US1249921A

US1249921A - Hydraulic air-compressor.

Info

Publication number: US1249921A
Application number: US17478217A
Authority: US
Inventors: Kennedy Dougan
Original assignee: Individual
Current assignee: Individual
Priority date: 1917-06-14
Filing date: 1917-06-14
Publication date: 1917-12-11
Anticipated expiration: 1934-12-11

Description

K. nous/w.

' HYDRAULIC AIR COMPRESSOR APPLICATION FILED JAN. 16. I909. RENEWED JUNE 4| 1911.

1 9% 49, 9% m Patented Dec. 11, 1917.

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K. DOUGAN.

HYDRAULIC AIR COMPRESSOR. APmcATmN FILED JAN 16. I909. RENEWED mm: M, 1917.

Patmrteol 10%. 11,1917,

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WITNESSES.

K.'DOUGAN. HYDRAULIC MR COMPRESSOR. APPLICATION nun Is. 1909. nzuzwzn sum WW bu 000cc till till

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Application filed l'anuary 16, 1909, Ecrial No. erases.

To all w/wmz't may concern:

Be it known that I, KENNEDY Deccan, a citizen of the United States, residing at Minneapolis, Hennepin county, Minnesota, have invented certain new and useful .l'llydraulie blur-Compressors, oil which the following is a specification.

This invention relates to. direct acting hydraulic air compressors, and has for its. object to provide a high efficiency air compressor in which the air will. be compressed directly by a column of water of uniform cross section throl'lghout; the volume. of air being so proportioned to the energy of the column of moving water that the water column is brought to rest at each stroke at the instant compression is completed.

Tn the preferred embodiment. of the invention two or more air compressing cylinders are employed, and. the column of water used for compressing the air is shifted alternately from one air compressing cylinder to another. All; the energy in1 the water is. utilized, or in other words, at each stroke the colunqm of utter is arrested by the air that has been compressed by that stroke.

Fiach figure of the accom ninying drawing is partly diagrannnatic with the exception of l igures 2 to 5 inclusive.

Briefly described, Fig. l an elevation, partly in section, of a twocylinder air compressor embodying the invention Fig. 2 is a vertical sectional view of one form of air-comprc ng. cylinder, detached;

F 3 is a section viewed on the irregular section line 3-3 on Fig. 2;

Fig. is a detail in section of water port it and its. valve; Fig. 5 is a central vertical section of the valved piston; Fig. 6 is an enlarged elevation, partly in section, of the driving mechanism shown in Fig. 1, partly broken away, looking in the direction of arrow 6; Figs. 7 and 7" are details of Fig. 6;

Fig. 8 is. a sectional view mechanism similar to that with a. slight modification valves;

Fig. 9 is a bottom plan of the cylinders of a two-cylinder compressor.

Referring to Fig. 1, numeral 1 designates a pipe, either vertical or inclined, having its lower end upturned. At its upper end pipe 1 is connected with a. source of water (indiot a compressor shown in F 1g. 2 of air admission Specificationof Letters Patent.

lltatented llltee. lllhl'lll'it. Renewed Jl'unel l, 191?. Serial lilo. 1%,?82;

cated by a reservoir 2) below which the air con'ipressor is located: 4t and 4t are two cylinders supported in an elevated and. substantially verticz l: position,by a frame lil'8. 'l hehlower ends of cylinders at, l are open. In practice, the diameter of the water column pipe 1 should be equal to. that of the cylindersd, 4 as shown. lllut the relative diameter may be varied. pipe section, thetuncti on of which is to admit the column oil water alternately into the cyliinlers st, t. The movable pipe section is to be arranged for oscillation.

The pipe section 9 is connected to. the stati onary pipe 1 by a substantially water-tight slip joint, comprising the

outside members

13, 13, the. pipe 9 being mounted on member 13.

The cylinders 4t, i are cast integral and, as shown in Fig. 9, are provided at their lower ends with flanges ll, which serve to prevent the water from escaping to atmosphere when the pipe section 9 is in motion.

