US2196993A

US2196993A - Expansion well pump

Info

Publication number: US2196993A
Application number: US106095A
Authority: US
Inventors: Joe H Kidder
Original assignee: Individual
Current assignee: Individual
Priority date: 1936-10-17
Filing date: 1936-10-17
Publication date: 1940-04-16
Anticipated expiration: 1957-04-16

Description

April 1940- J. H. KIDDER ,196,993

EXPANSIQN WELL PUMP Filed 0017. 17, 1936 2 Sheets-Sheet 1 xii/(@1116? April 16, 1940.

J. H. KIDDEZR EXPANSION WELL FUN P Filed Oct. 1'7, 1936 2 Sheets-Sheet 2 Patented Apr. 16, 1940 UNITED l STATES PATENT OFFICE 2,190,993 EXPANSION WELL PUMP Joe B. Kidder, m A ngeies, Calif.

Application October 17, 1936, Serial No. 108,095

1: claim. (circa-44) My invention relates to a pump more specifically for use in deep wells such as oil wells in which the pumping action is developed by compressed air conducted downwardly to the pump 5 through pipes provided for such purpose and in which the liquid, such as oil, to be elevated is forced upwardly preferably through oil tubes to the top of the well, such oil tubes being located within the well bore or well casing and providing a housing structure for the pump or pumps. In some cases the liquid may be forced upwardly above the pump through the well casing.

In the above mentioned type of pump an object and feature of my invention is to develop the.

" pumping action by the expansion and contraction of a flexible medium which when contracted by a reduced air pressure, allows inflow .of liquid such as oil into a pumping compartment on the ex terior of the expansible medium, such medium when subject to compressed air expanding and thereby forcing the liquid outwardly, whereby through the use of check valves the liquid can only have an upward direction of flow. .A more specific object and feature of my invention is in constructing the flexible medium of a rubber or similar tube securely attached to the air pipe, which pipe is perforated at the parts covered by the rubber tube. A pump structure forms a chamber for the liquid, such as oil, to be pumped,

'80 on the outside of the expansible tube and when the tube is collapsed in close contact with the air pipe through a reduction of air pressure, a considerable volume of liquid may fill this liquid chamber. However when the air pressure is increased, the rubber tube expands, thus increasing materially in diameter, and positively displaces a quantity of liquid such as oil, which is forced upwardly, through non-return check valves. In

this connection, to prevent undue expansion of the rubber tube, a confining cylinder, this being preferably perforated, is positioned outside of the rubber tube, the interior of this confining cylinder forming a part of the liquid or oilchamber,

the outside of this chamber being defined by a 46 cylindrical pump barrel.

Another object and feature of my invention as to one form of the pump, is in the construction and assembly of a cylindrical pump barrel having an inlet check valve at the bottom. This 50 barrel preferably has a perforated head and is attached to the air pipe so that it may be lowered into the well, the string of air pipe being built up as the pump barrel with the assembled puinp is lowered. Located inside of the pump barrel and 55 confined by lower and upper heads whichform the oil or liquid chamber.

seats, the lower seat having perforations, is the confining cylinder, the air pipe with the perforated section and the flexible rubber tube confined thereto. The upper head has check valves for non-return flow of the oil being elevated. 5 Therefore when the rubber tube is deflated it has a snug fit, on the perforated section of the air pipe and liquid such as oil may flow upwardly through the check valve in the lower head of the pump barrel and fill) the annular space be- 10 tween the pump barrel, the confining cylinder and through the perforations of this cylinder to the outside of the rubber tube. When the air pressure is'increased this rubber tube expands laterally, the limit being the confining cylinder, 16 and thus forces the oil inside of the confining cylinder outwardly. This pressure causes a seating of the lower check valve and opens the upper check valves for upward flow of the oil. In this type of pump it is preferable to have a packer 20 between the oil barrel and the well casing below the perforated head so that the oil passing upwardly through this perforated head of the pump barrel flows upwardly inside of the well casing.

