JPS61135998A - Multistage centrifugal compressor - Google Patents

Abstract

PURPOSE:To prevent the deterioration of efficiency of compressor by a method wherein a pivotable movable vane, regulating the inflow angle of fluid with respect to an impeller, is provided at the downstream side of a return guide vane provided at a middle stage. CONSTITUTION:The pivotable movable vane 7, continuous with the return guide vane 4 and regulating the inflow angle of the fluid with respect to the impeller, is provided at the downstream side of the return guide vane 4 provided between a plurality of impellers 3 while the center of pivot of the movable vane 7 is provided near the connecting section of the return guide vane 4. According to this method, the efficiency of compressor may be improved by regulating the inflow angle of the fluid into the impeller in the middle stage properly and maintaining the smooth flow of the fluid.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a multi-stage centrifugal compressor, and a multi-stage centrifugal compressor equipped with a return guide vane between an upstream impeller and a downstream impeller. It's about machines.

"Prior Art" Conventionally, as one type of multi-stage centrifugal compressor, a structure shown in FIG. 4, for example, is known.

The horizontal multi-stage centrifugal compression system 1 has a plurality of impellers 3 spaced apart from each other along its length on a rotating shaft 2. A large number of return guide vanes 4 are integrally provided between these impellers 3 and guide the fluid discharged from the impeller 3 on the upstream side to the suction section 3a of the impeller 3 on the downstream side. In addition, an inlet guide vane 5'f is installed upstream of the first stage impeller, and the intake fluid amount is adjusted by completely changing the inflow angle of the fluid into the impeller 3.
It has a general structure. The inlet guide vane 5 is rotated about its center to adjust the intake fluid amount as described above.

By the way, in such a multi-stage centrifugal compressor, the inlet guide vane 5? When the volume of suction fluid is reduced by throttling, the so-called surging phenomenon occurs where the pressure oscillates when the amount of suction fluid becomes less than a certain value. When the surging phenomenon occurs, vibrations are induced in the piping, etc., and as a result, there is a risk of damaging the piping, etc., so countermeasures are required.

Therefore, as a result of intensive research, the present inventor provided a movable vane 6 having the same configuration as the inlet guide vane 5 on the downstream side of the II turn guide 9 vane 4 installed after the second stage, and the movable vane 6 is rotated based on the amount of suction fluid to adjust the inflow angle of the fluid flowing into the impeller 3 (see Figure 5).

"Problems that the Invention Attempts to Address" The present invention solves the following problems that remain in adjusting the fluid inflow angle using the movable vanes described above. It's a turtle trying to solve the problem.

That is, the movable vane 6? When the inflow angle is adjusted using the movable vane 6, since the center of rotation of the movable vane 6 is in the center, the end of the movable vane 6 on the side of the vane 4 will move along the chain line in FIG. As shown in the figure, the obstruction #yJh protrudes into the adjacent flow path, disrupting the flow of the crossing body, and increasing the flow loss and reducing the efficiency of the compressor.
This is a problem such as lowering the performance.

"A precautionary measure to solve all the problems" The present invention aims to provide a complete multi-stage centrifugal compressor that can effectively solve the problems mentioned above. A rotatable movable vane that is continuous with the return guide vane and adjusts the inflow angle of the fluid to the impeller is provided, and a rotation center of the movable vane is provided. Was it installed near the continuous part with the return guide vane? Features.

"Operation" The multi-stage centrifugal compressor according to the present invention changes the flow path of the fluid guided by the return guide vane using the movable vane, thereby changing the inflow angle of the fluid to the impeller when the amount of fluid sucked is small. Optimize the adjustment and move the end of the movable vane near the return guide vane to smooth the fluid flow.

"Embodiments" Two preferred embodiments of the present invention will be described below with reference to FIGS. 1 to 3. , Incidentally, in the following explanation, the same reference numerals are used for parts common to FIGS. 4 and 5 to simplify the explanation.

First, to explain the outline of this embodiment, as shown in FIG.
A rotatable movable vane 7 that continuously adjusts the inflow angle of fluid to the impeller. The center of rotation of the movable vane 7 is located near the continuous portion with the return guide vane 4.

Next, in detail, as shown in FIG. It is integrally attached to a rotating shaft 9 that penetrates near the section, and as the rotating shaft 9 rotates, the rotating shaft rotates as shown by the arrow (A) in FIGS. 2 and 3. 2
It is designed to rotate in a plane perpendicular to the . .

