Exhaust valve assembly of carbon dioxide heat pump compressor

Abstract

The utility model provides an exhaust valve assembly of a carbon dioxide heat pump compressor, which comprises a valve plate, an exhaust valve plate and a lift limiter, the valve plate is provided with an exhaust hole and a buffer cavity, the head of the exhaust valve plate is covered on the exhaust hole, the lift limiter is fixed above the exhaust valve plate, and the buffer cavity is arranged on the valve plate. The buffer cavity is located on the lower side of the exhaust valve plate. According to the exhaust valve assembly, the impact between the exhaust valve plate and the lift limiter and between the exhaust valve plate and the valve plate can be reduced, the bending stress at the root of the exhaust valve plate can be reduced, the stress distribution of the exhaust valve is comprehensively improved, the exhaust valve assembly adapts to the severe working condition of the carbon dioxide compressor, and the service life of the exhaust valve assembly is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of semi-hermetic reciprocating compressor technology, and in particular to an exhaust valve assembly for a carbon dioxide heat pump compressor. Background Technology

[0002] Reciprocating compressors are widely used in carbon dioxide heat pump systems due to their excellent sealing properties. The gas valve is a key component of a reciprocating compressor, and improving its economy and reliability is crucial for enhancing the overall performance and extending the service life of the carbon dioxide heat pump compressor.

[0003] Reciprocating compressors rely on the closure of a valve to form a sealed volume. The crankshaft rotation drives the connecting rod to oscillate, and the piston to reciprocate, reducing the volume of the primary unit and thus increasing the gas pressure within the volume. When the pressure reaches the discharge pressure, the valve opens, and gas is discharged until the pressure inside the chamber falls below the discharge pressure, at which point the valve closes. Therefore, the valve plays a crucial role in the entire working cycle. During compressor operation, the valve continuously opens and closes, colliding with the valve plate and lift limiter, generating significant impact stress. Furthermore, the valve plate relies on its own deformation to open and close, and vibrations occur during opening, subjecting the valve plate to constantly changing bending stress. The valve operates under harsh conditions, making it highly susceptible to damage, especially in carbon dioxide heat pump compressors where high inlet and outlet pressures and large operating pressure differentials exacerbate the problem. Moreover, the quality of the valve design also affects inlet and outlet resistance losses, exhaust backflow, and other adverse factors, significantly impacting compressor performance. Therefore, developing a valve suitable for carbon dioxide compressors, addressing the valve's vulnerability, and improving overall efficiency are of paramount importance.

[0004] When the exhaust valve opens, its entire structure is obstructed by a lift limiter. The valve's movement is controlled by adjusting the shape of the lift limiter, thereby reducing both bending and impact stress on the valve plate. However, current research on specific improvements to the lift limiter's shape and the corresponding valve plate design is still limited. Utility Model Content

[0005] The purpose of this utility model is to provide an exhaust valve assembly for a carbon dioxide heat pump compressor, which controls the movement of the valve plate, reduces the vibration intensity of the valve plate, reduces the impact stress generated when the valve plate collides with the lift limiter, reduces the bending stress when the valve is opened and the impact stress between the exhaust valve plate and the valve seat when the valve is closed, adapts to the high pressure and large pressure difference working conditions in the carbon dioxide heat pump compressor, extends the service life of the exhaust valve in the compressor, reduces the overall energy consumption, and improves the overall efficiency.

[0006] According to one objective of this utility model, this utility model provides an exhaust valve assembly for a carbon dioxide heat pump compressor, including a valve plate, an exhaust valve plate, and a lift limiter. The valve plate has an exhaust hole and a buffer chamber. The head of the exhaust valve plate covers the exhaust hole. The lift limiter is fixed above the exhaust valve plate. The buffer chamber is located below the exhaust valve plate.

[0007] Furthermore, the exhaust valve plate includes a valve plate fixing part, a valve plate root part, a valve plate connecting part, and a valve plate head. The arc radius of the valve plate head is smaller than the arc radius of the valve plate fixing part, and the arc of the valve plate connecting part is connected to the arc of the valve plate head and the arc of the valve plate fixing part.

[0008] Furthermore, the buffer chamber is a waist-shaped buffer chamber, which is arranged perpendicular to the length direction of the exhaust valve plate.

[0009] Furthermore, the length of the waist-shaped buffer cavity is 1.5 to 2 times the width of the exhaust valve plate, and the depth of the waist-shaped buffer cavity is 0.8 to 1.2 times the thickness of the exhaust valve plate.

