CN221879725U - Centrifugal compressors and refrigeration equipment - Google Patents

Abstract

The utility model provides a centrifugal compressor and refrigeration equipment, the centrifugal compressor comprises a shell, an impeller assembly and a guide vane assembly, a compression cavity and a first-stage runner communicated with the compression cavity are arranged in the shell, the impeller assembly is rotatably arranged in the compression cavity, the impeller assembly comprises a first-stage impeller and a second-stage impeller, the gas outflow side of the first-stage impeller is communicated with the gas inflow side of the second-stage impeller through the first-stage runner, the guide vane assembly is arranged in the first-stage runner, and the guide vane assembly is used for guiding the airflow in the first-stage runner to flow so as to reduce the pressure loss of the airflow during flow. The impeller assembly is of an integrated structure, the impeller assembly is provided with two-stage impellers, the two-stage impellers are integrally milled or cast into a whole, the impeller assembly is simple to manufacture and low in cost, the number of compressor assemblies is reduced, and the assembly is convenient to install and maintain.

Description

Centrifugal compressors and refrigeration equipment

Technical Field

The utility model relates to the technical field of compressors, in particular to a centrifugal compressor. The utility model also relates to a refrigeration device.

Background Art

This section merely provides background information related to the present disclosure and is not necessarily prior art.

At present, the two-stage centrifugal compressors in the refrigeration industry mainly adopt two structural forms. One is that the two-stage impellers are hung at both ends of the motor in a back-to-back manner, and the other is that the two-stage impellers are hung at one end of the motor in a tandem manner, and the two-stage impellers are connected by a blade returner in the middle. There are two obvious defects in the existing technical solutions. First, the cost of the existing two-stage impeller is relatively high. Second, the existing impeller structure has many components, the structure is not compact enough, and the installation is complicated.

Utility Model Content

The purpose of the utility model is to at least solve the technical problem that the existing centrifugal compressor has a large gas flow pressure loss, resulting in low overall efficiency. This purpose is achieved through the following technical solutions:

The first aspect of the utility model provides a centrifugal compressor, the centrifugal compressor comprising:

A shell, wherein a compression chamber and a primary flow channel communicating with the compression chamber are provided in the shell;

an impeller assembly rotatably disposed in the compression chamber, the impeller assembly comprising a primary impeller and a secondary impeller, and a gas outflow side of the primary impeller and a gas inlet side of the secondary impeller are connected through the primary flow channel;

A guide vane assembly is arranged in the primary flow channel, and the guide vane assembly is used to guide the airflow in the primary flow channel to reduce the pressure loss of the airflow.

The centrifugal compressor of the utility model has a primary impeller and a secondary impeller. A guide vane assembly is provided in a primary flow channel connecting the primary impeller and the secondary impeller. The guide vane assembly can guide the airflow in the primary flow channel to make the airflow distribution in the primary flow channel more uniform and the flow more stable. For example, the guide vane assembly is provided at the turning point of the primary flow channel and the outlet end of the primary flow channel to organize the airflow therein so that the airflow distribution is uniform and the flow direction is stable, thereby reducing the pressure loss of the airflow flowing in the primary flow channel, thereby improving the efficiency of the centrifugal compressor.

In addition, the centrifugal compressor according to the utility model may also have the following additional technical features:

In some embodiments of the present invention, the primary flow channel includes a diffuser section and a flow channel section, the inlet end of the diffuser section is connected to the gas outflow side of the primary impeller, the outlet end of the diffuser section is connected to the inlet end of the flow channel section, and the outlet end of the flow channel section is connected to the gas inlet side of the secondary impeller.

In some embodiments of the present invention, the flow channel section includes a first flow channel and a second flow channel, the inlet end of the second flow channel is connected to the diffuser section, the outlet end of the second flow channel is connected to the first flow channel, the first flow channel is arranged on the radial outside of the gas inlet side of the secondary impeller, the first flow channel extends circumferentially along the gas inlet side of the secondary impeller, the first flow channel is connected to the gas inlet side of the secondary impeller, and the angle of the circumferential extension of the first flow channel along the gas inlet side of the secondary impeller is less than 360°.

