US2061938A

US2061938A - Method and apparatus for compressing gas

Info

Publication number: US2061938A
Application number: US724515A
Authority: US
Inventors: Donald G Griswold
Original assignee: Clayton Manufacturing Co
Current assignee: Clayton Manufacturing Co
Priority date: 1934-05-08
Filing date: 1934-05-08
Publication date: 1936-11-24
Anticipated expiration: 1953-11-24

Description

NOV. 24, 1936. SW LD I 2,061,938

METHOD AND APPARATUS FOR COMPRESSING GAS Filed May 8, 1954 2 Sheets-Shea 1 m 22 47 Ju 7 INVENTOR.

DONALD 6. GQISWOLD ATTORNEY.

w w 8 A 3 2 w M A R 1 v 9 m 0 O E e E Tw N 1 h w n N3 R 6 S m w E O 0 5 2 E V P S 7 7 n 2 n i U I me A m r e S A 2 w A N O D D. G. GRISWOLD METHOD AND APPARATUS FOR GOMPRESSING GAS Filed May 8, 1934 jlua/ Nov. 24, 1936.

Patented Nov. 24, 1936 METHOD AND APPARATUS FOR COMPRESSING GAS Donald G. Griswold,

by mesne assignments, turing Company, Alhambra,

tion of California Application May 8,

17 Claims.

This invention has to do with the compression of gas, and is more particularly related to improvements in methods and apparatus for compressing gas such as air whereby the compressing efficiency is greatly increased and the compressed gas is entirely free of entrained solid or liquid foreign material, such as the oil which is always present in air which has been compressed by the conventional mechanical air compressor.

My invention is especially adapted for use in pumping carbonated beverages such as beer Where it is necessary to maintain the. beverage under a. substantial pressure to prevent the same from becoming dead and to deliver the same to the dispensing valve. In conventional practice, twogeneral methods are employed for this purpose. The first involves the use of compressed carbon dioxide. This is extremely expensive since the carbon dioxide is used solely to maintain the necessary pressure and is virtually wasted after the beverage is used; there is also a tendency for the beverage to be overcharged with gas; and it is impossible to maintain uniform pressure on the beverage container during frequent withdrawals without making frequent adjustments of the regulator valve. The other method involves the use of an ordinary mechanical air compressor which has the disadvantage of being noisy and subject to leakage. The compressed air from a mechanical compressor is always contaminated with oil from the compressor and dust vapors, smoke etc. from the atmosphere which is a great disadvantage since the air must come in contact with the beer. Furthermore, the air is heated during compression so that the beer is not only contaminated with the foreign material, just mentioned, but the warm air causes the beer to lose its life or go flat before it is discharged through the draft arm, also the fact that the air is warmer than the beer, results in an absorption of heat from the air by the beer which is followed by the condensation of gases and vapors entrained in the warm air.

It is one object of this invention to produce an air compressor which is especially adapted for use in the above connection in that it has a low initial cost, it is cheap to operate, and it is noiseless in operation.

It is a primary object of this invention to produce an air compressor of the class described wherein the air is washed and cooled before delivery to the point of use and in this invention the air is washed and cooled both before and during its compression.

This last mentioned feature, in addition to the Los Angeles, Calif, assignor,

to Clayton Manufac- Calif., a corpora- 1934, Serial No. 724,515

obvious advantages for the particular purpose pointed out above, has the added advantage of greatly increasing the compressing efficiency of the unit. In other words, my invention contemplates a method for compressing a gas wherein the gas is either cooled or is maintained at a substantially uniform temperature during its compression, thereby avoiding the usual loss in efficiency due to cooling subsequent to compression.

The general construction of the device contemplated by this invention is similar to the apparatus disclosed in United States Letters Patent No. 1,903,108, issued to me on March 28, 1933, in that it is of the so-called liquid displacement type.

The device contemplated by this invention comprises two vertically spaced compartments connected by a single passage which is provided with a check valve. The lower compartment contains a liquid inlet and the liquid outlet, each provided with a Valve and a pressure-operated diaphragm associated with means for opening and closing the inlet and outlet valves respectively.

It is a feature of the apparatus that the inlet and outlet valves are operated so that there can be no dead center position in which the pressure liquid is passing directly through the apparatus. In other words, the inlet valve is always closed before the outlet valve is opened and the outlet valve is always closed before the inlet valve is opened.

The valves, as pointed out above, are actuated by a pressure diaphragm which in turn is controlled by a pilot valve adapted to deliver pressure fluid to and from opposite sides of the diaphragm. This pilot valve is operated so as to close the outlet and open the inlet by what I have termed a primary float situated in the bottom compartment, and the pilot valve is later operated to close the inlet and open the outlet by what I have termed a secondary float which is situated in the upper compartment, the operation of these two floats being entirely independent of each other.

