A ring hoop type closed impeller

Abstract

The present invention relates to the technical field of centrifugal compressors, and provides a hoop-type closed impeller, comprising: a shroud; an impeller, which is connected to the shroud through a hoop; and a hoop, which comprises: a shroud-side curled edge, which is connected to the shroud; an impeller-side curled edge, which is connected to the impeller; and a curled-edge connecting portion, which connects the shroud-side curled edge and the impeller-side curled edge. All the shroud, the hoop and the impeller of the present invention can be formed by machining, so the accuracy and roughness of the parts will be significantly better than those of traditional plaster die-castings. The strength of the closed impeller is sufficient to withstand the same rotational speed as that of the traditional open impeller, and the efficiency and surge margin are greatly improved compared with the traditional open impeller. In addition, compared with the closed impeller made by plaster die-casting, the efficiency and surge margin will also be significantly improved due to the improved accuracy and roughness.

Description

Technical Field

[0001] The present invention generally relates to the technical field of centrifugal compressors. Specifically, the present invention relates to a hoop-type closed impeller. Background Art

[0002] In existing small-power centrifugal compressors (such as centrifugal refrigeration compressors with a refrigerating capacity below 100 kW and centrifugal air compressors with a rated power below 20 kW), the impellers of the centrifugal compressors are usually open impellers. Since the impeller sizes of small-power centrifugal compressors are generally small, the tip clearances between the impellers are large, and the height of the tip clearance can account for more than 15% of the height of the impeller outlet blades, resulting in strong tip leakage flow, and thus significantly reducing the efficiency of the centrifugal compressor and significantly reducing the surge margin.

[0003] The centrifugal compressor using a closed impeller can replace the tip leakage loss with the return loss, significantly improving the efficiency and surge margin. However, the existing closed impellers are usually processed by plaster molding casting. Due to the small wheel diameter and outlet width of the closed impeller, there are deficiencies in the casting accuracy, surface finish, and yield. Summary of the Invention

[0004] To at least partially solve the above problems in the prior art, the present invention proposes a hoop-type closed impeller, comprising:

[0005] A shroud;

[0006] An impeller, which is connected to the shroud through a hoop; and

[0007] The hoop, which comprises:

[0008] A shroud-side curled edge, which is connected to the shroud;

[0009] An impeller-side curled edge, which is connected to the impeller; and

[0010] A curled-edge connecting portion, which connects the shroud-side curled edge and the impeller-side curled edge.

[0011] In an embodiment of the present invention, it is stipulated that the shroud comprises:

[0012] A shroud wall, at the center of which there is a shroud shaft hole;

[0013] Flow guide vanes, which are arranged on the shroud wall around the shroud shaft hole; and

[0014] A shroud hub, which is connected to the shroud wall through the flow guide vanes.

[0015] In an embodiment of the present invention, it is stipulated that the impeller comprises:

[0016] An impeller disk, having an impeller shaft hole at its center, wherein the impeller shaft hole is engaged with the hub of the cover to connect the impeller with the cover; and

[0017] Impeller blades, arranged on the impeller disk, the number of the impeller blades being the same as the number of the guide vanes.

[0018] In one embodiment of the present invention, it is stipulated that the diameter of the impeller disk is greater than or equal to 1.05 times the trailing edge diameter of the impeller blades.

[0019] In one embodiment of the present invention, it is stipulated that the impeller shaft hole and the hub of the cover connect the impeller with the cover by clearance fit, transition fit or interference fit; and / or

[0020] After connecting the impeller with the cover through the engagement of the impeller shaft hole and the hub of the cover, the impeller disk and the hub of the cover are welded.

[0021] In one embodiment of the present invention, it is stipulated that the thickness of the cover side curl and / or the impeller side curl is greater than or equal to 0.5 mm.

[0022] In one embodiment of the present invention, it is stipulated that the cover side curl is connected to the cover wall, and the impeller side curl is connected to the impeller disk, wherein a protrusion is formed on the impeller side curl.

[0023] In one embodiment of the present invention, it is stipulated that an impeller hoop groove is provided on the impeller disk, and the protrusion is embedded in the impeller hoop groove to position the hoop.

[0024] In one embodiment of the present invention, it is stipulated that the elastic modulus of the material of the hoop is greater than the elastic modulus of the material of the cover; and

[0025] The elastic modulus of the material of the hoop is greater than the elastic modulus of the material of the impeller.

