JPS6128787A - Liquid injection method for screw compressor of non-oil supply type - Google Patents

Abstract

PURPOSE:To cool the working fluid without causing corrosion to the casing for a shaft sealing member of rotor bearing part by forming a through hole at the casing so as to put the flushing liquid passage for shaft sealing in communication with the space encapsulated in the rotor chamber. CONSTITUTION:At the shaft sealing part of a screw compressor of liquid injection type, a shaft sealing space is formed by a shaft sealing housing 10, No.1, No.2 labyrinth rings 8, 9 and No.1, No.2 sleeves 6, 7 fitted between the rotor shaft 5 and the casing 1. A labyrinth 26 is formed at the bore of said No.2 labyrinth ring 9, while an O ring 27 is fitted on its periphery, to prevent leak of the flushing liquid as well at the bore as the periphery to inside the rotor chamber 2. Meantime, part of the flushing liquid is injected into the space limited by the rotor through No.2 through hole 28 penetrating from the front to the rear, so as to perform cooling of the working fluid.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a liquid injection method for a liquid injection type oilless screw compressor.

(Prior art) Conventionally, in this type of screw compressor, liquid (not including lubricating oil) is injected into the rotor chamber mainly for cooling. Method using a spray nozzle provided (
(Refer to Japanese Utility Model Application Publication No. 58-102794) is common, but other liquid film sealing methods are also used. Among these, the former method using a spray nozzle is a method in which the cooling liquid is injected from the spray nozzle, sucked together with the gun, and compressed to cool the gas.

In addition, the latter liquid film seal method creates a small gap between the rotor shaft and its bearing, and a part of the flushing liquid for sealing the shaft seal is injected into the rotor chamber through this gap. This is used to cool the gas.

By the way, in the rotor chamber, it is only necessary to inject liquid to cool the gas in the confined space during the gas compression stage, where the gas temperature tends to rise due to adiabatic compression.
The injected liquid absorbs energy from the compressed gas, evaporates, and is efficiently discharged from the discharge port together with the gas.

On the other hand, if liquid is injected into the part where gas is being sucked before adiabatic compression, that is, before gas entrapment, the gas temperature has not yet risen, so it will not evaporate and the rotor and casing in that part will simply become wet. It is better not to pour liquid into this area, as doing so alone will lead to corrosion, especially to the casing.

However, in both of the above methods, since the liquid is injected into the entire rotor chamber, there is a problem in that the casing is corroded at the gas suction portion as described above.

In addition, with the latter method, the gap in the bearing part inevitably varies due to manufacturing tolerances, and it also changes during operation, making it difficult to control the gap to a constant value and keep the discharge gas temperature constant. Therefore, there is a problem in that the amount of liquid injected with accuracy must be different for each bearing part (there are two places in each of the #&male rotors, for a total of four places).

(Object of the Invention) The present invention was made in view of the above-mentioned conventional problems, and a part of the flushing liquid for shaft sealing is also used for gas cooling.
Moreover, it is an object of the present invention to provide a liquid injection method for a liquid injection type oil-free screw compressor that makes it possible to inject liquid only into the gas entrapment portion.

(Structure of the Invention) In order to achieve the above object, the present invention provides a shaft sealing member for the shaft sealing member of the rotor shaft bearing portion or a casing around the shaft sealing member.
A through hole is formed to communicate the Lashinda liquid flow path and the enclosed space in the rotor chamber, so that a portion of the flushing liquid is introduced into the enclosed space.

(Example) Next, the present invention will be explained according to the drawings which are one example.

FIG. 1 shows a shaft seal of an injection type screw compressor to which the method according to the present invention is applied, and shows a rotor chamber 2 in a casing 1 of the compressor and a rotor rotatably supported in the rotor chamber 2. (It consists of a pair of male and female rotors.) It is located in the part located between the lubricating oil chamber 4 around the bearing part 3, and there are two places for each rotor 3, and a total of four places in the casing 1. It is.

The shaft seals each have a first shaft inserted between the rotor shaft 5 and the casing 1. 2nd sleeve 6°7, 1st sleeve. Second
An upward shaft sealing space is formed in the labyrinth rings 8, 9 and the shaft sealing housing 10, and this shaft sealing space is further formed in the first shaft sealing space.
．． The first liquid film seal ring 11.12 Second.
The third space portion is divided into three parts, 13 degrees and 14.15 degrees.

Here, an O-ring 16 is fitted between the rotor shaft 5 and the first sleeve 6 to eliminate the gap between them.

The first labyrinth ring 8 has a normal parallel labyrinth 17 on its inner surface, and a first through hole 18 for buffer gas supply that opens in the middle of the labyrinth 17 in the main body.
is formed. The buffer gas in the first through hole 18 maintains the inside of the labyrinth 17 at high pressure to minimize leakage of lubricating oil from the lubricating oil chamber 4 to the first space 13 and from the first space 13. Lubrication oil chamber 4 to 7
This is designed to suppress leakage of Ratsinda liquid.