The primary float operates to close the outlet and open the inlet at a point when there is a substantial quantity of liquid in the bottom of the lower compartment, and I locate the air inlet at a substantial distance below the bottom or normal level of the liquid in the lower compartment so that the air or other gas is always drawn into the lower compartment through the receding column of liquid whereby it is thoroughly washed and cooled prior to compression.

The air inlet is provided with a check valve and it is a feature of this invention that the check valve is constructed so as to receive positive movement from the mechanism which controls the liquid valves. The construction is, however, such that the check valve will act as a free-operating check valve immediately upon the opening of the liquid outlet, but the positive-operating mechanism is provided to avoid sticking in the check valve so that the same is always opened or closed at the proper time. In a preferred form of my invention the air inlet is provided with a seal cup or pocket, to eliminate the possibility of dripping during the operation of the inlet valve.

As pointed out above, the device comprises two compartments, and since the opening of the outlet valve is dependent upon the raising of a float in the upper compartment, it will be seen that there is always liquid in the upper compartment when the outlet valve is opened. The float in the upper compartment is associated with a check valve, the construction being such that the check valve is closed at a time when there is a substantial quantity of liquid in the upper compartment. With this construction, it will be seen that during the compression stroke, in other words, during such time as the air in the bottom compartment is being displaced by liquid admitted thereto, such air is forced upwardly through the check valve and through a body of water in the upper compartment from which it passes to a storage tank or a point of utilization. In other words, the air is cooled and Washed not only as it is drawn into the lower compartment but this same air is further cooled or is maintained at a substantially constant temperature and washed again during its compression. Thus I obtain a substantially isothermal compression of the air, making for maximum compressing efiiciency, and am able to deliver a cool compressed air directly from the compressor to the point of use.

It is an extremely important feature to the efficiency and quietness of my compressor that all of the valves associated with the main compressing chamber are constantly under a water seal. This reduces wear in the valves to a mini-- mum, permits the use of a composition valve or a composition valve seat, and prevents back leakage of the compressed gas through the compressor when it is idle. Inasmuch as the device contemplated by this invention has been designed primarily for use in pumping beer or other beverages, it is important that it be of foolproof construction, and further that its construction be such that none of the pressure liquid in the event the liquid inlet valve should stick or a part of the operating mechanism should break will pass over into the barrel which is being maintained under pressure.

It therefore, becomes a further object of this invention to provide safety valve means for positively preventing the passage of the pressure liquid completely through the compressor in the event the liquid inlet valve should stick open or a. part of the operating mechanism should break, to prevent closing of this valve.

The details in the construction of a preferred form of my invention, together with other ob jects attending its production, will be best understood from the following description of the accompanying drawings which are chosen for i1- lustrative purposes only, and in whichr Fig. l is a sectional elevation showing a preferred form of the invention;

Fig. 2 is a plan section taken in a plane repre sented by the line 2-2 of Fig. 1;

Fig. 3 is a fragmentary enlarged sectional elevation taken in a plane represented by the line 33 of Fig. 2 showing one form of air inlet valve;

Fig. 3A is a fragmentary sectional elevation similar to Fig. 3 illustrating a preferred form of an air inlet valve;

Fig. 4 is a plan section showing a preferred form of pilot valve contemplated by this invention, such .section being taken in a plane represented by the line 54 of Fig. 1;

Fig. 5 is an inverted plan section taken in a plane represented by the line 5-5 of Fig. l;

Fig. 6 is a fragmentary section taken in a plane represented by the line 6-6 of Fig. 5; and

Fig. '7 is a section taken in a plane represented by the line 1-1 of Fig. 4.

More particularly describing the invention as herein illustrated, reference numeral H indicates a housing which is shown as being comprised of cast sections and is divided by a partition plate iii to form what I may term a main compressing chamber or bottom compartment 2 3, and an auxiliary float and outlet chamber or top compartment M.

The main compressing chamber i3 is provided in its bottom portion with a liquid inlet l5 which communicates with an inlet housing it having a valve seat ll which in turn is associated with a valve H2. The valve 18 has a stem l9 received in a guide 22 and another stern 2i which is connected to a lever 22.