Leakage of water between the pipe section 9 and. the cylinder l: may be practically prevented by means of a. device shown in Fig. l. lhis comprises i. collar 7?, fitted snugly but slidably upon the upper end of said pipe section. The upper edge oi? said collar is shaped to it the concavity ot the lower surface oi the cylinder Flanges. Said collar is pressed against said surface by a number of suitable springs 7'8. Inequalities in length of the member 9, due to expansion or contraction, also wear in the slip joint at the lower end thereof, will be compensated for by this device.

A. preferred :torm oi? one oil. the air cylinders is shown in detail in Figs. 2 to 5, inelusive.

Referring to Fig. 9., the cylinder t from top to bottom is divided into three main compartn'mnts or chambers A, B and (1.

Chamber A is bounded by cylinder head 15 and a piston head 17. Chamber lid is bounded by a fixed partition 1.8 and a movable head 19, which rigidly connected to piston head 17 by a rod 20 passing slidably through partition 18. Chamber G extends from the valved head 19 to the bottom of the cylinder. is the air intake port having the admission valve 23. The piston 19 is provided with a. inlmber of lift valves 24, through which the air compressed in Chilll'l.

9 is a movable llllll ber C passes into chamber B. Chamber B is provided with the air outlet 25, from which leads a pipe 27, provided with a spring-closed valve 28, adapted to retain the air within chamber B until it reaches a predetermined pressure when the valve will open. The spring pressure on said valve 28, is regulable by means of a screw 30 having an operating handle 30.

The air chamber A is provided at its up per end with an air cock 32, having a needle valve.

34 is an annular wall inclosing two water chambers, D and E, surrounding a part of the cylinder 4 above the partition 18.

In the partition 36, separating said chambers, are a number of downwardly opening, spring-closed valves 35.

For adjusting the pressure of the springs 35", each of said springs is provided with a screw 35 having a hand wheel for easy adjustment.

Chamber D is provided with a pipe or tube 37 having a stop-cock 38. This device serves two different purposes, as presently described.

Chamber D has communication with chamber C, by a pipe 39, in which are a check-valve 40 and a hand-valve 42. Checkvalve 40 opens in the direction of the arrow.

Water chamber E has free connection with the space under the piston 17, by a number of water ports 43, whose combined area should be large, to permit quick flow of water therethrough. Also, said chamber E is in constant connection with chamber D, through a small port 44, formed in portion 45 and regulated by a hand valve 47. This valve is adjustable from the exterior of the machine, as shown in Fig. 3. The top of water chamber E is connected to atmosphere through a duct 48 which is normally closed by a cock 49 during operation 01": the compressor.

The position of the pistons 17 and 19 as seen in Fig. 2 is that which they will occupy when the compressor is not in use.

To start the compressor in operation, supposing the apparatus to contain air only, the operator opens cook 49 and closes cock 38. Geek 32 is slightly opened. By means of its handle 30 the closing spring of the air outlet valve 28 is so set that the valve will only be opened by a predetermined pressure of air within chamber B.

Pipe 9 being under chamber C, water is admitted slowly through a gate valve in pipe 1, said water filling chamber C and flowing through

valves

42, 40 and pipe 39, opens valves 35 and fills chamber E and flows through ports 43 into the cylinder 4 beneath piston 17. The water pressure under disks 19 and 17 causes said pistons 19 and 17 to move upward in chambers A and B compressing air therein until an equilibrium is produced between the water pressure below pistons 19 and 17 and the air pressure above said pistons. During the time required for this operation, water flows through valves 24 into chamber B. Pipe 9 is now shifted to the other cylinder 4, and the operation just described is duplicated. The gate valve in pipe 1 is now fully opened and pipe 9 caused to oscillate from cylinder to cylinder. Instead of the water flowing in slowly as before, it rushes in in a manner similar to that in a hydraulic ram. The air contained in chamber C is compressed and driven through valves 24. If the water strikes the piston 19, it may raise it slightly. During this time, valve 28 has offered resistance to the egress of the air from chamber B. This resistance has been little less per square inch than the pressure to which the air is to be compressed for use. At each stroke oi the compressing water column, air passes from chamber G into B and thence through valve 28 to a receiver, not shown, and as the air pressure rises therein the spring pressure on valve 28 is decreased by hand until the required pressure is reached, after which the pressure on valve 28 is reduced by hand until there is only suilicient pressure exerted thereon to close it, that is to say, it acts thereafter as a check valve only. \Vhen the pipe 9 is moved away the water ialls quickly from chamber C as the air inlet valve 23 opens.