[0026] In one embodiment of the present invention, it is stipulated that the cover is integrally formed by machining; and / or the impeller is integrally formed by machining; and / or

[0027] The hoop is formed by laser cutting.

[0028] The present invention has at least the following beneficial effects: In the hoop-type closed impeller according to the present invention, the shroud, the hoop, and the impeller can all be formed by machining, so the precision and roughness of the parts will be significantly better than those of traditional plaster mold casting parts. Through reasonable fixture design, the assembly qualification rate can be guaranteed to be above 95%; the impeller and the shroud of the closed impeller are connected by the way that the impeller shaft hole cooperates with the hub of the shroud, and the hoop connects the shroud wall and the impeller disc, so that the strength of the closed impeller is sufficient to withstand the same rotational speed as the traditional open impeller, and the efficiency and surge margin are greatly improved compared with the traditional open impeller; in addition, compared with the closed impeller cast by plaster mold, due to the improvement of precision and roughness, the efficiency and surge margin will also be significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] To further clarify the advantages and features possessed by and other aspects of the embodiments of the present invention, more specific descriptions of the embodiments of the present invention will be presented with reference to the drawings. It can be understood that these drawings only depict typical embodiments of the present invention and will not be considered as limiting its scope. In the drawings, for clarity, the same or corresponding components will be denoted by the same or similar reference numerals.

[0030] Figure 1 FIG. shows a schematic structural view of a hoop-type closed impeller in an embodiment of the present invention.

[0031] Figure 2A FIG. shows a front view of a shroud in an embodiment of the present invention.

[0032] Figure 2B FIG. shows a side view of a shroud in an embodiment of the present invention.

[0033] Figure 3A FIG. shows a front view of an impeller in an embodiment of the present invention.

[0034] Figure 3B FIG. shows a rear view of an impeller in an embodiment of the present invention.

[0035] Figure 4 FIG. shows a schematic structural view of a hoop in an embodiment of the present invention.

[0036] Figure 5 FIG. shows a schematic view of the connection between the hub of the shroud and the impeller shaft hole in an embodiment of the present invention.

[0037] Figure 6 FIG. shows an enlarged schematic view of the location where the hoop is arranged in an embodiment of the present invention.

[0038] Reference numerals: 101, wheel cover; 102, hoop; 103, impeller; 201, wheel cover wall; 202, guide vane; 203, wheel cover shaft hole; 204, wheel cover hub; 301, impeller disc; 302, impeller blade; 303, impeller shaft hole; 304, impeller hoop groove. Detailed implementation mode

[0039] It should be noted that the components in the drawings may be exaggerated for illustration purposes and not necessarily to the correct scale. In the drawings, the same or functionally identical components are provided with the same reference numerals.

[0040] In the present invention, unless otherwise specified, "arranged on...", "arranged above...", and "arranged over..." do not exclude the presence of an intermediate between the two. In addition, "arranged on or above..." only represents the relative positional relationship between two components, and in certain cases, such as after reversing the product direction, it can also be converted to "arranged under or below...", and vice versa.

[0041] In the present invention, each embodiment is only intended to illustrate the solution of the present invention and should not be construed as restrictive.

[0042] In the present invention, unless otherwise specified, the quantifiers "a" and "one" do not exclude the scenario of multiple elements.

[0043] It should also be noted here that in the embodiments of the present invention, for clarity and simplicity, only a part of the components or assemblies may be shown, but those of ordinary skill in the art can understand that, under the teaching of the present invention, the required components or assemblies can be added according to the specific scenario requirements. Additionally, unless otherwise stated, the features in different embodiments of the present invention can be combined with each other. For example, a certain feature in the second embodiment can be used to replace the corresponding or functionally identical or similar feature in the first embodiment, and the resulting embodiment also falls within the scope of the disclosure or the scope of the record of this application.

[0044] It should also be noted here that within the scope of the present invention, the terms "the same", "equal", "equals", etc. do not mean that the two values are absolutely equal, but allow for a certain reasonable error, that is, the said terms also cover "substantially the same", "substantially equal", "substantially equals". By analogy, in the present invention, the directional terms "perpendicular to", "parallel to", etc. also cover the meanings of "substantially perpendicular to" and "substantially parallel to".

