US3795460A

US3795460A - Sealing apparatus for gas compressor

Info

Publication number: US3795460A
Application number: US00205879A
Authority: US
Inventors: T Endo; S Sugimura
Original assignee: Mitsui Engineering and Shipbuilding Co Ltd
Current assignee: Mitsui Engineering and Shipbuilding Co Ltd
Priority date: 1970-12-16
Filing date: 1971-12-08
Publication date: 1974-03-05
Anticipated expiration: 1991-03-05
Also published as: JPS4929221B1

Abstract

Apparatus for sealing the rotor shaft of gas compressor by sealing liquid fed under pressure comprising buffer gas chambers for preventing the leakage of corrosive or noxious gas in the operating gas, non-corrosive and innoxious gas separated from the operating gas by condensation and evaporation being fed into the buffer gas chambers.

Description

Elnited States atent 1 1 m1 339mm Endo et a1. 1 an. 5, 1974 [54] SEALING APPARATUS FOR S FOREIGN PATENTS 0R APPLICATIONS COMPRESSOR Inventors: Takamasa Endo; Shojiro Sugimura,

' both of Okayama, Japan Assignee: Mitsui Shipbuilding and Engineering (10., Ltd., Tokyo, Japan Filed: Dec. 8, 1971 Appl. No; 205,879

Foreign Application Priority Data Doc, 16, 1970 Japan 45412108 US. Cl 415/175, 415/178, 415/179 int. C1. Fold 11/00, F()4d 29/08 Field of Search... 415/175, 176, 177, 178, 179

References Cited UNITED STATES PATENTS 8/1952 Ricc 415/175 1,125,782 7/1956 France 415/175 Primary Examiner-Henry F. Raduazo Attorney, Agent, or Firm-Howson and Howson [57] ABSTRACT Apparatus for sealing the rotor shaft of gas compressor by sealing liquid fed under pressure comprising buffer gas chambers for preventing the leakage of corrosive or noxious gas in the operating gas, noncorrosive and innoxious gas separated from the operating gas by condensation and evaporation being fed into the buffer gas chambers.

3 Claims, 2 Drawing Figures I" It; at; I

PATENTEDHAR W I 3.795.460

sum 1 or 2 FIG. 1

SEALING APIARATUS FOR GAS COMPRESSGR This invention relates to a gas compressor using buffer gas, and more particularly to sealing apparatus for such gas compressor.

The conventional rotary gas compressors are usually provided with equalizing gas chambers, sealing liquid chambers and atmospheric chambers which are arranged in juxtaposition along the axis of the rotor shaft for the purpose of sealing of the rotor shaft. Particularly in the gas compressor where a compressed gas or operating fluid containing corrosive or noxious gases a buffer gas must be used for preventing of leakage of the operating fluid. That is, an innoxious buffer gas under pressure is introduced into a buffer gas chamber formed between each said equalizing chamber and rotor, thereby to prevent corrosion of sealing sleeve in each sealing liquid chamber or danger to the human body. Such buffer gas, in prior art, is supplied from the outside, which means that operational cost is increased.

An object of the present invention is to eliminate such disadvantage of the conventional apparatus. Generally, saturation temperature of the corrosive or noxious gas and that of the principal constituent of operating fluid are different from each other. Thus, according to the present invention, operating fluid is cooled to separate the corrosive or noxious gases from the main constituent of operating fluid, and the non-corrosive and innoxious constituent of operating fluid is used as buffer gas.

The present invention is described hereinafter in detail with reference to the accompanying drawings, in

which:

FIG. 1 is a schematic illustration ofa gas compressor employing'the sealing apparatus according to the present invention; and

FIG. 2 is a schematic illustration of a gas compressor employing the another embodiment of the present invention.

Referring now to FIG. 1, there is shown diagrammatically a gas "compressor, generally designated by reference numeral 1, which, as will be seen, in provided with a rotor 3 enclosed by a casing 2. Each of the shafts 3a, 3b of said rotor 3 is enclosed by a buffer gas chamber 4, equilizing gas chamber 5, sealing liquid chamber 6 and atmospheric chamber 7 which are arranged in side by side relation in that order toward the outer end of each shaft as shown, and these chambers are partitioned from each other with labyrinth packings 8 or partition walls 9. In each of said sealing liquid chambers 6, are provided sealing sleeves 10, and sealing liquid is supplied to the chambers 6 through a sealing liq uid line 11.

Drain pipes

12 and 13 are connected to each equalizing gas chamber and atmospheric chamber '7, respectively, so that the sealing liquid flows into these chambers 5 and 7 is discharged therefrom through

drain pipes

12 and 13, respectively.

