Backpressure valve applied to supercritical system pipeline and using method

Abstract

The invention discloses a back pressure valve applied to a supercritical system pipeline and a using method, and relates to the field of fluid control and pressure regulation. A sapphire base is arranged at the bottom of a supporting base, a valve element base is arranged in a valve element base, the top of a spring base abuts against the bottom of the valve element base, a first spring is arranged at the bottom in the valve element base, and a gem base is arranged at the top of the valve element base; a ruby ball is attached to the upper end face of the jewel base, the upper end of the ruby ball abuts against an inlet of the sapphire base, the lower end of the jewel base gland is fixedly inserted into the valve element base, the jewel base is located in the jewel base gland, a jewel base is arranged in the jewel base gland, the jewel base is fixedly inserted into the jewel base, and a fastening nut is installed on the outer side of the top of the jewel base gland. Compression nuts are mounted on the outer sides of the bottom of the supporting seat and the top of the jewel seat, and gaps are reserved between openings of the compression nuts and the outer side of the jewel seat. Fluid is blocked by the ruby ball after entering the valve cavity of the upper valve body, downward thrust is generated on the ruby seat along the axis, after accumulation reaches the limit, the first spring is compressed by the ruby seat, the fluid jacks the ruby ball to form a channel, and the fluid flows out of the sapphire seat, the supporting seat and the outlet connector in sequence.

Description

Technical Field

[0001] The invention relates to the field of fluid control and pressure regulation, and in particular to a back pressure valve applied to a supercritical system pipeline and a use method thereof. Background Art

[0002] A supercritical system generally refers to a system with an effective multiplication coefficient greater than 1, in which the number of neutrons in the system will continue to increase over time. An effective multiplication coefficient greater than 1 can lead to an accelerated chain reaction, while a subcritical system is a system with an effective multiplication coefficient less than 1. In engineering, especially in the fields of thermodynamics and fluid mechanics, a supercritical system usually refers to a state in which the pressure and temperature of a fluid exceed its critical pressure and critical temperature.

[0003] As a special state of matter, supercritical fluid has unique physical and chemical properties. It has excellent plasticizing effect on polymers, excellent transfer performance and parameter adjustability, so it has high application value, which is reflected in improving solubility and plasticizing effect, environmental protection and energy saving, improving product quality and performance, and expanding application fields. These gains make supercritical fluid technology have broad application prospects and potential in the field of polymers. At the same time, when using a supercritical system, it is necessary to strictly control the key parameters of the system such as temperature, pressure, flow, etc. to ensure that they fluctuate within a safe and reasonable range.

[0004] Back pressure valve, also known as reverse valve, anti-backflow valve, is a valve used to control the one-way flow of fluid. It can automatically prevent the fluid from flowing back in the pipeline system, and effectively maintain the pressure in the pipeline. Back pressure valve is usually mainly composed of valve body, valve core and valve seat, and uses the relative movement between valve core and valve seat to control the on and off of fluid. In supercritical system, back pressure valve can adjust and stabilize the pressure in the system to ensure the stable operation of supercritical system under high pressure conditions.

[0005] In supercritical systems, back pressure valves control the pressure of the system by adjusting the opening of the valve to meet the needs of experiments or production. In addition to controlling pressure, back pressure valves can also adjust fluid flow to a certain extent. By adjusting the opening of the back pressure valve, the resistance of the fluid passing through the valve can be changed, thereby achieving precise control of the flow. In a high pressure environment, the back pressure valve can prevent the fluid from flowing back or excessive pressure from damaging the system equipment. It plays a role in protecting the equipment and extending the service life of the equipment.

