JPS60166794A - Centrifugal compressor - Google Patents

Abstract

PURPOSE:To reduce the friction loss by continuously installing channel diffusers having guide vanes into annular form, onto the outlet of the diffuser of a centrifugal compressor. CONSTITUTION:A part which forms a diffuser 5 between a compressor body 4 and a casing 8 onto which a suction pipe 7 in the center part is installed are installed onto the body 4. An annular channel diffuser 10 is installed between the spiral chamber 6 of the casing 8 and the diffuser 5. A number of guide vanes 9 are arranged, keeping a certain intervals, in the circumferential direction, onto the channel diffuser 10, and the guide vanes guide the fluid which flows-out from the outlet of the diffuser 5 through direction change by 90 deg. and allows the fluid to smoothly flow in divided form into the spiral chamber 6. Therefore, the speed of the fluid in the spiral chamber can be decelerated sufficiently, and the friction loss can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a centrifugal compressor in which a fluid has a diffuser that converts almost completely the velocity energy imparted by the impeller into pressure energy.

In this specification, the term "compressor" includes an air blower.

In a conventional centrifugal compressor, as shown in FIG. 1, a drive shaft 2 having an impeller 1 attached to its end is rotatably supported by a compressor body 4 through a bearing and a seal 3. and,
A volute chamber 6 is formed on its outer circumferential portion, a portion forming a diffuser 5 is provided on the radially inner side of the vortex chamber 6 and is open to the main body 4, and an axial cylindrical portion to which a suction pipe 7 is attached is provided in the central portion. The formed casing 8 is attached to the main body 4,
The impeller 1 is housed between the main body 4 and the main body 4.

The fluid sucked in the axial direction of the impeller 1 from the suction pipe 7 is
The rotating impeller 1 boosts the pressure and gives velocity energy, which is discharged from the impeller 1 in the radial direction and then enters the diffuser 5, where the velocity energy is converted into pressure energy and reaches the outlet of the diffuser 5, where it flows into a vortex. It flows out into the chamber 6 and is guided to a discharge pipe (not shown) while swirling.

When fluid exits radially through the diffuser into the vortex chamber, the larger the diameter of the diffuser, the more the fluid is decelerated and pressurized therein. Therefore, in order to obtain a highly efficient centrifugal compressor, the outlet diameter of the diffuser must be made sufficiently large, and the velocity of the fluid flowing out into the swirl chamber must be made sufficiently slow. However, since increasing the outlet diameter of the diffuser increases the size of the entire compressor, such a design is not realistic. Therefore, in conventional centrifugal compressors, the outlet diameter of the diffuser is kept small at the expense of compressor performance, and the fluid is allowed to flow out into the swirl chamber while still having sufficient velocity energy. In addition, in order to reduce friction loss caused by a good flow path in the volute chamber and a high fluid velocity, the volute chamber is designed with a large flow path area and the velocity of the fluid in the vortex chamber is lower than the velocity at the diffuser outlet. ing. Therefore, when the fluid flows out from the diffuser into the swirl chamber, a loss occurs due to the expansion of the flow path area, which reduces the efficiency of the swirl chamber.

By extending the length of the diffuser as much as possible, the present invention allows the fluid to almost completely convert the velocity energy imparted by the impeller into pressure energy and to flow into the volute chamber without loss due to enlargement of the flow path. Centrifugal compression with a diffuser that can improve efficiency by draining (
The purpose is to provide compensation.

The present invention is a centrifugal compressor characterized in that a channel diffuser having a guide vane is connected to the outlet of the diffuser in an annular manner. By extending the length, the conversion of velocity energy into pressure energy is almost complete, and the flow exits the diffuser smoothly with respect to the flow in the vortex chamber by the guide vanes without loss due to expansion of the fluid flow path. ■] It is possible to improve the efficiency of centrifugal compression.

The present invention will be described in detail below with reference to FIGS. 2 to 4.

As shown in FIG. 2, the compression system according to the present invention includes an impeller 1 at the end (1-digit drive shaft 2 is compressed by a bearing and a seal 3 (rotatably and hermetically supported by the main body 4). A casing 8 is attached to the main body 4, and the casing 8 is formed with a cylindrical part in the axial direction where the diffuser 5 is formed between the main body 4 and the central suction v7. The compressor is similar to the conventional compressor shown in FIG. 1 in that the impeller 1 is housed in the casing 8 and the diffuser 5. An annular channel diffuser 10 at the opening of 4
It differs from the conventional one in that it has an additional i11.

The channel diffuser 10 includes the fjS4 shown in FIG.
As shown in the figure, a number of guide vanes 9 are circumferentially spaced apart from the outlet of the diffuser 5.
The fluid that has been diverted and flowed out is guided so that it can be divided and flowed smoothly into the swirl chamber 6. In addition, the channel diffuser 10 has a flow path area that gradually increases from the diffuser 5 side to the swirl chamber 6 side.
From the diffuser 5 to the swirl chamber 6 like the one shown in the figure
This prevents losses due to sudden expansion of fluid passages.

Moreover, as shown in FIG. 3, the channel diffuser 10 can increase the length of the flow path by extending the indoor vanes 9 in the circumferential direction, so that pressure energy is converted into pressure energy in the diffuser '5. It is possible to almost completely convert residual velocity energy into pressure energy.

Although the embodiments shown in FIGS. 2 to 4 have a single volute chamber, the present invention is not limited thereto and can be applied to centrifugal compressors having multiple volute chambers.

The present invention converts residual velocity energy that could not be converted into pressure energy in the diffuser into pressure energy by connecting a channel diffuser having guide vanes in an annular manner to the outlet of the diffuser in a conventional compressor. By gradually increasing the flow area of the channel diffuser by 4d, the steep 't' of the flow path that occurs when the flow flows from the diffuser to the swirl chamber is reduced.
! By reducing the velocity of the fluid in the volute chamber sufficiently, friction loss in the volute chamber can be eliminated, and by forming the channel diffuser in an annular shape, the compressor can be kept in a relatively small diameter. This has remarkable effects, such as the ability to

[Brief explanation of drawings]

FIG. 1 is a sectional view of a part of a conventional compressor, FIG. 2 is a sectional view of a part of a compressor according to an embodiment of the present invention, and FIG. 3 is a sectional view of a part of a diffuser at diameter D4 in FIG. The developed view, Figure 4, is the same overall developed view, and corresponds to one spiral chamber (in the case of a single spiral chamber, A indicates a range of 360 degrees).
. 1-m-impeller, 2-m-drive shaft, 3-m-bearing and seal, 4-m-body, 5-m-diffuser, 6--
Swirl chamber, 7---Suction pipe, 8-11 casing, 9---
One guide vane, 10-m-channel diffuser. Patent applicant Masayuki Takagi, patent attorney representing Ebara Corporation

Claims (1)

[Claims] 1. A centrifugal compressor characterized in that a channel diffuser having a guide vane is arranged in an annular manner at the outlet of the diffuser. 2. The centrifugal compressor according to claim 1, wherein the guide vanes are arranged in the circumferential direction at the outlet of the diffuser or at a position after the flow has been turned by 90 degrees.