[0010] Furthermore, the length of the straight portion of the waist-shaped buffer cavity is greater than the width of the exhaust valve plate.

[0011] Furthermore, the radius of the arc of the valve head is 1 mm larger than the radius of the exhaust hole.

[0012] Furthermore, the length of the exhaust valve plate is 36 to 40 times the width of the exhaust valve plate.

[0013] Furthermore, the valve plate fixing part is provided with a semi-circular notch on one side.

[0014] Furthermore, the lift limiter includes a limiter fixing part, a limiter root part, a limiter connecting part, and a limiter head, and the limiter fixing part is provided with a limiter mounting hole.

[0015] Furthermore, the slope of the tangent line at each point of the curve at the root of the limiter and the curve at the head of the limiter is less than or equal to the slope of the tangent line at each point of the curve at the connection of the limiter.

[0016] The exhaust valve assembly of this utility model can reduce the impact between the exhaust valve plate and the lift limiter and the valve plate, reduce the bending stress at the root of the exhaust valve plate, comprehensively improve the stress distribution of the exhaust valve, adapt it to the harsh working conditions of the carbon dioxide compressor, and extend the service life of the exhaust valve assembly. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of an embodiment of the present utility model;

[0019] Figure 2 This is a schematic diagram of the valve plate structure in an embodiment of the present utility model;

[0020] Figure 3 This is a schematic diagram of the exhaust port and buffer cavity in an embodiment of the present invention;

[0021] Figure 4 This is a schematic diagram of the structure of the exhaust valve plate in an embodiment of this utility model;

[0022] Figure 5 This is a schematic diagram of the lift limiter according to an embodiment of the present invention;

[0023] In the diagram: 1-valve plate, 2-valve bolt;

[0024] 3-Lift limiter, 31-Limiter fixing part, 32-Limiter root, 33-Limiter connecting part, 34-Limiter head;

[0025] 4-Exhaust valve plate, 41-Valve plate fixing part, 42-Valve plate root, 43-Valve plate connecting part, 44-Valve plate head, 45-Valve plate mounting hole, 46-Notch;

[0026] 5-Exhaust port, 6-Waist-shaped buffer chamber, 7-Valve mounting screw hole, 8-Inlet port, 9-Valve plate mounting hole, 10-Main air inlet, 11-Main exhaust port, 12-Boss, 13-Groove. Detailed Implementation

[0027] The technical solution of this utility model will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0028] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0029] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0030] Example 1

[0031] A carbon dioxide heat pump system mainly consists of four components: a compressor, a condenser, a throttling valve, and an evaporator. The compressor compresses the carbon dioxide, increasing its pressure and dissipating the high-temperature, high-pressure gas. This gas then enters the condenser, where it exchanges heat with the surrounding environment, releasing heat – this is the heat the heat pump utilizes. The carbon dioxide condenses into a liquid in the condenser, releasing heat. After exiting the condenser, it passes through the throttling valve, where its pressure and temperature decrease. It then enters the evaporator, absorbs heat from the environment, and evaporates back into a gas. Finally, it returns to the compressor, completing one cycle. The above description represents only the most basic process. Actual systems may involve various auxiliary components and modifications, improvements, and optimizations, but the underlying principle remains the same.

[0032] In the above system, the compressor is the core, providing power for the entire cycle and being the main moving component. The compressor primarily determines the operating conditions the system can operate under. The compressor is also the main energy-consuming component in the system; therefore, improving compressor performance and efficiency is crucial for reducing overall system energy consumption.

[0033] Carbon dioxide has a low critical temperature and a high critical pressure. When a carbon dioxide heat pump system uses a transcritical carbon dioxide cycle, the heating efficiency will be greatly improved. However, the system pressure will be very high, especially the compressor, which needs to adapt to a high-pressure, large-pressure-difference operating condition, presenting many technical challenges. The gas valve, as a key component of the compressor, is therefore of paramount importance.

[0034] Commercial carbon dioxide heat pump systems typically use reciprocating compressors. For these compressors, the flow of exhaust gas is controlled by an exhaust valve assembly. The crankshaft drives the connecting rod, which in turn causes the piston to reciprocate between the top dead center and bottom dead center of the cylinder. As the piston moves from bottom dead center to top dead center, the gas is compressed, and the pressure increases. When the pressure exceeds the exhaust pressure, the exhaust valve opens, and the compressed, high-temperature, high-pressure gas is discharged from the cylinder. When the pressure inside the cylinder falls below the exhaust pressure, the exhaust valve closes, and no more gas flows out.

