Plug valve in CO2 air conditioning system

Abstract

A plug valve in a CO2 air conditioning system comprises a hollow valve body, a throttling column with a through hole is arranged in the valve body, and the throttling column is floatingly arranged in the inner cavity of the valve body, an expansion groove is arranged on the throttling column, cylindrical sealing parts are symmetrically arranged on the left and right sides of the throttling column, and the cylindrical sealing parts are provided with contact surfaces adapted to the outer shape of the throttling column to form a hard seal together; a guide tube, a conical ring gasket, a butterfly spring and a plug cover are also arranged in the inner cavity of the valve body on the left and right sides of the cylindrical seal, one end of the guide tube is sealingly supported on the cylindrical seal, and the other end of the guide tube is sealingly supported on the plug cover, a conical ring gasket and a butterfly spring are mounted on the guide tube, and the plug cover presses the butterfly spring to make the cylindrical seal tightly embrace the throttling column to form a seal.

Description

Technical Field

[0001] The present invention relates to a plug valve, and in particular to a plug valve used in a new CO2 air conditioning system. Background Art

[0002] The plug valve is a fast-opening straight-through valve that uses a plug body with a through hole as the opening and closing part. The plug body rotates with the valve stem to achieve the opening and closing action. The plug valve is the earliest type of valve used. It has a simple structure, fast opening and closing, low fluid resistance, is not restricted by the installation direction, and the flow direction of the medium can be arbitrary. Ordinary plug valves rely on the direct contact between the finely machined metal plug body and the valve body to seal, so the sealing performance is poor, the opening and closing force is large, and it is easy to wear. It can usually only be used for low pressures not higher than 1 MPa and occasions with a diameter of less than 100 mm. It can only play an opening and closing role, and cannot accurately adjust the flow or pressure. There will be impact when switching between opening and closing, causing a water hammer effect. Now many application scenarios, such as valves in refrigeration systems, need to be able to be accurately adjusted, have an expansion effect, and the refrigerant can flow in both directions, and can withstand high sealing requirements. At present, there is no valve that can meet these requirements in GB / T22130-2008, so multiple valves are installed to meet multiple needs. Summary of the invention

[0003] The present invention provides a multifunctional valve which can enhance the sealing effect of a plug valve, withstand high pressure, adjust flow pressure under working conditions with large temperature fluctuations, have an expansion effect and can flow in both directions.

[0004] A plug valve in a CO2 air conditioning system includes a hollow valve body, a throttling column with a through hole is arranged in the valve body, and the throttling column is floatingly arranged in the inner cavity of the valve body, an expansion groove is arranged on the throttling column, cylindrical sealing parts are symmetrically arranged on the left and right sides of the throttling column, and the cylindrical sealing parts are provided with contact surfaces adapted to the outer shape of the throttling column to form a hard seal together. A guide tube, a conical ring gasket, a butterfly spring and a plug cover are also arranged in the inner cavity of the valve body on the outside of the two cylindrical seals, one end of the guide tube is sealed and supported on the cylindrical seal, and the other end of the guide tube is sealed and supported on the plug cover, a conical ring gasket and a butterfly spring are mounted on the guide tube, and the plug cover presses the butterfly spring to make the cylindrical seal hold the throttling column tightly to form a seal.

[0005] The inner diameter of the flow guide tube is consistent with the inner diameter of the through hole.

[0006] The expansion groove extends on the outer wall of the throttle column in a manner away from the through hole and toward the inner cavity of the valve body, and the flow cross section can be reduced by the expansion groove to expand the fluid flowing through the plug valve.

[0007] The cylinder seal comprises a right cylinder seal and a left cylinder seal.

[0008] The left cylindrical seal, the left conical annular gasket, the left butterfly spring, the left plugging cover gasket and the left plugging cover are sequentially arranged on the left part of the inner cavity of the valve body. The left plugging cover is a hollow through-step hole structure, one end of the left guide pipe is inserted into the step hole of the left plugging cover, and the left guide pipe and the left plugging cover are sealed by a left guide pipe sealing ring; the other end of the left guide pipe passes through the left plugging cover gasket, the left butterfly spring and the left conical annular gasket are inserted into the hollow through-step hole reserved in the left cylindrical seal, and the left guide pipe and the left cylindrical seal are sealed by a left guide pipe sealing ring. The left guide tube is sealed and supported in the inner hole of the left cylindrical seal and the left plug cover step through the left guide tube sealing ring. The left cylindrical seal is sealed and supported in the valve body through the left cylindrical seal sealing ring. The left conical ring gasket, the left butterfly spring and the left plug cover gasket are sleeved on the left guide tube and located between the two left guide tube sealing rings on the left guide tube. The left plug cover is sealed and supported in the valve body through the left plug cover sealing ring and is threadedly connected with the valve body. A left plug cover gasket is arranged between the left plug cover and the left butterfly spring. The left plug cover is screwed into the valve body to compress the left butterfly spring, the left conical ring gasket and the left cylindrical seal, so that the left cylindrical seal and the throttling column are closely fitted to form a hard seal. After the head of the left plug cover contacts the valve body, the guide tube adjustment gap can still be retained between the end face of the guide tube and the left plug cover, and the two maintain a small gap fit.