[0045] In addition, the numbering of the steps of each method in the present invention does not limit the execution order of the method steps. Unless otherwise specified, the method steps can be executed in different orders.

[0046] The present invention will be further described below in conjunction with specific embodiments with reference to the accompanying drawings.

[0047] Figure 1 The structural schematic diagram of a ring - hoop type closed impeller in an embodiment of the present invention is shown. As Figure 1 shown, the closed impeller includes a shroud 101, a ring - hoop 102, and an impeller 103. Among them, the ring - hoop 102 connects the shroud 101 and the impeller 103. When the centrifugal compressor operates, the ring - hoop type closed impeller rotates at a high speed, and the gas passes through the flow path between the shroud 101 and the impeller 103, and is successively pressurized by the guide vanes 202 in the shroud 101 and the impeller vanes 302 in the impeller 103 to form high - pressure gas for discharge. The pressure difference between the pressure surface and the suction surface of the guide vanes 202 and the impeller vanes 302 will cause the gas to instinctively flow around the blade tip from one side of the blade to the other side, forming tip leakage flow. The presence of the shroud 101 can suppress the formation of tip leakage and improve the impeller efficiency.

[0048] Figure 2A The front view of a shroud in an embodiment of the present invention is shown. Figure 2B The side view of a shroud in an embodiment of the present invention is shown. As Figure 2A and Figure 2B shown, the shroud 101 includes a shroud wall 201, guide vanes 202, a shroud shaft hole 203, and a shroud hub 204. The shroud 101 can be integrally formed by machining. Among them, a shroud shaft hole 203 is provided at the center of the shroud wall 201, the guide vanes 202 are arranged around the shroud shaft hole 203 on the shroud wall 201, and the shroud hub 204 is connected to the shroud wall 201 through the guide vanes 202. The shroud wall 201 can form the main body of the shroud 101, and the guide vanes 202 can perform the first pressurization on the gas about to enter the impeller 103 to make the air flow smoothly enter the impeller vanes 302.

[0049] Figure 3A The front view of an impeller in an embodiment of the present invention is shown. Figure 3B The rear view of an impeller in an embodiment of the present invention is shown. As Figure 3A and Figure 3BAs shown, the impeller 103 includes an impeller disk 301, impeller blades 302, an impeller shaft hole 303, and an impeller hoop groove 304. The impeller 103 can be integrally formed by machining. At the center of the impeller disk 301, there is an impeller shaft hole 303, and at the edge of the impeller disk 301, there is the impeller hoop groove 304. The impeller blades 302 are arranged on the impeller disk 301. The diameter of the impeller disk 301 can be greater than or equal to 1.05 times the trailing edge diameter of the impeller blades 302. The number of the impeller blades 302 is the same as the number of the guide vanes 202. The impeller shaft hole 303 is matched with the hub of the cover 204 to connect the impeller 103 with the cover 101, and the matching method can be, for example, clearance fit, transition fit, or interference fit. The impeller disk 301 can form the main body of the impeller 103, and the impeller blades 302 can perform a second stage of pressurization on the air flow at the outlet of the guide vanes 202, enabling the air flow to be discharged smoothly and efficiently reaching the target pressure.

[0050] Figure 5 Fig. shows a schematic diagram of the connection between a hub of the cover and the impeller shaft hole in an embodiment of the present invention. As Figure 5 shown, after the impeller shaft hole 303 is connected to the hub of the cover 204 in a matching manner, in order to increase the connection strength, the impeller disk 301 and the hub of the cover 204 can be further welded together.

[0051] Figure 4 Fig. shows a schematic diagram of the structure of a hoop in an embodiment of the present invention. As Figure 4 shown, the hoop 102 includes a cover-side curled edge 401, an impeller-side curled edge 402, and a curled-edge connecting portion 403. The curled-edge connecting portion 403 connects the cover-side curled edge 401 and the impeller-side curled edge 402. The hoop 102 can be formed by laser cutting. The thickness of the cover-side curled edge 401 and / or the impeller-side curled edge 402 can be greater than or equal to 0.5 mm. Figure 6 Fig. shows an enlarged schematic diagram of the arrangement position of a hoop in an embodiment of the present invention. As Figure 6As shown, the side crimp 401 of the wheel cover is connected to the wheel cover wall 201, and the side crimp 402 of the impeller is connected to the impeller disk 301. A protrusion may be formed on the side crimp 402 of the impeller, and the protrusion may be embedded in the impeller hoop groove 304 to achieve the circumferential positioning of the hoop 102, preventing relative movement between the hoop 102 and the impeller 103 when the impeller 103 rotates at high speed. The elastic modulus of the material of the hoop 102 is greater than that of the wheel cover 101 and the impeller 103, which makes the deformation amount of the hoop 102 less than that of the wheel cover 101 and the impeller 103 when the impeller 103 rotates at high speed, thereby preventing the separation of the wheel cover 101 and the impeller 103.