In some embodiments of the present invention, the guide vane assembly includes a plurality of first guide vanes, wherein the plurality of first guide vanes are arranged inside a first flow channel, the plurality of first guide vanes are arranged at circumferential intervals along the first flow channel, the curvature of at least one of the plurality of first guide vanes is different from the curvature of other first guide vanes, and the first guide vanes are used to guide the gas in the first flow channel to the gas inlet side of the secondary impeller.

In some embodiments of the present invention, the length of the first guide plate is proportional to the maximum distance from the first guide plate to the gas outflow side of the second flow channel.

In some embodiments of the utility model, the flow channel section also includes a third flow channel, the third flow channel has a straight tube structure, the second flow channel is connected to the first flow channel through the third flow channel, and the guide vane assembly also includes a second guide vane, the second guide vane is arranged in the third flow channel, and the second guide vane is arranged deviating from the central axis of the third flow channel.

In some embodiments of the present invention, the guide vane assembly further includes a third guide vane, the third guide vane is disposed in the first flow channel, and the third guide vane is coplanar with the second guide vane.

In some embodiments of the present invention, the guide vane assembly further includes a fourth guide vane, and the fourth guide vane is disposed in the second flow channel, and the fourth guide vane is disposed offset from a central axis of the second flow channel.

In some embodiments of the utility model, the first-stage impeller and the second-stage impeller are an integrated structure, the first-stage working surface of the first-stage impeller is arranged opposite to the second-stage working surface of the second-stage impeller, and the side of the first-stage impeller facing away from the first-stage working surface is connected to the side of the second-stage impeller facing away from the second-stage working surface.

The second aspect of the utility model provides a refrigeration device, comprising the centrifugal compressor provided in the first aspect of the utility model.

The refrigeration device provided in the second aspect of the utility model has the same beneficial effects as the centrifugal compressor provided in the first aspect of the utility model.

BRIEF DESCRIPTION OF THE DRAWINGS

By reading the detailed description of the preferred embodiment below, various other advantages and benefits will become clear to those of ordinary skill in the art. The accompanying drawings are only used for the purpose of illustrating the preferred embodiment and are not to be considered as limiting the present invention. Moreover, the same reference numerals are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

FIG1 schematically shows a structural diagram of a centrifugal compressor from a first viewing angle according to an embodiment of the present utility model;

FIG2 schematically shows a structural diagram of a centrifugal compressor from a first viewing angle according to an embodiment of the present utility model;

FIG3 schematically shows a structural diagram of a centrifugal compressor according to an embodiment of the present utility model from a third viewing angle;

FIG4 schematically shows a cross-sectional structural diagram along the line A of FIG3 ;

FIG5 schematically shows a partially enlarged cross-sectional view of the structure at A in FIG4 ;

FIG6 schematically shows a schematic structural diagram of an impeller assembly according to an embodiment of the present utility model from a first viewing angle;

FIG7 schematically shows a structural diagram of an impeller assembly from a second viewing angle according to an embodiment of the present utility model;

FIG8 schematically shows a cross-sectional structural diagram of a flow channel section according to an embodiment of the present utility model;

100. Shell;

10. Compression chamber; 11. Driving shaft;

20. Primary flow channel; 21. Diffuser section; 22. Flow channel section; 221. First flow channel; 222. Second flow channel; 223. Third flow channel; 224. Notch; 225. First guide vane; 226. Second guide vane; 227. Third guide vane; 228. Fourth guide vane; 23. Secondary flow channel; 24. Sealing structure; 25. Air supply channel;

30. First-stage impeller; 301. First-stage working surface; 302. First wheel disc; 303. First blade; 31. Second-stage impeller; 311. Second-stage working surface; 312. Second wheel disc; 313. Second blade.

DETAILED DESCRIPTION

The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

It should be understood that the terms used herein are only for the purpose of describing specific example embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "include", "comprise", "contain", and "have" are inclusive, and therefore specify the existence of stated features, steps, operations, elements and/or parts, but do not exclude the existence or addition of one or more other features, steps, operations, elements, parts, and/or combinations thereof. The method steps, processes, and operations described herein are not interpreted as necessarily requiring them to be performed in the specific order described or illustrated, unless the execution order is clearly indicated. It should also be understood that additional or alternative steps may be used.

Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

For ease of description, spatial relative terms may be used herein to describe the relationship of one element or feature relative to another element or feature as shown in the figure, such as "inside", "outside", "inner side", "outer side", "below", "below", "above", "above", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure is turned over, then the elements described as "below other elements or features" or "below other elements or features" will subsequently be oriented as "above other elements or features" or "above other elements or features". Therefore, the example term "below..." can include both upper and lower orientations. The device can be oriented otherwise (rotated 90 degrees or in other directions) and the spatial relative descriptors used in the text are interpreted accordingly.

As shown in FIG. 1 to FIG. 8 , according to an embodiment of the present invention, the present invention provides a centrifugal compressor, which includes:

A housing 100, wherein a compression chamber 10 and a primary flow passage 20 communicating with the compression chamber 10 are provided in the housing 100;

An impeller assembly is rotatably disposed in the compression chamber 10, and the impeller assembly includes a primary impeller 30 and a secondary impeller 31, and a gas outflow side of the primary impeller 30 is connected with a gas inlet side of the secondary impeller 31 through a primary flow channel 20;

The guide vane assembly is arranged in the primary flow channel, and is used to guide the airflow in the primary flow channel to reduce the pressure loss of the airflow when it flows.

It is understandable that the housing 100 is the outer shell of the compressor, which can be made by casting or milling. The housing 100 can be assembled by two half shells. Inside the housing 100, the inner wall of the housing 100 defines a compression chamber 10, which is used to accommodate the impeller assembly. Therefore, the shape of the compression chamber 10 is adapted to the impeller assembly and can be cylindrical. One axial end of the compression chamber 10 is the inlet of the centrifugal compressor for gas or gas inhalation. The other axial end of the compression chamber 10 can be provided with a drive shaft 11 to connect the motor. The motor drives the drive shaft to rotate, and then drives the impeller assembly to rotate, so as to generate centrifugal force to inhale the gas or gas into the impeller assembly. The impeller assembly includes a primary impeller 30 and a secondary impeller 31. The primary impeller 30 and the secondary impeller 31 are integrally formed and can be made by casting or milling. The primary impeller 30 and the secondary impeller 31 can adopt open impellers to reduce production difficulty and cost. The primary impeller 30 is connected to the secondary impeller 31 through the primary flow channel 20, and the primary flow channel 20 is defined by the inner wall of the shell 100. One end of the primary flow channel 20 can be connected to the outlet end of the primary impeller 30, that is, the primary flow channel 20 corresponds to the circumferential outer position of the primary impeller 30, and the other end of the primary flow channel 20 can be connected to the inlet end of the secondary impeller 31, that is, the other end of the primary flow channel 20 corresponds to the rotation center of the secondary impeller 31 and is coaxially arranged.

The centrifugal compressor of the utility model has a primary impeller and a secondary impeller. A guide vane assembly is provided in a primary flow channel connecting the primary impeller and the secondary impeller. The guide vane assembly can guide the airflow in the primary flow channel to make the airflow distribution in the primary flow channel more uniform and the flow more stable. For example, the guide vane assembly is provided at the turning point of the primary flow channel and the outlet end of the primary flow channel to organize the airflow therein so that the airflow distribution is uniform and the flow direction is stable, thereby reducing the pressure loss of the airflow flowing in the primary flow channel, thereby improving the efficiency of the centrifugal compressor.

As shown in Figures 1 to 8, in some embodiments of the present invention, the primary flow channel 20 includes a diffuser section 21 and a flow channel section 22, the inlet end of the diffuser section 21 is connected to the outlet end of the primary impeller 30, the outlet end of the diffuser section 21 is connected to the inlet end of the flow channel section 22, and the outlet end of the flow channel section 22 is connected to the inlet end of the secondary impeller 31.