It will be understood that it is the intention to keep piston 19 and the parts connected thereto approximately in equilibrium vertically at the times when the full pressure of the compressed air is acting on the lower side of piston 19, in other words, keep the downward and the upward pressure on piston 19 and its connected parts equal, or nearly so.

In order to do this it is necessary to add pressure above piston 17 to compensate For the difference in pressure area on the upper side of piston 19 and that on its lower side, which difference is, of course, equal to the pressure that would be exerted upon the area. of the cross section of the rod 20.

One manner of doing this is as follows z- The springs 011 valves are caused to press them against their seats with such force that piston 17 will not move up when pres ur is applied below piston 19 until the entire pressure below 19 exceeds the entire pressure exerted on said piston in chamber 13 by an amount equal to the force which must be. exerted on piston 17 to draw water through the spring-pressure closed valves 35.

The water provided in chambers D, E and drawn in below piston 17, is for the purpose of preventing the compressed air above pistons 1.7 and 19 from forcing them down suddenly, as they can only descend at a rate proportional to the escape of water oil :na-aaeai through port hl, which is controlled by hand-valve 47.

llt is plain that piston 19 and connected parts will move slowly down except during a strokeot the water column when it will be checked and probably driven up again less or more, by being struck by the ascending column of water. But sinceit is driven up quickly and down slowly it will soon become adjusted automatically to the point where it will only be knocked up the same distance that it descends between strokes oi the water column. More or less water will pass through valves 24 and will either be carried out through valve 28 with the air by entrainment or will remain in cylinder l3 while the air passes through it. This water will, of course, be trapped out of the air by asuitable trap, after it has passed through valve 28.

To compensate for leakage and evaporation of water, at each. stroke of the column of water in U a small quantity of water is driven through valves 4:0, 412 and pipe 39 into chamber D, the amount so supplied being regulated by the hand valve 412. If chamber D becomes filled with water, the surplus will flow out through the tube 37 and the open cock 38.

l l hen piston 17 is driven up suddenly, an air cushion will be formed above it, but the air pressure thus created will fall as the air escapes through needle valve 32, thus leaving piston 17 normally exposed to atmospheric pressure.

lo the operation of this construction. with the air compressor delivering air to the receiver tank from which the air is being drawn for motors or other purposes, should the amount drawn from the tank be reduced, as for instance, by shutting oil? a number of the motors, the air pressure in the tank will rise, and the head 19, will immediately begin to adjust itself to the proper position in the cylinder to give air at the new pressure, and as the pressure continues to rise, the head 19 will continue to descend. An increased consumption of the air from the tank will cause the pressure therein to fall, head 19 will at once begin to adjust itself to the new conditions so as to supply air at the receiver pressure, and the elliciency of the compressor will be just as great with the head 19 at any point in the cylinder. This automatic action takes place when the air pressure above piston 19 becomes so great that the column of water will not compress the air between the valve 23 and piston 19 to such an extent that the column ot' water will strike piston 19, piston 19 will descend owing to leakage throug h cock 4 9, 2) that is to say. water leaking; through cook 49, allows piston 1'7 (and with it piston 19) to descend, and it will continue to descend slowly, between. strokes, until it reaches a point where the volume of air below the piston 19 is so small that the column 01? waterwill drive it through valves 24, and strike piston 19 with such force as to drive the piston slightly upward. lly reason oi this automatic adjustment oi the piston 19, (which in etlect the end all. oil the com.- pressor cylinder t) to the point in the oylinder where the body of air to be com pressed will check the column of water just as it reaches the piston or head 19, all ot the air in the cylinder is forced through the "alved opening 24. of the piston, and there is no waste of compressed air. To leave air under the head 19, compressed to a high degree to expand and es .HPO through the lower end of the cylinder when it is thrown open would be a great waste of energy. The little water which may pass through the valved openings Q l will not be obj ectionablc, for it can be readily trapped out of the air after leaving the compressor.

