US2547111A - Liquid seal compressor - Google Patents

Description

April 3, 1951 J. T. CAWLEY ETAL LIQUID SEAL COMPRESSOR 4 Sheets-Sheet 2 Filed Feb. 5, 1948 James 7'. Cowley Clifton M. Cowley INVENTORJ.

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1 Ira W Atlnrngyr April 1951 J.'T. CAWLEY ETI'AL 2,547,111

LIQUID SEAL COMPRESSOR Filed Feb. 5, 1948 4 Sheets-Sheet 5 F g I46 48 James 7'. Cowley Clifton M. Caw/ey INVENTORS BY wa con/yaw; 19%

April 3, 1951 J. T. CAWLEY ETAL LIQUID SEAL COMPRESSOR 4 Sheets-Sheet 4 Filed Feb. 5. 1948 Power Driven Compressor Power Driven Compressor Liquid Seo/ Separator Compressor A bs orb er Fig. 7.

James 7'. Cowley Clifton M. Cowley IN V EN TORJ.

By w Man s Patented Apr. 3, 19 ,51

LIQUID SEAL COM SS R James T. Cawley and Clifton M. Cawley, Silsbee, Tex.

Application February 5, 1948, Serial No. 6,526

'7 Claims.v

This invention relates generally to compressors, and more particularly to a compressor in which the energy released by gas while decreasing in pressure is utilized to increase the pressure of a separate body of gas.

A primary object of this invention is to use the potential energy in highly pressurized gas to increase the pressure of a separate body of gas by interposing mechanical means between 'conduits carrying the difierent bodies of gas, this mechanical means comprising a compressor operating with the high pressure gas as a closed system on one side of a piston in the compressor, while the initially low pressure gas is in a closed system on the other side of said piston, when the compressor comprises a simple cylinder with a reciprocating piston, it being understood that valve means must be provided tosynchronize the opening and closing of inlets and outlets and each end of the cylinder, and that such operation of the valves must be synchronized.

Another object of this invention is to provide improved specific means for carrying out this synchronization of valve operation.

Still another object of this invention, when the invention is applied to the oil refining industry, and whenever the gases are of such nature that a condensate is formed, is to provide means for draining off this condensate, this means com prising a device to decrease the volume of a liquid piston when such liquid piston is used in the invention.

Yet another object of this invention is to provide a compressor of the character mentioned above which will allow a substantially constant flow of the initially high pressure gas as well as of the initially lower pressure gas, this object being carried out in the embodiment of the in,- vention in which a pair of U-tubes are used, by providing an actuating valve, along with certain other structures, which allows high pressure gas to be admitted alternatively to the two tubes.

A highly important object of this invention is to provide a compressor which is particularly well suited for use in gasoline recycling plants where the pressure of the raw gas coming from the wells is reduced for absorption and then again raised in pressure sufiiciently high to allow this dry gas to be forced back into the oil sand in injection wells. The compressor will be operated by the energy released in the pressure re duction. At present this energy is not being utilized. The enriche as from the wells is at relatively high pressure, ordinarily at approximate 2600 pounds per square inch. The gas must be decreased in pressure'before being fed to the absorber which is a device to separate the easily available gasoline from the gas by the use of absorption oil, the pressure at which this absorp tion process is carried out'being'relat'ively low and in the order of 1600 pounds per square inch. At the present time the dry gas from the absorber is compressed by regular compressors operated by gasoline engines to a pressure" approximately 2750 pounds per square inch. By the useof'the instant invention it has been found possible'to use the wasted energy from the'hi'gh pressure gas to re-compress approximately sixty three per cent of the dry gas toa pressure in the order'of 2550 pounds per square inch. There" remains only the matter of re-compressing the thirtyseven per cent of the gas to the required 2750 pounds pressure and further compression of the sixty-three per cent ofthe gas from 2550 pounds pressure to 2750 pounds pressure. It will be obvious that a considerable saving is hereby accomplished.