It can be understood that the diffuser section 21 is the diffuser part of the centrifugal compressor. The function of the diffuser section 21 is that the gas flows through the diffuser, and the cross-sectional area of the diffuser section 21 increases, so that the speed of the airflow is reduced, and then the pressure of the airflow is further increased, and the kinetic energy of the airflow is converted into pressure energy. The airflow flowing out of the diffuser section 21 enters the flow channel section 22 and is transported out, and then enters the secondary impeller 31 for further compression. The diffuser section 21 and the flow channel section 22 are both defined by the inner wall surface of the shell 100. The cross-sectional area of the diffuser section 21 can be set to gradually expand, so that the airflow can reduce the speed and increase the pressure. The diffuser section 21 can be an annular flow channel structure, and the radial inner side of the annular diffuser section 21 is connected to the compression chamber 10, and is connected to the gas outflow side of the first-stage impeller 30, that is, the radial outer side of the first-stage impeller 30, so that the gas compressed by the first-stage impeller 30 can enter the diffuser section 21 to decelerate and increase the pressure. The flow channel section 22 connects the diffuser section 21 with the gas inlet side of the secondary impeller 31. The flow channel section 22 can be an arc-shaped structure, and the outlet end of the flow channel section 22 can be arranged in a circular ring shape to evenly guide the airflow at the outlet end to the inlet end of the secondary impeller 31. Guide vanes can also be arranged inside the flow channel section 22 according to the actual position and the flow characteristics of the airflow at that location to reduce pressure loss and improve the flow efficiency of the airflow.

As shown in FIGS. 1 to 8 , in some embodiments of the present invention, the diffuser section 21 is disposed radially outside the primary impeller 30 , and the diffuser section 21 extends along the circumferential direction of the primary impeller 30 .

It can be understood that, in order to facilitate the connection with the outlet end of the first-stage impeller 30, the diffuser section 21 can be arranged in a ring shape or in an arc shape along the circumferential extension of the first-stage impeller 30, so that the diffuser section 21 can surround the radial outer side of the first-stage impeller 30, and the side of the diffuser section 21 facing the first-stage impeller 30, that is, the radial inner side of the diffuser section 21 can be in a ring-shaped opening and connected with the compression chamber 10, so that the diffuser section 21 can connect with the gas outflow side of the first-stage impeller 30, thereby collecting the airflow compressed by the first-stage impeller 30, and reducing the speed and increasing the pressure of the airflow.

As shown in FIG. 4 , in some embodiments of the present invention, the axis of the inlet end of the flow channel section 22 is tangent to the axis of the outlet end of the diffuser section 21 .

It can be understood that the flow channel section 22 as a whole can be composed of multiple curved pipes and straight pipes. The inlet end of the flow channel section 22 can be a straight pipe, and the outlet end of the diffuser section 21 is an opening on the annular diffuser section 21 flow channel. The axis of the inlet end of the flow channel section 22 is tangent to the annular diffuser section 21 flow channel at the above-mentioned opening, so that the airflow after being decelerated and pressurized by the diffuser section 21 can smoothly enter the flow channel section 22, so as to reduce the pressure loss there and improve the compression effect.

As shown in FIG. 4 and FIG. 5 , in some embodiments of the present invention, the outlet end of the flow channel section 22 is coaxially arranged with the secondary impeller 31 .

It is understandable that the outlet end of the flow channel section 22 can be arranged in an annular shape or in a straight pipe shape, and the outlet end of the flow channel section 22 can have an annular guide channel, which extends along the circumference of the secondary impeller 31, and the center of the annular guide channel is connected to the inlet end of the secondary impeller 31, and the annular guide channel is arranged coaxially with the secondary impeller 31, and a guide vane can be arranged inside the annular guide channel to guide the airflow, increase the airflow velocity and reduce the pressure loss. A guide vane can also be arranged inside the flow channel section 22 to organize the airflow at the curved part of the flow channel section 22 to increase the flow velocity.

