JPH0618080Y2 - Multi-stage centrifugal compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an improvement of a multistage centrifugal compressor.

[Conventional technology]

FIG. 2 is a sectional view of a conventional multistage centrifugal compressor, in which 1 is a main shaft, 2 is an intermediate stage impeller, 3 is an intermediate stage diffuser, and 7
Is a return bend for guiding the flow to the next stage, and 8 is a return vane for guiding the flow to the next stage.

[Problems to be Solved by the Invention] The present invention is a conventional multistage centrifugal compressor in which a part of the flow rate of the intermediate stage is taken out to the outside for use. In this case, it is necessary that the pressure loss of the intermediate discharge flow be reduced and that the performance of the intermediate stage that performs the intermediate discharge is not deteriorated by the intermediate discharge.

Since the pressure drop of the intermediate discharge flow increases as the flow velocity at the time of branching from the intermediate stage increases, it is necessary to select the diversion point at a place where the flow velocity is low. It is necessary that the discharge flow uniformly flows out from the circumference.

Further, it is necessary to efficiently collect the fluid that uniformly flows out from the circumference and guide it to the discharge port.

The present invention is intended to provide a multi-stage centrifugal compressor that can satisfy the above conditions.

[Means for solving the problem] In the present invention, in order to reduce the pressure loss of the intermediate discharge flow and minimize the performance deterioration of the intermediate stage, the branch point of the intermediate stage is selected as the outlet part of the intermediate stage diffuser with a slow flow velocity. A multi-stage centrifuge is equipped with a circumferential slit as a flow path for the intermediate discharge flow to uniformly flow out from the circumference, and an intermediate discharge scroll for efficiently guiding the flow flowing from the circumferential slit to the intermediate discharge duct. It is characterized by constituting a compressor.

[Action]

Since the multistage centrifugal compressor of the present invention is configured as described above, when the main shaft and the intermediate stage impeller rotate, the fluid flows out of the impeller, passes through the intermediate stage diffuser, and partially exits the intermediate stage diffuser. Is guided to the intermediate discharge duct through the circumferential slit and the intermediate discharge scroll, and part of it is guided to the next stage through the return bend.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings.

FIG. 1 is a cross-sectional view of a multi-stage centrifugal compressor showing an embodiment of the present invention. In the figure, the same members as those shown in FIG.

In the figure, 4 is a circumferential slit for intermediate discharge, 5 is an intermediate discharge scroll, and 6 is an intermediate discharge duct. This part is a newly devised point.

In the multistage centrifugal compressor of the present embodiment configured as described above, when the main shaft 1 and the intermediate stage impeller 2 rotate, the fluid flows out from the intermediate stage impeller 2 and the intermediate stage diffuser 3
At the outlet of the intermediate diffuser 3, a part is guided to the intermediate discharge duct 6 through the circumferential slit 4 and the intermediate discharge scroll 5, and a part is further passed through the return bend 7 and the return vane 8. Guided to the stage.

[Effect of device]

As described in detail above, in the multistage centrifugal compressor of the present invention, since the intermediate stage branch point is provided at the outlet of the intermediate stage diffuser, the flow velocity at this point is low and the intermediate discharge flow is low. Is uniform on the circumference by the circumferential slit, and is efficiently guided to the intermediate discharge duct by the intermediate discharge scroll, so that the pressure loss of the intermediate discharge flow is suppressed to a minimum. As a result, the flow through the return bend is also uniform on the circumference, and the performance degradation of the intermediate stage is minimized.

[Brief description of drawings]

FIG. 1 is a sectional view of a multistage centrifugal compressor showing one embodiment of the present invention, and FIG. 2 is a sectional view of a conventional multistage centrifugal compressor. DESCRIPTION OF SYMBOLS 1 ... Main shaft, 2 ... Intermediate stage impeller, 3 ... Intermediate stage diffuser, 4 ... Circumferential slit for intermediate discharge, 5 ... Intermediate discharge scroll, 6 ... Intermediate discharge duct, 7 ... Return bend for guiding flow to the next stage , 8 ... Return vanes to guide the flow to the next stage

Claims (1)

[Scope of utility model registration request] 1. A circumferential slit for taking out a part of the flow rate of the intermediate stage from the compressor at an outlet portion of an intermediate stage diffuser of a multistage centrifugal compressor, and a fluid flowing out from the circumferential slit to an intermediate discharge duct. A multistage centrifugal compressor characterized by being provided with an intermediate discharge scroll for guiding.