And a last object to be mentioned specifically is to provide a device of this character which is relatively inexpensive and completely practicable to manufacture, which is extremely simple, practically automatic and safe to use, and which will give generally efficientand durable service.

With these objects definitely in view, together with several other objects of a specific character which will become apparent as this description proceeds, this invention resides in certain novel constructions, combination and arrangement of elements and portions as will be hereinafter described in the specification, particularly pointed out in the appended claims, and illustrated in the accompanying drawings which form a material part of this application, and in which:

Figure 1 is a side elevational view of this invention with the U-tubes shown in vertical section so as to disclose the arrangement of the floats and liquid pistons;

Figure 2 and Figure 3 are vertical sectional views of the upper portions of the longer legs of the U-tubes with what may be referred to here inafter as the compressor heads carried thereby;

Figure 4 is a vertical sectional view of actuating valve and contiguous structure including the upper ends of the shorter legs of the U-tubes;

Figure 5 is another view of the actuating valve in a second position;

Figure 6 is a view in vertical section of a modified form of compressor head and illustrating how this modified form of pressure head is utilized 2,547,111 s v is 63% of the gas. All of the gas is returned to the oil sand as indicated.

Similar characters of reference designate similar or identical elements and portions throughout the specification and throughout the several views of the drawings.

This invention contemplates provision of a pair of U-tubes It and I2, each having shorter legs I l and I6 which may be integrated, and longer legs I8 and 20. Each tube is partially filled with a liquid piston 22 and 2% which may be comprised of any suitable liquid, including condensate from the gas processed by the device, and floats 26, 28, 39 and 32 are mounted in float cages 34 at each end of each U-tube.

High pressure gas is led into the device through the pipe 36 and its branch 38, under control of a master valve 43, through the actuating valve assembly 32, and exits from the actuating valve assembly through the pipe ill controlled by the valve 46, the actuating valve assembly is represented in Figures 4 and 5 in detail.

The actuating valve includes a cylinder 48 and a plunger 56 adapted to close and open ports 52 and 54 in the high pressure head 56 secured to the ends of the shorter legs i l and E6 of the U- tubes. A pair of check valves 58 which are hollow and apertured as at 59 are mounted to control the ports 52 and 5 3, and have heads 62 adapted to seat on the suitably formed high pressure head 53, the valve heads 52 being reciprocable within chambers 84 in valve head casing '36 carried by the high pressure head 56 and located within the upper ends of the shorter legs IE- and It. It will be noted that the valve head casings -66 are apertured as at 68, ordinarily at four points, two of these apertures being illustrated in each valve head casing in Figure 4. The check valves 53 carry actuating pins It projecting into the shorter legs I4 and it for engagement by the floats 28 and 30. From the foregoing it will be clear that high pressure gas may be made to flow into and out of the said shorter legs I l and IS by the manipulation of the actuating valve plunger 59, means for which actuation will be described presently, and it will also be clear that the high pressure gas will be fed alternately to the shorter legs I and I6 and that provision for exhausting the initially high pressure gas into the low pressure gas pipe 44 has been made.

Referring now more particularly to the compressor heads I2 and 74, illustrated in Figures 2 and 3, and the valve structure carried thereby, it may be first noted that the floats 2t and 32 are adapted to actuate disc valves 16 having actuating pins I8 depending into the longer legs I8 and 2!! of the U-tubes. The disc valves it are apertured at 8i! and the disc valve casings 82 are similarly apertured at 8Q, so that these valves are open when in depressed position as illustrated in Figure 2, and closed when in elevated position as in Figure 3 with the valve head closing the ports 86 in compressor heads I2 and i l. The ports 86 lead through the channel 88 to branch channels 90 and 92 leading to suction valves $4 and discharge valves 96, respectively. It will be noted that the plungers of these valves are disposed on opposite sides of the valve head and that these valves are actually merely check valves and are named suction and discharge valves in order to differentiate the same from other valves in the system, the eXact character of these last mentioned valves being immaterial in this application.

