Two-stage screw compressor and air conditioning system

Abstract

The application provides a two-stage screw compressor and an air conditioning system. The two-stage screw compressor comprises a shell provided with an air inlet port and an air outlet port; a low-pressure stage screw set arranged in the shell in an axial direction and connected to the air inlet port; a high-pressure stage screw set arranged in the shell in an axial direction and connected to the air outlet port; a driving motor arranged in the shell in an axial direction; and a transmission gear set for transmitting torque provided by the driving motor to the low-pressure stage screw set and the high-pressure stage screw set; wherein the driving motor, the low-pressure stage screw set and the high-pressure stage screw set are arranged on the same side of the transmission gear set in an axial direction. The two-stage screw compressor and the air conditioning system with the same have a greatly reduced axial dimension, effectively improving the space utilization and reducing the size of the unit.

Description

Technical Field

[0001] This invention relates to the field of air conditioning, and more specifically, to a two-stage screw compressor and an air conditioning system having the same. Background Technology

[0002] Currently, refrigeration systems and related equipment are widely used in various temperature control fields, including residential air conditioning, commercial air conditioning, cold chain transportation, and cryogenic storage. For applications with low evaporation temperatures and high cooling capacity requirements, such as freezing and refrigeration, and low-temperature environment laboratories, large-scale refrigeration equipment is typically required. As the power supply device within these large-scale refrigeration systems, two-stage or three-stage screw compressors are generally selected to handle the relatively higher loads.

[0003] In a common two-stage screw compressor, the two rotors can be connected in series using a coupling. In this case, to ensure the coupling installation does not interfere, and considering the considerable length occupied by the series arrangement of the screw units, the unit itself needs to be designed with a larger volume. Furthermore, misalignment of the coupling can lead to increased noise and affect compressor operation, ultimately resulting in reduced compressor efficiency. Summary of the Invention

[0004] The present invention aims to provide a two-stage screw compressor and air conditioning system to at least partially solve or alleviate the problems existing in the prior art.

[0005] To achieve at least one objective of this application, according to one aspect of this application, a two-stage screw compressor is provided, comprising: a housing having an inlet port and an outlet port thereon; a low-pressure stage screw assembly axially disposed within the housing and connected to the inlet port; a high-pressure stage screw assembly axially disposed within the housing and connected to the outlet port; a drive motor axially disposed within the housing; and a transmission gear set for simultaneously transmitting the torque provided by the drive motor to the low-pressure stage screw assembly and the high-pressure stage screw assembly; wherein the drive motor, the low-pressure stage screw assembly, and the high-pressure stage screw assembly are axially arranged on the same side of the transmission gear set.

[0006] In addition to one or more of the features described above, or as an alternative, in another embodiment, the low-pressure stage screw assembly and the high-pressure stage screw assembly are arranged on the same side of the vertical plane containing the axis of the drive motor.

[0007] In addition to one or more of the features described above, or as an alternative, in another embodiment, the low-pressure stage screw assembly is arranged below the high-pressure stage screw assembly.

[0008] In addition to one or more of the features described above, or as an alternative, in another embodiment, the transmission gear set includes: a driving gear connected to the drive motor; a low-pressure driven gear connected to the low-pressure driving screw of the low-pressure screw set; and a high-pressure driven gear connected to the high-pressure driving screw of the high-pressure screw set; wherein the tooth ratio of the driving gear to the low-pressure driven gear is greater than the tooth ratio of the driving gear to the high-pressure driven gear.

[0009] In addition to one or more of the features described above, or as an alternative, in another embodiment, the tooth ratio of the driving gear to the low-pressure driven gear is 1:1 to 10:1; and / or the tooth ratio of the driving gear to the high-pressure driven gear is 0.5:1 to 9:1.

[0010] In addition to one or more of the features described above, or as an alternative, in another embodiment, a compression flow path is formed within the housing sequentially via the intake port, a first cavity accommodating the low-pressure stage screw assembly, a second cavity accommodating the drive motor, a third cavity accommodating the high-pressure stage screw assembly, and the exhaust port.

