Volute structure and centrifugal compressor

Abstract

The present invention relates to a volute structure including a casing, an air supply joint is provided on the casing, a volute is provided in the casing, the volute structure also includes a first partition and a second partition detachably connected to the casing, the first partition, the second partition and the volute are arranged at intervals along the axial direction of the casing, the first partition, the second partition and the casing form an air supply cavity, the air supply joint is connected to the air supply cavity, the second partition and the casing form a diffuser connected to the volute, the first partition and the second partition are both annular, the inner edge of the second partition extends to form a bushing that fits the first partition and is used to install an impeller. The volute structure of the present invention is easy to disassemble and assemble, and can reduce mold opening costs. The present invention also relates to a centrifugal compressor.

Description

Technical Field

[0001] The present invention relates to the technical field of refrigeration equipment, and in particular to a volute structure and a centrifugal compressor. Background Art

[0002] In a centrifugal compressor, the temperature of the gas will rise sharply after being compressed. At high temperatures, the specific volume of the gas is very large. While ensuring the same cooling capacity, the energy consumption of the compressor will increase sharply.

[0003] In order to reduce compressor power consumption and improve refrigeration capacity, multi-stage compression refrigeration cycle is often used. At present, the most widely used is the "two-stage compression intermediate incomplete cooling refrigeration cycle with a flash steam separator (commonly known as an economizer).

[0004] The two-stage compression refrigeration cycle mixes the flash steam separated from the economizer with the exhaust gas from the low-stage compression, which reduces the inlet temperature of the secondary compression, reduces the specific volume of the refrigerant gas, and reduces the energy consumption of the compressor.

[0005] However, the air replenishment solution in the prior art is usually to set a volute structure in the compressor, the volute structure includes a casing, a volute, an air replenishment cavity and a diffuser, and an impeller is installed in the volute structure to perform secondary compression. However, the casing, volute, air replenishment cavity and diffuser of the volute structure in the prior art are an integral casting, which makes the volute structure complex as a whole, inconvenient to disassemble and assemble, and has a high mold opening cost. Summary of the invention

[0006] Based on this, a volute structure is provided which has a simple structure, is easy to assemble and disassemble, and has a low mold opening cost.

[0007] A volute structure includes a casing, on which is provided an air supply joint, in which is provided a volute, and the volute structure also includes a first partition and a second partition located in the casing and detachably connected to the casing, the first partition, the second partition and the volute are arranged at intervals along the axial direction of the casing, the first partition, the second partition and the casing form an air supply cavity, the air supply joint is connected to the air supply cavity, the second partition and the casing form a diffuser connected to the volute, the first partition and the second partition are both annular, and the inner edge of the second partition extends to form a bushing that fits the first partition and is used to install an impeller.

[0008] Furthermore, the inner wall of the bushing includes a first surface disposed facing the wheel cover of the impeller, a gap is provided between the first surface and the wheel cover of the impeller, and a profile line of the first surface is the same as a profile line of the wheel cover of the impeller.

[0009] Furthermore, an inner wall of the bushing at one end facing the first partition plate is provided with an annular groove, and a wheel cover seal for sealing the gap is provided in the annular groove.

[0010] Furthermore, the inner wall of the bushing also includes a second surface with two ends respectively connected to the inner edge of the second partition plate and the first surface, the second surface is located at the inlet of the diffuser, and the second surface is an inclined surface.

[0011] Furthermore, the inner wall of the box body is provided with a first annular step groove, the first annular step groove is located on the outer side of the first partition plate and is farther away from the second partition plate relative to the first partition plate, the outer edge of the first partition plate extends to form a first annular step portion, the first annular step portion is located in the first annular step groove, and the first fixing member passes through the first annular step portion and is locked into the inner wall of the box body.

[0012] Furthermore, a second annular step groove is provided on the inner wall of the box body, the second annular step groove is located between the second partition plate and the first partition plate, the outer edge of the second partition plate extends to form a second annular step portion, the second annular step portion is located in the second annular step groove, and the second fixing piece passes through the second annular step portion and is locked into the inner wall of the box body.