To allow for variations in the rate of consumption oi the compressed air. the motor driving the pipe shiitimr mechanism may be regulated, either manually or automatically.

decor-ed around the pipe section 9 near its upper end is a band or collar 52 havinglug or lugs through which passes a pin, 54:. 55 is a horizontal crankshaft journaled on the standard and having a crank portion 56 comprising the crank-pin 57, wiich is connected with pin 54 by a pitnmn 58.

Mounted on crank shaft 5.) are two

clutch members

60, 61. ll lember (i0 is a gear wheel provided on its inner face with an inclined segmental lug 60. and is loose on the shaft. Clutch member (ll is provided on its inner face with two inclined segmental lugs 61, having shoulders (32. This clutch member is splined on the shaft by a sliding key as (Fig; 7.)

A spring 54. is caused by a collar (55 to bear this clutch member bl against the driving; clutch member 60. The combination may be termed a ratchet clutch, as it is designed to drive in one direction only and the lugs (30 61 are equivalent to ratchet teeth.

hileshingz with the teeth of wheel or clutch member (30 is a rack 66. The pguides for said rack are omitted for clearuess oi illustration. One end of the rack is rigidly connected with a piston rod 67, terminating in a piston (58 that is practically air tight within a cylinder 69, the upper end of which may be open.

The lower end of the cylinder is closed, except for a relief valve 70, epeniirg outward. it very small clearance is provided below this valve port so that the piston. will. be cushioned at the end of the down stroke, by air that will lllllVOhlill'llY leak into the cylinder in small quantities during operation.

lit-l9 71 is a ratchet wheel and 7 2, a gear wheel, independently rotatable on a shaft parallel to shaft 55. A wrist-pin 7 3 on wheel 71 is connected by a pitman '71 with a wrist-pin 75 on the rack 66. Gear wheel 72 carries a pawl 76 that drives the ratchet 71 and permits the latter to accelerate during the down stroke of the piston 68. The throw of the wrist-pin 73 is such as to impart a rotary oscillating motion of slightly more than 180 degrees to the driving clutch member 60, through the medium of the rack 66 and pitman 74.

Gear wheel 72 is driven by a pinion 77 having a pulley 78 which is driven continuously by any suitable motor, (not shown.)

The clutch 60-61 is so adjusted that the driven member 61 will come to rest just as the pitman 58 actuating the pipe section 9 comes to the end of its stroke.

The motor, through pulley 78, pinion 77, gear 72 and pawl 76, rotates ratchet wheel 71., which through pitinan 7 lforces up the rack 66 and piston 68, the latter creating a partial vacuum in the cylinder behind it. As soon as the wrist-pin 73 on ratchet wheel 71 is carried a little past its upper dead center, the piston 68 is quickly driven down by atmospheric pressure, drawing with it the rack 66 and pitman 7a. The rack rotates the driving clutch member 60 slightly more than one-half a revolution, during which time, lug 60 by engaging a lug 61 of member 61, drives the latter exactly onehalf a revolution. This motion is transmitted through shaft 55, crank 56 and pitnian 58 to the pipe section 9, which is thus thrown quickly from one cylinder to the other. As the crank 56 stops on its dead center the initial and final part of the throw of the pipe ection 9 will be devoid of sudden shock. During the down stroke of the piston 68, the pitman 74 is of course drawn down quickly, in fact so quickly as to rotate the ratchet wheel 71 faster than the same is rotated by the pawl 7 6. During this movement the ratchet wheel teeth will slip beneath the pawl. The instant the piston reaches the end of its down stroke the pawl positively reengages the ratchet, and the above described operations will be repeated.

The driving clutch member 60 i turned in opposite directions alternately, but the driven member 61 is turned always in the same direction. As the driving lug 60 rides up the surfaces of the lugs 61 the member 61 is moved laterally against the spring 6 1, which restores it the instant the lug 60 has passed off the lug 61.