A swing arm 10 is provided perpendicularly to the portion of the rotation shaft 9 exposed from the diaphragm 8, and these
The movable vane 7, the rotation shaft 9, and the swing arm 10 are provided corresponding to each of the return guide vanes 4.

On the other hand, a drive mechanism ll for rotating each rotary shaft 9 is provided at a position surrounding the plurality of rotary shafts 91).

The drive mechanism 1.1 includes an annular rail 12 and the rail 1.
2? Support and movement in the circumferential direction? A plurality of guide rollers 13 for guiding and the plurality of guide rollers 1319
- It is composed of a fixed pole 14 for rotatably mounting on the die ÷ 7 ridge 58, and an annular rack 15 attached along the outer peripheral side of the rail 12. ), a connecting rod 18 rotatably attached to the rail 12 and the swinging end of each swing arm 10 by pins 16 and 17IC, respectively. It is connected to each rotating shaft 9 via the rotating shaft 9.

However, what is the suction amount of fluid for the single multi-stage centrifugal compressor of this embodiment, which is completely blind with such a configuration? If you want more, moveable vane 7? For example, rotate it! By placing it in the fully open state as shown by the chain line in FIG. 2, the inflow angle of the fluid into the impeller 3 is made appropriate.

On the other hand, when the suction volume is reduced by tightening the inlet guide page 75, it gradually approaches the surging region, but by adjusting the inflow angle of the fluid to the repeller, it is possible to move it to the surging region, where the air volume is small. It becomes possible.

Also, in the process of rotation of the movable vane 7, the movable vane 7
Since the center of rotation of the movable vane 7 is located close to the return guide vane 4 at the end of the movable vane 7, the movable vane 7 protrudes into the adjacent flow path over its entire rotation range. Never. In addition, communication between the fluid contact surface of the movable vane 7 and that of the return kite vane 4 is maintained in a smooth state at all times. Therefore, the shapes and dimensions of each component shown in the above practical example are merely examples, and can be changed in various ways based on design requirements. It's thick.

For example, the movable vane 7 may be provided in all stages after the second stage (or it may be provided in every second stage). It goes without saying that various actuators using fluid pressure can also be used.

"Effects of the Invention" As explained above, the multistage centrifugal compressor according to the present invention provides the following excellent effects.

■ Even if the amount of fluid intake is reduced,
The movable vane allows the angle of inflow of fluid into the impeller 3 at the intermediate stage to be properly adjusted, thereby preventing the occurrence of surging in lc when a small amount is sucked.

Therefore, the surging area can be narrowed down to the extent possible and the entire movable range can be expanded.

When adjusting the inflow angle of the fluid, maintaining the guide part that comes into contact with the fluid as a continuous surface prevents the formation of obstacles in the flow path and allows the fluid to flow smoothly. In combination with the above effects, the efficiency of the compressor can be improved.

[Brief explanation of the drawing]

1@1ryJ ~ 1ryJ ~ Shows an example of a single Ming winding. Figure 1 is a partially sectional front view, Figure 2 is an enlarged view of the main part, and Figure 3 is a diagram of ■- in Figure 2. ■ Cross-sectional view along the line, erased 4
The figure is a partially sectional front view showing an example of a structure of a multi-stage centrifugal compressor, and FIG. 5 is a diagram showing an example of a structure for changing a fluid flow path in an intermediate stage. l...Multi-stage centrifugal compression type 2... Rotating shaft 3... Impeller 3a... Suction part 4... Return kite vane 7... ...Movable vane 9... Rotating shaft 10 ... Swinging arm 11 ... Drive mechanism 12 ... Rail 13 ... Guide 90 -Ra 14...Fixing bolt 15...Rack 16, 1' 7...Pin 18...Connection rod.

Claims (1)

[Claims] A multi-stage centrifugal comprising a plurality of impellers mounted on a single shaft and a number of return guide vanes installed between each impeller to guide the fluid discharged from the upstream impeller to the suction section of the downstream impeller. In the compressor, a rotatable movable vane that is continuous with the return guide vane and adjusts the inflow angle of the fluid into the impeller is provided downstream of the return guide vane installed at an intermediate stage, and A multistage centrifugal compressor characterized in that a rotation center is provided near a continuous portion with the return guide vane.