[0052] In the present invention, since the wheel cover 101, the hoop 102, and the impeller 103 can all be formed by machining, the accuracy and roughness of the parts will be significantly better than those of traditional plaster die-castings. Through reasonable tooling design, the assembly qualification rate can be guaranteed to be above 95%. The impeller 103 and the wheel cover 101 of the closed impeller are connected by the way that the impeller shaft hole 303 cooperates with the wheel cover hub 204, and the wheel cover wall 201 and the impeller disk 301 are connected by the hoop 102, which can make the strength of the closed impeller sufficient to withstand the same rotational speed as the traditional open impeller, and greatly improve the efficiency and surge margin compared with the traditional open impeller. In addition, compared with the closed impeller cast by plaster die-casting, due to the improvement of accuracy and roughness, the efficiency and surge margin will also be significantly improved.

[0053] Although the embodiments of the present invention have been described above, it should be understood that they are presented only as examples and not as limitations. It is obvious to those skilled in the relevant art that various combinations, variations, and changes can be made to them without departing from the spirit and scope of the present invention. Therefore, the width and scope of the present invention disclosed herein should not be limited by the above-disclosed exemplary embodiments, but should be defined only by the appended claims and their equivalents.

Claims

1. A hoop-type closed impeller, characterized in that, Comprising: Wheel cover; An impeller connected to the wheel cover through a hoop; And The hoop, which includes: A wheel cover side crimp connected to the wheel cover; An impeller side crimp connected to the impeller; and A crimp connection part connecting the wheel cover side crimp and the impeller side crimp.

2. The hoop-type closed impeller according to claim 1, wherein, The wheel cover includes: A wheel cover wall with a wheel cover shaft hole provided at its center; Flow guiding vanes arranged on the wheel cover wall around the wheel cover shaft hole; and A wheel cover hub connected to the wheel cover wall through the flow guiding vanes.

3. The hoop-type closed impeller according to claim 2, characterized in that, The impeller includes: An impeller disc with an impeller shaft hole provided at its center, and the impeller shaft hole is matched with the wheel cover hub to connect the impeller and the wheel cover; and Impeller blades arranged on the impeller disc, and the number of the impeller blades is the same as that of the flow guiding vanes.

4. The hoop-type closed impeller according to claim 3, wherein, The diameter of the impeller disc is greater than or equal to 1.05 times the trailing edge diameter of the impeller blades.

5. The hoop-type closed impeller according to claim 3, characterized in that, The impeller shaft hole and the wheel cover hub connect the impeller and the wheel cover through clearance fit, transition fit or interference fit; and / or After connecting the impeller and the wheel cover by matching the impeller shaft hole and the wheel cover hub, the impeller disc and the wheel cover hub are welded.

6. The hoop-type closed impeller according to claim 1, wherein, The thickness of the wheel cover side crimp and / or the impeller side crimp is greater than or equal to 0.5 mm.

7. The hoop-type closed impeller according to claim 3, wherein, The wheel cover side crimp is connected to the wheel cover wall, and the impeller side crimp is connected to the impeller disc, and a protrusion is formed on the impeller side crimp.

8. The hoop-type closed impeller according to claim 7, wherein, An impeller hoop groove is provided on the impeller disc, and the protrusion is embedded in the impeller hoop groove to position the hoop.

9. The hoop-type closed impeller according to claim 1, wherein, The elastic modulus of the material of the hoop is greater than the elastic modulus of the material of the wheel cover; and The elastic modulus of the material of the hoop is greater than the elastic modulus of the material of the impeller.

10. The hoop-type closed impeller according to claim 1, characterized in that, The wheel cover is integrally formed by machining; and / or The impeller is integrally formed by machining; and / or The hoop is formed by laser cutting.

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