[0009] The right cylindrical seal, right conical ring gasket, right butterfly spring, right plugging cover gasket and right plugging cover are arranged in sequence on the right part of the inner cavity of the valve body. The right plugging cover is a hollow through-step hole structure. One end of the right flow guide pipe is inserted into the step hole of the right plugging cover. The right flow guide pipe and the right plugging cover are sealed and supported by a right flow guide pipe sealing ring. The other end of the right flow guide pipe passes through the right plugging cover gasket. The right butterfly spring and the right conical ring gasket are inserted into the hollow through-step hole reserved in the right cylindrical seal. The right flow guide pipe and the right cylindrical seal are sealed and supported by a right flow guide pipe sealing ring. The right flow guide pipe is sealed and supported in the right cylindrical seal and the inner hole of the step of the right plugging cover through the right flow guide pipe sealing ring. The right cylindrical seal is sealed and supported in the valve body through the right cylindrical seal ring. The right conical ring gasket, the right butterfly spring and the right plug cover gasket are mounted on the right guide tube and are located between the two right guide tube sealing rings on the right guide tube. The right plug cover is sealed and supported in the valve body through the right plug cover sealing ring and is threadedly connected with the valve body. A right plug cover gasket is arranged between the right plug cover and the right butterfly spring. The right plug cover is screwed into the valve body to compress the right butterfly spring, the right conical ring gasket and the right cylindrical seal, so that the right cylindrical seal and the throttling column are closely fitted to form a hard seal. After the head of the right plug cover contacts the valve body, the end face of the guide tube and the right plug cover can still maintain a small gap fit.

[0010] The left cylindrical seal and the right cylindrical seal have the same structure, both are hollow cylindrical structures, one end face is a concave curved surface that matches the outer contour of the throttling column, and the other end face is a convex spherical table. A sealing ring groove is arranged on the cylindrical surface.

[0011] The left conical ring gasket and the right conical ring gasket have the same structure, both of which are hollow flat cylinders, one end surface is a plane, and the other end surface is a concave contact surface, and the concave contact surface is in line contact with the convex ball table on the left cylindrical seal and the right cylindrical seal. The cooperation between the ball table and the concave contact surface enables the left and right cylindrical seals to float and surround the throttling column.

[0012] The flow guide pipe comprises a left flow guide pipe and a right flow guide pipe. The inner diameter of the flow guide pipe is consistent with the inner diameter of the through hole.

[0013] The bottom surface of the expansion groove is a curved surface and the center of the curved surface deviates from the center of the cylindrical surface. The groove depth of the expansion groove gradually changes with the curved surface to achieve linear throttling. The expansion angle of the expansion groove is 50 degrees.

[0014] A ball convex support is arranged at the bottom of the throttling column and is supported at a corresponding position of the valve body.