Reference numeral 23 indicates an outlet connection, such connection being provided with a valve seat 2-4 and an outlet valve 25. The valve 25 has a guide stem 25 which is also pivotally connected to the lever 22. The relation between the valves 28 and 25 and the lever 22 is such that the pivot point on the valve 25 constitutes a fulcrum for the lever when the valve 25 is seated so that the valve it; must be closed before the valve 25 can be opened. After the valve i8 is closed, it will be apparent that the pivot point of the lever on the stem 23 becomes the fulcrum point for the lever. The lever 22 is operated by a link 29, the upper end of which is pivotally connected to a control lever 36, such lever being pivoted at 3! in a housing 32 and having its inner end 33 bifurcated and engaged between collars 34 on a bushing which is pinned to a mandrel 35. The upper end of the mandrel 35 is slidably received in a recess 36 formed in a guide standard 3'! which is mounted in the tip of the housing 32. The lower end of the mandrel 35 extends downwardly through a spring-pressed packing gland 38 which is mounted in the top of a diaphragm housing 39. The diaphragm housing 39 contains a flexible diaphragm 60 to which the bottom of the mandrel 35 is secured as indicated at 4|. This construction is such that when the diaphragm 4| is forced into the upper position, as shown in the drawings, the outlet valve 25 is closed and the inlet valve I3 is opened as shown. When the diaphragm 48 is forced downwardly to its lowermost position, the inlet valve is closed and the outlet valve is opened. This diaphragm is actuated by pressure fluid admitted to and released from the diaphragm housing by means of a pilot valve unit which includesv a block or casting and associated ports generally indicated by reference numeral 42.

into the bearing region of the valve by means of' In Fig. 1, the ports have all been shown in the same section plane in order to clarify the drawings. It is to be understood, however, that in actual construction the various ports may be in different planes.

The valve unit 42 as shown in Fig. 1 comprises a block or housing which has what I may term a pressure or inlet port or duct 43 which leads from the inlet housing I6 to a distributing or valve chamber in the valve not shown in Fig. 1.

Reference numeral 44 indicates an outlet duct which leads from the distributing chamber to a pipe 45 for communicationwith the outlet or.

drain 23.

Reference numerals 46 and 41 indicate ducts which lead from the distributing chamber into the top and bottom portions respectively of the diaphragm housing.

- The valve 42 may be any conventional four-way valve, its function obviously being to alternately connect the ducts 46 and 41 with the

ducts

43 and 44 so as to withdraw and admit pressure fluid to opposite sides of they diaphragm.

One preferred construction of such a valve is best illustrated in Figs. 4 to '7 inclusive, wherein it will be noted that the block or casting 42 carries a housing 50 which has a base plate 5| pro vided with a projection 52 which extends a short distance up into a valve chamber 53 formed in the housing 50.

Reference numeral 54 indicates a valve core which is shown as being formed of two circular plates held in spaced relation by means of pins 55. This core is held with its bottom face in sealing engagement with the upper face of the projection 52'by means of a compression spring 56 which is contained in the spring chamber 51 and bears against a pressure plate 58, such plate being held against rotation by a pin 59 which is received in a groove or passage 69) formed in the wall of the chamber 53. This groove or passage 60 communicates through a port 6| in the bottom of the housing 50 with the pressure or inlet duct 43. With this arrangement, it will be seen that pressure fluid is always maintained in the space between the two plates of the valve core.

The bottom plate of the valve core is provided with two

passages

62 and 63 which extend completely through such plate and adapted upon the proper positioning of the core to establish communication between the chamber in the core and ports 62 and 63' which communicate with the ducts 41 and 46 leading to the bottom and the top respectively in the diaphragm chamber.

The drainage duct 44 communicates with a port 65 (see Fig. 6) which has an opening in the projection 55 directly below the center of the plug 50. The bottom section of the plug 50 is provided with a U-shaped duct 66 which has one opening in the center of the plug immediately above the opening of the port 65 and has another opening or leg 61 positioned so as to be in registration with either the upper diaphragm port 53' or the lower diaphragm port 62 when one of the

passages

62 or 63 is in alignment with the other of such'ports. In other words, the rotation of the valve core into either of its two positions establishes communication with one of the

ports

62 or 63 with the inlet chamber and the other port 63 or 62' with the U-shaped duct leading to the drainage pipe.

Reference numeral 61 indicates a grease passage which is formed in the bottom plate of the core and is adapted to be filled with grease when the valve is assembled. This grease is forced opening Bil which the pressure fluid.

For the purpose of actuating the valve core, I provide the same with a stem 59, which extends through a packing gland iii, which is compressed by the action of the compression spring against plate II. This stem is provided with an operating lever 12 which is shown as being associated with a counter-balance 13.

The pilot valve just described is provided for the. purpose of controlling the movement of the diaphragm 45 which in turn actuates the inlet and outlet valves l8 and 25 respectively.

In order to accomplish the contemplated objects of this invention, it is important that the diaphragm be automatically actuated through the pilot valve so as to close the outlet and open the inlet when the liquid in the main compressing chamber has receded to a predetermined point above the bottom of the chamber and to close the inlet and open the outlet when the housing has been supplied with liquid to such an extent that a substantial depth of liquid is in the top compartment.