As shown in FIG8 , in some embodiments of the utility model, the outlet end of the flow channel section 22 is an annular asymmetric structure, and the outlet end of the flow channel section 22 is provided with a first flow channel 221, and the first flow channel 221 is arranged around the inlet end of the secondary impeller 31, and the first flow channel 221 is coaxially arranged with the inlet end of the secondary impeller 31, and the radial inner side of the first flow channel 221 is open and communicated with the compression chamber 10. One radial end of the first flow channel 221 is connected to the flow channel section 22, and the other radial end of the first flow channel 221 has a notch 224, that is, the first flow channel 221 is an incomplete annular shape, and the position of the notch 224 deviates from the line connecting the center of the first flow channel 221 and the axis of the flow channel section 22. The asymmetric structure of the first flow channel 221 can make the airflow from the flow channel section 22 evenly distributed along the annular shape, and the setting of the notch 224 prevents the airflows on both sides of the first flow channel 221 from colliding, thereby reducing pressure loss. The notch 224 may be disposed close to the curved arc center of the flow channel section 22 , so that the airflow on both sides of the first flow channel 221 is more uniform, thereby improving the performance of the compressor.

As shown in Figure 8, in some embodiments of the present invention, the curvatures of the multiple first guide vanes 225 in the first flow channel 221 at the outlet end of the flow channel section 22 are not equal. Specifically, the curvature of the first guide vane 225 close to the outlet end of the flow channel section 22 is smaller and closer to a straight plate type, while the curvature of the first guide vane 225 away from the outlet end of the flow channel section 22 is larger and more curved. From the outlet end of the flow channel section 22 to the notch 224, the curvatures of the multiple first guide vanes 225 gradually increase and become more and more curved. The above structure enables the airflow from the flow channel section 22 to be guided by the first guide vane 225, so that the airflow can enter the inlet end of the secondary impeller 31 from the flow channel section 22 to the first flow channel 221 at a similar angle, so that the airflow is more uniform and the pressure loss is reduced.

As shown in FIG8 , in some embodiments of the present invention, the lengths of the plurality of first guide plates 225 in the first flow channel 221 at the outlet end of the flow channel section 22 are not equal. Specifically, the length of the first guide plate 225 close to the outlet end of the flow channel section 22 is shorter, and the length of the first guide plate 225 far from the outlet end of the flow channel section 22 is longer, that is, the length of the first guide plate 225 close to the notch 224 is longer. From the outlet end of the flow channel section 22 to the notch 224, the length of the first guide plate 225 gradually increases. This is because, The outlet end of the flow channel section 22 is aligned with the inlet end of the secondary impeller 31, and the airflow directly entering the inlet end of the secondary impeller 31 from the outlet end of the flow channel section 22 requires a smaller diversion strength, so the length of the first guide vane 225 at this location can be set shorter, and the position close to the notch 224 requires the airflow to be deflected at a larger angle to align with the inlet end of the secondary impeller 31, and a greater intensity of diversion effect is required, so the first guide vane 225 close to the notch 224 needs to be set longer and with a larger arc to control the airflow deflection angle. The above structure makes the air intake of the secondary impeller 31 more uniform, reduces pressure loss, and improves the overall performance of the centrifugal compressor.

As shown in Figure 8, in some embodiments of the present invention, the flow channel section 22 includes a third flow channel 223 and a second flow channel 222 connected in sequence, the third flow channel 223 is connected to the first flow channel 221, and a second guide plate 226 is provided in the third flow channel 223. The second guide plate 226 extends along the airflow direction in the third flow channel 223. Along the radial direction of the third flow channel 223, the ratio of the distance between the two sides of the second guide plate 226 and the inner wall of the third flow channel 223 (the ratio of b1 to b2) is between 0.75 and 0.55. A third flow channel 223 is arranged at the end of the flow channel section 22. The third flow channel 223 is a straight tube structure. The axis of the third flow channel 223 is aligned with the center of the inlet end of the secondary impeller 31, so that part of the airflow of the third flow channel 223 can directly enter the secondary impeller 31 to reduce pressure loss. A second guide vane 226 is arranged in the third flow channel 223. The second guide vane 226 can be a straight plate structure. The distances between the second guide vane 226 and the inner wall of the third flow channel 223 on both sides of the radial direction of the third flow channel 223 are not equal. The distance between the second guide vane 226 and the inner wall of the third flow channel 223 on one side close to the arc center of the second flow channel 222 is greater than the distance on the other side. According to gas analysis, such a structure makes the gas outlet of the third flow channel 223 more uniform, so as to reduce pressure loss and improve the performance of the compressor.

