is forwardly conducted.

[0032] The valve body 1 includes a valve body shell 11, a support frame 12 and a sealing ring. Figure 1-4 As shown, the valve body 1 has an inlet 13 and an outlet 14, the valve body shell 11 is provided with through threaded holes at the inlet 13 and the outlet 14, the valve body shell inlet 13 and the outlet 14 are provided with trapezoidal annular grooves 111, the valve body shell 11 is provided with internal threads at the inner diameter of the inlet 13, the support frame 12 is a hollow cylindrical tube, the outer diameter of the support frame 12 cylindrical tube is provided with threads, the inner diameter threads of the valve body shell 11 and the outer threads of the support frame 12 are matched and connected, and a support frame boss 121 is provided on the inner cavity wall of the support frame 12, and the boss is annular , a threaded hole 122 penetrating the boss is provided on the boss 121 of the support frame, a cylindrical rib plate 123 and a connecting platform 124 are provided in the inner cavity of the support frame 12, the connecting platform 124 is arranged in a stepped shape, and has the largest diameter near the valve body inlet 13, the connecting platform 124 is provided with a threaded hole 125 at the largest diameter of the connecting platform and a threaded hole 126 at the smallest diameter of the connecting platform, a latch hole 128 is provided at one end of the plane of the support frame 12, a sealing groove 127 is provided on the outer wall of the support frame 12, and a sealing ring is installed in the sealing groove 127. When the support frame 12 and the valve body shell 11 are installed and disassembled, the latch is installed in the latch hole 128 of the support frame, and the support frame 12 is screwed in and out of the valve body shell 11 by applying torque to the latch. When the valve body 1 is filled with fluid, the inner wall of the valve body 1 will be subjected to the fluid pressure. In this state, the stress and deformation of the valve body 1 are calculated. The maximum stress of the valve body 1 meets the strength requirements. The maximum deformation position of the valve body 1 is at the connection between the valve body and the valve seat. In case of damage inside the valve body, the support frame can be removed for repair without damaging the valve body shell. This is simple, convenient and more economical in practical applications.

[0033] The opening and closing device 2 includes a valve seat and a valve disc 23. The valve seat includes an outer valve seat 22 and an inner valve seat 21. One end of the opening and closing device 2 is connected to the support frame 12 at the inlet 13 of the valve body 1 through the inner valve seat 21 and the outer valve seat 22 by bolts. The other end of the opening and closing device 2 is connected to the spring guide seat 31 of the elastic device 3 through the valve disc 23 through a cone pin 32. The other end of the elastic device 3 is installed in the guide diffuser mounting hole 411 of the buffer structure 4 by a spring 33. The buffer device 3 is connected to the support frame 12 of the valve body 1 through the guide diffuser mounting platform 412 by a bolt assembly.

[0034] like Figure 1 , 5As shown, threaded holes are arranged on one of the planes of the inner valve seat 21 and the outer valve seat 22, and the threaded holes of the inner valve seat 21 and the threaded holes 125 at the maximum diameter of the connecting platform of the support frame 12 are connected by a bolt assembly, and the threaded holes of the outer valve seat 22 and the threaded holes 122 of the inner wall boss 121 of the support frame 12 are connected by a bolt assembly, and sealing ring grooves are arranged on the two planes of the inner and outer valve seats, and the sealing ring 24 is installed in the sealing ring groove. The sealing ring 24 is a non-metallic sealing ring, and the material is polyetheretherketone material, which has higher and more stable sealing performance at ultra-low temperature, good temperature resistance and stability, and its sealing performance is relatively slightly higher than that of other non-metals. Polyetheretherketone can well meet the requirements as a sealing gasket, and the sealing ring 24 is installed in the sealing grooves of the inner and outer valve seats. When the valve seat is connected to the support frame 12, the sealing ring 24 will be squeezed, and the sealing ring 24 will fill the gap between the two, thereby improving the sealing performance of the connection between the valve seat and the valve body 1. Four mounting holes are circumferentially arranged on the two circular rings at the rear end of the valve flap 23. When the valve is opened, the valve flap 23 and the valve seat are separated, and both are only subjected to the medium pressure from the fluid; when the valve is closed, the valve flap 23 and the valve seat are in contact, the fluid flows in the opposite direction, and the fluid medium pressure will cause the valve flap 23 to squeeze the valve seat.

[0035] The elastic device 3 includes a spring guide seat 31, a cone pin 32 and a spring 33. Figure 6 , 7 As shown, symmetrical circular holes 311 are circumferentially arranged on the outer wall of the spring guide seat 31, one end of the cone pin 32 is installed in the circular hole 311 of the spring guide seat, and the other end of the cone pin 32 is installed in the valve disc installation hole. A spring guide seat groove 312 is arranged at one end of the spring guide seat 31, and a spring guide seat threaded hole 313 axially penetrating the bottom of the groove is arranged on the spring guide seat 31. The spring guide seat 31 is connected to the valve disc 23 through the cone pin 32 to prevent the valve disc 23 from radially rotating due to the impact of the fluid during the opening and closing process, and the flow state of the fluid is not disturbed. The spring 33 is sleeved on the spring guide seat 31.

