JPS6030522Y2 - Pressure equalization structure of shaft sealing device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a pressure equalization structure between shaft sealing devices at both shaft ends of a barrel-type compressor or the like.

In the shaft seal devices at both ends of the turbo compressor, each unit shaft seal group is arranged in several stages in the axial direction, and between the unit shaft seal groups there is a chamber for equalizing the pressure between both shaft seal devices. The structure has a pressure chamber.

On the other hand, in order to increase the critical speed of the rotor, it is necessary to reduce the distance between the rotor bearings as much as possible, and for this purpose, the axial length of the bearings themselves must be short.

The pressure equalization chamber occupies a part of the bearing length, but in conventional structures, its axial length must be approximately equal to the diameter of the pressure equalization hole connected to this chamber, so the pressure equalization hole chamber space is more than necessary. It has an axial length of .

The present invention provides the required cross-sectional area of the pressure equalization hole by making the pressure equalization hole narrow in the axial direction and wide in the cross section direction.
As a result, the length of the pressure equalizing chamber in the axial direction can be reduced to the necessary limit, the length of the bearing can be shortened, and the bearing distance of the rotor can be made correspondingly smaller.

FIGS. 1 and 2 show a conventional example.

Figure 1 is a sectional view of the upper half of the barrel-type turbo compressor, including the shaft 5 with the shaft kept horizontal, up to the casing 1 at the end cover 2 on the right side, and Figure 2 is a cross-sectional view of the upper half thereof. FIG. 3 is a cross-sectional view of the lead-out portion of the pressure equalization hole from the pressure equalization hole chambers a', b', and C'.

In the figure, 1 is a casing, 2 is an end cover, 4 is a shaft seal ring forming a support for the unit shaft seal group (fin group) 11, 5 is a rotor shaft, and 7'
is an annular passage block in which the shaft sealing ring 4 is concentrically housed, and is concentrically inserted into the end cover 2.

Between the fin group 11, there are pressure equalization chambers a', bl,
cI, which is the hole 10 of the passage block 7', the end cover 2
The pressure equalizing pipe 12 is connected to a pressure equalizing pipe 12 through a hole in the wall thickness of the compressor, and the pressure equalizing pipe 12 is connected to a pressure equalizing chamber at a symmetrical position in the shaft sealing part on the left side of the compressor.

Here, the diameter d (Fig. 2) of the hole A in the end cover must give the required cross-sectional area as a pressure equalizing hole, and a passage block connecting this hole A to the pressure equalizing chamber a' or BL, cI. The through hole 10 in 7' also needs to have approximately the same diameter as the diameter d of hole A, and accordingly the pressure equalizing chamber at.

The axial lengths of bl and cI must also approximately match the diameter d of hole A, and there are limits to reducing the axial length of the shaft sealing device, that is, the bearing.

In the present invention, as shown in FIG.
It is constructed as a stack of circular rings 7a which are brought together in the axial direction at points b and c, and the groove 2 for pressure equalization is made small in depth, that is, shallow, on the circular ring surface as shown in Figures 4 and 5. is machined in the radial direction by increasing the width in the cutting line direction to provide the required cross-sectional area as a pressure equalizing hole, and making it communicate with the pressure equalizing chamber on the shaft seal ring side, and into the pressure equalizing hole in the end cover on the opposite side. It has a hole for communication.

By configuring the pressure equalization hole with a shallow groove as described above, the pressure equalization chamber that follows it can also be made narrower in the axial direction.
This makes it possible to shorten the bearing length, and thus the distance between the shafts.

[Brief explanation of the drawing]

Figures 1 and 2 show conventional examples of the shaft seal part. Figure 1 is a cross section of the upper half of the shaft seal device in the right end cover, and Figure 2 shows the condition of the pressure equalization hole drawn out in the shaft seal part. In cross section, Figure 3 shows the first
The device of the present invention is shown in the same cross section as the figure. 4 and 5 are front views of a ring constituting the passage block of the present invention. 1...Casing, 2...End cover, 4.
...Shaft seal ring, 5...Shaft, 7, 7'...
...Aisle block.

Claims (1)

[Scope of utility model registration request] An annular pressure equalizing hole passage block 7 is fitted concentrically into the end cover, a shaft seal ring 4 serving as a support for the fin group 11 is concentrically fitted in the passage block 7, and a shaft seal is placed between the fin groups. When a pressure chamber is provided, it is constructed as a stack of several rings 7a that overlap in the axial direction at the passage block pressure equalization chamber, and the depth and width are made small on this toroidal surface to form the required pressure equalization hole. A pressure equalizing structure for a shaft seal device in which a pressure equalizing groove with a cross-sectional area is machined in the radial direction, and this communicates with the pressure equalizing chamber on the shaft sealing side and the pressure equalizing hole in the end cover on the opposite side. .