[0006] For a general back pressure valve, the fluid enters from the inlet of the back pressure valve and is first blocked by the diaphragm inside the valve. At this time, the fluid exerts an upward pressure on the diaphragm. As the fluid pressure gradually increases, the pressure on the diaphragm also increases. When the pressure reaches a sufficient level, the pressure on the diaphragm compresses the spring, causing the diaphragm to move upward, thereby opening the valve channel. Once the diaphragm is lifted, the fluid can flow out of the outlet of the back pressure valve through the formed channel. If the fluid pressure is not large enough to lift the diaphragm, a pressure holding phenomenon will occur. This will cause the inlet pressure to rise until it reaches the rated pressure of the back pressure valve. When the pressure reaches the rated value, the diaphragm is lifted, forming a passage, and the fluid can flow out. The rated pressure of the back pressure valve is adjustable, and the rated pressure is usually adjusted by adjusting the push rod at the upper end of the spring to change the length of the spring. The main function of the back pressure valve in the pipeline is to cut off and throttle. It can control the pressure of the fluid in the pipeline, prevent the fluid from flowing back or back, and regulate the flow of the fluid. Back pressure valves are widely used in systems that require stable fluid pressure, such as water supply systems, steam systems, chemicals, petroleum, natural gas, water treatment and other fields.

[0007] The back pressure valve generally adjusts the pressure in the pipeline by the valve opening. In order to stabilize the pressure in the pipeline, the pressure control accuracy of the back pressure valve is relatively high. The Chinese patent with application number 202010809018.1 and titled "An adjustable back pressure valve device for high pressure system and use method" discloses an adjustable back pressure valve device for high pressure system, which includes a connected upper valve body and a lower valve body, a joint is provided at the top of the upper valve body, a valve seat is provided in the upper valve body, and a sapphire seat is provided in the bottom of the valve seat for interference fit, a spring base is provided at the top of the lower valve body, a valve core base is provided on the top surface of the spring base, a first spring is provided on the valve core base, a gem base is provided on the top of the first spring, and a gem seat is provided above the gem base. The gem base is an equal height sleeve, the upper part of the equal height sleeve is located in the cavity of the gem seat, and the ruby ​​ball is located at the top of the equal height sleeve. A valve stem is provided on the inner lining of the handle, a second spring is provided on the top of the valve stem, a spring base is provided on the top of the second spring, and the valve core base is provided on the spring base. Although the adjustable back-pressure valve device achieves the effects of adjustable back-pressure range and high applicable pressure, since the spring base directly contacts the valve core base, if the lower valve body is tightened, it will be stuck with the valve core base, causing the second spring to fail. If the lower valve body is too loose, the connection between the lower valve body and the upper valve body will be unreliable. At the same time, the sapphire seat is embedded in the valve seat. If the pressure is too high, the sapphire seat will be separated from the valve seat, causing the entire back-pressure valve to fail. Summary of the invention

[0008] In view of the problems existing in the prior art, the present invention provides a back-pressure valve applied to a supercritical system pipeline and a method of use, wherein the top of the spring base is pressed tightly against the bottom of the valve core seat, and even if the lower valve body is tightened, the spring base will not be stuck to the valve core seat, and the upper and lower supporting structures of the ruby ​​ball are protected by tightening nuts and compression nuts, and even if the pressure is very high, the sapphire seat will not be separated from the supporting seat and cause the entire back-pressure valve to fail.

[0009] The present invention is achieved through the following technical solutions: A back pressure valve used in a supercritical system pipeline comprises an upper valve body and a lower valve body connected to each other, and a support seat, a valve core base and a jewel seat gland arranged in the upper valve body; An inlet joint and an outlet joint are respectively provided on one side and the top of the upper valve body, the upper end surface of the support seat is connected to the lower end surface of the outlet joint, the lower end surface of the support seat is located in the valve cavity of the upper valve body, and a sapphire seat is provided at the bottom of the support seat; A spring seat is provided at the top of the lower valve body, the valve core seat is seal-jointed at the junction of the lower valve body and the upper valve body, a valve core seat is provided in the valve core seat, the top of the spring seat is pressed tightly against the bottom of the valve core seat, the bottom of the valve core seat supports a first spring in a compressed state, a gem seat is provided at the top of the first spring, a ruby ​​ball is fitted on the upper end surface of the gem seat, and the upper end of the ruby ​​ball is pressed tightly against the entrance of the sapphire seat; The lower end of the gem seat pressure cover is fixedly inserted in the valve core seat, the gem base is located in the gem seat pressure cover, a gem seat is provided in the gem seat pressure cover, the gem base is fixedly inserted in the gem seat, the gem seat is higher than the gem base and the gem seat pressure cover, the ruby ​​ball is located on the inner side of the upper end of the gem seat, a fastening nut is installed on the outer side of the top of the gem seat pressure cover, and a clamping nut is installed on the outer side of the bottom of the support seat and the outer side of the top of the gem seat, and a gap is left between the opening of the clamping nut and the outer side of the gem seat.

