Integrated structure of refluxer and pressure diffuser, and centrifugal compressor

Abstract

An integrated structure of a return device and a pressure diffuser, and a centrifugal compressor are provided. The structure includes a pressure diffuser portion and a return device portion integrally molded with the pressure diffuser portion. The pressure diffuser portion is configured to form a pressure diffusion flow channel. The return device portion has a return channel. The return channel is in communication with the pressure diffusion flow channel, and is configured to guide gas from the pressure diffusion flow channel. The structure of the present invention eliminates a need of independently installing a return device and a pressure diffuser, and eliminates connection seams caused by assembly and misalignment caused by accumulated errors. Therefore, gas can smoothly flow through the pressure diffusion flow channel into the return channel, such that a gas flow is well guided, and the gas flow uniformity is better.

Claims

1. An integrated structure of a return device and a pressure diffuser, comprising a pressure diffuser portion and a return device portion integrally molded with the pressure diffuser portion; wherein; the pressure diffuser portion is configured to form a pressure diffusion flow channel; the return device portion has a return channel; the return channel is in communication with the pressure diffusion flow channel, and is configured to guide gas from the pressure diffusion flow channel; the return channel has an inlet and an outlet, and a width a of the inlet is less than or equal to a width b of the outlet; and the width b of the outlet is configured to be not greater than four times the width a of the inlet.

2. The integrated structure of the return device and the pressure diffuser according to claim 1, wherein the pressure diffuser portion and the return device portion are integrally molded by casting.

3. The integrated structure of the return device and the pressure diffuser according to claim 1, wherein; one side of the return channel is vertical, and another side of the return channel is gradually flared outward in a direction from the inlet to the outlet; an angle between said another side and a vertical direction is β, wherein 0≤β≤45°.

4. The integrated structure of the return device and the pressure diffuser according to claim 1, wherein; an inner wall of the return channel is provided with return vanes; and the return vanes are distributed evenly in serial arrays or in a single array.

5. The integrated structure of the return device and the pressure diffuser according to claim 4, wherein for each return vane; an outer edge of the return vane is rigidly connected with an inner wall of the return channel; a vane mounting angle α is formed between a first tangent line of the return vane, the first tangent line of the return vane being located at a position where the return vane contacts the inner wall of the return channel, and a second tangent line of the return vane also located at the position where the return vane contacts the inner wall of the return channel; and the vane mounting angle α ranges from 10° to 80°.

6. The integrated structure of the return device and the pressure diffuser according to claim 1, further comprising pressure diffusion vanes arranged inside the pressure diffusion flow channel.

7. The integrated structure of the return device and the pressure diffuser according to claim 6, wherein; for each pressure diffusion vane: a width of the pressure diffusion vane is not greater than a width of an impeller, and the impeller is arranged opposite to the pressure diffusion vane to feed gas into the pressure diffusion flow channel.

8. A centrifugal compressor, comprising a main shaft, an impeller installed on the main shaft, and a pressure diffuser cover plate, wherein: the centrifugal compressor further comprises the integrated structure of the return device and the pressure diffuser defined in claim 1; and the pressure diffuser cover plate is opposite to the pressure diffuser portion to form the pressure diffusion flow channel.

9. The centrifugal compressor according to claim 8, wherein; the centrifugal compressor has at least two stages; an accommodating space is disposed between the return device portion of a front stage and a second-stage impeller of a subsequent stage; and the accommodating space is in communication with a gas supplying passage, and the gas supplying passage is configured to supply gas into the accommodating space.

10. The centrifugal compressor according to claim 9, wherein the gas supplying passage is in communication with an expansion valve, and is configured to feed a part of refrigerant expanded by the expansion valve into the accommodating space to lower temperature and to supply gas.

11. The centrifugal compressor according to claim 8, wherein the pressure diffuser portion and the return device portion are integrally molded by casting.

12. The centrifugal compressor according to claim 8, wherein an inner wall of the return channel is provided with return vanes; and the return vanes are distributed evenly in serial arrays or in a single array.

13. The centrifugal compressor according to claim 12, wherein for each return vane; an outer edge of the return vane is rigidly connected with an inner wall of the return channel; a vane mounting angle α is formed between a first tangent line of the return vane, the first tangent line of the return vane being located at a position where the return vane contacts with-the inner wall of the return channel, and a second tangent line of the return vane also located at the position where the return vane contacts the inner wall of the return channel; and the vane mounting angle α ranges from 10° to 80°.

14. The centrifugal compressor according to claim 8, further comprising pressure diffusion vanes arranged inside the pressure diffusion flow channel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In order to describe the solutions of the prior art or the solutions of embodiments of the present invention more clearly, the present disclosure will be described briefly with reference to the figures used in describing the embodiments or the prior art. It is obvious that, for those skilled in the art, other figures can be obtained according to the figures provided hereafter without any creative work.