The compression heads l2 and it have each a vent valve assembly generally indicated at 33 and including a plunger Hill, a removable valve head I02 and an actuating plunger I6 1. The actuating plunger IM reciprocates within a channel 88 and is provided with a valve stem I96 and a coiled spring I98 compressed between the plunger I04 and an adjacent portion of each of he compressor heads 12 and. l t. The plunger It!) is also spring biased as indicated at till and the lower portion of the plunger Ififi is adapted to be engaged by the valvesstem we and the valve I84 is raised by pressure of the remaining gas in the ends of the longer legs i8 and 2d exerted on this plunger I84 through the apertures as, 86 after the disc valve Iii has closed the ports 36. t will thus be seen that the vent valve plunger Hm is used to open the port H4 to the port H6 at the end of the discharge stroke of the liquid piston 22 or 24, and if refernce be had to Figure 1 it will be seen that vent lines H8 are connected between the ports H6 and the low pressure pipe 44. The ports IIG are connected by pipes I20 to the ports I22 in the actuator valve cylinder 48, so that gas is vented to the lower pressure pipe i l through the vent line M8, the chamber in the valve head casing 562, through the bore I22 in the plunger Iilfi, the lateral port I26 provided in this plunger, and the pipe I20, allowing the high pressure gas continually admitted to the ends of the actuating valve cylinder d8 to drive the plunger 56 either to the right or to the left, as indicated in Figures 5 and 4.

The structure above described in brief, comprises a complete operative assembly, and the structure to be now described is an auxiliary system adapted to control the level of the top of the lower end of the pressurized liquid piston, so that condensate from the gas admitted under high pressure through the pipes 36 and 38 will not make the system inoperative. To carry out this level control, this means includes drain pipes I24 communicating with lower end portions of the U-tubes Ii] and I2. A valve I26 is inserted in each of these drain lines l24 and is operated by a piston, not shown, within a cylindrical casing I28. One end of this casing is connected by the pipe I30 to the low pressure pipe 4d, so that one side of the piston in the cylindrical casing I28 is at constant low pressure. The other end of. the

cylindrical casing I23 is connected by the pipe I32, in each case, to the vent line I I8, and a diaphragm operated valve 134 is operatively connected in each vent line M8, the diaphragm assembly casings being indicated at I36 and the diaphragms being remotely controlled, preferably hydraulically, as indicated by pipes I 38, by a, float mechanism, the exact detail of which is unimportant in this application, indicated at I46 and including chambers Hi2 connected by elbowed pipes I44 with the shorter legs M and I6. The float mechanisms will be arranged to retain the valves I34 in position to close either Of the vent lines H8, as long as the level of the liquid piston is above a predetermined height in the shorter legs and I6. This construction, therefore, provides means for creating a differential of pressure in the pipes I30 and I32 as long as the level in the cylinder legs M and I6 is above this predetermined height and a valve I 26 will be opened under these conditions by the action of a piston Within the casing I28. It should be carefully noted that this difierential in pressure can occur only after the vent valve plunger I09 has been operated at the end of the stroke of this liquid piston 22 or 24 in exhausting gas from the longer legs I8 and 29 of the U-tubes. As soon as the level of the liquid piston is lowered to the predetermined height required, the fioat mechanism referred to above will be actuated to open the valve I 34 concerned by remote control, Whereupon the tube 532 will have the pressure reduced therein to the same pressure as that in the tube I30 and the valve I26 which had been held in open position momentarily at the end of the said stroke will again be closed.