[0011] In addition to one or more of the features described above, or as an alternative, in another embodiment, an intermediate air inlet is provided on the housing, which is connected to the second cavity.

[0012] In addition to one or more of the features described above, or as an alternative, in another embodiment, the intake port is radially connected to the low-pressure stage drive screw of the low-pressure stage screw assembly.

[0013] In addition to one or more of the features described above, or as an alternative, in another embodiment, the exhaust port is axially connected to the high-pressure stage driven screw of the high-pressure stage screw assembly.

[0014] To achieve at least one objective of this application, according to another aspect of this application, an air conditioning system is also provided, comprising: a two-stage screw compressor as described above.

[0015] According to the two-stage screw compressor of this application, on the one hand, the torque of the drive motor is simultaneously transmitted to the low-pressure stage screw assembly and the high-pressure stage screw assembly via a transmission gear set, improving the traditional series screw arrangement to a parallel screw arrangement, effectively shortening the axial dimension of the compressor; on the other hand, compared with the traditional direct connection between the motor and the screws, the gear transmission method can achieve a change in transmission direction, thereby arranging the drive motor, the low-pressure stage screw assembly, and the high-pressure stage screw assembly axially on the same side of the transmission gear set, which further reduces the axial dimension of the compressor. This arrangement transforms the overall space occupied from a cuboid-like shape to a cube-like shape, effectively improving space utilization and reducing the unit size. The air conditioning system of the two-stage screw compressor with this arrangement also has corresponding technical benefits. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of one embodiment of the two-stage screw compressor of this application.

[0017] Figure 2 This is a schematic diagram of an embodiment of the two-stage screw compressor of this application, wherein part of the housing outside the transmission gear set is omitted.

[0018] Figure 3 This is a schematic diagram of an embodiment of the two-stage screw compressor of this application, wherein the transmission gear set, the low-pressure stage screw set, and part of the outer housing of the high-pressure stage screw set are omitted.

[0019] Figures 4 to 10 The various stages of the refrigerant flow path within the two-stage screw compressor of this application are shown from different cross-sections and perspectives. Detailed Implementation

[0020] The present application will now be described in detail with reference to exemplary embodiments shown in the accompanying drawings. However, it should be understood that the present application may be implemented in many different forms and should not be construed as limited to the embodiments set forth herein. These embodiments are provided herein to make the disclosure of the present application more complete and exhaustive, and to fully convey the concept of the present application to those skilled in the art.

[0021] Furthermore, for any single technical feature described or implied in the embodiments mentioned herein, or any single technical feature shown or implied in the various figures, this application still allows for any combination or deletion of these technical features (or their equivalents) without any technical obstacle, thereby obtaining more other embodiments of this application that may not be directly mentioned herein.

[0022] To facilitate the description of the embodiments mentioned herein, axial, radial, and vertical coordinates are introduced as a reference coordinate system. These directions are described to express the structural characteristics of each component and the relative positional relationships between components, rather than to restrictively constrain their absolute positional relationships. Figure 3 In the two-stage screw compressor illustrated, the screw is used as an example. The axial direction refers to the direction of the screw's axis of rotation, or the direction of its length extension, while the radial direction refers to the direction of the screw perpendicular to the axial direction, or the direction of its radius extension. Furthermore, the two-stage screw compressor illustrated is vertical from bottom to top. To more clearly illustrate the positional relationships, some figures show the axial direction as the X-axis, the radial direction as the Y-axis, and the vertical direction as the Y-axis.