A detail feature of my invention resides in the 25 manner ofv attaching the rubber tube at its upper and lower ends to the air pipe surrounding the perforated section. For this purpose it is preferable to have the rubber tube with upper and lower flanges or beads and engaged by upper and 30 lower split bushings; Each bushing is threaded into-a plug, there being a lower plug seating on the lower head or seat in the pump barrel, such being above the bottom head having the intake check valve and the upper head having the check 35 valves therein for the upward flow of oil from These bushings are flared on the inside to give a gradual curvature to-the end portions of the expansible rubber tube so that no sharp bends accrue during the expano slon and contraction of this rubber expander. The bushings are brought into contact with the confining cylinder. It is also preferable in the rubber expander to incorporate fabric at the end portions where there is but little expansion as a stiffening structure but to have the expanding section formed of resilient rubber.

Another feature of my invention provides for the blowing out of water condensation or other liquid from the air pipe. This pipe therefore at the bottom is provided with an outlet valve which incidentally prevents inflow of oil when the assembiy is lowered into a well, and as the portion of the air pipe having the rubber expander thereon may be slightly elevated or unseated, the q building up or an air pressure in the air pipe will thus blow of! any water condensation or other liquids. v

Another feature of my invention is arranging the pump assembly so that, for instance, the air pipe with the rubber expander attached thereto by bushings may be unseated and elevated or this removable assembly may include the confining cylinder. 7

Another object and feature of my invention is in the provision and construction for pumping the liquid or oil from. deep well pumps in stages, that is, from a bottommost pump to a pump next above and from this second pump to a; still higher pump is necessary so that each stage will not have too great a lift. In this construction the pump barrel for each pump has an oil tube connected thereto and extending to the pump next above. In this case the provision can be made for withdrawing the upper pump assembly only and the oil tube is preferably of substantially the same diameter as the pump barrels. In this type of construction for pumping in stages, the oil tubing connected to the bottom of an upper pump barrel is perforated so that the oil may flow outwardly through these perforations into the'well casing above a packer. This is done as all of the pumps operate simultaneously in expansion and contraction of the rubber expander on account of. having a single string of air pipe extending downwardly to supply all of the pumps and thus a lower pump builds up a hydraulic head of oil in the casing surrounding the pump barrel of the pump next above on the lift or expansion stroke as the intake check valves of all the pumps are simultaneously closed and then on the contraction action the oil flows from this body surrounding an upper pump into the oil chamber of such upper pump and is elevated on the next expansion stroke.

It will be noted that a characteristic feature of my invention is that no air escapes into the body of liquid being elevated but that the pumping is done by the expansion and contraction of the rubber expanders, the action of which is developed by increasing and decreasing the air pressure in the air pipe. Hence a further detail feature of my invention resides inthe control of an air compressor or the air confined in .a storage tank under pressure. This is arranged so that for instance the compressor for a period of time builds up a compression in the air pipe and then for another predetermined period such air is released and may be discharged to atmosphere, thus reducing the pressure. This action is automatically arranged by operation of an air valve which may be automatically connected to an air compressor or other moving mechanism. It will be appreciated that in my invention that although the expansion as to diameter of the rubber expander is somewhat limited due to the usual diameters of oil 'wells or the like. nevertheless these rubber tubes forming the expander may be of very considerable length compared to their diameter and thus at each expansion cause the movement upward by displacement of a relatively large body of liquid. The pumping however is somewhat slow on account of the time period necessary to build up the air pressure'in a long string of air pipe and to release such pressure.

My invention is illustrated in connection with the accompanying drawings, in which:

Fig. 1 is a vertical section through a portion of a well casing and one form of my pump taken 2,198,993 v I i I substantially on the line l lof Figs. 2 01*:3 in the Fig. 3 is a horizontal section on the line 1-3 of Fig. 1 in the direction of the arrows.

Fig. 4 is a vertical section through an assembly of pumps for multiple stage pumping from a deep well. I a

Fig. 5 is a diagram in elevation showing a supply and control inechanisrn for the compressed air. l,

Fig. 6 is a vertical section showing a modified form of the pump elements, this including a flexible inflatable bag.

