JPS61223300A - Construction of half turbo machine - Google Patents

Abstract

PURPOSE:To make sure the fixing of a half turbo machine by providing a faucet groove along the surface of half construction and casing,and fixing them via a key coupled to said faucet groove. CONSTITUTION:Both sides of a faucet part are provided with a screw hole 45, and a key groove 46 is formed on an inner casing 60, so that a key 22 will be fixed to the said inner casing 60, using two bolts 23. As compared with the fixed die of conventional monolithic type in respect of tensile stress, the fixed die of keyed construction according to this invention is exposed to about a half of an axial load and about one-third to one-fourth of stress. Consequently, the fixing means according to this invention is well adaptable to a large-sized turbo machine.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a structure of a half-split turbomachine incorporating a half-split structure.

[Background of the invention]

FIG. 1 shows a cross section of the main part of the structure of a conventional turbomachine.

In the figure, the flow enters from the suction port (not shown) of the casing, is pressurized by the impeller 1a, passes through the diaphragm 51 to the next stage impeller 2a, and passes through the diaphragm 5'2 to the next stage impeller 2a. It is guided to the impeller 3a and transferred to a predetermined location 11h from the discharge port.

Further, a labyrinth 55 is provided between the diaphragms 51, 52 and the impeller. 'In the structure of such a turbomachine, the diaphragms 51 and 52 forming the fluid passage portion and the inner cage ring 60
, the labyrinth 55 is structurally divided into upper and lower halves.

Further, the canning 40 also has a structure in which it is divided into upper and lower halves.

In addition, the assembly and disassembly of a turbomachine is performed by dividing the structure into three main parts: the upper and lower half casing parts, the rotor part, and the upper half casing part. is incorporated, and the fixation with the casing is fixed at the spigot groove 41. However, in the case of the upper half casing part, when the built-in parts of the upper half part are assembled into the upper half casing, it is impossible to fix the built-in parts with the spigot groove part 4 alone. In other words, the contents inside the upper half of the casing will fall from the upper half of the casing due to its own weight. As shown, the casing has screws 42 and notches 43 on the side.
A notch 61 is provided on the built-in part side, and the inner casing is fixed to the casing with a fixing piece of a special bolt 20 with a round head.

Further, the fixing between the inner casing (inner casing) and the diaphragm, and the fixing between the diaphragm and the labyrinth are also done in accordance with FIG. 2(a), FIG. 2(b), and 2nd WA(Q).

Figure 3 (a) is from the half-cut surface 31 in Figure 2 (a) -
FIG.

Recently 1. The capacity of turbomachinery such as centrifugal compressors has increased,
Along with this, the members constituting the turbomachine have also become larger, and naturally the built-in parts of the half-split structure built into the casing have also become larger.

As a result, the weight of built-in objects also increased, and the fixed frame parts that prevent built-in objects from falling had to be increased in size to match the weight.

However, the problems associated with the increase in size will be discussed below.

In Fig. 3(a), if the fixed piece 20 is increased in size, it will become as shown in Fig. 3(b), and since it will interfere with the holes 44 for tightening the upper and lower casings, increasing the size is at a structural limit. There is.

Therefore, as shown in Fig. 3(a), we have a structure that uses 212 fixed pieces, that is, if the size is increased by one fixed piece and there is a problem, two fixed pieces are used to tighten the upper and lower casing through holes. In order to avoid interference, it is impossible to apply the load of the inner casing 60 evenly to the two fixed pieces, and when selecting the fixed piece size,
Considering safety, we selected the size considering the load of the inner casing on one fixed piece, so in the end,
It is sized to be supported by one fixed frame.

Same result as above.

Incidentally, prior art related to the structure of this type of half-split turbomachine is disclosed in Japanese Utility Model Publication No. 52-16401.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fixing device for a half-split turbomachine that can cope with an increase in the size of the structure of a half-split turbomachine.

[Summary of the invention]

The present invention relates to the structure of a half-split turbomachine that incorporates a half-split structure divided into an upper half and a lower half. The feature is that a pilot groove is provided across the surface, and the half structure is fixed to the half casing via a key fitted in the pilot groove, and it is suitable for increasing the size of the half turbo machine. This means that appropriate fixing measures have been taken.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3(C) and FIG. 4(a) show structures that deal with the problem when two fixed pieces are used.

A screw hole 45 is provided on both sides of a part of the inlet, a key $46 is provided in the casing and inner casing, and the key 22 is provided.
Fix the inner casing with two bolts 23.