[0023] See Figures 1 to 3 This illustration shows an embodiment of a two-stage screw compressor according to the present application. The two-stage screw compressor 100 includes a housing 110 and a low-pressure stage screw assembly 120, a high-pressure stage screw assembly 130, a drive motor 140, and a transmission gear set 150 disposed within the housing 110. The housing is also provided with an inlet port 111 and an outlet port 112, wherein the inlet port 111 is connected to the low-pressure stage screw assembly 120, and the outlet port 112 is connected to the high-pressure stage screw assembly 130, so that fluid flows into the compressor 100 and flows out of the compressor 100 after compression.

[0024] The low-pressure stage screw assembly 120 includes a low-pressure stage driving screw 121 and a low-pressure stage driven screw 122 that mesh with each other, and there is a compression chamber between the meshing parts of the two for fluid to flow through. The air inlet port 111 is connected to the low-pressure stage driven screw 122 of the low-pressure stage screw assembly 120 in a radial Y direction so as to realize the first stage compression of the fluid flowing in from here.

[0025] The high-pressure stage screw assembly 130 includes a high-pressure stage driving screw 131 and a high-pressure stage driven screw 132 that mesh with each other, and there is a compression chamber between the meshing parts of the two for fluid to flow through, so as to realize the second stage compression of the fluid that flows into the chamber after undergoing the first stage compression. The exhaust port 112 is connected to the high-pressure stage driven screw 132 of the high-pressure stage screw assembly 130 along the axial direction X, thereby guiding the fluid after undergoing the second stage compression to flow out of the two-stage screw compressor 100.

[0026] To enable the transmission of power between the drive motor 140 and the screw assembly, the transmission gear set 150 can be connected to the drive motor 140, the low-voltage screw assembly 120 and the high-voltage screw assembly 130 respectively, thereby enabling the torque provided by the drive motor 140 to be transmitted to both the low-voltage screw assembly 120 and the high-voltage screw assembly 130 simultaneously.

[0027] In addition, in order to optimize the space inside the compressor and achieve a compact and reasonable arrangement of various components, the low-pressure stage screw assembly 120, the high-pressure stage screw assembly 130 and the drive motor 140 can all be axially (X) arranged inside the housing 110, and the drive motor 140, the low-pressure stage screw assembly 120 and the high-pressure stage screw assembly 130 are arranged on the same side of the transmission gear set 150 along the axial direction X.

[0028] In this arrangement, on the one hand, the torque of the drive motor is simultaneously transmitted to both the low-pressure and high-pressure screw stages via a transmission gear set, improving the traditional series screw arrangement to a parallel screw arrangement, effectively shortening the axial dimension of the compressor. On the other hand, compared to the traditional direct connection between the motor and screws, the gear transmission method allows for a change in transmission direction, enabling the drive motor, low-pressure screw stage, and high-pressure screw stage to be arranged axially on the same side of the transmission gear set. This further reduces the axial dimension of the compressor. This arrangement transforms the overall space occupied from a cuboid-like shape to a cube-like shape, effectively improving space utilization and reducing the unit size.

[0029] The following will illustrate further modifications to the two-stage screw compressor by way of example, in order to further improve its efficiency, reliability, or for other improvements.

[0030] For example, to further optimize the compactness of the compressor housing, the low-pressure stage screw assembly 120 and the high-pressure stage screw assembly 130 can be arranged on the same side of the drive motor 140. Considering that the radial dimension of the drive motor is usually larger than that of the low-pressure stage screw assembly 120 and the high-pressure stage screw assembly 130, this arrangement can more rationally allocate the arrangement space along the radial Y direction within the housing. More specifically, one of the low-pressure stage screw assembly 120 and the high-pressure stage screw assembly 130 can be arranged below the other. In this case, the three are arranged in a roughly triangular manner along the radial Y direction, making full use of the radial space while significantly shortening its axial length. Since the low-pressure chamber corresponding to the low-pressure stage screw assembly 120 usually needs to be equipped with an unloading valve for pressure relief, when it is arranged at the bottom, the unloading valve can be directly installed at the bottom of the housing. However, if the low-pressure stage screw assembly 120 is arranged at the top, additional space needs to be reserved for the unloading valve, which will result in a slight increase in compactness. Therefore, it is recommended to arrange the low-pressure stage screw assembly 120 below the high-pressure stage screw assembly 130.

