JPH0613879B2 - Vane fixing device for centrifugal compressor - Google Patents

Description

The present invention relates to a fixing device for a differential user vane of a high-speed centrifugal (radial) compressor used in a gas turbine or the like.

[Conventional technology and its problems]

Generally, the diff user of the compressor used in the gas turbine works to slow down the high-speed fluid that has exited the impeller of the compressor to increase the pressure. Since the action of the vanes is positively used, large deceleration is possible in a small space. On the other hand, it is said that the collision loss at the vane inlet increases and the efficiency of the diff user decreases.

Therefore, in the vane which is sandwiched between the front and rear casings and fixed by tightening bolts, high speed fluid from the upstream collides with the tip of the vane, causing so-called aerodynamic interference, and is constantly excited (P in FIG. 2). (See arrow), if this is a high frequency, it may cause fatigue fracture or crack in a very short period.

Therefore, conventionally, the method of increasing the thickness of the vane to increase the strength, the method of increasing the number of fastening bolts for fixing to strongly fix the vane, and the material strength is increased by using a hard and highly tough material for the vane. Although measures such as methods are provided, these measures have the following inconveniences. In other words, increasing the thickness of the vane reduces the Diff user effect, and
The flow rate also decreases. In addition, the tightening bolt cannot fix the thin portion of the vane tip, and the vane material is already of the highest grade. If the hardness is higher than this, the manufacturing description and the manufacturing cost will not hold.

[Means for solving problems]

Therefore, the present invention has been made to eliminate such inconveniences, and the gist thereof is to be sandwiched between the front casing and the rear casing of a high-speed centrifugal compressor, and
In a Diff user having a vane for fastening and fixing both of these casings with a fastening bolt inserted, the vane is made of a material that is at least harder than the surface material of one of these casings, and the vane is secured by the fastening bolt. In the vane fixing device of the centrifugal compressor, characterized in that the side surface of the vane is tightened so that the surface material of the casing is destroyed to the depth of the group.

〔Example〕

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

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

The first embodiment is suitable for an industrial small gas turbine, and in FIGS. 1 to 4, 1 is an impeller of a compressor, and 2 is a compressor impeller.
Is an impeller rim, 3 is a rotor shaft, 4 is an intake shroud, 5 is an intake hub, 6 is an air inlet, 7 is a front casing, 8 is a rear casing, and 10 is a discharge part.

Here, in this embodiment, a differential user 11 is formed between the front casing 7 and the rear casing 8, and the vane 12 is fixed thereto. That is, the vane 12 made of stainless steel (SCS24) is attached to the rear sac 8
Integrated into the ductile cast iron (FCD4
For the front casing 7 consisting of 2), this vane 12
Is clamped through one tightening bolt 13 and tightened, so that the side surface of the vane 12 is destroyed and fixed. Therefore, one end 15 of the vane 12 is integrated with the rear casing 8 and the other end is fixed to the casing 7 by being depressed to a slight depth 14 to prevent the exciting force.

In the second embodiment, as shown in FIG. 5, the vane 12a made of stainless steel has the front and rear casings 7,
It is constructed as a separate body from 8, and is tightened with a tightening bolt 13 so as to be fixed to both casings 7 and 8 at a slight depth 14 so as to be destroyed.

In the third embodiment, as shown in FIG. 6, a plate body 16 made of a material having low hardness is attached to the surface of the front casing 7 in the differential user 11, and the vane 12b is attached to the plate body 16. Are tightened with the tightening bolts 13, so that they are fixed to the plate body 16 at a slight depth 14 by being depressed.

Note that the present invention is not necessarily limited to a compressor for an industrial small gas turbine, but can be applied to any compressor that rotates at a high speed.

Further, a part of the side surface of the vane 12 which is to be destroyed may be provided with a hollow at a slight depth in advance.

〔The invention's effect〕

According to the present invention, since the tip of the vane is fixed by being cut into at least one surface of the sandwiched casing, the accelerated compressor suppresses the excitation force,
Fatigue damage and cracks can be prevented. Moreover, since the vane is not thick, the flow rate does not decrease. In addition, since the tip of the vane is fixed during tightening and fixing, a simple fixing method can be achieved.

[Brief description of drawings]

1 is an overall sectional view of a first embodiment of the present invention, FIG. 2 is a sectional view taken along line AA of FIG. 1, FIG. 3 is a sectional view taken along line BB of FIG. 2, and FIG. FIG. 5 is a sectional view taken along line C-C in FIG. 3, and FIG. 5 is a second embodiment showing a portion corresponding to FIG. 3 of the first embodiment.
FIG. 6 is a third embodiment and shows a portion corresponding to FIG. 3 of the first embodiment. 7, 8 ... Front and rear casings, 11 ... Diff user, 12 ... Vane, 13 ... Tightening bolt, 14 ... Depth.

Claims (1)

[Claims] 1. A diff user having a vane that is sandwiched between a front casing and a rear casing of a high-speed centrifugal compressor and that is fastened and fixed to both casings by a fastening bolt that is inserted. , The vane is made of a material that is harder than at least one of the casing surface materials, and the vane is tightened by the tightening bolt so that the side surface of the vane is slightly deepened into the casing surface material. A vane fixing device for a centrifugal compressor, characterized by the above.