The movements of the pipe section 9 are timed by the time required for the water to enter the chamber C and come to rest. The said section is held stationary only for a snliicient interval to permit the water to en ter and come to rest in the chamber C. During this interval the motor causes the piston 68 to be fully raised and turns clutch member 60 to initial position. Then the pipe section is shifted to and stops under the other cylinder. During this time the water in the first cylinder has ample time to be discharged by gravity.

I do not limit the invention to the oscillating mechanism shown and described, as the desired moven'lent may be ell'ectcd by different means.

Fig. 8 shows an air compressor like l in. 2, slightly modified. This form has a hollow piston rod 20 which extends from the piston 19, through the piston 17 and through the top of the cylinder -11. Both ends of the hollow piston are open. A rod 11?) passes through the hollow rod 20 and carries at its lower end a puppet valve it to control the open lower end of the hollow rod 20. The upper end of the rod 145 passes through a guide a, and carriesa(ljustin 1' nuts I). A spring (1 surrounds the projecting end of the rod and is located between the guide a and the nuts 7). This spring serves to hold the puppet valve a l normally seated on the lower end of the hollow rod 520. The pistons 17 and 19 are freely movable and self-adjusting as in Fig. 2. In this (.OliSlli'lWi'iOii air is admitted through the valve i l" above the column of water when it. is being (lischarged. To permit the ascending water column to acquire velocity and energy, openings 149 are provided in the cylinder below the lower end of hollow piston rod 20' to permit the escape of air until the water has covered said openings. These openings are provided with outwardly-closing valves 150 which are held open by delicate springs 151, except when closed by the pressure of the moving water. Guides 153 are provided for the valve stems 152, which project beyond the guides 153, and on each valve stem is a nut 15 1 and a jam nut 155. Nuts 151- act as stops for the valves when the valves are intended to be opened. When the valves are to be held closed, the stems 152 are drawn out as far as they will go and the valves tightly closed by turning the nuts 151-.

I claim:

1. A hydraulic air compressor comprising a cylinder in which the air is compressed by a moving column of water, means h aving intermittent communication with said cylinder for admitting and directing the water suddenly into the same, said means operat ing thereafter to open the cylinder and permit the escape only of that part of the column of water which had entered the said cylinder.

2. A hydraulic air compressor comprising a cylinder in which the air is compressed by a moving column of water, said cylinder being open at the bottom, a vibrating water pipe having connection with a head of water titl tltl

esa-eat and adapted to register at one point in its movement with the open end of the cylinder and to clear said openpipe at another point in its movement, and means to vibrate the pipe.

3. A hydraulic air compressor comprising a pair of angularly disposed cylinders in which the air is compressed by a moving column of water, said cylinders having open-ended mouths arranged in an arc of a circle, a vibrating pipe having connection witha head of water and provided with an open-ended mouth adapted to register with and clear the mouth of each cylinder at opposite points in the extent ot' vibration of said pipe, and means to vibrate the pipe:

l. in a hydraulic air ended air compression cylinder having an air outlet; a valved piston intermediate the open end and the air outlet of said cylinder; a water-columntube having substantially the same bore as said cylinder through out the length thereof and in direct lcngitudinal communication with the open end of the cylinder; and means for alternately admitting a column of water under head from said tube into the open end oil said cylinder and cutting oil said column.

5. in a hydraulic air compressor, an open ended air compression cylinder having an air outlet; a piston intermediate the open end and the air outlet of said cylinder having normally closed valves; a water-column tube and means for alternately admitting a column. of water under head from said tube into the open end of said cylinder and permitting the discharge of the water from the cylinder.

6. In a hydraulic air compressor, an open ended air compression cylinder having an air outlet; a valve piston intermediate the open end and the air outlet of said cylinder; a water-column tube and means for moving the discharge end of said tube in and out of register withthe open end oi said cylinder, for periodically admitting a water column under head into the open end oi said cylinder and cutting ott' such column alternately.

7. lln a hydraulic air compressor, an open ended air compressing cylinder having an air outlet, a valved piston intermediate the open end and the air outlet of said cylinder; a tube adapted to conduct a columnot water to said cylinder, and having substantially the same here as said cylinder, throughout its length, and means for alternately opening and closing communication between said water tube and said cylinder.