[0015] The beneficial effect of this solution is that the flow guide pipe is arranged inside the valve body to reduce the pressure area, reduce the pressure on the valve core, reduce the movement of the valve core, and reduce the pressure on the sealing ring. Combined with the cylindrical seal, conical ring gasket, butterfly spring and plug cover and the sealing ring structure arranged in multiple places, the plug valve can withstand the high pressure of 3.5MPa-12MPa and has good sealing performance in the temperature range of -40℃-150℃. Since the valve body adopts a symmetrical arrangement to resist the movement variable caused by the pressure on the valve core, and an expansion groove is arranged on the throttling column, the conversion between opening and closing is gradually completed, and it can play a role in regulation. By adjusting the transmission shaft, the flow rate can be accurately adjusted between closed and fully open, and the flow cross-sectional area is adjusted at the same time, so that the fluid flowing through the plug valve expands, and the groove depth gradually increases from 0mm to 1.8mm, which has an expansion effect. The plug valve has a variety of operating conditions and can be applied to a variety of scenarios. The pressure drop in the fully open state is small, less than 20KPa. In the fully open condition at a pressure of about 3.5MPa, the flow rate can reach 150Kg / h150Kg / h. In the fully open state at a pressure of about 8MPa, the temperature of the CO2 passing through is about 45℃, and the flow rate is 150Kg / h; in the fully open state at a pressure of about 8MPa, the temperature of the CO2 passing through is about 45℃, and the flow rate is 150Kg / h. In the shut-off state, the high pressure is 8MPa, about 20℃, the low pressure is 3.5MPa, and the flow rate reaches 100Kg / h. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the plug valve structure in the CO2 air conditioning system. Figure 2It is a structural diagram of the plug valve in the fully open state. Figure 3 It is a structural diagram of the plug valve in the cut-off state. Figure 4 It is a structural diagram of the plug valve in the expanded position. Figure 5 It is a schematic diagram of the assembly of plug valve components. Figure 6 It is a schematic diagram of the structure in which the concave surface of the cylindrical seal is at the front. Figure 7 Schematic diagram of the structure of the cylindrical seal with the convex surface in front. Figure 8 It is a schematic diagram of the structure of a conical ring gasket. Fig. 9 It is a schematic diagram of the structure of a cylindrical seal. Fig.10 Figure 5 A partial enlargement of the middle left half.

[0017] In the figure: 1-through hole; 2-expansion groove; 3-right butterfly spring; 4-right conical annular gasket; 5-right plugging cover gasket; 6-valve body; 7-right plugging cover; 8-right cylindrical seal; 9-drive shaft stop flange; 10-drive shaft; 11-throttle column; 12-right guide pipe; 13-right plugging cover sealing ring; 14-right cylindrical seal sealing ring; 15-rotating shaft sealing ring; 16-rotating shaft stop flange upper sealing ring; 17-rotating shaft stop flange lower sealing Ring; 18-left cylindrical seal; 19-left cylindrical seal sealing ring; 20-left conical annular gasket; 21-left butterfly spring; 22-left plugging cover gasket; 23-left plugging cover; 24-left guide tube sealing ring; 25-through hole; 26-inner concave surface; 27-ball table; 28-inner concave contact surface; 29-sealing ring groove; 30-right guide tube sealing ring; 31-left guide tube; 32-left plugging cover sealing ring; 33-ball convex; 34-guide tube adjustment gap. DETAILED DESCRIPTION

[0018] like Figure 1 As shown, a plug valve in a CO2 air conditioning system includes a hollow valve body 6, a throttling column 11 with a through hole 1 is arranged in the valve body 6, the throttling column 11 is floatingly arranged in the inner cavity of the valve body 6, and an expansion groove 2 is arranged on the throttling column 11. The expansion groove 2 extends on the outer wall of the throttling column 11 in a manner away from the through hole 1 and toward the inner cavity of the valve body 6, and the flow cross section can be reduced through the expansion groove 2 to expand the fluid flowing through the plug valve. Cylindrical seals are arranged on both sides of the throttling column 11, and contact surfaces that are adapted to the shape of the throttling column 11 and precisely matched are arranged on the cylindrical seal to form a hard seal together. The cylindrical seal includes a right cylindrical seal 8 and a left cylindrical seal 18. The right cylindrical seal 8 is sealed relative to the valve body 6 by the right cylindrical seal sealing ring 14.

[0019] A flow guide tube, a conical ring gasket, a butterfly spring and a plugging cover are also arranged on the outer side of the two cylindrical seals in the inner cavity of the valve body 1. One end of the flow guide tube is sealed and supported on the cylindrical seal, and the other end of the flow guide tube is sealed and supported on the plugging cover. A conical ring gasket and a butterfly spring are mounted on the flow guide tube. The plugging cover presses the butterfly spring to make the cylindrical seal hold the throttling column 11 tightly to form a seal. The inner diameter of the flow guide tube is consistent with the inner diameter of the through hole 1. The flow guide tube is made of 304 stainless steel.

[0020] like Figure 6 and Fig.10 As shown, a left cylindrical seal 18, a left conical annular gasket 20, a left butterfly spring 21, a left plugging cover gasket 22 and a left plugging cover 23 are sequentially arranged on the left part of the inner cavity of the valve body 6.