1st. Second. The third space portions 13, 14, and 15 communicate with a liquid supply port 19, a liquid drain port 20, and a drain outlet 21 formed in the casing 1, respectively. And 'jl
E [valve 22. Flushing liquid for liquid film sealing is supplied from the liquid supply port 19 via the first flow rate detection device 23 to the first sleeve 6 and the first sleeve 6. The lubricating oil is led to the drain port 20 and the drain outlet 21 through the gap between the second liquid film seal ring 11 and the second liquid film seal ring 11 and 12, so that even if lubricating oil leaks from the labyrinth 17 to the first space 13, , preventing any further flow toward the rotor chamber 2 side. On the other hand, the flushing liquid discharged from the drain port 20 is discharged from the second flow rate detection device 24. Fluid injection amount The flushing fluid from the drain outlet 21 may be discharged to the outside as it is or reused via the funnel valve 25, but the flushing fluid from the drain outlet 21 may be mixed with a small amount of lubricating oil from the labyrinth 17, so the fluid is not drained. It is sent to a processing device.

The second labyrinth ring 9 is located between the third space 15 and the rotor chamber 2, and has a splash labyrinth 26 on its inner circumference.
, and an O-ring 27 is inserted into the outer periphery of the O-ring 27 to completely prevent the flushing liquid from leaking into the rotor chamber 2 from the inner and outer peripheries.
8 to supply a portion of the flushing liquid into the rotor chamber 2.

That is, an appropriate number of second through holes 28 are provided at positions that communicate only with the confined space within the rotor chamber 2,
The liquid is not injected into the suction space inside, but only into the confined space.

And the first. By connecting the second flow rate detection devices 23 and 24 to a flow rate difference detection device 29 that detects the difference between the two detected values, and by connecting a manual controller 30 to the flow rate difference detection device 29, the detected value can be detected. By adjusting the liquid injection amount control valve 25 based on the difference, the amount of liquid injection into the confined space can be adjusted as appropriate.

As described above, the device ♂τ with the above configuration injects a portion of the flushing liquid into the confined space in the rotor chamber 2 through the second through hole 28 formed to communicate only with the confined space. In this manner, the shaft seal portion also has a liquid injection function, and the temperature in the confined space is maintained at a predetermined value by appropriately adjusting the amount of liquid injection.

In the above embodiment, the second through hole 28 was provided through the second labyrinth ring 9, but the present invention is not limited to this. Lubrication may be performed using the seal.

That is, in the shaft seal shown in FIG. 2, a second through hole 28a is formed across the second labyrinth 9 and the casing 1.1. The other parts are substantially the same as those shown in FIG. 1, and corresponding parts are given the same numbers.

(Effects of the Invention) As is clear from the above description, according to the present invention, a through hole (shown as a second through hole in the embodiment) that communicates the flushing liquid flow path with the confined space in the rotor chamber is provided. and to direct a portion of the flushing liquid into the confined space. This eliminates the need for liquid to be injected into the suction space in the rotor chamber, reducing the occurrence of corrosion on the casing, eliminating the need to use expensive corrosion-resistant materials as the casing material1), and lowering the cost of the casing. becomes possible.

In addition, by adjusting the supply amount of flushing liquid,
It becomes possible to easily adjust the amount of liquid injected into the confined space, and the temperature of the confined space and discharged gas can be kept constant with high accuracy.

Note that the amount of liquid injected is usually very small compared to the amount of flushing liquid supplied, and even if a part of it is used for injection, the shaft sealing function will not be affected.

Furthermore, since the liquid is injected simply by drilling into the shaft sealing member or the casing surrounding it, the processing of the liquid portion can be simplified.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view of the shaft sealing portion of a rotor of a liquid injection type oil-free screw compressor to which the liquid injection method according to the present invention is applied, and a diagram showing a flushing liquid supply means. It is a partial sectional view of the shaft seal part to which the Example is applied. DESCRIPTION OF SYMBOLS 1... Casing, 2... Rotor chamber, 3... Rotor, 5... Rotor shaft, 9... Second labyrinth, 28.
28a... second through hole. Patent Applicant Kobe Steel Co., Ltd. Agent Patent Attorney 2 persons (Figure 1, Section 2)

Claims (1)

[Claims] (1) A through hole is formed in the shaft sealing member of the rotor shaft bearing part or the casing around it to communicate the shaft sealing flushing liquid flow path with the confined space in the rotor interior, so that a part of the flushing liquid is transferred. A method for injecting liquid into an oil-injection type oil-free screw compressor, characterized in that the liquid is introduced into the confined space.