[0035] The above process occurs once per revolution of the compressor. The exhaust valve plate is constantly deformed and subjected to alternating bending stress, making it prone to fatigue damage. Furthermore, the exhaust valve plate continuously collides with the lift limiter and valve plate, enduring impact stress. When the exhaust valve is closed, the pressure difference between the upper and lower surfaces of the valve plate causes it to indent towards the exhaust port, also resulting in significant stress. Clearly, the working environment of the exhaust valve is harsh, making it highly susceptible to damage. Moreover, in a carbon dioxide compressor, the high pressure and large pressure difference further exacerbate the risk of exhaust valve failure.

[0036] Based on this, the present invention proposes an exhaust valve assembly for a reciprocating compressor of a carbon dioxide heat pump, in order to solve the problem of easy damage to the exhaust valve of such compressors, reduce the maximum stress of the exhaust valve during the entire working process, reduce the vibration of the exhaust plate, and extend the service life of the exhaust valve assembly.

[0037] like Figures 1-5 As shown, an exhaust valve assembly for a carbon dioxide heat pump compressor includes a valve plate 1, a lift limiter 3, and an exhaust valve plate 4. The lift limiter 3 is disposed on the exhaust valve plate 4, and a valve bolt 2 passes through the lift limiter 3 and the exhaust valve plate 4 to fix the lift limiter 3 and the exhaust valve plate 4 to the valve plate 1.

[0038] like Figure 3 As shown, the valve plate 1 is provided with an exhaust hole 5 and a waist-shaped buffer cavity 6. The waist-shaped buffer cavity 6 is located on one side of the exhaust hole 5. The outer side of the exhaust hole 5 is provided with a boss 12 and a groove 13. The valve plate 1 is also provided with a valve mounting screw hole 7, an air inlet hole 8, a valve plate mounting hole 9, a main air inlet 10, and a main exhaust port 11.

[0039] like Figure 4 As shown, the exhaust valve plate 4 includes a valve plate fixing part 41, a valve plate root part 42, a valve plate connecting part 43 and a valve plate head 44, and a valve plate mounting hole 45 is provided on the valve plate fixing part 41.

[0040] like Figure 5 As shown, the lift limiter 3 includes a limiter fixing part 31, a limiter root part 32, a limiter connecting part 33, and a limiter head 34. The limiter fixing part 31 has a limiter mounting hole. The valve bolt 2 passes through the mounting hole on the limiter fixing part 31 and the mounting hole 45 on the valve plate fixing part 41 and is fixed to the valve plate 1.

[0041] The valve head 44 of the exhaust valve plate 4 covers the exhaust hole 5 on the valve plate 1, and the limiter head 34 of the lift limiter 3 is located directly above the valve head 44. When the valve is opened, the exhaust valve plate 4 deforms and fits against the lift limiter 3, and the limiter head 34 of the lift limiter 3 will collide with the exhaust valve plate 4.

[0042] When the gas pressure inside the cylinder is greater than the exhaust pressure, the exhaust valve opens, and exhaust occurs. At this time, the gas flows out from the exhaust hole 5 on the valve plate 1. Under the impact of the airflow and the pressure difference between the upper and lower surfaces, the valve head 44 of the exhaust valve plate 4 moves upward, thereby causing the valve plate connecting part 43 and the valve plate root 42 to deform and lift upward. Subsequently, the exhaust valve plate 4 collides with the lift limiter 3. After vibrating several times, the exhaust valve plate 4 and the lift limiter 3 are in contact or continue to vibrate slightly. When the cylinder pressure drops below the exhaust pressure, the exhaust valve plate 4 falls back, its deformation returns to normal, and the exhaust valve plate 4 collides with the valve plate 1. The exhaust valve plate 4 covers the exhaust hole 5, sealing off the gas flow.

[0043] In this embodiment, the valve head 44 of the exhaust valve plate 4 covers the exhaust hole 5 on the valve plate 1, and the lift limiter 3 is located above the exhaust valve plate 4, which blocks the movement of the exhaust valve plate 4. The shape of the lift limiter 3 is a combination of multiple curves.