As shown in FIG. 8 , in some embodiments of the present invention, the centrifugal compressor further includes a third guide vane 227 . The third guide vane 227 is disposed in the first flow channel 221 . The third guide vane 227 and the second guide vane 226 are disposed coplanarly.

It can be understood that in the first flow channel 221 at the outlet end of the flow channel section 22, the third guide vane 227 closest to the flow channel section 22 is a straight plate structure and is located in the same plane as the second guide vane 226 located in the flow channel section 22. The third guide vane 227 closest to the flow channel section 22 is set to align with the outlet end of the flow channel section 22, and the third guide vane 227 can be set parallel to the axis of the outlet end of the flow channel section 22. Since the outlet end of the flow channel section 22 corresponds to the inlet end of the secondary impeller 31, the airflow from the flow channel section 22 can directly enter the secondary impeller 31. Therefore, the third guide vane 227 located downstream of the outlet end of the flow channel section 22 can be set to a straight plate type to organize the airflow, so that the airflow is aligned with the axis of the secondary impeller 31 and directly enters the secondary impeller 31, reducing the pressure loss there, increasing the airflow speed, and thus improving the overall performance of the centrifugal compressor.

More specifically, the third guide vane 227 is arranged in the first flow channel 221 and is located between the two first guide vanes 225 closest to the second flow channel 222. The third guide vane 227 is located between the axis of the secondary impeller 31 and the second guide vane 226. In addition, since the second guide vane 226 is arranged to one radial side of the second flow channel 222, the third guide vane 227 is also not arranged in the middle of the second flow channel 222, that is, the third guide vane 227 is also arranged to one radial side of the first flow channel 221, so that the third guide vane 227 is aligned with the second guide vane 226, the airflow organization is smoother, and the pressure loss is reduced. By setting the third guide vane 227, the gas flowing out of the second flow channel 222 can be guided to the inlet end toward the secondary impeller 31, reducing the pressure loss and improving the overall efficiency of the centrifugal compressor.

As shown in FIG8 , in some embodiments of the present invention, a fourth guide plate 228 is provided inside one end of the second flow channel 222 connected to the third flow channel 223. The fourth guide plate 228 is arc-shaped and matches the curvature of the second flow channel 222. Along the radial direction of the second flow channel 222, the ratio of the minimum distance between the side of the fourth guide plate 228 facing the arc center of the second flow channel 222 and the inner wall of the second flow channel 222 to the diameter of the second flow channel 222 (the ratio of Ri to Ra) is between 0.2 and 0.4. A fourth guide vane 228 is arranged in the curved portion of 22, and the fourth guide vane 228 is an arc-shaped plate structure, and its arc bending angle is adapted to the curvature of the second flow channel 222. The radial position of the fourth guide vane 228 in the second flow channel 222 can be arranged close to the curved arc of the second flow channel 222. Since the airflow velocity distribution in the second flow channel 222 is uneven, arranging the fourth guide vane 228 at the above position can reduce the rotational loss of the airflow at the bending part of the second flow channel 222, thereby reducing the pressure loss and thereby improving the performance of the compressor.

As shown in Figures 1 to 8, in some embodiments of the present invention, the centrifugal compressor also includes a secondary flow channel 23, which is arranged on the radial outside of the secondary impeller 31, and the secondary flow channel 23 extends along the circumference of the secondary impeller 31, and the secondary flow channel 23 is connected to the outlet end of the secondary impeller 31.

It can be understood that the secondary flow channel 23 can be arranged in a ring shape on the radial outside of the secondary impeller 31, and the radial inside of the secondary flow channel 23 has an opening, which is connected to the compression chamber 10 and docked with the outlet end of the secondary impeller 31, that is, the radial outside of the secondary impeller 31, so that the airflow compressed by the secondary impeller 31 can be received by the secondary flow channel 23 and directed to the downstream equipment of the centrifugal compressor.

As shown in FIG. 6 and FIG. 7 , the impeller assembly includes a primary impeller 30 and a secondary impeller 31 . The primary impeller 30 and the secondary impeller 31 are integrally formed. The primary working surface 301 of the primary impeller 30 and the secondary working surface 311 of the secondary impeller 31 are arranged back to back.