[0031] For example, as a specific implementation of the transmission gear set 150, it may include a driving gear 151 fixedly connected to the output shaft of the drive motor 140, a low-pressure driven gear 152 fixedly connected to the end of the low-pressure driven screw 121 of the low-pressure driven screw set 120, and a high-pressure driven gear 153 fixedly connected to the end of the high-pressure driven screw 131 of the high-pressure driven screw set 130; wherein the gear ratio of the driving gear 151 to the low-pressure driven gear 152 is greater than the gear ratio of the driving gear 151 to the high-pressure driven gear 153. In this case, the driving gear 151 is driven by the drive motor 140, rotates along with its output shaft, and transmits torque to both the low-pressure driven gear 152 and the high-pressure driven gear 153 in a meshing relationship. Because the low-pressure stage driven gear 152 has fewer teeth than the high-pressure stage driven gear 153, under the same drive gear transmission, the low-pressure stage driven gear 152 rotates faster, causing the corresponding low-pressure stage drive screw 121 and its mating low-pressure stage driven screw 122 to rotate rapidly and compress the fluid at low pressure. Conversely, the high-pressure stage driven gear 153 rotates slower but has greater torque, causing the corresponding high-pressure stage drive screw 131 and its mating high-pressure stage driven screw 132 to rotate slowly and compress the fluid at high pressure. More specifically, the tooth ratio of the drive gear 151 to the low-pressure stage driven gear 152 is 1:1 to 10:1; and / or the tooth ratio of the drive gear 151 to the high-pressure stage driven gear 153 is 0.5:1 to 9:1. This allows for synchronous drive of the two-stage compression screw assembly and effectively achieves the compression difference between them and the overall compression efficiency of the compressor.

[0032] For example, in one instance, a specific compression flow path can be formed within the housing 110 to guide the flow and compression of the fluid. Specifically, this compression flow path can be formed sequentially via an inlet port 111, a first chamber 110a accommodating the low-pressure stage screw assembly 120, a second chamber 110b accommodating the drive motor 140, a third chamber 110c accommodating the high-pressure stage screw assembly 130, and an exhaust port 112.

[0033] Based on this, in order to achieve the gas replenishment and enthalpy increase effect of the two-stage compressor, an intermediate stage gas replenishment port 113 can be provided on the casing 110 of the compressor, which is connected to the second cavity 110b along the axial direction X, so that the gas phase fluid formed by flash evaporation of the economizer can be introduced into the compressor.

[0034] The following is combined with the appendix Figures 4 to 10 This diagram describes the compression process of the fluid to be compressed (using refrigerant as an example) within the two-stage screw compressor of this application. Arrows in the diagram indicate the direction of refrigerant flow. First, see... Figures 4 to 5Low-pressure refrigerant is drawn into the first chamber 110a of the two-stage screw compressor radially Y through the inlet port 111, and is compressed by the low-pressure screw assembly 120 disposed within the first chamber 110a during its axial flow along the X direction. (Continue to see...) Figures 6 to 7 After the first stage of compression, the refrigerant flows radially Y into the second chamber 110b, where the drive motor 140 is located. Simultaneously, if the gas injection function is activated, external gaseous refrigerant also flows into the second chamber 110b through the intermediate stage gas injection port 113, where it mixes thoroughly with the refrigerant after the first stage compression. See next... Figures 8 to 9 The mixed refrigerant is then guided from the second chamber 110b to the third chamber 110c, where the high-pressure stage screw assembly 130 is located. See last for further details. Figure 10 The refrigerant entering the third chamber 110c is compressed by the high-pressure screw assembly 130 located in the third chamber 110c as it flows along the axial direction X. After completing two stages of compression, the refrigerant flows out of the two-stage screw compressor 100 through the exhaust port 112.