[0036] The buffer device 4 includes a flow guide diffuser 41, a gasket 42 and a leaf spring 43. Figure 1 , 8As shown, the guide diffuser 41 is formed by a trapezoidal side surface, four mounting holes 411 are arranged inside the guide diffuser 41, the spring 33 is installed in the guide diffuser mounting hole 411, a guide diffuser boss 412 is arranged near the guide diffuser mounting hole 411, two threaded holes are arranged on the guide diffuser boss 412, a guide diffuser mounting platform 413 is arranged at the inner ring of the annular guide diffuser 41, and threaded holes are arranged on the guide diffuser mounting platform, one end of the leaf spring 43 is arranged with a threaded hole, and the other end is arranged with two threaded holes, one end of the leaf spring 43 is arranged with the threaded hole 313 of the spring guide seat through a bolt assembly, two threaded holes are arranged on the gasket 42, the threaded holes on the guide diffuser boss 412, the threaded holes on the leaf spring 43 and the threaded holes on the gasket 42 are connected through a bolt assembly, and the connection between the leaf spring and the spring guide seat effectively reduces the vibration and noise of the valve, ensures the stability of the movement of the valve disc 23, and is conducive to improving the adaptability to different fluid pressures.

[0037] The check valve provided in this example opens or closes the flow channel in the valve cavity through the reciprocating motion of the valve disc 23 during the working stage. When the valve is opened, the force of the fluid medium overcomes the spring force and friction force, pushing the valve disc 23 away from the valve seat; the force of the fluid medium acting on the valve disc 23 is absorbed by the spring 33 and the leaf spring 43, and the spring 33 and the leaf spring 43 play a buffering role; when the force of the fluid medium acting on the spring is less than the elastic force of the spring, the spring 33 will push the valve disc 23 to gradually close the valve, and the arc surface of the valve disc 23 and the conical surface of the valve seat form a line seal through the close fit between the valve disc 23 and the valve seat. When the fluid flows in the reverse direction, the pressure of the fluid will make the valve seat and the valve disc 23 fit more closely, effectively preventing the backflow of the fluid medium. During the reciprocating motion of the valve disc 23, the vibration of the valve disc 23 is reduced through the action of the leaf spring 43 and the guide diffuser 41, and the radial rotation of the valve disc 23 is limited by the cone pin 32.

Claims

1. A check valve for liquefied natural gas storage and transportation, characterized in that: The check valve for storage and transportation of liquefied natural gas comprises a valve body, an opening and closing device, an elastic device, a buffer device and a pipeline connecting device. The opening and closing device, the elastic device and the buffer device are installed inside the valve body. The valve body comprises a valve body shell and a support frame. The support frame has a support cylinder, which is connected to a connecting platform inside the support cylinder by a rib plate. The support frame and the valve body shell are detachably connected together by threads. A latch hole is provided at one end of the support frame at the inlet of the valve body shell. The inlet and outlet of the valve body shell are respectively provided with flanges. The pipeline connecting device is also provided with flanges. The inlet and outlet of the valve body shell are respectively connected to a pipeline connecting device by bolts. The opening and closing device comprises a valve seat and a valve disc. The valve seat is connected to the support frame by bolts. The valve disc is connected to a spring guide seat of the elastic device by a cone pin. A spring is sleeved on the spring guide seat. The other end of the spring is installed in the guide diffuser mounting hole of the buffer device. The guide diffuser mounting platform is connected to the support frame by bolts.

2. The check valve for liquefied natural gas storage and transportation according to claim 1, characterized in that: The inner cavity of the valve body is streamlined, trapezoidal annular grooves are arranged at the inlet and outlet of the valve body shell, and an internal thread is arranged at the inlet of the valve body shell; an external thread is arranged on the support tube, the internal thread of the valve body shell and the external thread of the support frame are matched and connected, an annular boss is arranged on the inner wall of the support frame, a threaded hole is arranged on the boss, the connecting platform is stepped, a sealing groove is arranged on the outer wall of the support tube, and a sealing ring is installed in the sealing groove.

3. The check valve for liquefied natural gas storage and transportation according to claim 2, characterized in that: The valve seat comprises an outer valve seat and an inner valve seat. The inner valve seat is fixed on the supporting frame connecting platform, and the outer valve seat is fixed on the inner wall of the supporting tube. The inner valve seat and the outer valve seat are both provided with sealing ring grooves, and a sealing ring is installed in each sealing ring groove. A plurality of mounting holes are arranged circumferentially on the two circular rings of the valve disc, and a plurality of spring guide seat circular holes are arranged on the spring guide seat. A tapered pin is inserted into the mounting hole and the corresponding spring guide seat circular hole to fix the valve disc and the spring guide seat together.

4. The check valve for liquefied natural gas storage and transportation according to claim 3 is characterized in that: The elastic device comprises a spring guide seat and a spring. A spring guide seat groove is arranged at one end of the spring guide seat. The spring guide seat groove is provided with a spring guide seat threaded hole which axially penetrates the bottom of the groove.

5. The check valve for storage and transportation of liquefied natural gas according to claim 4, characterized in that: The buffer device includes a guide diffuser and a leaf spring. The guide diffuser is a multi-groove body with a bottom. A cylindrical guide diffuser mounting platform is arranged in the center of the guide diffuser. The annular cavity between the guide diffuser mounting platform and the outer wall of the guide diffuser is divided into an inner ring groove and an outer ring groove by an intermediate cylinder. The guide diffuser mounting hole and the guide diffuser boss are arranged at intervals in the outer ring groove. Two threaded holes are arranged on the guide diffuser boss, and a threaded hole is arranged on the guide diffuser mounting platform. One end of the leaf spring is connected to the axial threaded hole of the spring guide seat by a bolt assembly. The other end of the leaf spring is connected to the guide diffuser boss by a bolt assembly.

6. The check valve for liquefied natural gas storage and transportation according to claim 5, characterized in that: The flange of the pipeline connecting device is provided with a trapezoidal ring groove, and a sealing ring is installed between the trapezoidal ring groove of the flange and the trapezoidal ring groove on the valve body shell.

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