[0013] Furthermore, the internal flow channel of the air supply joint gradually narrows from the air inlet end of the air supply joint to the air outlet end of the air supply joint.

[0014] Furthermore, a portion of the inner wall of the box body facing the air supplement cavity is provided with an annular expansion groove.

[0015] Furthermore, a plurality of air supplement cavity outlets are provided on the first partition plate, and the plurality of air supplement cavity outlets are arranged at equal intervals on the first partition plate along the circumferential direction.

[0016] The present invention also relates to a centrifugal compressor, comprising an impeller and a transmission shaft, and also comprising the above-mentioned volute structure, wherein the impeller is installed in the bushing, and the transmission shaft passes through the housing.

[0017] The volute structure in the centrifugal compressor of the present invention is detachably connected to the casing in which the volute is set through the first partition plate and the second partition plate. The first partition plate and the second partition plate form an air replenishing chamber with the casing, and the second partition plate and the inner wall of the casing form a diffuser connected to the volute. Compared with the volute casing in the prior art in which the casing, the air replenishing chamber and the diffuser are integrally formed, the volute structure of the present invention has a simple structure, is easy to disassemble and assemble, and can reduce the mold opening cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a three-dimensional structural schematic diagram of the volute structure of an embodiment of the present invention.

[0019] Figure 2 yes Figure 1 Schematic diagram of the cross-sectional structure.

[0020] Figure 3 superior Figure 2 Schematic diagram of the combination of the first partition and the second partition.

[0021] Figure 4 yes Figure 2 Schematic diagram of the shell part.

[0022] Figure 5 The present invention is a cross-sectional structural schematic diagram of a centrifugal compressor using a volute structure developed by the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] See also Figure 1-5 The present invention provides a centrifugal compressor, including a volute structure 100, an impeller 200 installed in the volute structure 100, and a transmission shaft 300 passing through the volute structure 100. The volute structure 100 includes a casing 1, a volute 2 arranged in the casing 1, and a first partition 3 and a second partition 4 arranged in the casing 1 and detachably connected to the casing 1. An air supply joint 11 is provided on the casing 1. The first partition 3, the second partition 4 and the volute 2 are arranged at intervals along the axial direction of the casing 1. The first partition 3, the second partition 4 and the casing 1 form an air supply chamber 5, and the air supply joint 11 is connected to the air supply chamber 5. The second partition 4 and the casing 1 form a diffuser 6 connected to the volute 2. The first partition plate 3 and the second partition plate 4 are both annular, and the inner edge of the second partition plate 4 is extended to form a bushing 40 that fits the first partition plate 3. The first partition plate 3 and the second partition plate 4 are both annular, and the transmission shaft 300 can pass through, so that the transmission shaft 300 can pass through the housing 1. The impeller 200 is installed on the transmission shaft 300 and is located in the bushing 40.

[0025] Specifically, the housing 1 is a casting, and is used to install most of the parts constituting the compressor, such as an impeller, a transmission shaft, a diffuser, etc. An oil passage and an air passage are provided in the housing 1, and the air passage has an air inlet end. The first partition plate 3 is closer to the air inlet end of the air passage than the second partition plate 4.

[0026] In this embodiment, the inner wall of the bushing 40 includes a first surface 401 disposed facing the wheel cover of the impeller 200, and the first surface 401 is spaced from the wheel cover of the impeller 200, that is, there is a gap between the first surface 401 and the wheel cover of the impeller 200 to facilitate the rotation of the impeller 200. It can be understood that due to the existence of the gap, the airflow flowing out of the outlet of the impeller 200 will leak out from the inlet end of the impeller 200 through the gap, and the gap constitutes a channel for airflow leakage. In order to reduce the gas flow at this position, in this embodiment, the cross-sectional profile of the first surface 401 is the same as the wheel cover profile of the impeller 200, so that there is a uniform gap between the first surface 401 of the inner wall of the bushing 40 and the wheel cover of the impeller 200, which can reduce the channel size of the airflow leakage of the impeller 200, thereby reducing the airflow at this position, and effectively reducing the friction loss on the wheel cover side of the impeller 200.