The actuating valve plunger has recesses I46 and I48, whereby the pipes 36 and 38 are selectively connected with the ports 52 and 54, while the low pressure pipe 44 is continuously connected with the recess M8 and selectively with either one of the said ports 52 and 54. The high pressure pipes 36 and 38 are each connected by pipes I50 having needle valves I52 therein, to ports I54 in either end of the actuating valve, so that gas under high pressure is admitted alternatively to the two ends of the cylinder 48 to drive the plunger 56 alternatively as to the right and to the left in Figures 4 and 5, in each case the gas at the opposite end of the plunger is exhausted through the corresponding pipe I28 through the vent valve assembly 98 to the exhaust vent line H8. Obviously when one of the valves I34 is closed and when the liquid piston of the corresponding longer leg I8 or 283 has operated the vent valve plunger I630 into the position illustrated in Figure 3, a pressure will be built up in the portion of the vent line I53 between the closed valve I34 and the vent valve,

and a differential in pressure in the pipes I 39 and I32 is achieved and utilized for the purpose of draining oiT excess fluid, as described.

The modified form of this invention in which a metal piston I5$ is inserted in each of longer legs I8 and 20, taking the place or" the floats 26 and 32 and float cages 34, is used when the suction pressure is considerably less than the exhaust pressure and when there is a considerable amount of condensate in the gas that is used to drive the compressor. This metal piston or nonmetallic solid piston, if material other than metal is desired to be used, forms a seal between the liquid piston and the gas that is to be compressed, thereby permitting the condensate from the gas flowing through the high pressure pipes 36 and 38 to be used as the liquid piston without possibility of the relatively dry gas that is to be compressed absorbing and becoming enriched from the condensate. Furthermore, the solid piston can be so designed that it will overcome the difference in the suction pressure and the exhaust pressure, and the solid piston will prevent any possibility of the liquid piston escaping through the discharge line.

This modified form of the invention employing the solid piston I56 is illustrated in Figure 6 and it will be noted that this solid piston has sealing rings I 58 and may be of considerable length and that the solid piston will rest immediately upon the upper end of the liquid piston.

The upper ends or heads I60 of the longer legs I8 and 20 will also be modified slightly, to include suction and discharge valves I 52 and 564, respectively, for connection to the corresponding suction pipe I66 and discharge pipe Isis such as are shown in Figures 1 and 6. The vent valve assembly 98 is very similar in this modified form to the vent valve assembly 98 already described, the plunger Iilll being actuated by the pin I carried by a piston I04. The piston I cs is actuated by the continued movement of the solid piston I 56 after the port closed by the outlet Valve I I56 has been closed by the upper end of the said solid piston, the gas enclosed in the upper portion of the head I 69 being compressed to force the piston I64 upwardly as in Figure 6 to move the plunger I66 into the position shown. As before, this action allows gas under high pressure from the pipes I50 to escape from one end of the actuating piston and reverse the plunger 59. Reference to Figure '7 may be made iriconnection with the penultimate and the primary object of this invention, to illustrate further how this invention may be implemented. In this figure certain lines have been numbered to indicate the corresponding portions in Figure 1. The pipes leading to the intake and outlet valves 96 and 96 being numbered I66 and I68, respectively, in both figures. Compressor pipes are not shown in duplicate.

In operation, gas under pressure admitted through the actuating valve to one of the cylinder legs I4 or IE, forces the liquid piston downwardly until this same liquid piston rises in the longer legs I8 or 20 sufficiently to raise the float 26 or 32 and to actuate the disc valve it to close the corresponding ports 88 and pressure is still being applied to the liquid piston and the same will move still further to cause the piston I04 or I04 to raise the plunger I09 or Hill and this action allows high pressure gas from one of the pipe I59 to circulate through the end chamber of the actuating valve and through the pipe I 29 into the port H4 and through the hollow plunger I06 or Illil and into the vent line H8. Thisvent line will be open, provided the valve I 34 is not actuated as a result of the raising of the volume of the liquid piston beyond the required amount as already described in detail, and as soon as the plunger 50 is moved into its reverse position, a new charge of the gas to be compressed is allowed to feed into the longer leg I8 or 26 through the valves 9 while the as from the high pressure pipes 36 and 38, that is,