It can be understood that the primary working surface 301 of the primary impeller 30 refers to the side of the primary impeller 30 where the blades are arranged and facing the inlet of the centrifugal compressor, that is, the side of the wheel disc of the primary impeller 30 where the blades are arranged. The working surface of the secondary impeller 31 is also the side of the secondary impeller 31 where the blades are arranged and facing the air inlet direction or the liquid inlet direction. The utility model sets the primary working surface 301 of the primary impeller 30 and the secondary working surface 311 of the secondary impeller 31 opposite to each other so that the primary impeller 30 and the secondary impeller 31 are set back to back, which is convenient for making an integrally formed impeller assembly through a milling process, and the inlet end of the secondary impeller 31 is one axial end of the impeller assembly, which is convenient for setting the direction of the primary flow channel 20, so as to guide the gas or liquid flowing out of the primary impeller 30 to the secondary impeller 31 for further pressurization.

As shown in Figures 6 and 7, in some embodiments of the present invention, the first-stage impeller 30 includes a first wheel disc 302 and a plurality of first blades 303, and the plurality of first blades 303 are arranged on a first-stage working surface 301 located on one axial side of the first wheel disc 302. The second-stage impeller 31 includes a second wheel disc 312 and a plurality of second blades 313, and the second wheel disc 312 and the first wheel disc 302 are an integral structure, and the plurality of second blades 313 are arranged on a second-stage working surface 311 on one axial side of the second wheel disc 312, and the other axial side of the second wheel disc 312 is connected to the other axial side of the first wheel disc 302.

It can be understood that the first wheel disc 302 is the wheel body part of the first-stage impeller 30 and serves as the bearing structure of the first blade 303. The first wheel disc 302 can be a disc-shaped structure, and the center of the first wheel disc 302 has a truncated cone or a conical structure, so that the outer surface of the axial side of the first wheel disc 302 is an arc-shaped surface, which is the first-stage working surface 301 of the first-stage impeller 30, and the outer surface is a structure that gradually tilts inward from the radial outer edge. The first blade 303 can refer to the blades of the existing impeller, and the first blade 303 can have a certain twist so that it generates a stronger centrifugal force. The first blade 303 is integrally formed with the first wheel disc 302 through milling or casting. The second wheel disc 312 can be a disc-shaped structure, and the center of the second wheel disc 312 has a truncated cone or a conical structure, so that the outer surface of the axial side of the second wheel disc 312 is an arc-shaped surface, which is the second-stage working surface 311 of the second-stage impeller 31, and the outer surface is a structure that gradually tilts inward from the radial outer edge. The second blades 313 may refer to the blades of the existing impeller, and the second blades 313 may also have a certain degree of twisting so as to generate a stronger centrifugal force. The second blades 313 are integrally formed with the second wheel disc 312 by milling or casting.

As shown in FIG. 5 , in some embodiments of the present invention, the centrifugal compressor further includes a sealing structure 24, which is disposed on a portion of the inner wall of the casing 100 between the diffuser section 21 and the secondary flow channel 23, and the position of the sealing structure 24 in the axial direction of the impeller assembly corresponds to the first wheel disc 302 and/or the second wheel disc 312;

Alternatively, the sealing structure 24 is arranged on the radial outer wall of the first wheel disc 302 and/or the radial outer wall of the second wheel disc 312, and the axial position of the sealing structure 24 corresponds to the part of the inner wall of the casing 100 located between the diffuser section 21 and the secondary flow channel 23.

It is understandable that a sealing structure 24 needs to be provided between the impeller assembly and the inner wall of the housing 100 to prevent the airflow compressed by the first-stage impeller 30 from being blown into the second-stage impeller 31 and affecting the overall compression effect. The sealing structure 24 may be a labyrinth sealing structure 24, i.e., a plurality of protrusions arranged at intervals. A plurality of protrusions may be provided on the portion of the inner wall of the housing 100 located between the diffuser section 21 and the secondary flow channel 23. The plurality of protrusions are arranged at intervals along the axial direction of the impeller assembly and are spaced from the impeller assembly to form a labyrinth seal. The sealing structure 24 may also be integrally formed and provided on the radial outer side of the first wheel disc 302 and/or the second wheel disc 312, spaced from the inner wall of the compression chamber 10 to form a labyrinth seal. Reduce the phenomenon of blowby between stages.