[0021] The left plugging cover 23 is a hollow through-through step hole structure, one end of the left air guide pipe 31 is inserted into the step hole of the left plugging cover 23, and the left air guide pipe 31 and the left plugging cover 23 are sealingly supported by a left air guide pipe sealing ring 24; the other end of the left air guide pipe 31 passes through the left plugging cover gasket 22, the left butterfly spring 21 and the left conical annular gasket 20 are inserted into the hollow through-through step hole reserved in the left cylindrical seal 18, and the left air guide pipe 31 and the left cylindrical seal 18 are sealingly supported by a left air guide pipe sealing ring 24. The left flow guide tube 31 is sealed and supported in the inner hole of the step of the left cylindrical seal 18 and the left plugging cover 23 through the left flow guide tube sealing ring 24. The left cylindrical seal 18 is sealed and supported in the valve body 6 through the left cylindrical seal sealing ring 19. The left conical ring gasket 20, the left butterfly spring 21 and the left plugging cover gasket 22 are sleeved on the left flow guide tube 31 and are located between the two left flow guide tube sealing rings 24 on the left flow guide tube 31. The left plugging cover 23 is sealed and supported in the valve body 6 through the left plugging cover sealing ring 32 and is threadedly connected with the valve body 6. The left plugging cover gasket 22 is arranged between the left plugging cover 23 and the left butterfly spring 21. The left plugging cover 23 is screwed into the valve body 6 to compress the left butterfly spring 21, the left conical ring gasket 20 and the left cylindrical seal 18, so that the left cylindrical seal 18 and the throttling column 11 are closely fitted to form a hard seal. After the head of the left plugging cover 23 contacts the valve body 6 , a flow guide tube adjustment gap 34 can still be retained between the end surface of the flow guide tube and the left plugging cover, and the two maintain a small gap fit.

[0022] like Figure 5As shown, the right cylindrical seal 8, the right conical ring gasket 4, the right butterfly spring 3, the right plugging cover gasket 5 and the right plugging cover 7 are sequentially arranged in the right part of the inner cavity of the valve body 6. The right plugging cover 7 is a hollow through-going step hole structure. One end of the right guide pipe 12 is inserted into the step hole of the right plugging cover 7. The right guide pipe 12 and the right plugging cover 7 are sealed and supported by a right guide pipe sealing ring 30. The other end of the right guide pipe 12 passes through the right plugging cover gasket 5. The right butterfly spring 3 and the right conical ring gasket 4 are inserted into the hollow through-going step hole reserved in the right cylindrical seal 8. The right guide pipe 12 and the right cylindrical seal 8 are sealed and supported by a right guide pipe sealing ring 30. The right guide pipe 12 is sealed and supported in the right cylindrical seal 8 and the step inner hole of the right plugging cover 7 through the right guide pipe sealing ring 30. The right cylindrical seal 8 is sealed and supported in the valve body 6 through the right cylindrical seal ring 14. The right conical ring gasket 4, the right butterfly spring 3 and the right plugging cover gasket 5 are mounted on the right guide tube 12 and are located between the two right guide tube sealing rings 30 on the right guide tube 12. The right plugging cover 7 is sealed and supported in the valve body 6 through the right plugging cover sealing ring 13 and is threadedly connected with the valve body 6. The right plugging cover gasket 13 is arranged between the right plugging cover 7 and the right butterfly spring 3. The right plugging cover 7 is screwed into the valve body 6 to press the right butterfly spring 3, the right conical ring gasket 4 and the right cylindrical seal 8, so that the right cylindrical seal 8 and the throttling column 11 are closely fitted to form a hard seal. After the head of the right plugging cover 7 contacts the valve body 6, the end face of the guide tube and the right plugging cover can still maintain a small gap fit.

[0023] like Figure 6 and Figure 7 and 9 As shown, the left cylindrical seal 18 and the right cylindrical seal 8 have the same structure, both are hollow cylindrical structures, one end surface is a concave curved surface 26 adapted to the outer contour of the throttling column 11, and the other end surface is a convex spherical table 27. A sealing ring groove 29 is provided on the cylindrical surface.

[0024] like Figure 8 As shown, the left conical ring gasket 20 and the right conical ring gasket 4 have the same structure, both are hollow flat cylindrical, one end face is a plane, and the other end face is a concave contact surface, the concave contact surface is in line contact with the convex ball table on the left cylindrical seal and the right cylindrical seal, and the concave contact surface 28 is a 140-degree concave conical surface. The cooperation between the ball table and the concave contact surface 28 enables the left and right cylindrical seals (18, 8) to float and surround the throttling column 11.