(2) FIG. 1 is a schematic structural view of an integrated structure of a return device and a pressure diffuser according to the present invention.

(3) FIG. 2 is a schematic structural view illustrating the return vanes distributed in serial arrays in the return channel.

(4) FIG. 3 is a schematic structural view illustrating the return vanes distributed in a single array in the return channel.

(5) FIG. 4 is a cross-sectional view of the integrated structure installed on a main shaft according to the present invention.

(6) FIG. 5 is a schematic structural view illustrating the first-stage pressure diffusion vane distributed in the pressure diffusion flow channel.

(7) FIG. 6 is a schematic structural view illustrating the second-stage pressure diffusion vane distributed in the pressure diffusion flow channel.

(8) FIG. 7 is a cross-sectional view of the integrated structure provided with the first-stage pressure diffusion vane and the second-stage pressure diffusion vane and installed on the main shaft.

(9) The above figures include the following reference numerals:

(10) 1—pressure diffuser portion, 10—pressure diffusion flow channel, 13—pressure diffusion vane, 2—return device portion, 20—return channel, 21—inlet, 22—outlet, 23—return vane, 4—pressure diffuser cover plate, 5—accommodating space, 6—gas supplying passage, 7—second-stage impeller, 8—second-stage pressure diffusion flow channel, 9—second-stage pressure diffuser cover plate.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(11) The technical solutions of the present invention will be described with reference to the accompanying figures. Obviously, what described below are several but not all embodiments of the present invention. For those skilled in the art, other embodiments obtained based on the embodiments of the present invention without creative work are within the scope of the present invention.

(12) It should be specified that, the terms “first” and “second” in the description are just used to describe the object, but should not be understood to indicate or imply the relative importance. What's more, the technical features described below in different embodiments of the present invention may be combined with each other, so long as there are no conflicts.

The First Embodiment

(13) This embodiment provides an integrated structure of a return device and a pressure diffuser. As shown in FIG. 1, the integrated structure includes a pressure diffuser portion 1 and a return device portion 2 integrally molded with the pressure diffuser portion 1. The pressure diffuser portion 1 is configured to form a pressure diffusion flow channel 10. The return device portion 2 has a return channel 20. The return channel 20 is in communication with the pressure diffusion flow channel 10, and is configured to guide the gas from the pressure diffusion flow channel 10.

(14) In the integrated structure of the return device and the pressure diffuser of the embodiment, the pressure diffuser portion 1 and the return device portion 2 are integrated to be one component, which is no longer a prior art structure formed by secondarily connecting and integrating a separate pressure diffuser and a separate return device with screws, pins or welding. With such a configuration, the integrated structure of the present invention not only eliminates a need of independently installing a return device and a pressure diffuser, but also eliminates connection seams caused by assembly and misalignment caused by accumulated errors, etc. Therefore, the gas can smoothly flow from the pressure diffusion flow channel 10 into the return channel 20, and the energy loss is small; in the integrated structure of the return device portion 2 and the pressure diffuser portion 1, the return vane 23 is separately arranged in the return channel 20 and is not connected to the pressure diffuser any longer, which eliminates the problem in the prior art that air leakage is caused due to a seam between the end of the return vane 23 and the pressure diffuser, and eliminates the phenomenon that part of the gas is leaked from the seam, avoiding the guiding action of the return device and affecting the gas guided by the return device. Therefore, when the integrated structure of the present invention is applied in a centrifugal compressor, it can improve the flow guiding effect and the gas flow uniformity. In this embodiment, the pressure diffuser portion 1 and the return device portion 2 are integrally molded by casting.

(15) As shown in FIGS. 2-4, the return channel 20 has an inlet 21 and an outlet 22, and the width a of the inlet 21 is less than or equal to the width b of the outlet 22. The gas flow flowing from the pressure diffusion flow channel 10 into the return channel 20 is an unstable flow with a larger velocity, and the flow loss is larger, therefore the configuration that the width a of the inlet 21 is less than or equal to the width b of the outlet 22 enables the return channel 20 to perform a certain function of pressure diffusion, thereby reducing the flow velocity and improving the stability of the gas flow. Considering that the roughness of the inner surface of the return channel 20 is relative large, the width b of the outlet 22 is further configured to be not greater than four times the width a of the inlet 21, thereby ensuring the gas to flow through the return channel smoothly; in this embodiment, the width a of the inlet 21 is four-fifths of the width b of the outlet.