[0010] Preferably, the upper valve body and the lower valve body are connected by threads, the upper valve body and the inlet joint are connected by threads, and the upper valve body and the outlet joint are connected by threads.

[0011] Preferably, a sealing groove is provided at the center of the upper end surface of the support seat, and the lower end of the outlet joint is sealingly connected to the upper end surface of the support seat via a first O-ring embedded in the sealing groove.

[0012] Preferably, the support seat is sealingly connected to the inner cavity of the upper valve body through a first support ring and a second O-ring which are distributed in an upper and lower manner. A groove with the same outer diameter as the sapphire seat is opened at the bottom center of the support seat. The sapphire seat is fixedly inserted in the groove, and a second support ring is installed between the upper end of the sapphire seat and the top of the groove.

[0013] Preferably, the lower end of the sapphire seat extends out of the support seat, and a gap is left between the clamping nut and the lower end surface of the support seat.

[0014] Preferably, the gem seat cover, gem seat and gem base are all hollow cylinders, the central axes of the gem seat cover, gem seat and gem base coincide, both ends of the gem seat cover and gem seat are open, the gem seat is T-shaped and narrow at the top and wide at the bottom, the opening at the upper end of the gem seat cover is extended inward, and the upper end of the gem seat cover overlaps the junction of the upper and lower ends of the gem seat.

[0015] Preferably, the valve core seat is located at the center of the valve core base and the upper end extends out of the valve core base, and an annular gap is left between the upper half of the valve core seat and the inner wall of the valve core base. The bottom of the gap is circumferentially sealed with a fourth O-ring and a fourth support ring, and the fourth support ring is located at the bottom of the fourth O-ring. The upper end of the gap is sealed with a tightening cover.

[0016] Preferably, a valve stem is provided at the axial center of the lower valve body, and a thrust ball bearing is provided at the bottom of the valve stem. The upper end of the thrust ball bearing is pressed against the valve stem, and the lower end is pressed against a pressure plate sleeved on the valve stem. The lower end of the pressure plate is provided with a first retaining spring and a second retaining spring from outside to inside, the second retaining spring is sleeved on the valve stem, the first retaining spring is clamped in the lower valve body, and a second spring is sleeved on the valve stem. The lower end of the second spring is away from the thrust ball bearing, and the upper end of the second spring is sleeved on the bottom of the spring base.

[0017] Preferably, it further comprises a regulator, a key slot is provided on the side wall of the lower valve body, the regulator is sleeved on the valve stem through a thread, the lower end of the second spring contacts the regulator, and the regulator is fixed to the lower valve body through a first fixing screw provided on the key slot; The bottom of the valve stem is fixedly connected to the handle via a second fixing screw.