[0025] The flow guide pipe includes a left flow guide pipe 31 and a right flow guide pipe 12. The inner diameter of the flow guide pipe is consistent with the inner diameter of the through hole.

[0026] The bottom surface of the expansion groove is a curved surface and the center of the curved surface deviates from the center of the cylindrical surface. The groove depth of the expansion groove gradually changes with the curved surface to achieve linear throttling. The expansion angle of the expansion groove is 50 degrees.

[0027] A ball protrusion 33 is provided at the bottom of the throttling column 11 and supported at a corresponding position of the valve body.

[0028] When the left plugging cover 23 and the right plugging cover 7 are screwed into the valve body 6, the left butterfly spring 21 and the right butterfly spring 3 are gradually compressed, so that the left cylindrical seal 18 and the right cylindrical seal 8 hold the throttle column 11 tightly to form a contact seal, which can withstand a high pressure of 3.5MPa-12MPa. At the same time, the left cylindrical seal 18 and the right cylindrical seal 8 made of metal have good high and low temperature performance and can have good sealing performance in the temperature range of -40℃-150℃.

[0029] A transmission shaft stop flange 9 is also provided on the upper part of the valve body 6. A transmission shaft 10 is accommodated in the transmission shaft stop flange 9. A protrusion is provided at the lower end of the transmission shaft 10. The protrusion and the matching groove at the top of the throttle column are matched with each other to transmit the rotational movement of the transmission shaft 10 to the throttle column 11. The transmission shaft 10 and the transmission shaft stop flange 9 are sealed by a transmission shaft sealing ring 15. The transmission shaft stop flange 9 and the valve body 6 are sealed by a transmission shaft stop flange lower sealing ring 17. The throttle column 11 is rotated by the transmission shaft 10 installed in the transmission shaft stop flange 9.

[0030] like Figure 4 As shown, when the valve needs to be closed, the throttle column 11 rotates to the cut-off position, and the upper cylindrical surface of the throttle column 11 blocks the through holes 25 on the left and right cylindrical sealing members (18, 8), and the valve is cut off.

[0031] like Figure 2 As shown, when the valve needs to be opened, the throttle column 11 rotates to the fully open position, the through holes 25 on the left and right cylindrical sealing members (18, 8) are fully connected to the through hole 1 on the throttle column 11, and the valve is fully open.

[0032] like Figure 5 As shown, when the flow needs to be adjusted, the throttle column 11 moves to the position of the expansion groove 2, and the expansion groove 2 on the throttle column 11 moves to the corresponding position of the through hole 25 on the left and right cylindrical seals (18, 8), changing the flow cross-section size, reducing the cross-section to expand the fluid passing through the valve,

[0033] According to the rotation angle of the transmission shaft 10, the expansion groove 2 on the throttle column 11 changes the flow cross-sectional size so that the flow rate of the valve can change with the rotation angle of the transmission shaft 10.

Claims

1. A plug valve in a CO2 air conditioning system, comprising a hollow valve body, a throttling column with a through hole arranged in the valve body, characterized in that The throttling column is arranged in a floating manner in the inner cavity of the valve body, an expansion groove is arranged on the throttling column, cylindrical sealing parts are symmetrically arranged on the left and right sides of the throttling column, and a contact surface adapted to the shape of the throttling column is arranged on the cylindrical sealing part to form a hard seal together; a guide tube, a conical ring gasket, a butterfly spring and a plugging cover are arranged in the inner cavity of the valve body on the outside of the two cylindrical sealing parts, one end of the guide tube is sealingly supported on the cylindrical sealing part, and the other end of the guide tube is sealingly supported on the plugging cover, and a conical ring is sleeved on the guide tube. The washer, butterfly spring and plugging cover compress the butterfly spring to make the cylindrical seal hold the throttling column tightly to form a seal; the inner diameter of the guide tube is consistent with the inner diameter of the through hole; the left cylindrical seal, the left conical annular washer, the left butterfly spring, the left plugging cover washer and the left plugging cover are arranged in sequence on the left part of the inner cavity of the valve body; the left plugging cover is a hollow through-step hole structure, one end of the left guide tube is inserted into the step hole of the left plugging cover, and the left guide tube and the left plugging cover are sealed and supported by a left guide tube sealing ring; the other end of the left guide tube passes through the left plugging cover washer The left butterfly spring and the left conical annular gasket are inserted into the hollow through-step hole reserved in the left cylindrical seal. The left guide tube and the left cylindrical seal are sealed and supported by a left guide tube sealing ring; the left guide tube is sealed and supported in the inner hole of the left cylindrical seal and the left plugging cover step by the left guide tube sealing ring. The left cylindrical seal is sealed and supported in the valve body by the left cylindrical seal sealing ring. The left conical annular gasket, the left butterfly spring and the left plugging cover gasket are sleeved on the left guide tube and are located at two on the left guide tube. Between the left guide tube sealing ring, the left plugging cover is sealingly supported in the valve body through the left plugging cover sealing ring and is threadedly connected with the valve body; a left plugging cover gasket is arranged between the left plugging cover and the left butterfly spring, and the left plugging cover is screwed into the valve body to compress the left butterfly spring, the left conical annular gasket and the left cylindrical seal, so that the left cylindrical seal and the throttling column are tightly fitted to form a hard seal; after the head of the left plugging cover contacts the valve body, the guide tube adjustment gap can still be retained between the end face of the guide tube and the left plugging cover, and the two maintain a small gap fit.

