US1757782A - High-pressure piston or reciprocating compressor - Google Patents

Description

May 6, 1930. c. SCHAER 1,757,782

HIGH PRESSURE PISTON OR RECIPROCATING COMPRESSOR Filed Feb. 16, 1928 2 Sheets-Shet l I Fh/ENTU R:

May 6, 1930.' c. SCHAER 1,757,782.

HIGH PRESSURE PISTON OR REQIPROCATING COMPRESSOR Filed Feb. 16, 1928 2 Sheets-Sheet 2,

INVENTU R: 61% QMW BY wawxwfaw ATI'DRNEYS Patented May 6, 1930 UNI-TED 'STAT'EVSVPATEN'F oFFicE GHARLES SCHAER, F LANGENTHAL, swITzER-LAE AssreivoR To THE FIRM scLzER FRERES SOCIETE ANONYJVIE, OF

INTERTH R, SWITZERLAND HIeE-rREssURE PISTON 0R RECIPROGATING OoMPRESSOR I Application filed February 16, 1928, SerialNo. 254,728, and in Switzerland October S, 1927. v

' This'invention relates to high pressure piston or reciprocating compressors or the like of the kind in which the driving apparatus drives the compressor piston or intermediate piston'connected thereto through the medium of an oscillating column of liquid.

' ings,in' which According tothepresent invention each liquid column is provided with at least one automatically opening closure member. The closure member may constitute a relief valve for the escape of air from the liquidcolumn, or a safety device which opens when a maximum permissible pressure is exceeded. When at least two liquid columns and more than one valve or closure -mem ber are provided, the liquid columns may be connected together by valves by means of which the pressure difference can again be correctly adjusted automatically when excessive differencesin pressure occurbetween the liquid columns. Preferably each liquid column isnot' only provided with at least one closure member in the form with at least one closure member in the form of a safety device. In addition atleast one of'the closure members may serve asa' feed device for the liquid column.

The invention is particularly applicable to compressors of the above type in which the intermediate piston, i. e. the piston which drives the compressor piston, is exposed on both faces to the said column.

A few constructional examples of the in vention in its application to a high pressure reciprocating compressor are illustrated by wayof example in the accompanying draw,-

Figure 1 showsa compressor according to the invention partly in section, and partlyin elevation, V I Figures 2, 3 and 4 show modified forms of compressor according to the invention, and

Figure 5 showsa detail. In the construction illustrated in Figure 1 the primary piston 2 of the driving machine (not shown) reciprocates within a: cylinder 1 while the intermediate pistons 5 and 6 re ciprocate within cylinders 3 and 4 respec tively and actuatethe compressor pistons .7 and 8. On the casings 9 and 10 are mounted The feed devices are of a relief valve, but also end position.

the compressor cylinders A and B. In the cylinder. spaces to the left and right of the piston 2 are disposed the driving liquid columns I and II, whilst in the connecting meme ber 11 is enclosed a connecting liquid column III. Oil is preferably used as the pressure transmitting medium and this'is supplied to the columns III, I and II by the feed devices 15, 16 and 17 respectively. Each of the chambers, containing the liquid columns III, I and II is'provided with a closure member in the form of a safety device 12,13 and 14 respectively and with at least one closure member in the form of an airrelief valve 18, 18 or 19 or 20. The safety devices may, for example, be in the form of outlet valves of known construction and may terminate in a collecting pipe ora collecting tank not shown. connected to a pressure supply pipe, or to apressure supply tank not shown. In addition to the above mentioned devices the piston 2 of the driving machine is provided with valves 21 and 22 and'the pistons 5-and 6 with valves 23, 24 and 25, 26 respectively, For the sake of clearness' the valves, which are spring controlled, are shown as open in the mid position of the piston, whilst in the dotted end positions of the. piston they are shown in the position which they then occupy. p 1

The displacement volume (stroke m'piston area). of the primary piston 2 ofthe driving machine'is'larger than the displacement volumes ofthe intermediate pistons 5 and 6 6 is limited by stops 40 and 41 and 42 and 43 respectively. As a result, the intermediate plstons will reach the limits of their strokes before the primary piston 2 has reached its Excessively high pressures would therefore occur inthe oil columns if means were not provided for controlling these pressures. According to Figure 1 this is effected by providing in each piston 2, 5

as describedabove, and so constructing these valves that whe Prgssure on-one. face and 6 two valves 21, 22 and'23, 24 and 25, 26

of the piston exceedsthat on the other face by a predetermined amount, oil can pass through. If now the piston 5 reaches the end of its stroke before the piston 2 has reached the end of its stroke, i. e. while it is still moving to the left, the oil, which the latter piston continues to displace until it reaches its left hand reversing point passes through the valve 23 into the liquid column III", thus relieving the excess pressure. Should the piston 6 have already reached the up er end of its stroke oil will flow from the chamber III through the valve 26 into the liquidcolumn II. The oil which has been a lost during the operation by leakages is replaced through the feed valves 15, 16 and 17. If, for example, liquid has been lost from the column I through the stufling boxes, the piston 5 will reach the stop limiting the upward stroke before the piston 2 has reached the end of its stroke to the right. A vacuum would therefore be produced on the lefthand side of the piston 2 in the liquid column I if the oil were not automatically replaced through the valve 16 which, during a predetermined portion of the stroke has a'higher pressure than the liquid column itself. The replacementof oil in the oil columns II and III is efl'ected'ina similar manner.