[0018] A method for using a back pressure valve applied to a supercritical system pipeline, based on any one of the above-mentioned back pressure valves applied to a supercritical system pipeline, comprises the following steps: S1, after the fluid enters the valve cavity of the upper valve body from the inlet joint, the ruby ​​ball is in close contact with the sapphire seat. After the fluid accumulates in the valve cavity of the upper valve body, it enters the lower end of the sapphire seat through the gap between the clamping nut opening and the outer side of the sapphire seat, and is then blocked by the ruby ​​ball. The fluid generates a downward thrust on the sapphire seat along the axis; S2, when the thrust accumulates to the limit, the fluid pushes the gem seat and the gem base to move downward as a whole, the gem base compresses the first spring, the fluid lifts the ruby ​​ball to form a channel, and flows out from the sapphire seat, the support seat and the outlet joint in sequence.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects: The invention discloses a back pressure valve applied to a pipeline of a supercritical system. The fluid can enter the valve cavity of an upper valve body from an inlet joint. The valve core base seal overlaps the joint of a lower valve body and an upper valve body, and a sealing structure can be formed at the bottom of the upper valve body. At this time, the ruby ​​ball is in close contact with the sapphire seat through the thrust exerted by the jewel base. After the fluid is continuously accumulated in the valve cavity of the upper valve body, the fluid enters the lower end of the sapphire seat through the gap between the opening of a clamping nut and the outer side of the jewel seat, and is then blocked by the ruby ​​ball. The fluid generates a downward thrust along the axis on the jewel seat. After that, the fluid pressure is continuously accumulated. At this stage when the ruby ​​ball is not pushed open, a pressure is formed in the valve cavity, so that the outlet pressure rises. The tightening nut and the clamping nut protect the upper and lower supporting structures of the ruby ​​ball. Even if the pressure is very large, the sapphire seat will not be separated from the valve seat. When the thrust accumulates to a certain extent and reaches a limit, the fluid pushes the jewel seat and the jewel base to move downward as a whole. The jewel base compresses a first spring, and the fluid pushes up the ruby ​​ball to form a channel, and flows out from the sapphire seat, the support seat and the outlet joint in sequence. In the present invention, the top of the spring base is pressed tightly against the bottom of the valve core seat. Even if the lower valve body is tightened, the spring base will not be stuck to the valve core seat. The upper and lower supporting structures of the ruby ​​ball are protected by the tightening nut and the compression nut. Even if the pressure is very high, the sapphire seat will not be separated from the supporting seat and cause the entire back pressure valve to fail. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the back pressure valve of the present invention.

[0021] Figure 2 is a curve of the number of rotations and the back pressure according to the embodiment of the present invention.

[0022] Figure 3 for Figure 1 Enlarged view of the middle valve core.

[0023] Figure 4 for Figure 3 Enlarged view of the position of the center compression nut and gem seat.

[0024] In the figure: 1-outlet connector, 2-first O-ring, 3-upper valve body, 4-support seat, 5-first support ring, 6-second O-ring, 7-second support ring, 8-inlet connector, 9-pressure nut, 10-sapphire seat, 11-jewel seat, 12-ruby ball, 13-fastening nut, 14-jewel base, 15-third O-ring, 16-third support ring, 17-pressure cover, 18-first spring, 19-valve core base, 20-jewel seat pressure cover, 21-fourth O-ring, 22-fourth support ring, 23-valve core seat, 24-spring base, 25-second spring, 26-lower valve body, 27-regulator, 28-first fixing screw, 29-valve stem, 30-thrust ball bearing, 31-pressure plate, 32-first retaining spring, 33-second retaining spring, 34-handle, 35-second fixing screw. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0026] The present invention provides a back pressure valve for use in a supercritical system pipeline, such as Figure 1 As shown, it includes a lower valve body 26 and an upper valve body 3 connected to each other, and a support seat 4, a fastening nut 13, a valve core base 19 and a jewel seat cover 20 distributed in the upper valve body 3.

[0027] An inlet joint 8 is provided on one side of the upper valve body 3 near the upper end, an outlet joint 1 is provided on the top of the upper valve body 3, the upper end surface of the support seat 4 is sealedly connected to the lower end surface of the outlet joint 1, the lower end surface of the support seat 4 is located in the valve cavity of the upper valve body 3, a sapphire seat 10 is provided at the bottom of the support seat 4, and the channels of the outlet joint 1, the support seat 4 and the sapphire seat 10 are located at their respective centers, and the central axes coincide, so they are connected in sequence. A spring base 24 is provided at the top of the lower valve body 26, the bottom of the valve core base 19 is overlapped on the opening position of the lower valve body 26, a valve core seat 23 is provided at the center of the valve core base 19, the top of the spring base 24 is pressed tightly against the bottom of the valve core seat 23, a first spring 18 is provided in the valve core seat 23, the first spring 18 is in a compressed state, a second spring 25 is provided at the lower end of the spring base 24, the bottom of the first spring 18 is supported on the bottom of the valve core seat 23, a gem base 14 is provided at the top, a ruby ​​ball 12 is fitted on the upper end surface of the gem base 14, and the upper end of the ruby ​​ball 12 is pressed tightly against the entrance of the sapphire seat 10.