For the purpose of delivering liquid from the bottom compartment to the top compartment and also to admit air from the bottom compartment to the top compartment, I show the partitioning plate 52 as being provided with a central is provided with a bushing 8| having a passage 82 therethrough. The top of the bushing is formed with a valve seat adapted to receive and support a check valve 84. The valve 34 is provided with a sealed valve stem 85 which projects downwardly therefrom through a guide passage 86 in the bushing, the valve and the stem constituting a connecting link in the link system which operates the pilot valve lever as will now be described.

Assuming the liquid inlet and

outlet valves

18 and 25 to be in the position shown in Fig. 1, it will be seen that pressure liquid is entering the main.

compressing chamber and displacing the air con-- tained therein, such air having been admitted through a passage which will be hereinafter more fully described. This liquid as it rises, forces the air through the passage 82 in the bushing 80 and upwardly through the check valve 84. When the unit has been in operation, the upper compartment, into which the air is forced, contains a substantial quantity of water so that the air as it is compressed and forced into the upper compartment is washed and cooled. The pressure liquid which will ordinarily be water from the conventional water main forces its way up filling the main compressing chamber and eventually entering the top compartment or the auxiliary float and outlet chamber through the check valve 84. For the purpose of reversing the position of the pilot valve when the pressure liquid has reached a predetermined level in this chamber, I provide what I may term a secondary float indicated by reference numeral 88. This float is shown as being of an inverted cup type and has a series of legs 89 which normally support it on the partition plate 82.

Reference numeral 90 indicates a rod which is secured in the float and is shown as being positioned centrally therein in alignment with the valve 84 and the valve passage 86. The upper end of the rod extends into a guide fitting 9|- instances, when it is not necessary or desirable to employ the safety float mechanism, be mounted in the top of the auxiliary float and outlet chamber. As shown, the same fitting which carries the guide 9I is provided with a relatively small outlet port 93 through which the compressed air leaves the auxiliary float chamber.

As a first measure of safety to prevent passage of liquid from the chamber below the partition 92 in the event something should interfere with the proper operation of the inlet valve I8, I provide the top of the float 88 with a composition valve member 95 which is adapted to seat in a recess 96 situated below the port 93. I might also add that, during the initial filling of the housing with pressure liquid when there is no back pressure on the unit, the liquid may enter with such velocity that the floats do not have an opportunity to actuate the pilot valve before the housing is completely filled. The provision of the partition 92 and the small outlet port therein provides suflicient back pressure to safeguard against this occurring when the machine is first started.

As was previously pointed out, the valve and its associate valve stem constitute a link in the mechanism which controls the pilot valve from the float 88. This is accomplished by extending the rod 95) downwardly into a pocket formed in the valve where the lower end of the rod is provided with a head The depth of the pocket which contains the head 96' is such that the valve is permitted free action as a check valve when the legs 89 of the float are resting on the partition plate l2.

Reference numeral 98 indicates a link mounted on the lower end of the valve stem 85 having a sliding connection 99 with a pilot valve actuating rod I09, such rod extending through a guide bracket IUI mounted on the upper end of the standard 37 and having its lower end portion connected through a finger I 92 with the pilot valve actuating lever 12 as shown in Fig. 2.

From the construction so far described, it will be seen that as the float is raised by the liquid entering the top compartment through the valve 84 it lifts the valve stem 85 through the medium of the valve 84 and through the action of the connecting link 98 is efiective to swing the pilot valve into a position where the pressure liquid is admitted to the top of the diaphragm chamber and the bottom of the diaphragm chamber is connected with the liquid outlet. When this occurs, the diaphragm is immediately forced downwardly, swinging the lever 30 about its fulcrum pin 3| and opening the liquid outlet valve 25 and closing the liquid inlet valve I8. When this occurs, the liquid immediately starts to recede from the housing, first flowing from the top compartment through the passage 80 until the float rests upon the partition I2 and the check valve 84 is closed. As the liquid recedes in the bottom compartment,it createsa differential pressure between the interior of the compartment and the atmosphere, and it is during this receding movement that the air to be compressed is admitted into the bottom compartment. As I explained above, the compressed air leaving the bottom compartment and entering the top compartment is washed in the liquid L which is always contained in the top compartment above the valve 84.

One of the most important features of this invention resides in the fact that the air is also washed and cooled as it is being drawn into the bottom compartment prior to compression. In

this form of my invention, I effect this by positioning the air inlet, which is generally indicated at I05 in broken lines in Fig. 1, a substantial distance below the normal liquid level in the bottom compartment so that such air must pass upwardly through the receding column of the liquid during the entire period over which the liquid drains from the bottom compartment. The air inlet I05 is of course provided with a check valve, a preferred construction of which will be hereinafter described.