If an extremelyrapid'adjustment is required to avoid large increases in pressure,

closure members 12, 13 and 14: in the form of 7 safety valves, are provided. The valves 21 to- 26 are not absolutely essential as their purpose can be fulfilled by the safety devices 12,113 and 14.. I

The construction shown in Figure2 differs from that shown in Figure 1 in that two feedrvalves 15 are provided for the connecting liquid column III. One of these, for" example, the left-hand one, supplies pressure transmitting liquid of normal pressure when the. device is inoperative,vwhile the righthand one-supplies liquid at increased pressure. The piston 2 of the driving machine and the intermediate pistons 5 and 6are not 7 provided with valves in this construction.

In place thereof there is providedan automatically opening closure member which acts as a by-pass device. The liquid column I is connected by the valve 27 and the bypass pipe 28 tothe coupling liquid column III, whilst the liquid column II is connected to.

the liquid column III by the valve 29 and the bypass pipe 30.

In accordance with the method of construction adopted, the displacement volume of the piston 2 is larger than that of the pistons 5 and 6; thelatter therefore reach the limits of their strokes before the piston 2 has. reached itsdead point positions. If an excess pressure now occurs, for example in the 'columnI relatively to the column III,

this pressure will be adjusted by a correspending "discharge through the overflow Figure 3' hows an application to a compressor 1n which the connecting liquid column is located above the piston 2 of the driving machine and in this case separate. by-passmembers, or piston, valves of equivalent action are not provided. For the purpose ofreplenishing all three columns, feed valves 15, 16 and 17 are, however, provided and in addition to the closure members 18, 18, 19

and 20, formed as air escape valves, there are provided safety valves 12, 13 and 14 which open is exceeded. fIf during" the operation too much oil is present in any column for any reason,it can flow out through the safety when almaximum permissible pressure 7 valves, also a deficiency in oil isjimmediately made up when the pressure in one of the columns has been reduced to a value below that of the replenishing oil.

' In order to avoid shocks, or knocking, the intermediate pistons 5 and 6 may also be provided with extensionsld a'nd'45-which in the neighbourhood of the dead point engage with a stop,such for example'as 43 or 40,to limit their stroke, in such a manner that the liquid displaced by the pistons is throttled. In this manner the movement of the pistons 5 and 6is retardedtowards the end of the stroke and they comeinto contact with an oil cushion 17 as isindicated by dotted lines-in the case of the driving piston 6-shown in Figure 5. V

In the single stage compressor illustrated in Figure 4, twofeed valves 31 and 32,- and two equalizing valves 36 and 37 are provided for adjusting thepressure in the liquid columns, an air relief valve 38'beingprovided {for theliquid column'I. Similarly the coL umn II has two air relief valves 39 and 4 6 and each column has a safety valve 33 and 34;

These only come .into operation when the pressure in the liquid columns exceeds a predetermined amount, for example should the valves 36 and 37 fail. The method of opera- 7 tion corresponds with that of the piston machines previously described. If desired, the air relief valve-may be. connected to a. safety device. i

I claim:

1. Ina high pressure reciprocating compressor, the combination witha primary-piston effecting a positive movement, ofatle'astone intermediate piston, a'compressor piston connected to said intermediate piston, an oscillating column of liquid between said primary and intermediate pistons, means for supplying liquid to said liquid column, and means for allowing the escape of air from said liquid column.

2. In a high pressure reciprocating compressor, the combination with a horizontally arranged primary piston effecting a positive.

movement, of a plurality of vertically arranged intermediate pistons, a compressor piston connected to each intermediate piston, an oscillating column of liquidbetween one side of said primary piston and one of said intermediate pistons, a second oscillating liquid column between the other side of said primary piston andanother of said intermediate pistons, a third oscillating column of liquid between said intermediate pistons, means for supplying liquid to said liquid columns, and a air from each of said liquid columns.

3. In a high pressure reciprocating compressor the combination with a primary piston effecting a positive movement, ofat least one intermediate piston, a compressor piston connected to said intermediate piston, an oscillating column of liquid between said primary and intermediate supplying liquid to said liquid column, a relief valve for the escape of air from said liquid column, and a safety device which opens when a maximum permissible pressure in said liquid column is exceeded.

4:. In a high pressure reciprocating compressor the combination with a horizontally arranged primary piston effecting a positive movement, of a plurality of vertically arranged intermediate pistons, a compressor piston connected to each intermediate piston, an oscillating column of liquid between'one side of said primary piston andone of said intermediate pistons, liquid column between the other side of said primary piston and another of said inter mediate pistons, a third oscillating column of liquid between said intermediate pistons, means for supplying liquid to said liquid columns, a relief valve for the escape of air from each of said liquid columns, and a safety device which opens when a maximum permlssible exceeded.

In testimony whereof I have affixed my signature. 7

CHARLES SOHAER.

pressure in said liquid columns is relief valve for the escape of Y pistons, means fora second oscillating

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