[0027] In order to further reduce the air flow at the above-mentioned position, an inner wall of the bushing 40 at one end facing the first partition plate 3 is provided with an annular groove 402, and a wheel cover seal 7 is provided in the annular groove 402. The wheel cover seal 7 can seal the above-mentioned gap, that is, the channel for airflow leakage, thereby reducing the air flow in the channel for airflow leakage. The wheel cover seal 7 is installed on the bushing 40 by means of fixing parts such as countersunk screws, wherein the wheel cover seal 7 is existing and will not be described in detail here.

[0028] Specifically, the end of the bushing 40 facing the first partition 3 has an outer end surface, and the first partition 3 has a first end surface facing the second partition 4 and a second end surface away from the second partition 4. The bushing 40 and the first partition 3 are fitted together, which means that the outer end surface of the bushing 40 is fitted together with the first end surface of the first partition 3. In this embodiment, the annular groove 402 runs through a part of the outer end surface of the bushing 40, so that the wheel cover seal 7 is also fitted with the first end surface of the first partition 3, thereby enhancing the sealing performance between the first partition 3 and the bushing 40. Furthermore, the outer end surface of the bushing 40 (specifically, the part without the annular groove 402) is provided with a first annular groove 403, which is installed in the first annular groove 403 by a sealing ring, so that when the bushing 40 and the first partition 3 are fitted together, the sealing performance between the bushing 40 and the first partition 3 is further enhanced.

[0029] In this embodiment, the second end face of the first partition plate 3 , that is, the end face facing away from the second partition plate 4 , is inclined at the connection with the first partition plate 3 to form a drainage port, which is trumpet-shaped to facilitate airflow to enter the impeller 200 .

[0030] In this embodiment, the first end face of the first partition plate 3 is provided with an adaption groove 31 extending from the inner edge to the outer edge of the first partition plate 3 , and one end of the bushing 40 facing the first partition plate 3 is located in the adaption groove 31 , so that the bushing 40 is positioned and installed on the first partition plate 3 .

[0031] It should be noted that the second partition plate 4 includes a first end surface facing the first partition plate 3 and a second end surface facing away from the first partition plate 3. An annular plane 12 facing the second end surface of the second partition plate 4 is formed on the inner wall of the housing 1. The second end surface of the second partition plate 4 and the annular plane 12 constitute the above-mentioned diffuser 6. In this embodiment, the inner wall of the bushing 40 also includes a second surface 404 connecting the inner edge of the second partition plate 4 and the first surface 401 at both ends. The second surface 404 is located at the channel of the diffuser 6. The outlet of the impeller 200 is located at the second surface 404, and the second surface 404 is an inclined surface. It can be understood that the outlet of the impeller 200 constitutes the inlet part of the diffuser 6, and the second surface 404 can effectively converge the impeller outlet airflow and introduce it into the channel of the diffuser 6.

[0032] In this embodiment, the first partition 3 is detachably connected to the inner wall of the box body 1 by a first fixing member such as a countersunk screw. Specifically, the inner wall of the box body 1 is provided with a first annular step groove 13, the first annular step groove 13 is located on the outer side of the first partition 3, and is farther away from the second partition 4 than the first partition 3, the outer edge of the first partition 3 extends to form a first annular step portion 32, the first annular step portion 32 is located in the first annular step groove 13, the first fixing member passes through the first annular step portion 32 and is locked into the inner wall of the box body 1, so that the first partition 3 is detachably fixed in the box body 1, and the purpose of setting this structure is to realize the positioning and installation of the first partition 3 in the box body 1.