[0028] The lower end of the gem seat cover 20 is fixedly inserted in the valve core seat 23, the gem seat 14 is located in the gem seat cover 20, the inner wall of the gem seat cover 20 is fitted with the gem seat 11, the gem seat 14 is fixedly inserted in the gem seat 11, the gem seat 11 is higher than the gem seat cover 20 and the gem seat 14, the ruby ​​ball 12 is located on the inner side of the upper end of the gem seat 11, the top outer side of the gem seat cover 20 is installed with a fastening nut 13, and the outer side of the top of the gem seat 11 and the outer side of the bottom of the support seat 4 are installed with a compression nut 9. Figure 4 As shown, a gap is left between the opening of the compression nut 9 and the outer side of the gem seat 11 .

[0029] Specifically, the upper valve body 3 and the lower valve body 26 are connected by threads, and the upper valve body 3 is connected to the inlet connector 8 and the outlet connector 1 in turn by threads. The sapphire seat 10 is used as the valve seat, and the ruby ​​ball 12 is used as the valve core; the support seat 4 is placed into the upper valve body 3 from the upper part of the upper valve body 3; a sealing groove is opened at the center of the upper end surface of the support seat 4, and the lower end of the outlet joint 1 is sealed and connected with the upper end surface of the support seat 4 through the first O-ring 2 embedded in the sealing groove; the support seat 4 and the inner cavity of the upper valve body 3 are sealed by the first support ring 5 and the second O-ring 6, and the first support ring 5 and the second O-ring 6 are distributed in a close fit up and down, and a second support ring 7 is installed between the bottom of the support seat 4 and the sapphire seat 10. Specifically, a groove with the same outer diameter as the sapphire seat 10 is opened at the center of the bottom of the support seat 4, and the sapphire seat 10 is fixedly inserted in the groove, and a second support ring 7 is installed between the upper end of the sapphire seat 10 and the top of the groove, and the sapphire seat 10 is embedded in the support seat 4 by the tightening nut 9. The sapphire seat 10 is used to serve as the valve seat of the back pressure valve.

[0030] like Figure 3 As shown, the lower end of the sapphire seat 10 extends out of the support seat 4, so the lower end surface of the support seat 4 is higher than the lower end surface of the sapphire seat 10, and a gap is left between the clamping nut 9 and the lower end surface of the support seat 4. The gem seat cover 20, the gem seat 11 and the gem base 14 are all hollow cylinders, and the central axes of the gem seat cover 20, the gem seat 11 and the gem base 14 coincide with each other. The two ends of the gem seat cover 20 and the gem seat 11 are open. The gem seat 11 is T-shaped and narrow at the top and wide at the bottom. The opening at the upper end of the gem seat cover 20 is extended inward, and the upper end of the gem seat cover 20 overlaps the junction of the upper and lower ends of the gem seat 11.

[0031] The valve core base 19 is T-shaped and narrow at the top and wide at the bottom. It is arranged at the bottom of the upper valve body 3. The narrow part of the upper end of the valve core base 19 is sealed with the upper valve body 3 through the third O-ring 15 and the third support ring 16. The valve core seat 23 is connected to the jewel seat gland 20 by threads. The valve core seat 23 is placed at the center of the valve core base 19 and the upper end extends out of the valve core base 19. An annular gap is left between the upper half of the valve core seat 23 and the inner wall of the valve core base 19. The bottom of the gap is sealed with a fourth O-ring 21 and a fourth support ring 22 along the circumferential direction. The fourth support ring 22 is located at the bottom of the fourth O-ring 21. The upper end of the fourth O-ring 21 is sealed with a clamping cover 17, so the clamping cover 17 is plugged into the upper end of the gap. A fastening nut 13 is provided at the top of the jewel seat gland 20 near the valve core seat 23 to ensure the structural stability of the ruby ​​ball 12.

