JPS62251498A - Securing method of vane for centrifugal compressor - Google Patents

Abstract

PURPOSE:To facilitate the securing, when inserting a fastening bolt into a vane and fastening, by securing such that the sideface of the vane sinks by some depth into the surface material of casing. CONSTITUTION:A diffuser 11 is formed between a front casing 7 and a rear casing 8 so as to secure a vane 12. One tip 15 of the vane 12 is secured integrally with a rear casing 8 while the other is sunk by some depth 14 into the casing 7 so as to block the exciting force. Consequently, fatigue breakdown or crack can be prevented and the tip of vane can be secured easily.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for fixing a diffuser vane of a high-speed centrifugal (radial) compressor used in a gas turbine or the like.

[Conventional technology and its problems]

-a, compressor diffusers used in gas turbines work to increase pressure by slowing down the high-speed fluid that exits the compressor's impeller.Among these, vaned diffusers are By actively utilizing the action, large decelerations can be achieved in a small space. On the other hand, it is said that the collision loss at the vane inlet increases and the diffuser efficiency decreases.

Therefore, in a vane that is sandwiched between the front and rear casings and fixed through a tightening bolt, the tip of the vane collides with high-speed fluid from upstream, causing so-called aerodynamic interference, and is constantly excited (P in Figure 2). (see arrow), if this is a high frequency, fatigue failure or cracking may occur in a very short period of time.

Therefore, conventional methods include increasing the thickness of the vane to increase its strength, increasing the number of fastening bolts for stronger fixation, and even increasing the material strength by using a hard, high-toughness material for the vane. However, these measures have the following disadvantages. That is, increasing the thickness of the vane reduces the diffuser effect;
The flow rate also decreases. In addition, the tightening bolt cannot fix the thin part of the tip of the vane, and the material used for the vane is already of the highest quality, and it is not possible to use a material with higher hardness in terms of manufacturing technology and manufacturing cost.

[Means for solving problems]

Therefore, the present invention was created to eliminate such inconveniences, and in a vane-equipped diffuser for a centrifugal compressor, at least the surface of the casing is made of a material whose hardness is lower than that of the vane, and the material is fixed through tightening bolts. To provide a vane fixing method for a vane-equipped diffuser in which the side surface of the vane is reduced.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be explained in detail below with reference to embodiments shown in the accompanying drawings.

FIG. 1 is an overall sectional view of the first embodiment of the present invention, FIG. 2 is a sectional view taken along line AA in FIG. 1, FIG. 3 is a sectional view taken along line 3-13 in FIG. 3 is a C-CIJIT plane view, FIG. 5 is a second embodiment, showing a portion corresponding to FIG. 3 of the first embodiment, and FIG. 6 is a third embodiment, showing a portion corresponding to the first embodiment. A portion corresponding to FIG. 3 of the embodiment is shown.

The first embodiment is suitable for a small industrial gas turbine, and in FIGS. 1 to 4, 1 is a compressor impeller, 2
3 is an impeller rim, 3 is a rotor shaft, 4 is an intake shell, 5 is an intake hub, 6 is an air inlet, 7 is a front casing, 8 is a rear casing, and IO is a discharge part.

Here, in this embodiment, a diffuser 11 is formed between the front casing 7 and the rear casing 8, and vanes 12 are fixed thereto. That is, stainless steel (
The vane 12 made of ductile cast iron (FCD42) is integrated into the rear casing 8.
), the vane 12 is 1
By inserting and tightening the two tightening bolts 13, the sides of the vane 12 are reduced and fixed. Therefore, one of the tips 15 of the heel 712 is integrally fixed to the rear casing 8, and the other end is fixed to the casing 7 by a certain depth.
4 and is fixed, thereby blocking the excitation force.

In the second embodiment, as shown in FIG. 5, vanes 12a made of stainless steel are attached to the front and rear casings 7.
8, and is fixed by tightening with a tightening bolt 13 to a slight depth 14 in both casings 7 and 8.

In the third embodiment, as shown in FIG. 6, a plate body 16 made of a material with low hardness is pasted on the surface of the diffuser 11 of the front casing 7, and the cough plate body 16 is
By tightening the vane 12b with a tightening bolt 13, the vane 12b is fixed to the cough plate body 16 by being retracted to a slight depth 14.

Note that the present invention is not necessarily limited to compressors for small industrial gas turbines, but is applicable to at least any compressor that rotates at high speed.

Moreover, a hollow of some depth may be provided in advance at a portion where the side surface of the vane 12 is reduced.

2) In short, the present invention employs the configuration described in the claims, and therefore has the following effects.

〔Effect of the invention〕

Since the tip of the vane is reduced and fixed to at least one surface of the sandwiched casing, the compressor can be increased in speed, suppressing excitation force, and preventing fatigue failure and cranking. Moreover, since the vanes are not made thick, the flow rate does not decrease.

Further, since the tip of the vane is fixed during the fastening process, a simple IM fixing method can be used.

[Brief explanation of drawings]

FIG. 1 is an overall sectional view of the first embodiment of the present invention, FIG. 2 is a sectional view taken along line AA in FIG. 1, FIG. 3 is a sectional view taken along line nn in FIG. The cross-sectional view taken along the line C-C in the figure, FIG. 5, shows the second embodiment, and shows a portion corresponding to FIG. 3 of the first embodiment, and FIG. A portion corresponding to FIG. 3 of the example is shown. 7.8...Front, rear casing, 11...Diffuser, 12...Vane, 13...Tightening bolt, 1
4...Depth.

Claims (1)

[Claims] In a differential user of a high-speed centrifugal compressor, the vane is sandwiched between a front casing and a rear casing and is tightened and fixed to both casings with a tightening bolt inserted therein. , the vane is made of a material that is harder than at least the surface material of any of these casings, and when the tightening bolt is passed through the vane and tightened, the side surface of the vane is slightly deeper into the surface material of the casing. A centrifugal compressor vane fixing method that fixes the vanes in such a way that they are compressed.