For the purpose of reversing the position of the pilot valve when a predetermined quantity of the pressure liquid has been withdrawn from the main compartment, I provide what I may term a primary float I07 which is shown as being of the cup type having a guide sleeve I98 at its center, such sleeve being slidably received on the stand ard 31 and the movement of such sleeve being limited by the bracket or cap IIII. This float is also provided with a tubular guide passage I09 through which the pilot valve operating rod I00 extends, and the rod is provided with a stop collar IIG situated at a point well above the air inlet I05, the collar being effective when engaged by the downwardly moving float to move the rod and the pilot valve operating lever into the position shown in Fig. 1, where pressure liquid is admitted below the diaphragm and is exhausted from above the diaphragm, thereby forcing the diaphragm upwardly to first close the outlet valve 25 and then also the inlet valve I8. It will thus be seen that the primary float Ifi'I functions only to control the closing of the outlet and the opening of the inlet, and the secondary float 88 functions solely for the purpose of controlling the closure of the inlet valve and the opening of the outlet valve.

As pointed out above, the primary float I 01 is of the cup type so that it is always filled with liquid. The weight of the float shell is balanced by a counterweight I I 5 mounted on the end of the lever IIB which is pivoted in the bracket II! on the collar member IOI. lever is connected to the float through a link I I8.

In order to prevent a failure in operation due to the air inlet valve sticking, I propose to provide means for positively actuating such valve, such means being constructed, however, so that the valve will function as an ordinary check valve immediately when the liquid inlet is closed and the liquid outlet opened. One form of this air inlet construction is best illustrated in Figs. 2 and 3 where reference numeral I20 indicates an air inlet valve housing mounted in the bottom portion of the main compressing chamber. This housing contains a valve chamber IZI which is positioned in alignment with an air inlet duct I 22 leading to the atmosphere as indicated at I23.

The valve chamber I2I contains a small piston member I24, the bottom of which is provided with a composition disk I25 adaptedto fit on a valve-seat bushing I26. The bottom of the valve chamber I24 in the region of the valve seat is provided with a port I21 which communicates with an air passage I28. The top portion of the piston member I24 is provided with an elongated notch or undercut portion I29 which is situated opposite an elongated slot I30 formed in the wall of the housing I 20.

Reference numeral I 3| indicates a pin which is mounted in the lever member 30 and has its end portion extending through the slot I39 into the notch I 29 in the piston member. The position of the valve housing, the pin, and its asso- 7 The free end of this ciated slot and notch are such that the lower edge of the notch I29 is engaged by the pin I3I when the lever member 30 is in the position shown in Fig. 1.

When the diaphragm is moved downwardly to swing the lever into a position for closing the inlet and opening the outlet valves, the first movement of the lever lifts the pin I3I away from the engaged shoulder, thereby permitting the piston I2I to function as an ordinary check valve. In the event the piston sticks, the continued movement of the lever member 30 brings the pin I3I into engagement with the top shoulder in the notch, thereby positively lifting the piston member away from the seat. During the reverse operation of the diaphragm, the pin I3I similarly functions to positively close the air inlet valve as the liquid inlet valve is opened.

In Fig. 3A I show a preferred form of air inlet connection and valve mechanism indicated generally by reference numeral I05; all of the parts corresponding to those shown in Fig. 3 being represented with the same reference numerals distinguished by the prime mark. Reference numeral I20 indicates an air inlet valve housing mounted on the top the diaphragm housing 39, the housing I20 being provided with a valve passage I2I' which communicates through a port I21 with an air passage I28. The valve passage I2I' is situated above a well I60 provided in the top of the diaphragm housing, such well ,communicating with the air inlet duct I22 at a point above the bottom of the well.

The bottom of the valve passage I2I is provided with a seat member I26 which has a downwardly projecting nipple IIiI extending into the well I60 below the bottom level of the duct I22. In this form of my invention I provide the valve passage I2I with a hollow piston type valve, shown as comprising a cylindrical shell I2 which is flanged at its lower edge to support a composition valve disc I25. The disc I25 is engaged by a metal disc I62 which is held in pressure engagement therewith by an inverted cup I63, such cup being locked in the shell I24 by a pressure fit or in any other suitable manner. The top of the inverted cup IE3 is provided with an aperture. through which an operating stem I64 slidably extends. The stem I64 has a head I65 on its lower end and is attached at its upper end to the pin I3 I which is mounted in the lever 36. Reference numeral I66 indicates a compression spring which is secured at its upper end to the top of the stem and is of a length such that there is a slight clearance between the bottom of the spring and the top of the cup I63 when the stemis in its uppermost position. In this construction the spring is effective to place the valve under pressure afterit has been closed and before the hydraulic pressure in the compression chamber has had an opportunity to build up. Also the well I and the nipple I6I provide a liquid seal and eliminate the possibility of dripping during the operation of the valve.