(16) One side of the return channel 20 is vertical, and the other side is gradually flared outward in the direction from the inlet 21 to the outlet 22. The angle between the other side and the vertical direction is β, and 0≤β≤45°. Such a structure can guide the gas to flow to a preset side, thereby improving the flow guiding effect.

(17) As shown in FIG. 2, the inner wall of the return channel 20 is provided with return vanes 23, which are distributed evenly in serial arrays. The thickness of the return vane 23 is ranged from 5 mm to 40 mm, and the number of the return vanes is ranged from 3 to 50. For an ordinary model with lower requirements for the gas flow uniformity, as shown in FIG. 3, the return vanes may also be distributed evenly in a single array.

(18) The outer edge of the return vane 23 is rigidly connected with the inner wall of the return channel 20. A vane mounting angle α is formed between a first tangent line of the return vane 23, which is located at a position where the return vane 23 contacts with the inner wall of the return channel 20, and a second tangent line at a corresponding position of the inner wall of the return channel 20. The vane mounting angle α is ranged from 10° to 80°. Such a structure makes the vane mounting angle α of the return vane 23 relatively identical to an actual flow angle of the gas flow, thereby reducing the impact loss.

(19) As shown in FIGS. 5-7, pressure diffusion vanes 13 are further arranged inside the pressure diffusion flow channel 10, and the pressure diffusion vanes 13 may also be disposed on the return device portion 2. The gas flow entering the pressure diffusion flow channel 10 is preliminarily guided by the pressure diffusion vane 13, and then is secondarily guided after flowing into the return channel 20, thereby further improving the gas flow uniformity. In addition, the pressure diffusion vane 13 may be arranged on the pressure diffuser cover plate 4 which, together with the pressure diffuser portion 1, forms the pressure diffusion flow channel.

(20) The width of the pressure diffusion vane 13 is not greater than the width of the impeller 3, which is arranged opposite to the pressure diffusion vane to feed the gas into the pressure diffusion flow channel 10. As shown in FIG. 7, c is the thickness of the primary pressure diffusion vane 13, and d is the thickness of the secondary pressure diffusion vane 13; the thickness of the primary pressure diffusion vane 13 is less than the width B1 of the impeller 3 shown in FIG. 1, and the thickness of the secondary pressure diffusion vane 13 is less than the width B2 of the second-stage impeller 7 shown in FIG. 1, thereby preventing gas reflux, and ensuring the convergence of the flow.

(21) The integrated structure of this embodiment can be applied not only in a two-stage centrifugal compressor, but also in a three-stage or multiple-stage centrifugal compressor.

The Second Embodiment

(22) This embodiment provides a centrifugal compressor, including a main shaft, an impeller 3 installed on the main shaft, and a pressure diffuser cover plate 4, and further including the integrated structure described in the first embodiment; the pressure diffuser cover plate 4 is opposite to the pressure diffuser portion 1 to form the pressure diffusion flow channel 10.

(23) The centrifugal compressor of this embodiment employs the integrated structure above, therefore it has all of the advantages brought by the integrated structure above.

(24) The centrifugal compressor has two stages, and an accommodating space 5 is disposed between the return device portion 2 of the front stage and the second-stage impeller 7 of the subsequent stage. The accommodating space 5 is in communication with the gas supplying passage 6, and the gas supplying passage 6 is configured to supply gas into the accommodating space 5, thereby improving the compression efficiency.

(25) The operating process of the two-stage centrifugal compressor is as follows: the main shaft drives the impeller 3 to rotate, throwing the gas into the pressure diffusion flow channel 10, which is formed by the pressure diffuser cover plate 4 and the pressure diffuser portion 1; the gas from the pressure diffusion flow channel 10 flows through the return channel 20, and then enters the accommodating space 5; the second-stage impeller 7 is driven by the main shaft to rotate as well, throwing the gas in the accommodating space 5 into the second-stage pressure diffusion flow channel 8, which is formed by the second-stage pressure diffuser cover plate 9 and the integrated structure, thereby further increasing the gas pressure.

(26) In an embodiment, when the centrifugal compressor of this embodiment is applied in a refrigerating apparatus, the gas supplying passage 6 is in communication with an expansion valve and configured to feed a part of the refrigerant expanded by the expansion valve into the accommodating space 5 to lower the temperature and supply gas, thereby performing the functions of not only supplying gas, but also lowering the temperature.

(27) It is obvious that, what described above are preferred embodiments to provide illustration for the examples clearly, but not intended to limit the present invention. For those skilled in the art, various changes or modifications can be made based on the description above. There is no need for the disclosure to exhaustively describe all possible embodiments. Any obvious changes or modifications derived from the present disclosure are all within the scope of the present invention.