In this method, as shown in Fig. 4(b), if the load on the inner casing is W, the pilot groove width is Q2, and the distance from the pilot groove to the screw hole 45 is nl, the load W is between the pilot groove width 6. , Since the load condition (concentrated load divided into one equal load and no load) is not determined, the load when selecting the Luji hole and bolt size is as follows.
For safety reasons, W1 load will be selected instead of W/2. Therefore, we decided to adopt the idea shown in Figure 4(c).

Its structure is shown in FIG. 4(d).

That is, the load W is applied as a concentrated load to the central part of the key. As a result, the load when selecting the screw hole and bolt size can be set to W/2.

Next, its structure will be explained.

As shown in Figure 4-6, which shows the key shape,
The distance between the two drilled holes 24 for fixing the key is L, and a tapered surface Δa is provided at the center between the L and both end surfaces 25 of the key, and the tapered surface and the key center are defined by the R dimension. A curved surface is provided at the center of the key.

FIG. 4(6) is a structural diagram showing the key shown in FIG. 4(f) being attached to the casing with two bolts.

In addition, FIG. 4(d) is also similar to FIG. 4(e).
It is a structural diagram in which the key shown in f) is attached to the casing with two bolts, and the inner casing is supported by the curved surface at the center of the key.

1 Next, we will consider the strength aspect, and Figures 5(a) and 5(b) show the method of examination.

1. Figure 5(a) shows a fixing piece for a special bolt with a round head, which was the previous shape.As you can see from the figure, there are two parts: the part that receives the load, and the part that transmits the load to the casing. Since the screw part and the screw part are integrated, the strength of this type of fixed piece is considered as follows.

゛If the load of the built-in object is W, and the distance between the load point and the center of the bolt is Ω, one bending moment is wx rts,
The stress generated in the cross-sectional area 91 of the neck of the bolt is the stress due to the sum of the bending moment WXn- and the tensile force W.

Figure 5(b) shows a method of fixing according to the present invention, in which a key and two bolts are used to fix the built-in parts, with the key part receiving the load and the screw part transmitting the load to the casing. is made up of separate parts.

Therefore, this type of strength study can be considered as first-order.

1) As can be seen from Fig. 4(f), the key itself has sufficient rigidity when compared with the previous shape shown in Fig. 5(a).

2) Due to 1), even if a load W is applied to the center of the key, it will deform as shown by the dotted line in Figure 1, and the convexity of the curved shape at the center of the key and the dimension AQ from the key end face will decrease. ,
Decide AQ so that it does not become O.

3) From items 1) and 2), when load iw is added.

The conventional bending moment does not act on the cross-sectional area 92 of the neck of the bolt, but only tensile stress acts on it.
The tensile force at that time is W/2. By determining the allowable value of this tensile stress, it is possible to determine the allowable value of the load W based on the allowable stress.

4) In other words, when comparing the tensile stress in the case of the fixing piece 17 with an integral droplet up to 3 points and in the case of the fixing piece with the key structure of the present invention, the axial load value is about 172 and the stress value is about 173.
~1/4.

[Effects of the Invention] As explained above, according to the present invention, a pilot groove is provided across the surface of a half-split structure and a half-split casing that houses the half-split structure, and a key fitted in the pilot groove is provided. I decided to fix it via .

The load can be supported by approximately 174 mm with respect to the fixing means using the fixed piece.

[Brief explanation of drawings]

Figure 1 is a sectional view of the main part of the structure of Jourai's turbomachine, Figure 2
Figure (a) is a cross-sectional view of the upper half casing of the first shell, Figure 2 (b) is an enlarged view of the fixed piece in Figure 2 (a), and Figure 2 (6) is a cross-sectional view of the upper half casing of the first shell. ), Figure 3 (“
a) - Fig. 3(b) is a plan view of the half section of Fig. 1, Fig. 3(C), Fig. 4(a) to Fig. 4(f), Fig. 5(a),
FIG. 5(b) is an explanatory diagram showing an embodiment of the present invention. la, 2a, 3a...impeller, 51.52...diaphragm, 60...inner casing, 55...
Labyrinth, 40...Casing, 20.21...
Fixed bud 1 Ryome 2 Cause (YU) Moga 3 Figure (a)

Claims (1)

[Claims] 1. In the structure of a half-split turbomachine that incorporates a half-split structure divided into an upper half and a lower half, a structure that straddles the surface of the half-split structure and the half-split casing that houses this half-split structure 1. A structure for a half-split turbomachine, characterized in that a spigot groove is provided in the spigot groove, and the halved structure is fixed to a half-split casing via a key fitted in the spigot groove.