It also was mentioned in the early part of the specification as a further object of this invention to provide, in the device of the class described which is adapted for use in pumping beer and the like, a safety valve which will positively prevent any of the pressure liquid being carried over into the pumped beverage. The safety valve support 92 has previously been described in connection with the guide fitting 9L and as has been previously pointed out, the partition member 9i may,

for ordinary purposes where this extra safety precaution is not desired, constitute the top of the housing. For the purpose described, however, I provide in the top compartment or the auxiliary float and outlet chamber It a second chamber formed by the partition 532 which I have indicated by reference numeral Iii]. This chamber which I may term a safety float chamber has a fitting Hit in its top, such fitting being provided with a small port M2 communicating between a recessed portion M3 in its bottom and a connection I'M which leads to the source of storage or utilization. This fitting is also provided with a guide recess Hi5 which receives a stem 5% on the top of what I may term a safety float M'I. This float M! is also shown as being of the inverted type and its bottom portion is guided by virtue of a central opening M3 which slides over a projection on the guide fitting EN. The top of the safety fioat is provided with a composition washer I50 which is positioned so that it will be pressed into engagement with the bottom face of the outlet fitting M2 in the event liquid should rise into the safety float chamber Hit. It will be understood that this safety float will function only in the event of failure in the operating mechanism contained in the main compressing chamber, and is, therefore, only a safety measure.

It will be apparent from the foregoing description that my invention contemplates a novel method of compressing gas in which the gas is washed and cooled both prior to and during its compression, and that the invention further contemplates the novel apparatus for effecting the method in which all of the valves associated with the compressing chamber are constantly maintained under liquid seal.

It is to be understood that, while I have herein described and illustrated one preferred form of my invention and one important application thereof the invention is not limited to the precise construction or the particular use described above, but includes within its scope whatever changes fairly come within the spirit of the appended claims.

I claim as my invention:

1. The method of compressing a gas which includes the steps of: completely filling a chamber with a pressure liquid to displace the gas therein; draining part of said liquid from said chamber by gravitation, thereby forming a receding column of liquid in said chamber; admitting substantially all of the gas to be compressed into said chamber through said receding column of liquid thereby washing and cooling said gas; and then forcing pressure liquid into the chamber to displace and compress said gas.

2. The method of compressing ,a gas which includes the steps of: completely filling a chamber with a pressure liquid to displace the gas therein; draining part of said liquid from said chamber by gravitation, thereby forming a receding column of liquid in said chamber; admitting substantially all of the gas to be compressed into said chamber through said receding column of liquid thereby washing and cooling said gas; then forcing pressure liquid into the chamber to displace and compress said gas; and forcing the compressed gas through a second body of liquid to further wash and cool said gas.

3. A gas compressor of the class described embodying: a housing having a main compressing chamber and an auxiliary float and outlet chamher; a check valve between said chambers; a liquid inlet in said main compression chamber; a liquid drain connection extending through the bottom of said main compression chamber; an air inlet in said main compression chamber below the normal liquid level therein; valves in said liquid inlet and outlet and in said air inlet; and float means in said chambers for controlling the actuation of said last mentioned valves.

4. A gas compressor of the class described embodying: a housing having a main compressing chamber and an auxiliary float and outlet chamber; a check valve between said chambers; a liquid inlet and a liquid outlet in said main compressing chamber; valves in said liquid inlet and said liquid outlet; float means in said chambers for actuating said liquid inlet and. outlet valves; a valved gas inlet in said main compressing chamber; a compressed gas outlet port in said auxiliary float and outlet chamber; and a float actuated valve in said last mentioned chamber for closing said compressed gas outlet port after a predetermined quantity of liquid has been admitted to said housing.

5. A gas compressor of the class described embodying: a housing having a main compressing chamber and an auxiliary float and outlet chamber; a check valve between said chambers; a liquid inlet and a liquid outlet in said main compressing chamber; valves in said liquid inlet and outlet; a diaphragm chamber in said housing; a diaphragm in said diaphragm chamber; means actuated by said diaphragm for opening and closing said liquid inlet and outlet valves respectively; conduit means for delivering a pressure fluid successively to said diaphragm chamber at opposite sides of said diaphragm; a pilot valve for controlling the delivery of pressure fluid to and from opposite sides of said diaphragm chamber; a float in said main compressing chamber for positively moving said pilot valve in one direction; a second float in said auxiliary chamber for positively moving said pilot valve in the other direction; and a gas inlet in said main compressing chamber.