[0035] Furthermore, although not shown in the figures, an embodiment of an air conditioning system according to this application is also provided herein. This air conditioning system includes the two-stage screw compressor described in any of the foregoing embodiments or combinations thereof, and thus also possesses the corresponding technical effects, which will not be elaborated further here.

[0036] It should be understood by those skilled in the art that the air conditioning system proposed in this application does not narrowly refer to air conditioners used in buildings that have outdoor cooling / heating units and indoor heat exchange units. Rather, it should be understood as a type of thermodynamic system that achieves air conditioning function, driven by various power sources (such as electricity), and achieves heat exchange with the air at the location to be conditioned through the phase change of the refrigerant within the system. For example, when this air conditioning system is used in building HVAC, it may be a refrigeration system with cooling function only, or it may be a heat pump system with both cooling and heating capabilities. Furthermore, when this air conditioning system is used in the cold chain field, it may be a transport refrigeration system, or it may be a refrigeration / freezing system. However, regardless of the specific form of the air conditioning system, a two-stage screw compressor is required for the concept of this application to be applicable.

[0037] The above examples primarily illustrate the two-stage screw compressor and air conditioning system of the present invention. Although only some embodiments of the invention have been described, those skilled in the art will understand that the invention can be implemented in many other forms without departing from its spirit and scope. Therefore, the examples and embodiments shown are to be considered illustrative rather than restrictive, and the invention may encompass various modifications and substitutions without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A two-stage screw compressor, characterized in that The two-stage screw compressor comprises: a housing, on which an intake port and an exhaust port are arranged; a low-pressure stage screw set arranged in the housing in an axial direction and connected to the intake port; a high-pressure stage screw set arranged in the housing in an axial direction and connected to the exhaust port; a driving motor arranged in the housing in an axial direction; and a transmission gear set for transmitting torque provided by the driving motor to the low-pressure stage screw set and the high-pressure stage screw set at the same time; wherein the driving motor, the low-pressure stage screw set and the high-pressure stage screw set are arranged on the same side of the transmission gear set in an axial direction; wherein a compression flow path is formed in the housing in sequence via the intake port, a first cavity accommodating the low-pressure stage screw set, a second cavity accommodating the driving motor, a third cavity accommodating the high-pressure stage screw set and the exhaust port; wherein an intermediate stage air supplement port is further arranged on the housing and connected to the second cavity.

2. A two-stage screw compressor according to claim 1, characterized in that The low-pressure stage screw set and the high-pressure stage screw set are arranged on the same side of a vertical plane in which an axis of the driving motor is located.

3. A two-stage screw compressor according to claim 2, characterized in that The low-pressure stage screw set is arranged below the high-pressure stage screw set.

4. A two-stage screw compressor according to claim 1, characterized in that The transmission gear set comprises: a driving gear connected to the driving motor; a low-pressure stage driven gear connected to a low-pressure stage driving screw of the low-pressure stage screw set; and a high-pressure stage driven gear connected to a high-pressure stage driving screw of the high-pressure stage screw set; wherein a tooth number ratio of the driving gear to the low-pressure stage driven gear is greater than a tooth number ratio of the driving gear to the high-pressure stage driven gear.

5. The two-stage screw compressor according to claim 4, wherein the tooth number ratio of the driving gear to the low-pressure stage driven gear is 1:1 to 10:1; and / or the tooth number ratio of the driving gear to the high-pressure stage driven gear is 0.5:1 to 9:

1.

6. Two-stage screw compressor according to any of claims 1 to 5, characterized in that The intake port is connected to a low-pressure stage driving screw of the low-pressure stage screw set in a radial direction.

7. A two-stage screw compressor according to any one of claims 1 to 5, characterized in that The exhaust port is connected to a high-pressure stage driven screw of the high-pressure stage screw set in an axial direction.

8. An air conditioning system characterized by, The two-stage screw compressor according to any one of claims 1 to 7. ​

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