[0032] A valve stem 29 is provided at the axial center of the lower valve body 26, a thrust ball bearing 30 is provided at the bottom of the valve stem 29, the upper end of the thrust ball bearing 30 is pressed against the valve stem 29, and the lower end is pressed against a pressure plate 31 sleeved on the valve stem 29, a first retaining spring 32 and a second retaining spring 33 are fixedly provided at the lower end of the pressure plate 31 from outside to inside, the second retaining spring 33 is sleeved on the valve stem 29, the first retaining spring 32 is clamped in the lower valve body 26, and the second spring 25 is sleeved on the valve stem 29 and is higher than the thrust ball bearing 30. The top of the pressure plate 31 is clamped in the lower valve body 26, and the upper end of the second spring 25 is sleeved on the bottom of the spring base 24. A keyway is provided on the side wall of the lower valve body 26, and the regulator 27 is threadedly connected to the valve stem 29 and sleeved on the valve stem 29. The lower end of the second spring 25 contacts the regulator 27, and the regulator 27 is fixed to the lower valve body 26 by a first fixing screw 28 provided on the keyway, so that the regulator 27 can slide axially in the keyway of the lower valve body 26. The bottom of the valve stem 29 is connected to the handle 34 by the second fixing screw 35, and the handle 34 can be rotated clockwise to drive the regulator 27 on the valve stem 29 to move upward, thereby compressing the second spring 25, so that the spring base 24 increases the pressing force on the valve core seat 23, which can further increase the back pressure effect.

[0033] The first O-ring 2, the second O-ring 6, the third O-ring 15 and the fourth O-ring 21 are all made of rubber. The first support ring 5, the second support ring 7, the third support ring 16 and the fourth support ring 22 are all made of polytetrafluoroethylene.

[0034] The present invention discloses a back pressure valve applied to a supercritical system pipeline, and its working process is as follows: After the fluid enters the valve cavity from the inlet connector 8, the ruby ​​ball 12 (i.e., the valve core) is in close contact with the sapphire seat 10. After the fluid accumulates in the valve cavity of the upper valve body 3, it enters the lower end of the sapphire seat 10 through the gap between the opening of the compression nut 9 and the outer side of the sapphire seat 11, and is then blocked by the ruby ​​ball 12 and cannot flow out of the valve cavity through the channel of the sapphire seat 10. Therefore, the fluid generates a downward thrust along the axis on the sapphire seat 11 in the valve core. When the thrust accumulates to a certain extent and reaches the limit, the fluid pushes the sapphire seat 11 and the sapphire base 14 to move downward as a whole, the sapphire base 14 compresses the first spring 18, and the fluid pushes up the ruby ​​ball 12 to form a channel, and flows out from the sapphire seat 10, the support seat 4 and the outlet connector 1 of the back pressure valve in sequence; If the fluid pressure is not enough, pressure will be built up in the valve cavity, causing the outlet pressure to rise until the ruby ​​ball is pushed open to form a channel.

[0035] Figure 2 It is a curve of the opening number of the back pressure valve of the present invention and the back pressure. At room temperature, the initial flow rate of the metering pump is 20g / min, and the opening of the pump is kept unchanged. The handle 34 is rotated clockwise for two circles, and the average value of the back pressure reaches 7.4MPa, reaching the critical pressure of supercritical carbon dioxide. After rotating 6.5 circles, the average value of the back pressure reaches 22.5MPa, reaching the critical pressure of supercritical water.

[0036] The present invention discloses a back pressure valve applied to a supercritical system pipeline, and its use process is as follows: Step 1. Select a suitable installation location according to system requirements. For a large-flow pump with a long and thin outlet pipe, the back pressure valve should be installed close to the filling point to reduce the siphon tendency. Install a pressure gauge on the pipe at the inlet end of the back pressure valve to monitor the pressure change in real time. Turn the handle 34 counterclockwise to adjust the second spring 25 so that the siphon tendency is in a pressure-free state.