[0033] Furthermore, the outer edge of the first partition plate 3 is bent in a direction away from the second partition plate 4 to form an arc portion 33, and the first annular step portion 32 is formed at the free end of the arc portion 33. The purpose of providing the arc portion 33 is to form a U-shaped bend with the first-stage diffuser 400 in the centrifugal compressor to assemble the return flow device 500. The structure is described in detail below.

[0034] In this embodiment, the second partition plate 4 is detachably connected to the inner wall of the housing 1 by a second fixing member such as a countersunk screw. Specifically, the inner wall of the housing 1 is provided with a second annular step groove 14, which is located between the second partition plate 4 and the first partition plate 3. The outer edge of the second partition plate 4 extends to form a second annular step portion 44, which is located in the second annular step groove 14. The second fixing member passes through the second annular step portion 44 and is locked into the inner wall of the housing 1, so that the first partition plate 3 is detachably fixed in the housing 1. The purpose of setting this structure is to achieve the positioning of the second partition plate 4 in the housing 1. Further, in order to prevent the air flow in the diffuser 6 channel from leaking from the junction of the second annular step portion 44 and the inner wall of the housing 1 to the supplementary air chamber 5, a second annular groove 440 is provided on the surface of the second annular step portion 44 facing the second annular step groove 14, and a sealing ring is installed in the second annular groove 440 to seal the second annular step portion 44 and the housing 1. In other embodiments, the second annular groove may also be provided on the wall surface of the second annular step portion 44 of the second annular step groove 14 .

[0035] In this embodiment, a plurality of air-filling cavity outlets 34 are provided on the first partition plate 3. For a centrifugal refrigeration compressor, the refrigerant gas from the economizer enters the air-filling cavity 5 of the volute structure 100 through the pipeline from the air-filling joint 11, and then leaves the air-filling cavity 5 from the air-filling cavity outlets 34, so that the gas from the economizer is replenished and enters the gas flow path of the compressor. In this embodiment, the air-filling cavity outlets 34 are arranged at equal intervals on the first partition plate 3 along the circumferential direction to stabilize the air flow in the air-filling cavity 5, thereby reducing the noise of the compressor.

[0036] In this embodiment, the internal flow channel of the air-filling joint 11 gradually narrows from the air inlet end of the air-filling joint 11 to the air outlet end of the air-filling joint 11, so that when the gas entering the air-filling joint 11 flows in the air-filling joint 11, the flow rate gradually increases. When entering the air-filling cavity 5, due to the large space of the air-filling cavity 5, the airflow will expand after entering the air-filling cavity 5. In this way, even if there is a small liquid mixed in the airflow, the small liquid will become gas due to expansion, thereby preventing liquid from entering the air-filling cavity 5. Furthermore, in order to increase the space of the air-filling cavity 5. The inner wall of the box body 1 is provided with an annular expansion groove 15 on the part facing the air-filling cavity 5, so that the space of the air-filling cavity 5 becomes larger.

[0037] It should be noted that, in order to enhance the compression effect, the centrifugal compressor usually includes a two-stage compression mechanism. The volute structure 100 and the impeller 200 in the present invention constitute the two-stage compression mechanism of the compressor. Correspondingly, the impeller 200 in the volute structure 100 is a two-stage impeller, and the diffuser 6 is a two-stage diffuser 6. Of course, the centrifugal compressor of the present invention also includes a first-stage compression mechanism, which includes a first-stage diffuser 400, a return flow device 500 and a first-stage impeller 600 to constitute a first-stage compression component of the compressor. The first-stage diffuser 400 is adapted to form a U-shaped bend with the first partition 3. The installation method of the first-stage diffuser 400, the return flow device 500 and the first-stage impeller 600 is the same as that of the prior art and will not be repeated here.