2. The plug valve in the CO2 air conditioning system according to claim 1 is characterized in that The expansion groove extends on the outer wall of the throttle column in a manner away from the through hole and toward the inner cavity of the valve body, and the flow cross section can be reduced by the expansion groove to expand the fluid flowing through the plug valve.

3. The plug valve in the CO2 air conditioning system according to claim 1 is characterized in that A right cylindrical seal, a right conical annular gasket, a right butterfly spring, a right plugging cover gasket and a right plugging cover are sequentially arranged on the right part of the inner cavity of the valve body. The right plugging cover is a hollow through-going step hole structure. One end of the right flow guide pipe is inserted into the step hole of the right plugging cover. The right flow guide pipe and the right plugging cover are sealed and supported by a right flow guide pipe sealing ring. The other end of the right flow guide pipe passes through the right plugging cover gasket. The right butterfly spring and the right conical annular gasket are inserted into the hollow through-going step hole reserved for the right cylindrical seal. The right flow guide pipe and the right cylindrical seal are sealed and supported by a right flow guide pipe sealing ring. The right flow guide pipe is sealed and supported in the right cylindrical seal and the inner hole of the step of the right plugging cover through the right flow guide pipe sealing ring. The right cylindrical seal is sealingly supported in the valve body by the right cylindrical seal sealing ring; the right conical annular gasket, the right butterfly spring and the right plugging cover gasket are mounted on the right guide tube and are located between the two right guide tube sealing rings on the right guide tube; the right plugging cover is sealingly supported in the valve body by the right plugging cover sealing ring and is threadedly connected to the valve body; a right plugging cover gasket is arranged between the right plugging cover and the right butterfly spring; the right plugging cover is screwed into the valve body to compress the right butterfly spring, the right conical annular gasket and the right cylindrical seal, so that the right cylindrical seal and the throttling column are tightly fitted to form a hard seal; after the head of the right plugging cover contacts the valve body, a small clearance fit can still be maintained between the end face of the guide tube and the right plugging cover.

4. The plug valve in the CO2 air conditioning system according to claim 1 or 3, characterized in that The left cylindrical seal and the right cylindrical seal have the same structure, both are hollow cylindrical structures, one end face is a concave surface that matches the outer contour of the throttling column, and the other end face is a convex spherical table; a sealing ring groove is arranged on the cylindrical surface.

5. The plug valve in the CO2 air conditioning system according to claim 1 or 3, characterized in that The left conical annular gasket and the right conical annular gasket have the same structure, both of which are hollow flat cylindrical shapes, one end face is a plane, and the other end face is a concave contact surface. The concave contact surface is in line contact with the convex ball tables on the left cylindrical seal and the right cylindrical seal; the cooperation between the ball table and the concave contact surface enables the left and right cylindrical seals to float and surround the throttling column.

6. The plug valve in the CO2 air conditioning system according to claim 1 or 3, characterized in that The bottom surface of the expansion groove is a curved surface and the center of the curved surface deviates from the center of the cylindrical surface; the groove depth of the expansion groove gradually changes with the curved surface to achieve linear throttling; the expansion angle of the expansion groove is 50 degrees.

7. The plug valve in the CO2 air conditioning system according to claim 1 is characterized in that A spherical projection is arranged at the bottom of the throttling column and supported at a corresponding position of the valve body.

Images