[0037] Step 2: Connect the back pressure valve to the pump and piping system correctly, ensure that the joints are sealed reliably and leak-free, and ensure that the back pressure valve and related equipment such as power supply, pressure sensor, etc. are in good condition and can operate normally.

[0038] Step 3, start the system where the back pressure valve is located to put it into working state. The back pressure valve detects the pressure in the pipeline through the pressure sensor and transmits it to the controller.

[0039] Step 4, open the pipeline valve to make the outlet of the back pressure valve at normal pressure.

[0040] Step 5. After starting the pump, rotate the back pressure valve clockwise to adjust the second spring 25, and observe the pressure gauge at the same time, and gradually adjust to the required pressure value. When adjusting the back pressure valve pressure, proceed slowly and pay attention to the changes in the pressure gauge to avoid excessive adjustments at one time that may cause excessive fluctuations in system pressure.

[0041] Step 6: During the operation of the system, continuously monitor the pressure gauge of the back pressure valve to ensure that the pressure value is stable within the set range. Before stopping the system, turn off the pump and pipeline valves first, and then turn off the system where the back pressure valve is located.

Claims

1. A back pressure valve used in a supercritical system pipeline, characterized in that: It comprises an upper valve body (3) and a lower valve body (26) connected to each other, and a support seat (4), a valve core base (19) and a gem seat gland (20) arranged in the upper valve body (3); An inlet joint (8) and an outlet joint (1) are respectively provided on one side and the top of the upper valve body (3); an upper end surface of the support seat (4) is connected to a lower end surface of the outlet joint (1); a lower end surface of the support seat (4) is located in the valve cavity of the upper valve body (3); and a sapphire seat (10) is provided at the bottom of the support seat (4); A spring base (24) is provided at the top of the lower valve body (26), a valve core base (19) is sealingly overlapped at the junction of the lower valve body (26) and the upper valve body (3), a valve core seat (23) is provided in the valve core base (19), the top of the spring base (24) is pressed against the bottom of the valve core seat (23), the bottom of the valve core seat (23) supports a first spring (18) in a compressed state, a gem base (14) is provided at the top of the first spring (18), a ruby ​​ball (12) is fitted on the upper end surface of the gem base (14), and the upper end of the ruby ​​ball (12) is pressed against the entrance of the sapphire seat (10); The lower end of the gem seat cover (20) is fixedly inserted in the valve core seat (23), the gem seat (14) is located in the gem seat cover (20), a gem seat (11) is provided in the gem seat cover (20), the gem seat (14) is fixedly inserted in the gem seat (11), the gem seat (11) is higher than the gem seat (14) and the gem seat cover (20), the ruby ​​ball (12) is located on the inner side of the upper end of the gem seat (11), a fastening nut (13) is installed on the outer side of the top of the gem seat cover (20), and a clamping nut (9) is installed on the outer side of the bottom of the support seat (4) and the outer side of the top of the gem seat (11), and a gap is left between the opening of the clamping nut (9) and the outer side of the gem seat (11).

2. The back pressure valve used in supercritical system pipeline according to claim 1, characterized in that: The upper valve body (3) and the lower valve body (26) are connected by threads, the upper valve body (3) and the inlet joint (8) are connected by threads, and the upper valve body (3) and the outlet joint (1) are connected by threads.

3. The back pressure valve used in supercritical system pipeline according to claim 1, characterized in that: A sealing groove is provided at the centre of the upper end surface of the support seat (4), and the lower end of the outlet joint (1) is sealingly connected to the upper end surface of the support seat (4) via a first O-ring (2) embedded in the sealing groove.