[0038] The volute structure in the centrifugal compressor of the present invention is detachably connected to the casing 1 in which the volute 2 is disposed through the first partition plate 3 and the second partition plate 4. The first partition plate 3 and the second partition plate 4 form an air replenishing chamber 5 with the casing 1. The second partition plate 4 and the inner wall of the casing 1 form a diffuser 6 connected to the volute 2. Compared with the volute casing in the prior art in which the casing, the air replenishing chamber and the diffuser are integrally formed, the volute structure of the present invention has a simple structure, is easy to disassemble and assemble, and can reduce the mold opening cost.

[0039] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A volute structure, comprising a housing (1), wherein the housing (1) is provided with an air supply joint (11), and wherein a volute (2) is provided inside the housing (1), characterized in that: The volute structure further comprises a first baffle (3) and a second baffle (4) which are located on the casing (1) and are detachably connected to the casing (1); the first baffle (3), the second baffle (4) and the volute (2) are arranged at intervals along the axial direction of the casing (1); the first baffle (3), the second baffle (4) and the casing (1) form an air replenishment chamber (5); the air replenishment joint (11) is connected to the air replenishment chamber (5); the second baffle (4) and the casing (1) form a diffuser (6) which is connected to the volute (2); the first baffle (3) and the second baffle (4) are both annular; the inner edge of the second baffle (4) is extended to form a bushing (40) which is in contact with the first baffle (3) and is used to mount the impeller (200); The inner wall of the bushing (40) comprises a first surface (401) disposed facing the wheel cover of the impeller (200), a gap being provided between the first surface (401) and the wheel cover of the impeller (200), and a profile line of the first surface (401) being the same as a profile line of the wheel cover of the impeller (200); An inner wall of the bushing (40) at one end facing the first partition plate (3) is provided with an annular groove (402), and a wheel cover seal (7) for sealing the gap is provided in the annular groove (402); The bushing (40) has an outer end surface at one end facing the first partition (3), a portion of the outer end surface is penetrated by the annular groove (402), and the other portion is provided with a first annular groove (403), and a sealing ring is installed in the first annular groove (403).

2. The volute structure according to claim 1, characterized in that: The inner wall of the bushing (40) further comprises a second surface (404) whose two ends respectively connect the inner edge of the second partition plate (4) and the first surface (401); the second surface (404) is located at the inlet of the diffuser (6), and the second surface (404) is an inclined surface.

3. The volute structure according to claim 1, characterized in that: The inner wall of the box body (1) is provided with a first annular step groove (13), the first annular step groove (13) is located on the outer side of the first partition plate (3) and is farther away from the second partition plate (4) than the first partition plate (3), the outer edge of the first partition plate (3) extends to form a first annular step portion (32), the first annular step portion (32) is located in the first annular step groove (13), and the first fixing member passes through the first annular step portion (32) and is locked into the inner wall of the box body (1).

4. The volute structure according to claim 1, characterized in that: The inner wall of the box body (1) is provided with a second annular step groove (14), the second annular step groove (14) is located between the second partition plate (4) and the first partition plate (3), the outer edge of the second partition plate (4) extends to form a second annular step portion (44), the second annular step portion (44) is located in the second annular step groove (14), and the second fixing piece passes through the second annular step portion (44) and is locked into the inner wall of the box body (1).

5. The volute structure according to claim 1, characterized in that: The internal flow channel of the air supply joint (11) gradually narrows from the air inlet end of the air supply joint (11) to the air outlet end of the air supply joint (11).

6. The volute structure according to claim 1, characterized in that: An annular expansion groove (15) is provided on the portion of the inner wall of the box body (1) facing the air supplement chamber (5).

7. The volute structure according to claim 1, characterized in that: The first partition plate (3) is provided with a plurality of air-replenishing cavity outlets (34), and the plurality of air-replenishing cavity outlets (34) are arranged at equal intervals on the first partition plate (3) along the circumferential direction.

8. A centrifugal compressor, comprising an impeller (200) and a transmission shaft (300), characterized in that: It also includes a volute structure as described in any one of claims 1 to 7, the impeller (200) is installed in the bushing (40), and the transmission shaft (300) passes through the housing (1).

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