[0044] like Figure 2As shown, in this embodiment, the waist-shaped buffer cavity 6 on the valve plate 1 is located below the valve plate connecting portion 43 of the exhaust valve plate 4, and the position of the waist-shaped buffer cavity 6 is perpendicular to the length direction of the exhaust valve plate 4. Thus, when exhaust ends, the exhaust valve plate 4 falls back towards the valve plate 1. In the waist-shaped buffer cavity 6 directly below the valve plate connecting portion 43 of the exhaust valve plate 4, because the exhaust valve plate 4 moves towards the waist-shaped buffer cavity 6, some gas cannot flow out in time, resulting in a certain degree of compression. This gas generates a certain airflow thrust on the exhaust valve plate 4, reducing the impact speed between the exhaust valve plate 4 and the valve plate 1, thereby reducing impact stress and improving the reliability of the exhaust valve assembly. Simultaneously, the waist-shaped buffer cavity 6 has a waist-shaped hole structure, and its position is perpendicular to the length direction of the exhaust valve plate. In this way, the gas in the waist-shaped buffer cavity 6 can mainly flow out from the semi-circular sides of the waist-shaped buffer cavity, providing a certain thrust to the exhaust valve plate 4 while flowing away in time, without affecting the timely closing of the exhaust valve plate 4. Moreover, the gas will flow out to both sides of the exhaust valve plate 4 in the width direction and will not flow to the exhaust port 5, thus reducing exhaust backflow and improving compressor efficiency.

[0045] In this embodiment, the length of the waist-shaped buffer chamber 6 is 1.5 to 2 times the width of the exhaust valve plate 4, and the depth is 0.8 to 1.2 times the thickness of the exhaust valve plate 4. This reasonable size selection ensures that the waist-shaped buffer chamber 6 functions effectively. The length of the waist-shaped buffer chamber 6 is based on the width of the exhaust valve plate 4. While ensuring that the length of the waist-shaped buffer chamber 6 is greater than the width of the exhaust valve plate 4 to allow gas to flow out, the length cannot be too long to avoid insufficient airflow thrust. The depth of the waist-shaped buffer chamber 6 is based on the thickness of the exhaust valve plate 4, because the thickness determines the stiffness of the exhaust valve plate 4. The greater the thickness, the greater the stiffness. When the exhaust valve plate 4 falls back, the elastic force it generates will increase the impact velocity. Therefore, the depth is based on the thickness; timely increasing the depth allows more gas to be compressed in the waist-shaped buffer chamber 6, effectively increasing the airflow thrust and weakening the impact.

[0046] In this embodiment, the length of the straight section of the waist-shaped buffer cavity 6 is slightly greater than the width of the exhaust valve plate 4. This ensures that the exhaust valve plate 4 does not obstruct the semicircles on both sides of the waist-shaped buffer cavity 6, allowing the airflow to exit relatively smoothly and not affecting the timely closing of the exhaust valve.

[0047] In this embodiment, as Figure 4 As shown, the valve plate fixing part 41, the valve plate connecting part 43 and the valve plate root part 42, and the valve plate head 44 of the exhaust valve plate 4 are all composed of arc structures. In this way, the shape of the exhaust valve plate 4 is entirely composed of arcs, and the size transition is smooth. Since the exhaust valve plate 4 will continuously deform and generate bending stress, using smooth arcs throughout can effectively avoid stress concentration and reduce stress.

[0048] In this embodiment, the radius of the arc of the valve head 44 of the exhaust valve plate is smaller than the radius of the arc of the valve plate fixing part 41. The arcs at the valve root 42 and the valve plate connecting part 43 are respectively connected to the arcs of the valve head 44 and the valve plate fixing part 41, and the arc connections are tangent to each other. Thus, the radius of the arc of the valve plate fixing part 41 is larger, and the valve root 42 is connected to the valve plate fixing part 41, so the width of the valve root 42 is larger. Since the exhaust valve plate 4 is similar to a cantilever beam, the bending stress is greatest at the valve root 42. Increasing the width of the valve root 42 can effectively reduce the stress at this point. At the arc connections of the entire exhaust valve plate 4, the arcs are tangent to each other, which can ensure a smooth transition at all parts of the exhaust valve plate, avoid defects, and reduce stress concentration.

[0049] In this embodiment, the radius of the arc of the valve head 44 of the exhaust valve plate 4 is 1 mm larger than the radius of the exhaust hole 5 on the valve plate 1. Thus, the exhaust valve plate 4 will seal the edge of the exhaust hole 5 by more than 1 mm. Setting the size to 1 mm ensures a good seal, preventing leakage from the exhaust hole, while also preventing the exhaust valve plate 4 from being too large and occupying too much installation space.