6. A gas compressor of the class described embodying; a housing having a main compressing chamber and an auxiliary float and outlet chamber; a check valve between said chambers, a liquid inlet and a liquid outlet in said main compressing chamber; valves in said liquid inlet and outlet; a diaphragm chamber in said housing; a diaphragm in said diaphragm chamber; means actuated by said diaphragm for opening and closing said liquid inlet and outlet valves respectively; conduit means for delivering a pressure fluid successively to said diaphragm chamber at opposite sides of said diaphragm; a pilot valve for controlling the delivery of pressure fluid to and from opposite sides of said diaphragm chamber; a float in said main compressing chamber for positively moving said pilot valve in one direction; a second float in said auxiliary chamber for positively moving said pilot valve in the other direction; and a gas inlet in said main compressing chamber below the normal liquid level therein.

'7. A gas compressor of the class described embodying: a housing having a main compressing chamber and an auxiliary float and outlet chamber; a check valve between said chamber; a liquid inlet and a liquid outlet in said main compressing chamber; valves in said liquid inlet and outlet; a diaphragm chamber in said housing; a diaphragm in said diaphragm chamber; means actuated by said diaphragm for opening and closing said liquid inlet and outlet valves respectively;

conduit means for delivering a pressure fluid successively to said diaphragm chamber at opposite sides of said diaphragm; a pilot valve for controlling the delivery of pressure fluid to and from opposite sides of said diaphragm chamber; a float in said main compressing chamber for positively moving said pilot valve in one direction; a second float in said auxiliary chamber for positively moving said pilot valve in the other direction; a gas inlet in said main compressing chamber below the normal liquid level therein; a Valve in said gas inlet; and means actuated by said diaphragm for positively opening and closing said gas inlet valve.

8. A gas compressor of the class described embodying: a housing having a main compressing chamber and an auxiliary float and outlet chamber; a check valve between said chambers; a liquid inlet and a liquid outlet in said main compressing chamber; valves in said liquid inlet and. outlet; a diaphragm chamber in said housing; a diaphragm in said diaphragm chamber; means actuated by said diaphragm for opening and closing said liquid inlet and outlet valves respectively; conduit means for delivering a pressure fluid successively to said diaphragm chamber at opposite sides of said diaphragm; a pilot Valve for controlling the delivery of pressure fluid to and from opposite sides of said diaphragm chamber; a float in said main compressing chamber for positively moving said pilot valve in one direction; a second float in said auxiliary chamber for positively moving said pilot valve in the other direction; a gas inlet in said main compressing chamber below the normal liquid level therein; a valve in said gas inlet; and means actuated by said diaphragm for positively opening and closing said gas inlet valve, said last mentioned valve actuating means being constructed so as to permit free movement of said air inlet valve into engagement with its seat and out of engagement with its seat immediately upon the opening of said liquid inlet Valve and the opening of said liquid outlet valve respectively.

9. A gas compressor of the class described embodying: a housing having a main compressing chamber and an auxiliary float and outlet chamber; a check valve between said chambers; a valved gas inlet in said main compressing chamber; a liquid inlet and a liquid outlet in said main chamber; valves in said inlet and outlet; means for actuating said valves in opposed relation with each other; a float in said main chamber associated with said valve actuating means; a second float in said auxiliary chamber associated with said valve actuating means; a partition in said auxiliary chamber above said float; a port in said partition; and a valve on said float in alignment with said port.

10. A gas compressor of the class described embodying: a housing having a main compressing chamber and an auxiliary float and outlet chamber; an outlet check valve between said chambers; a valved gas inlet in said main chamber; a liquid inlet and a liquid outlet in said main chamber; valves in said liquid inlet and outlet; means for actuating said inlet and outlet valves; a primary float in said main chamber associated with said valve actuating means; a secondary float in said auxiliary chamber associated with said actuating means; a safety float support in said auxiliary chamber above said secondary float; an outlet port in the top of said auxiliary chamber; a safety float movably mounted on said safety float support below said outlet port; and a valve on said safety float for closing said outlet port in the event said safety float is buoyed up by liquid in said auxiliary chamber.

11. A gas compressor of the class described embodying: a housing having a main compressing chamber and an auxiliary float and outlet chamber; an outlet check valve between said chambers; a valved gas inlet in said main chamber; a liquid inlet and a liquid outlet in said main chamber; valves in said liquid inlet and outlet; a primary float in said main chamber; a secondary float in said. auxiliary chamber; means associated with said floats for actuating said liquid inlet and outlet valves; a partition in said auxiliary chamber above said secondary float forming a gas chamber in the top of said auxiliary chamber; a port in said partition; an outlet port in said gas chamber; and a normally open safety valve associated with said outlet port and adapted to be closed by liquid entering said gas chamber.

