US759659A - Stuffing-box for gas-compressors. - Google Patents

Description

No. 759,659. PATENTED MAY 10, 1904. G. BRAUNGART, (In.

STUFFING BOX FOE GAS GOMPRESSORS.

APPLICIATION FILED $BIT. 12, 1903.

- N0 MODEL.

l ressure -a Z A? 5 Z6 3:? gi s: C. fly

" UNITED STATES Patented-Mayra 190 1.

PATENT OF ICE.

s ruF me-aox Fon eAs-coMPREssons.

' SPEGIFIOATIONformingpart or ma as No..759,659,-datedMay 10, 1904.

I 3 Application filed September 12, 1903- Serial No. 172,894. (No model.)

To all whom it may concern:

' Be it known that I, GEORGE BRAUNGART,J1'. a citizen of the United States of America, and a resident of'Chicago,.in the county of Cook, State of Illinois, have invented certain new and useful Improvements in Stufiing-Boxes for Gas-Compressors, of which the following is a specification.

v vide efiicient means I i I the piston-rod, "a liquid under stuiiing-box-is My invention relates to stuffing-boxes for gas-compressors, and is especially useful for preventing the leakage of gas along the piston-rods of high-pressure gas-compressors.

The main objects of my invention are to proprovide means for lubricating to provide means for causing pressure to resist theleakage of gas from the stufling-box of a gas-com pressor, and to provide means for automatically varying the pressure on said liquidso compressor, to

7 that same will always be proportionately more intense than the pressure of the gas leaking from said compressor, to avoid the necessity ing-box and oil-pressure 35 q of having such liquid pressure unnecessarily high, and to provideYmeans for maintaining such liquid-pressure with the leastexpenditure ,of' mechanical energy. I accomplish these objects by the device shown in .the accompanyjng drawing,- which represents a longitudinal section, partly broken away, of one frigerating-machine having thereon a stuff- 7 device constructed according to my invention. i the cylinderthe construction :shown head 1 of the gas-compressor has a piston-rod 2 extending longitudinally through the mid die of same and is provided .with a stuffing box of special form, as will be hereinafter described. The remainder of the cylinder and the piston are not shown, since'my inventionappliesmore particularly to the stufling-box and the means for preventing, leakage'along the piston-rod. The casing or shell 3 of the the head- 1. Within the counterbore of the shell of the stufling-box are seated a bushing 5, which serves as a guide to the piston-rod for preventing loss of gas j through leakage along the piston-rod of a gasother half, 24, and a piston 25 is slidably vwith cupleather packing-rings 28 for preat 29 with the air, so that the piston 25will be free to move in the cylinder 19 when the the chamber 13. A checkwalve 32 is propreferably made integral with vided in the pipe 31 to prevent a return flow 2, and aplurality of cup-leather packing-rings 5 6, preferably arranged as shown. Theleather packing-rings are secured in position by means of a plurality ofmetal rings 7, 8, 9, 1 and 10, and the cylindrical flaps of'the leather cups 6 are urged into close contact with the piston-rod 2 by means of the rubber-rings 11. Two of the rings 9 and 10 are preferably formed as shown,'so.as to provide annular chambers 12 and 13 around the piston-rod 2. The outer end 14 of the stufling-box is provided with packing-rings 15 and lfi which are compressed by glands l'l and 18, as is usual in devices of this class. An auxiliary cylinder 19 is secured to the. stufling-box and has its heads 20 and 21 con- I18Gl3d,-" respectively, with the chambers 12 I and 13 by means of the pipes 22. One half, 23, of the interior of the cylinder is bored to a considerably greater diameter than the mounted within the cylinder. Each of the 1 ends 26 and 27 of the piston, respectively, 1 fits the bore of the corresponding part of the cylinder. The piston 25 is also provided venting the leakage of the-contents of the cylinder between its respective ends, and the middle part of the cylinder communicates pressurejupon its opposite ends are not in equilibrium. The clearance-space at the left-- .hand end ofthe cylinder 19 communicates with a pressure-gage at 30, the pressure-gage being omitted in the drawing. The end 27 of the piston 25 is of considerably less area than the end 26, so that the piston 25 will be in equilibrium only when the contents of the chamber 13 are at considerably higher pressure than the contents of the chamber '12.

.9 The chamber 13 also communicates by means 'of a pipe 31 with an oil-supply, which is not shown in the drawing and which is adapted to supply oil at a certain constant pressure to of liquid from-the chamber 13 toward the oilsupplyand permit the pressure in the champredetermined oil-pressure, and thereby prethe 'by-pass of the oil-pump is set.

vent wasting of power atthe oil-pump. This oil-pressure is slightly greater than the low pressure (suction-pressure) of the gas in the compressor and is sufficient to prevent a leak age of gas while the piston is on its back stroke.