[0050] In this embodiment, the length of the exhaust valve plate 4 is 36 to 40 times its width. Thus, selecting the length based on the width of the exhaust valve plate 4 ensures that it possesses suitable rigidity. Furthermore, the length being significantly greater than the width is also intended to maximize the length of the exhaust valve plate 4, thereby minimizing the average deformation of the exhaust valve plate 4 under a given lift and reducing bending stress.

[0051] In this embodiment, the aforementioned "lift" refers to the distance between the center of the exhaust hole 5 and the center of the valve head 44 of the exhaust valve 4 on the surface of the exhaust valve 4 in contact with the valve plate 1 when the exhaust valve plate 4 is fully open.

[0052] In this embodiment, as Figure 4 As shown, the valve plate fixing part 41 of the exhaust valve plate 4 has a semi-circular notch 46 on one side. This allows the front and back sides of the exhaust valve plate 4 to be marked. Since the side of the exhaust valve plate 4 that contacts the valve plate 1 needs to seal the exhaust hole 5, the surface roughness of this side is required to be less than Ra0.2, which is a very high requirement. Other sides do not require this, so only this side is machined to save costs. The semi-circular notch 46 marks the surface that needs to be finely machined, making it easy to distinguish when installing the exhaust valve plate 4. Moreover, the notch 46 is located in the valve plate fixing part 41, where no stress will be generated, so adding the notch 46 will not cause stress concentration.

[0053] In this embodiment, as Figure 5As shown, the profile of the lift limiter 3 consists of a straight line and three curves. The limiter fixing part 31 is a straight structure, which flattens the exhaust valve plate 4 and prevents it from deforming; the limiter root 32, the limiter connecting part 33, and the limiter head 34 each have a corresponding curve, thereby controlling the deformation displacement of the exhaust valve plate 4 at various points, and thus controlling the deformation law of the exhaust valve plate 4, thereby reducing the bending stress and vibration degree of the exhaust valve plate 4.

[0054] In this embodiment, as Figure 5 As shown, the slopes of the tangents at all points on the curves of the limiter root 32 and the limiter head 34 of the lift limiter 3 are less than or equal to the slopes of the tangents at all points on the curve of the limiter connection 33. The smaller slopes of the tangents at the limiter root 32 of the lift limiter 3 are to reduce the deformation of the valve root 42 of the exhaust valve plate 4 and reduce the stress on the valve root 42. The smaller slopes of the tangents at the limiter head 34 are because the valve head 44 of the exhaust valve plate 4 has the largest movement distance and the most intense collision; a smaller slope allows for a larger contact area when the valve head 44 of the exhaust valve plate 4 collides with the lift limiter 3, thereby reducing impact stress. The tangency between the curve segments ensures that the lift limiter is subjected to reasonable force, avoids stress concentration, and also allows for smooth deformation of the exhaust valve plate 4.

[0055] In this embodiment, the exhaust valve assembly is used in a semi-hermetic reciprocating heat pump compressor. This type of compressor is bolted together, sealed with gaskets, and can be disassembled for maintenance. The motor and crankcase are housed in the same housing, preventing leakage at the shaft seal. The exhaust valve assembly of this invention is used in this type of compressor. The semi-hermetic reciprocating heat pump compressor is used in a transcritical carbon dioxide cycle system. This cycle is more efficient but has high pressure and a large pressure differential. This invention can adapt to such high-pressure, large-pressure-differential operating conditions and can be used in compressors within transcritical carbon dioxide cycle systems.

[0056] When the exhaust valve plate falls back, the waist-shaped buffer chamber located below the exhaust valve plate connection on the valve plate can form an air cushion. When the valve plate impacts the valve plate, the gas in the buffer chamber is compressed to a certain extent, the pressure increases, and a force is generated on the valve plate in the opposite direction to the valve plate's closing direction, thereby reducing the impact speed of the exhaust valve plate and reducing impact stress. At the same time, the waist-shaped shape allows gas to flow away from both sides of the buffer chamber, reducing the impact without affecting the timely closing of the exhaust valve and reducing losses caused by exhaust backflow.

[0057] When the valve opens, due to the different curvatures of the lift limiter profile at various points, the curvature of the curve at the connection point is greater than that at the root and the head. The exhaust valve plate will first contact the root of the lift limiter. When it is about to be fully opened and the exhaust valve plate is in contact with the lift limiter, the head of the exhaust valve plate will collide with the lift limiter with a larger area, reducing the impact stress.