As shown in FIG. 1 to FIG. 4 , in some embodiments of the present invention, the centrifugal compressor further includes an air supply passage 25 , and the air supply passage 25 is in communication with the primary flow passage 20 .

It is understandable that the primary flow channel 20 may be connected to the air supply channel 25, which may be defined by the inner wall of the housing 100. The air supply channel 25 is used to supply air through an external device when the compression capacity of the centrifugal compressor is insufficient, so as to improve the compression performance. The air supply channel 25 may be a straight pipe structure and be tangent to a certain elbow portion of the primary flow channel 20 to reduce pressure loss.

The third aspect of the present invention provides a refrigeration device, comprising the centrifugal compressor provided in the second aspect of the present invention.

The refrigeration device provided in the third aspect of the utility model has the same beneficial effects as the centrifugal compressor provided in the second aspect of the utility model.

The above are only preferred specific implementations of the utility model, but the protection scope of the utility model is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the utility model should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model shall be based on the protection scope of the claims.

Claims (10)

1. A centrifugal compressor, the centrifugal compressor comprising:

The shell is internally provided with a compression cavity and a primary flow passage communicated with the compression cavity;

An impeller assembly rotatably disposed in the compression chamber, the impeller assembly including a primary impeller and a secondary impeller, and a gas outflow side of the primary impeller being in communication with a gas inflow side of the secondary impeller through the primary flow passage;

The guide vane assembly is arranged in the primary flow channel and used for guiding airflow in the primary flow channel to flow so as to reduce pressure loss of the airflow during flow.

2. The centrifugal compressor of claim 1, wherein the primary flow passage includes a diffuser section and a flow passage section, an inlet end of the diffuser section being in communication with a gas outflow side of the primary impeller, an outlet end of the diffuser section being in communication with an inlet end of the flow passage section, and an outlet end of the flow passage section being in communication with a gas inlet side of the secondary impeller.

3. The centrifugal compressor of claim 2, wherein the flow path section includes a first flow path and a second flow path, an inlet end of the second flow path communicates with the diffuser section, an outlet end of the second flow path communicates with the first flow path, the first flow path is disposed radially outward of a gas inlet side of the secondary impeller, the first flow path extends circumferentially of the gas inlet side of the secondary impeller, the first flow path communicates with the gas inlet side of the secondary impeller, and an angle at which the first flow path extends circumferentially of the gas inlet side of the secondary impeller is less than 360 °.

4. A centrifugal compressor as claimed in claim 3, wherein the vane assembly comprises a plurality of first vanes disposed within the first flow passage, the plurality of first vanes being circumferentially spaced along the first flow passage, at least one of the plurality of first vanes having a different curvature than the other of the plurality of first vanes, the first vanes being configured to direct gas within the first flow passage to the gas inlet side of the secondary impeller.

5. The centrifugal compressor of claim 4, wherein a length of the first baffle is proportional to a maximum distance of the first baffle from a gas outflow side of the second flow passage.

6. The centrifugal compressor of claim 5, wherein the flow path section further comprises a third flow path having a straight pipe structure, the second flow path communicating with the first flow path through the third flow path, the baffle assembly further comprising a second baffle disposed in the third flow path, the second baffle being disposed offset from a central axis of the third flow path.

7. The centrifugal compressor of claim 6, wherein the baffle assembly further comprises a third baffle disposed within the first flow passage, the third baffle disposed coplanar with the second baffle.

8. The centrifugal compressor of claim 7, wherein the baffle assembly further comprises a fourth baffle disposed in the second flow passage, the fourth baffle disposed offset from a central axis of the second flow passage.

9. The centrifugal compressor according to any one of claims 1 to 8, wherein said primary impeller and said secondary impeller are of unitary construction, a primary working surface of said primary impeller is disposed opposite a secondary working surface of said secondary impeller, and a side of said primary impeller facing away from said primary working surface is connected to a side of said secondary impeller facing away from said secondary working surface.

10. Refrigeration device, characterized by comprising a centrifugal compressor according to any one of claims 1 to 9.