8. ln a hydraulic air compressor, a plurality of open ended air compression cylinders arranged with open ends in proximity, each cylinder having an air outlet and a valved piston intermediate said outlet and the open end of the cylinder, a tube adapted compressor, an open) head to said cylinders, and means for moving the discharge end sively into register with the open ends of the cylinders and arrestingit momentarily in each of said positions.

10. in a hydraulic air compressor, an open ended air compression cylinder having an air. outlet; a slidable valved piston intermediate the open end and the air outlet of said'cylinder; a water-column tube having substantially the same here as said cylinder throughout the length thereof; and means for alternately admitting a column of water under head from said tube into the open end of said cylinder and cutting off said column at the entrance to said cylinder.

11. In a hydraulic air compressor, a vertical cylinder having an open lower end and divided transversely by a fixed partition; a piston in the cylinder above said partition, a valved piston in the cylinder below said partition, a rod connecting said pistons, the valves of said valved piston opening upward, a Water chamber, water ports entering the cylinder between the first piston and the partition and communicating with said water chamber, check valves permitting of said tube, succesquick flow of water into the cylinder through said ports, and a restricted water outlet from the cylinder for the purpose specified.

12. In a hydraulic air compressor, a vertical cylinder having an open lower end and divided transversely by a fixed partition; piston in the cylinder above said partition, a valved piston in the cylinder below said partition, a rod COHIIGClIlHg said pistons, a water chamber, Water ports entering the cylinder between the first piston and the parti-- tion and communicating with said water chamber, check valves permitting quick flow of water into the cylinder through said ports, a restricted water outlet from the cylinder for the purpose specified; and a tube connecting the upper part of said water chamber to atmosphere, said tube being provided with a valve.

13. In a hydraulic air compressor, an open ended air compression cylinder having an air outlet; a valved piston intermediate the open end and the air outlet of said cylinder; a water-column tube having substantially the same bore as said cylinder throughout the length. thereof; and means for alternately admitting a column of Water under head from said tube into the open end of said cylinder and permitting the discharge of the water from below said valved piston.

14. In a hydraulic air compressor a cylinder having an open end and divided transversely by a fixed partition; a piston in the cylinder above said partition, a valved piston in the cylinder below said partition, a rod connecting said pistons, an air outlet from the cylinder between the partition and the valved piston, and means for equalizing the downward pressure upon the valved piston with the upward pressureupon the same during operation of the compressor.

15. In a hydraulic air compressor, a vertical cylinder having an open lower end and divided transversely by a fixed partition; a piston in the cylinder above said partition, a valved piston in the cylinder below said partition, a rod connecting said pistons, an air outlet from the cylinder between the partition and the valved piston, and means for equalizing the downward pressure upon the valved piston with the upward pressure upon the same during operation of the compressor.

16. In a hydraulic air compressor, the combination with an open-ended cylinder, of a pipe section movable into and out of communication with the open end of said cylinder, of a crank shaft provided with a crank, a pitman connecting said crank to said pipe section, a gear wheel on said crank shaft, means for convertingoscillation of said gear wheel into stepby-step rotation of the crank shaft, a rack engaging said gear wheel, a dashpot cylinder, a piston therein connected to said rack, power driven means for-intermittently actuating said rack and piston in one direction, and automatic means to permit the rack to be actuated in the opposite direction independently of said power-driven means; substantially as described.

17. In a hydraulic air compressor, the combination with an open-ended cylinder, of a pipe section movable into and out of communication with the opened end of said cylinder, of a crank shaft provided with a crank, a pitman connecting said crank to said pipe section, a gear wheel on said crank shaft, a ratchet clutch also on said shaft, a rack engaging said gear wheel, a dashpot cylinder, a piston therein connected to said rack, a ratchet wheel provided with a pitman connected to said rack, and a continuously rotated member carr ing a pawl engaging and driving said ratchet wheel during substantially one-half of each revolution of said continuously rotated member; substantially as described.