It will be also noted that bleeder pipes 14 and an out let pipe 15 are connected to the casing 2 of the gas compressor 1, and heat exchangers or gas coolers l6 and 17 are provided in the pipes 14 and 15, respectively. The bottoms of the

gas coolers

16 and 17 are connected by pipes to

condensate tanks

18 and 19, respectively. The number of the

gas coolers

16 and 17 and the

condensate tanks

18 and 19 may be suitably selected in accordance with a desired quantity of buffer gas and other factors. An end of a buffer gas pipe line 20 is connected to the top space in each of the

condensate tanks

18 and 19, the other end of the pipe line 20 being connected to the buffer gas chambers 41 of gas compressor 1.

During operation of the gas compressor 1, the operating fluid compressed by the compressor 1 is flown into the

gas coolers

16, 17 through bleeder pipes 14 or outlet pipe 15, and a part of the operating fluid is condensed at the gas coolers. The corrosive or noxious gas having higher saturation temperaturethanthat of the main constituent of the operating fluid is condensed and accumulated in the

condensate tanks

18, 19. Therefore, the gas accumulated in the tanks 1% 19 is non-corrosive and innoxious, and the gas is supplied to the buffer gas chambers 4 through the buffer gas pipe line 20. Thus the operating fluid in the gas compressor is perfectly isolated from the chambers 5, 6 and 7. Pressure in the buffer gas chamber 4 is relatively low because pressure in the chamber 21 adjacent thereto on the rotor side is kept at a relatively low level by means of labyrinth packing or other like means, so that buffer gas in the

condensate tanks

18, 19 may be introduced directly into the buffer gas chamber 4.

Referring now to FllG. 2, there is shown an another embodiment which is suited for the case where the innoxious gases or non-corrosive gases contained in the operating fluid have easily condensable disposition. In FIG. 2, same reference numerals are used to denote same parts as in the arrangement of FIG. 1, and no explanation is repeated here for these parts. The differences of this embodiment from that of FIG. 1 are that an end of the buffer gas pipe line 26 is connected not to the top space in each of the

condensate tanks

18, 19, but to a lower part thereof, and that an evaporator 22 is incorporated in the line 29.

According to this arrangement, the innoxious or noncorrosive gas in the operating fluid is reevaporated in the evaporator 22 to utilize it as buffer gas.

From the foregoing, it will be understood that according to the present invention required buffer gas is easily obtained from the apparatus itself without introducing from other buffer gas sources. Also, by enlarging the capacities of the

condensate tanks

18, 19, it is possible to protect the sealing sleeves from damage and the operator from danger when the gascompressor is stopped.

We claim:

1. in a gas compressor apparatus having a rotor mounted on a driven shaft for compressing an operating fluid, sealing portions at opposite ends of said driven shaft and buffer gas chambers mounted around said shaft intermediate said rotor and said sealing portions to exclude flow of operating fluid from said rotor into said sealing portions, the improvement including a heat exchanger for the operating fluid flowing through said rotor, means to extract a portion of the operating fluid from said heat exchanger including a tank for containing the extracted fluid, said tank comprising means for separating corrosive or noxious components of the extracted operating fluid from the remainder, and means for directing at least a portion of said remainder into said buffer gas chambers in gaseous form whereby said buffer gaschambers are supplied with a gas which is free from corrosive or noxious components which may adversely affect said bearing portions and is composed only of the remainder of the operating fluid which does not contaminate said operating fluid.

2. Apparatus according to claim 1 wherein said corrosive or noxious components of said operating fluid have a higher saturation temperature than the remainder, said extracting means comprising a conduit connected to said heat exchanger to direct condensate therefrom into said tank, said tank operating to separate said components by selective evaporation of the condensate, the means for directing at least a portion of said remainder comprising a conduit having one end connected to the top of said tank and its other end connected into said buffer chambers.

3. Apparatus according to claim 1 wherein said noxbuffer chambers.

Claims

1. In a gas compressor apparatus having a rotor mounted on a driven shaft for compressing an operating fluid, sealing portions at opposite ends of said driven shaft and buffer gas chambers mounted around said shaft intermediate said rotor and said sealing portions to exclude flow of operating fluid from said rotor into said sealing portions, the improvement including a heat exchanger for the operating fluid flowing through said rotor, means to extract a portion of the operating fluid from said heat exchanger including a tank for containing the extracted fluid, said tank comprising means for separating corrosive or noxious components of the extracted operating fluid from the remainder, and means for directing at least a portion of said remainder into said buffer gas chambers in gaseous form whereby said buffer gas chambers are supplied with a gas which is free from corrosive or noxious components which may adversely affect said bearing portions and is composed only of the remainder of the operating fluid which does not contaminate said operating fluid.

3. Apparatus according to claim 1 wherein said noxious or corrosive components have a lower saturation temperature than the remainder, said extraction means comprising a conduit connected to collect condensate from said heat exchanger and direct it into said tank, said means to direct at least a portion of said remainder from said tank comprising a conduit having one end connected to the bottom of said tank and its other end connected to said buffer chambers and an evaporator in said conduit to convert the remainder from condensate form to gaseous form prior to admission into said buffer chambers.