the gas in the corresponding lower leg I lor IE, will be exhausted into the low pressure pipe 45. An exact reversal of operations will be coincident in'the outer U-tube assembly, so that a substantially steady now of gas, both that to be reduced in pressure and that to be increased in pressure, will be maintained. Thus, gas from the wells is reduced in pressure as it passes through the liquid seal compressor for processing in an absorber to remove the easily available gasoline. Energy released by this reduction in pressure is used to operate the liquid seal compressor which raises approximately 63% of the original gas to a pressure nearly equal to the original gas pressure. The other 37%, as well as the above mentioned 63%, must be further raised in pressure if the same is to be used for re-pressuring the oil field, but it will be clear that this invention lessens the amount of power required to be provided by independently driven pumps.

Minor variations in the details of construction, and proportionment of the various elements of this invention may be resorted to without departure from the spirit and scope of this invention. The drawings, particularly, should be thought of as illustrative rather than limiting and the scope of the invention should be determined only in accordance with a proper interpretation of the terminology used in the invention, what is chronizing the opening and closing of the firstv mentioned inlet and the second mentioned outlet with the closing and opening respectively of the first mentioned outlet and the second mentioned inlet, whereby the energy released by said initially high pressure gas in decreasing in pressure is utilized, in part, to increase the pressure of said initially low pressure gas.

2. A compressor comprising a U-tube, a liquid piston in said U-tube, an inlet for initially high pressure gas and an outlet for lowered pressure gas at one end of the U-tube, an inlet for initially low pressure gas and an outlet for gas raised to an intermediate pressure on the other end of said U-tube, valves controlling each of said inlets and outlets, and means for synchronizing the opening and closing of the first mentioned inlet and the second mentioned outlet with the closing and opening respectively of the first mentioned outlet and the second mentioned inlet, whereby the energy released by said initially high pressure gas in decreasin in pressure is utilized, in part, to increase the pressure of said initially low pressure gas.

3. A compressor comprising a U-tube, a liquid piston in said U-tube, an inlet for initially'high pressure gas and an outlet for lowered pressure gas at one end of the U-tube, an inlet for ini tially low pressure gas and an outlet for gas raised to an intermediate pressure on the other end of said U-tube, valves controlling each of said inlets and outlets, and means for synchronizing the opening and closing of the first mentioned inlet and the second mentioned outlet with the closing and opening respectively of the first mentioned outlet and the second mentioned inlet, whereby the energy released by said initially high pressure gas in decreasing in pressure is utilized,-in part, to increase the pressure of said initially low pressure gas, said liquid pistonhavin a solid sealing pistonat one end thereof and movable therewith.

4. A compressor comprising a U-tube, a liquid piston in said U-tube, an inlet for initially high pressure gas and an outlet for lowered pressure gas at one end of the U-tube, an inlet for initially low pressure gas and an outlet for gas] raised to an intermediate pressure on the other end of said U-tube, valves controlling each'of said inlets and outlets, and means for synchronizing the opening and closing of the first mentioned inlet and the second mentioned outlet with the closing and opening respectively of "the first mentioned outlet and the second'mentioned inlet, whereby the energy released by said ini'-' tially high pressure gas in decreasing in pressure is utilized, in part, to increase the pressure of said initially low pressure gas, said means includ ing a vent valve operated by said piston and an actuating valve havin a plunger and spaced ports, said vent valve controlling flow of gas under pressure to said ports and actuating said plunger to open and close said first mentioned flow of both said initially high and initially low I pressure gas is achieved.

6. A compressor according to claim 5 and ineluding check valves on said one end of the first mentioned'U-tube and a corresponding end of the second mentioned U-tub'e, and a float moving said check valves.

7. A compressor according to claim 5 and including means to drain off a portion of said fluid piston when the volume thereof is increased as by absorption of condensate.

' JAMES T. CAWLEY.

CLIFTON M. CAWLEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 960,729 Sweeny June 7, 1910 2,300,578 Lane Nov. 3, 1942

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