12. A gas compressor of the class described embodying: a vertical housing; a partition across said housing forming top and bottom chambers therein; a liquid inlet and a liquid outlet in said bottom chamber; valves in said liquid inlet and outlet; means including a pilot valve and a hydraulic diaphragm for actuating said inlet and outlet valves in opposed relation with each other; an operating lever on said pilot valve; a vertical rod secured to said operating lever; a primary float in said bottom chamber; a stop on said rod adapted to be engaged by said float during its downward movement to actuate said pilot valve whereby said outlet valve is closed and said inlet valve is opened; a secondary float in said top chamber; link means connecting said secondary float to said rod whereby said rod and said pilot valve are actuated upon upward movement of said secondary float so as to close said inlet valve and open said outlet valve; a gas inlet in said bottom chamber below the normal liquid level therein; a check valve in said gas inlet; a check valve in said partition; and a com pressed gas outlet port in the top of said top chamber.

13. A gas compressor of the class described embodying: a vertical housing; a partition across said housing forming top and bottom chambers therein; a liquid inlet and a liquid outlet in said bottom chamber; valves in said liquid inlet and outlet; means including a pilot valve and a hydraulic diaphragm for actuating said inlet and outlet valves in opposed relation with each other; an operating lever on said pilot valve; a vertical rod secured to said operating lever; a primary float in said bottom chamber; a stop on said rod adapted to be engaged by said float during its downward movement to actuate said pilot valve whereby said outlet valve is closed and said inlet valve is opened; a secondary float in said top chamber; link means connecting said secondary float to said rod whereby said rod and said pilot valve are actuated upon upward movement of said secondary float so as to close said inlet valve and open said outlet valve; a gas inlet in said bottom chamber below the normal liquid level therein; a check valve in said gas inlet; a check valve in said partition; and a compressed gas outlet port in the top of said top chamber, said last mentioned check valve being mounted for limited movement on the link means which connects said secondary float to said rod.

14. A gas compressor of the class described embodying: a vertical housing; a partition across said housing forming top and bottom chambers therein; a liquid inlet and a liquid outlet in said bottom chamber; valves in said liquid inlet and outlet; means including a pilot valve and a hydraulic diaphragm for actuating said inlet and outlet valves in opposed relation with each other; an operating lever on said pilot valve; a vertical rod secured to said operating lever; a primary float in said bottom chamber; a stop on said rod adapted to be engaged by said float during its downward movement to actuate said pilot valve whereby said outlet valve is closed and said inlet valve is opened; a secondary float in said top chamber; link means connecting said secondary float to said rod whereby said rod and said pilot valve are actuated upon upward movement of said secondary float so as to close said inlet valve and open said outlet valve; a gas inlet in said bottom chamber below the normal liquid level therein; a check valve in said gas inlet; a check valve in said partition; and a compressed gas outlet port in the top of said top chamber, said primary float comprising a cup and a counterbalance for offsetting the weight of said cup.

15. In a gas compressor of the class described having two vertically spaced compartments and a passage therebetween; liquid inlet and outlet valves in the bottom compartment; a primary float in the bottom compartment; means assooiated with said primary float for closing the liquid outlet valve and opening the liquid inlet valve when the liquid level has receded to a predetermined point; a valved gas inlet in said bottom compartment; a secondary float in the top compartment; means associated with said secondary float for closing the liquid inlet valve and opening the liquid outlet valve when said float has been buoyed up to a predetermined point, said last mentioned means including a rod mounted in said secondary float in alignment with the passage connecting said compartments, a valve mounted for limited movement on the lower end of said rod and adapted to seat in said passage; a valve stem sealed to said valve and extending downwardly therebelow; and link means connecting said valve stem with the remainder of said liquid inlet and outlet valve actuating means.

16. A gas compressor of the class described embodying: a housing having a main compressing chamber and an auxiliary float and outlet chamber; a check valve between said chambers; a liquid inlet in said main compressing chamber; a liquid drain connection in the bottom portion of said main compressing chamber; an air inlet in said main compressing chamber below the lowermost liquid level therein; valves in said liquid inlet and outlet and in said air inlet; and float means including a. float in each of said chambers for controlling the actuation of said last mentioned valves.

17. A gas compressor of the class described embodying: a housing having a main compressing chamber and an auxiliary float and outlet chamber; a check valve between said chambers; a liquid inlet and a liquid outlet in said main compression chamber; an air inlet in said main compression chamber below the normal liquid level therein; .valves in said liquid inlet and outlet and in said air inlet; and float means in said chambers for controlling the actuation of the three last mentioned valves.

DONALD G. GRISWOLD.