It will be understood that the .oil pump maintains a constant pressure on the oil in the pipe 31 and causes oil to flow into the chamber 13 whenever the pressure on the oil in said chamber is below the pressure at which As soon as the pressure in the chamber 13 becomes equal to or greater than the pressure to which the by-pass is -set the bye-pass valve opens, and the pump merely expends the amount of energy which is necessary for overcoming its own friction and maintaining the fixed pressure in the pipe 31. 2 i

- The operation of the device shown is as fol.- lows': Asit is almost impossible to prevent some leakage of gas along :the piston-rod of a Y 7 gas-compressor working under high pressure,

the leather packings will become sufficiently worn after a few strokes of the piston to allow a small leakage of gas along the pistonrod andinto the chamber 12. For reasons which will be hereinafter explained the pressure on the oil in the chamber 13 is always greater than the pressure of the gas in the chamber 12. The piston-rod moving through the chamber 13 in contact with the oil' carries with it a film of oil, and thus thoroughly lubricates itself. The oil used is preferably one which will not absorb the gas, and the film of oil surrounding the piston-rod between the chambers 12 and 13, being under greater pressure than the gas in the chamber 12, ef-

fectually prevents such gas from working its way along the piston-rod and toward the chamber 13. Since there is a slight leakage between the compression-cylinder and the chamber 12,the pressure of the gas 'in the chamber '12 will be variable, being at any instant approximately the same as the prevailing pressure in the compression-cylinder.

The oilpump is regulated to supply oil at a pressure greater than the exhagsting-pressure in the gas-compressing cylin er, and the oil-pressure at the pump is therefore normally higher than the lowest pressure in the gasleakage chamber 12. During the forward stroke of the piston-rod 2 the pressure in the gas-compression cylinderincreases and corre- I spondingly causes an increase ofthe pressure in the gas-leakage chamber 12. This causes a greater pressure on the end 26 ofthe piston 25 in 'the auxiliary cylinder 19 than is caused by the oil on the smaller end 27 of said piston, and the, piston therefore moves to the left until the resultant pressures on its ends 26 and 27 balance each other. Since the end 27 of the piston 26 is smaller in area than the end 26, equilibrium will occur only when the movement of the piston has increased the oilpressure in the chamber 13 to a pressure some chamber 12 changes and will therefore always be somewhat greater than the pressure on' said gas. The pressure on the oil in the chamber 13 will, however, never be excessively greater than that on the gas in the chamber 12, but will be maintained at an intensity just sufficiently greater to prevent'leakage of gas between the two chambers.

The work required of the oil-pump is just suflicient to supply at a pressure equal to the lowest pressure of oil required in the chamber 13 the amount of oil required for lubricating the piston-rod 2. The work, it will be seen, is very much less than the work which would be The opposing pressures on the piston required of the oil-pump if the pressure of oil in the chamber 13 were constantly maintained'at an intensity greater than the highest pressure in the cylinder of the gas-compressor, as has been already done in devices of this class. It will be seen that the auxiliary cylinder forms an oil-pressure regulator and results in a great saving of mechanical energy. 7

The pressuregage serves to indicate the varying pressures on the oil in the chamber 13, and thus assists in the adjustment of the by-pass outhe oil-pump.

It will be seen that numerous details of the construction shown may be altered without departing .from the spirit of my invention. I therefore do not confine myself to such deitails except as hereinafter limited in the claims.

What I claim as my invention, and desire to secure by Detters Patent, is v 1. In a device of the class described, the combination of a gas-compressing cylinder having a piston-rod extending through one end of same; a stufling-boxsurrounding said piston-rod; a chamber in said stuffing-box, extending around said piston-rod and adapted to receive gaseous leakage from said cylinder; asecond chamber in said stuffing-box,extend ing around said piston-rod, at the side of said first chamber which is away from the gas-compressing cylinder, and adapted to contain a liquid under pressure; and means operated by the pressure of the gas in said first chamber and adapted to exert on the liquid in saidsec- 0nd chamber a pressure greater than that of described.

2. In' a device of the class described, the i combination of a gas-compressing cylinder having a piston-rod extending through one end of same; a stufing-box surrounding said piston-rod; a chamber in said stufing-box eaautomatically maintain said liquid at a pro portionately higher pressure than the gas in said first chamber, substantially as described.

3. In a device of the class described, the combination of a gas-compressing cylinder having a piston-rod extending through one end of same; a stulfingbox surrounding said piston-rod; a chamber in said stufing-box extending around said piston-rod and adapted to receive gaseous leakage from said cylinder; a second chamber in said stuifing-box extending around said piston=rod at the side of said first chamber which is away from the gas-cornpressing chamber, and adapted to contain a liquid under pressure; means for supplying liquid at constant pressure to said second chamber; and means for automatically changing the pressure on saidiliquid and maintaining same at a proportionately higher pressure than the gas in said gas-chamber, substantially as described.

4:. In a device of the class described, the combination of a gas-compressing cylinder having a piston-rod extending through one end of same; a stuffing-box surrounding said piston-rod; a gas-chamber in said stufiing-box extending around said piston-rod and adapted to receive gaseous leakage from said cylinder;

a second chamber in said stufiing-box extending aroundsaid piston-rod, at the side of said first chamber which is away from the gas-compressing cylinder, and adapted to contain a liquid under pressure; an auxiliary cylinder having its ends connected respectively to said gas and liquid chambers; and a differential piston slidably mounted in said auxiliary cylinder and having its large end exposed to the gas so as to maintain a pressure on said liquid proportionately greater than the pressure on the gas in said gas-chamber, substantially as described;

Signed at Chicago, Illinois, this 5th day of September, 1903.

GEORGE BRAUNGART, J R.

Witnesses:

Runow RUMMLER, EUGENE A. RUMMLER.

Images