TURBO COMPRESSOR

Abstract

A first compression stage and a second compression stage being arranged at positions adjacent to each other. The first centrifugal impeller and the second centrifugal impeller are arranged in such an orientation that back sides of the first centrifugal impeller and the second centrifugal impeller face to each other. A connection flow path is formed in the first housing and the second housing for introducing the compressed fluid from the first compression stage into the second compression stage. An upstream portion of the connection flow path is formed integrally with the first housing, and a downstream portion of the connection flow path is formed integrally with the second housing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing a structure of a conventional turbo compressor;

FIG. 2 is a view showing a structure of a conventional turbo compressor;

FIG. 3 is a view showing a structure of a refrigerating circuit of a turbo refrigerator to which a turbo compressor in accordance with the present invention is applied;

FIG. 4 is a view showing a structure of a turbo compressor in accordance with an embodiment of the present invention;

FIG. 5 is a partial enlarged view showing the structure of the turbo compressor in accordance with the embodiment of the present invention;

FIG. 6 is a view showing a shape of an inner scroll chamber and an outer scroll chamber in a cross section along a line A-A in FIG. 5;

FIG. 7 is a perspective view of a first housing in the turbo compressor in accordance with the embodiment of the present invention; and

FIG. 8 is a cross sectional view along a line B-B in FIG. 5.

Claims

1. A turbo compressor comprising: a first compression stage for sucking and compressing a fluid, having a first centrifugal impeller and a first housing surrounding the first centrifugal impeller; anda second compression stage for further compressing the compressed fluid from the first compression stage, having a second centrifugal impeller coupled to the first centrifugal impeller via a rotating shaft and a second housing surrounding the second centrifugal impeller,the first compression stage and the second compression stage being arranged at positions adjacent to each other,wherein the first centrifugal impeller and the second centrifugal impeller are arranged in such an orientation that back sides of the first centrifugal impeller and the second centrifugal impeller face to each other,a connection flow path is formed in the first housing and the second housing for introducing the compressed fluid from the first compression stage into the second compression stage, andan upstream portion of the connection flow path is formed integrally with the first housing, and a downstream portion of the connection flow path is formed integrally with the second housing.

2. The turbo compressor as claimed in claim 1, wherein the first housing has a first scroll chamber surrounding the first centrifugal impeller and into which the fluid from the first centrifugal impeller is introduced, and an outlet flow path communicating with an end portion of the first scroll chamber and open to the second housing side, the second housing has: an introduction flow path curved from an axial direction to a radial direction and open to the first housing side to communicate with the outlet flow path such that the compressed fluid from the first compression stage is introduced thereinto; and a suction scroll chamber annularly surrounding a periphery of the rotating shaft for expanding the fluid from the introduction flow path in a circumferential direction; and a suction flow path for introducing the fluid from the suction scroll chamber into the second impeller, and the connection flow path is formed by the outlet flow path and the introduction flow path.

3. The turbo compressor as claimed in claim 2, wherein the first scroll chamber is formed by an inner scroll chamber surrounding the first centrifugal impeller and into which the fluid from the first centrifugal impeller is introduced, and an outer scroll chamber positioned on an outer side in a radial direction than the inner scroll chamber to communicate with an outlet portion of the inner scroll chamber, the outer scroll chamber extending in a circumferential direction so as to at least partially surround the inner scroll chamber, having a cross sectional flow path area larger than that of the inner scroll chamber, and forming the connection flow path together with the outlet flow path and the introduction flow path, andthe outer scroll chamber, the outlet flow path and the introduction flow path are formed so as to have flow path cross sections of a quadrilateral shape.

4. The turbo compressor as claimed in claim 2, wherein a curved portion of the connection flow path is formed as a gradually curved flow path so as to suppress peeling by fluid.

5. The turbo compressor as claimed in claim 2, wherein the first housing or the second housing is provided with a gas injection portion for additionally injecting a gas to the connection flow path.

6. The turbo compressor as claimed in claim 5, wherein the gas injection portion has a gas injection opening formed so as to inject the gas in a direction along a fluid flow in the connection flow path.

7. The turbo compressor as claimed in claim 6, wherein the gas injection opening is formed in the curved portion of the connection flow path.

8. The turbo compressor as claimed in claim 3, wherein the first housing or the second housing is provided with a gas injection portion for additionally injecting a gas to the connection flow path.