4. The back pressure valve used in supercritical system pipeline according to claim 1, characterized in that: The support seat (4) is sealedly connected to the inner cavity of the upper valve body (3) via a first support ring (5) and a second O-ring (6) which are arranged in a fit with each other. A groove having the same outer diameter as the sapphire seat (10) is provided at the bottom center of the support seat (4). The sapphire seat (10) is fixedly inserted in the groove. A second support ring (7) is installed between the upper end of the sapphire seat (10) and the top of the groove.

5. The back pressure valve used in supercritical system pipeline according to claim 4, characterized in that: The lower end of the sapphire seat (10) extends out of the support seat (4), and a gap is left between the clamping nut (9) and the lower end surface of the support seat (4).

6. The back pressure valve used in supercritical system pipeline according to claim 1, characterized in that: The gem seat cover (20), the gem seat (11) and the gem base (14) are all hollow cylinders, the central axes of the gem seat cover (20), the gem seat (11) and the gem base (14) coincide with each other, both ends of the gem seat cover (20) and the gem seat (11) are open, the gem seat (11) is T-shaped and narrow at the top and wide at the bottom, the opening at the upper end of the gem seat cover (20) is extended inwardly, and the upper end of the gem seat cover (20) is overlapped at the junction of the upper and lower ends of the gem seat (11).

7. The back pressure valve used in supercritical system pipeline according to claim 1, characterized in that: The valve core seat (23) is located at the center of the valve core base (19) and the upper end thereof extends out of the valve core base (19). An annular gap is left between the upper half of the valve core seat (23) and the inner wall of the valve core base (19). A fourth O-ring (21) and a fourth support ring (22) are provided at the bottom of the gap in a circumferential sealing manner. The fourth support ring (22) is located at the bottom of the fourth O-ring (21). A clamping cover (17) is provided at the upper end of the gap in a sealing manner.

8. The back pressure valve used in supercritical system pipeline according to claim 1, characterized in that: A valve stem (29) is arranged at the center of the axis of the lower valve body (26), and a thrust ball bearing (30) is arranged at the bottom of the valve stem (29). The upper end of the thrust ball bearing (30) is pressed against the valve stem (29), and the lower end is pressed against a pressure plate (31) sleeved on the valve stem (29). A first retaining spring (32) and a second retaining spring (33) are arranged from outside to inside at the lower end of the pressure plate (31). The second retaining spring (33) is sleeved on the valve stem (29), and the first retaining spring (32) is clamped in the lower valve body (26). A second spring (25) is sleeved on the valve stem (29), and the lower end of the second spring (25) is away from the thrust ball bearing (30). The upper end of the second spring (25) is sleeved on the bottom of the spring base (24).

9. The back pressure valve used in supercritical system pipeline according to claim 8, characterized in that: The valve body (26) further comprises a regulator (27), wherein a key slot is formed on a side wall of the lower valve body (26), the regulator (27) is sleeved on the valve stem (29) by means of a thread, the lower end of the second spring (25) is in contact with the regulator (27), and the regulator (27) is fixed to the lower valve body (26) by means of a first fixing screw (28) disposed on the key slot; The bottom of the valve stem (29) is fixedly connected to the handle (34) via a second fixing screw (35).

10. A method for using a back pressure valve applied to a supercritical system pipeline, characterized in that: The back pressure valve applied to a supercritical system pipeline according to any one of claims 1 to 9 comprises the following steps: S1, after the fluid enters the valve cavity of the upper valve body (3) from the inlet joint (8), the ruby ​​ball (12) is in close contact with the sapphire seat (10). After the fluid accumulates in the valve cavity of the upper valve body (3), it enters the lower end of the sapphire seat (10) through the gap between the opening of the clamping nut (9) and the outer side of the sapphire seat (11), and is then blocked by the ruby ​​ball (12). The fluid generates a downward thrust along the axis of the sapphire seat (11); S2, when the thrust accumulates to a limit, the fluid pushes the gem seat (11) and the gem base (14) to move downward as a whole, the gem base (14) compresses the first spring (18), and the fluid lifts the ruby ​​ball (12) to form a channel, and flows out from the sapphire seat (10), the support seat (4) and the outlet joint (1) in sequence.

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