18. A hydraulic air compressor comprising a cylinder in which the air is compressor by a moving column of water, means having intermittent communication with said cylinder for admitting and directing the water suddenly into the same, and means to permit the escape to atmosphere of a portion of the air in the cylinder beiore compression begins.

19. ii hydraulic air compressor comprising a cylinder in winch the air is compressed by a moving column of water, means having intermittent communication with said cylinder for admitting and directing the water suddenly into the same, said connmmication being for a definitely timed period, and means to permit the escape to atmosphere oi a portion of the air in the cylinder belore compression begins.

20. In a hydraulic air compressor a cylinder in which the air is compressed, by a column of water, means for admitting the water suddenly, an air outlet 'lirom the cylinder between the ends of the cylinder, and a normally open valve in said outlet, said valve being closed by the force of the water after a part of the air has been expelled through said outlet.

21. In a hydraulic air compressor, a cylinder in which the air is compressed by a column of water, means for admitting the water suddenly, a vertically movable valved head in the cylinder, means for holding said head at any suitable height, an air inlet passage running from atmosphere lhrough said holding mean into the interior ol the cylinder, and a spring-closed valve normally closing said air passage.

22. In a hydraulic air compressor, av cylinder in which the air is compressed, by a column of water, means for admitting the water suddenly, a tubular rod passing through a closed end of the cylinder, a valved head mounted on said rod within the cylinder, and a spring closed valve normally closing the air passage through said rod, said valve when open admiitin atmospheric air to the interior of the cylinder.

23. In a hydraulic air compressor, a. vertical cylinder having an open lower end and divided transversely by a fixed partition; a piston in the cylinder above said partition, a valved piston in the cylinder below said partition, a rod connecting said pistons, a water chamber, water ports entering the cylinder between the valvcless piston and the partition and communicating with said water chamber, check valves permitting quick flow of water into the cylinder through said ports, a restricted water outlet from the cylinder for the purpose specified, means for permitting the escape from the cylinder below the valved piston of: a. portion of the air before compression, and means for admitting air from atmosphere through the piston rod, substantially as described.

24. In a hydraulic air compressor, the combination with an air compression cylinall) ' sion.

26. in a hydraulic air compressor, the combination with a compressor cylinder having a compressed air outlet, or means alternately projecting a column of Water into and discharging it from the cylinder, a movable member in the cylinder controlling the degree of air compression, a receiving tank for the compressed air, the compressed air in the tank reacting on the movable member to assist in automatically causing the movable member to automatically adjust itself according to the degree of air compression in the tank.

27. lln a hydraulic air compressor, the combination with an air compression cylinder having a compressed air outlet, of means alternately projecting a column of water into and discharging it from said cylinder, and automatically acting means controlling the degree of air compression in the cylinder.

28. In a hydraulic air compressor, the combination with an air compression cylinder having a compressed air outlet, of means alternately projecting a column of water topics or this patent may be obtained for into and discharging it from the cylinder, a movable member in the cylinder controlling the degree of air compression, said member acted upon by water and air pressure to cause automatic adjustment of said movable member tor the purpose described.

29. In a hydraulic air compressor, the combination with a vertical air compression cylinder having an open lower end and a compressed air escape at its upper portion, of a pipe movable into and out of communication with said lower open end of the cylinder.

30. In a hydraulic air compressor, the combination with an air compression cylinder having a compressed air outlet, means alternately projecting a vertical column oi. water into and discharging it from the cyl inder, a movable compression member for the cylinder acted upon by the previously compressed air to automatically adjust itself to a position to cause all the air in said cylinder to be expelled from the cylinder by the column of water.

31. In a hydraulic air compressor, the combination with an air compression cylinder having a compressed air escape, means alternately projecting a vertical column oi water into and discharging it from the cylinder, a movable compression member for the cylinder acted upon by water and by the previously compressed air to automatically adjust itself to position to cause all the compressed air to be expelled from the cylinder by the columns of water.

KENNEDY DUUGAN.

VVitnesses':

L. It. CLEMENT, O. O. GREEBMAR.

Washington, Iii. ill,

till