[0058] When the exhaust valve opens, the root of the exhaust valve plate first comes into contact with the lift limiter, the free movement length of the exhaust valve plate decreases, and the stiffness of the valve plate increases. This increases the elasticity of the exhaust valve plate itself, thereby slowing down the collision between the valve plate and the lift limiter.

[0059] Because the fixed part of the exhaust valve plate has a large radius of curvature and the head part has a small radius of curvature, the two are connected by a larger radius of curvature, avoiding stress concentration caused by the small radius of curvature at the connection between the connecting part and the head part. The larger radius of curvature of the fixed part makes the root of the valve plate wider, and with the smaller curvature and lower height at the root of the rise limiter, the bending stress at the root can be significantly reduced.

[0060] The exhaust valve head is far from the fixed part, and its movement displacement is the greatest, making it most prone to severe vibration. In contrast, the slope of the tangent line between the root and head of the lift limiter is relatively small, allowing the exhaust valve head to fit better with the lift limiter, thereby reducing the amplitude of vibration.

[0061] The radius of the arc at the head of the exhaust valve plate is more than 1mm larger than the radius of the exhaust port. The reasonable size selection ensures that the leakage from the exhaust valve is minimal when the exhaust valve is closed, while also ensuring that the exhaust valve plate is not too large and does not occupy the limited installation area.

[0062] The exhaust valve assembly of this invention can reduce the impact between the exhaust valve plate and the lift limiter and the valve plate, reduce the bending stress at the root of the exhaust valve plate, comprehensively improve the stress distribution of the exhaust valve, adapt it to the harsh working conditions of the carbon dioxide compressor, and extend the service life of the exhaust valve assembly.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. An exhaust valve assembly for a carbon dioxide heat pump compressor, characterized in that, It includes a valve plate, an exhaust valve plate, and a lift limiter. The valve plate has an exhaust hole and a buffer chamber. The head of the exhaust valve plate covers the exhaust hole. The lift limiter is fixed above the exhaust valve plate. The buffer chamber is located below the exhaust valve plate.

2. The exhaust valve assembly of the carbon dioxide heat pump compressor according to claim 1, characterized in that, The exhaust valve includes a valve fixing part, a valve root part, a valve connecting part, and a valve head. The radius of the arc of the valve head is smaller than the radius of the arc of the valve fixing part, and the arc of the valve connecting part is connected to the arc of the valve head and the arc of the valve fixing part.

3. The exhaust valve assembly of the carbon dioxide heat pump compressor according to claim 1, characterized in that, The buffer chamber is a waist-shaped buffer chamber, and the waist-shaped buffer chamber is arranged perpendicular to the length direction of the exhaust valve plate.

4. The exhaust valve assembly of the carbon dioxide heat pump compressor according to claim 3, characterized in that, The length of the waist-shaped buffer cavity is 1.5 to 2 times the width of the exhaust valve plate, and the depth of the waist-shaped buffer cavity is 0.8 to 1.2 times the thickness of the exhaust valve plate.

5. The exhaust valve assembly of the carbon dioxide heat pump compressor according to claim 4, characterized in that, The length of the straight section of the waist-shaped buffer cavity is greater than the width of the exhaust valve plate.

6. The exhaust valve assembly of the carbon dioxide heat pump compressor according to claim 2, characterized in that, The radius of the arc at the head of the valve disc is 1 mm larger than the radius of the exhaust port.

7. The exhaust valve assembly of the carbon dioxide heat pump compressor according to claim 1, characterized in that, The length of the exhaust valve plate is 36 to 40 times the width of the exhaust valve plate.

8. The exhaust valve assembly of the carbon dioxide heat pump compressor according to claim 2, characterized in that, The valve plate fixing part is provided with a semi-circular notch on one side.

9. The exhaust valve assembly of the carbon dioxide heat pump compressor according to claim 1, characterized in that, The lift limiter includes a limiter fixing part, a limiter root part, a limiter connecting part, and a limiter head. The limiter fixing part has a limiter mounting hole.

10. The exhaust valve assembly of the carbon dioxide heat pump compressor according to claim 9, characterized in that, The slope of the tangent line at the root of the limiter and the curve at the head of the limiter is less than or equal to the slope of the tangent line at the connecting part of the limiter.

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