Dealing first with the construction of Figs. 1, 2 and 3, this is illustrated by a portion of a well casing ll havinga cap l2 with an outlet t3 for oil. The cap is provided with a packing and packing assembly 14..

The pump proper designated by the numeral has a cylindrical pump barrel'2l with a bottom head 22 secured therein in any suitable manner, this head being provided with an intake check valve 23 shown as a oall valve.

A lower v combination head and seat 24 is secured in the 1 pump barrel and has a series of perforations or passages leading upwardly from the bottom oil compartment 26. There is anupper combination head and seat'2'l having ports 28 with'nonreturn check valves 29 allowing upflow of oil or liquid but preventing the downflow. This hasan upper sloping seat 30. v

A confining cylinder has an upper end 36 fitted to the head 21 by an annular depending rib 31. The lower end 38 is secured at 39 to the lower head 24 which has an inner tapered seat member 4| and an end 42 with a plugged opening 43.

The compressed air pipe 45 extends downwardly through the cap I2 and has a sliding fit with the neck 46 of an upper head 41 of the pump barrel 2|, there being a screw "threaded connection 48. This upper head is shown as sloping and having a series of perforations 49. A collar 50 to engage I with this head is secured to the air pipe 45.

The expander assembly designated by the numeral utilizes a perforated section 56 of the air pipe and over this is fitted an expandible tube 51, this being preferably formed of rubber and is illustrated as having ends as with a bead 59 lower end of the air pipe section 56 and has the lower split bushing 60, screw threaded thereon. It will be noted that these bushings have an outward flare 64 to confine the end portions of the rubber tube to a gradualexpansion on an easy curve. The bushings extend outwardly suba stantially to the confining cylinder 35.

A check valve I0 is mounted in the bottom of the lower plug 63 and has a light spring to retain the valve closed. This preventsentry 'of oil or liquid into the air pipe 45 at the bottom when the pump is lowered into a well and also operates as a blow'ofl' valve to blow condensed water or other liquids out of the air pipe.

In the operation of the device as shownin '15 as sections are added to the-compressed air pipe 48. In this action the collar 89 engages the head 49, this unseatlng the

plugs

82 and 88 from their respective seats and the pump assembly being supported by the engagement of the collar 99 and the head 48. when the pump is at the desired depth for instance in the portion of the casing for oil, a packer II is fitted between the pump barrel 2| and the casing II. It thus seals off the upper part of the casing to the top of the'well. The air pipe 48 with the expander assembly 88 may then be lowered until the

plugs

82 and 99 seat on the respective seating heads 24 and 21. As above mentioned, the check valve I9 prevents entrance of oil into the air pipe sections 98.

The assembly is now in position for pumping action which is done by alternately and at a slow rate forcing compressed air downwardlythrough the pipe 45 until the rubber expander tube 91 is pumped outwardly, the. limit of the expansion being the confining cylinder 98. This cylinder in practice is'placed asv close,to the pump barrel 2| as possible, leaving however sufficient room for the passages or

perforations

25 and 28 and the check valves 29. The oil flows in through the checkvalve 28, and manifestly when the rubber tube expands the oil trapped in the chamber 44 can only move upwardly through the-check valves 29 and thence through the perforations 49 in the head 41 and upwardly in the well casing I I. When the air pressure is reduced in the air pipe 45 the rubber expander tube 51 collapses, thus allowing for an inflow of a secondchargeof oil through the valve 28 due to the Y pressure in the well. The action isthen repeated.

If a liquid such as water condenses in the lower part 59 of the air pipe -45, the air pipe with the assembly of pl'ugs82 and 98 may be lifted about a foot or so, so as to break the seal at the tapered seat 4|.

extension 56, however this does not expand the rubber tube ill but causes the check valve 19 to open and flow any condensed liquid out of the air pipe.- This only requires a slight increase of pressure over that of theoil from the well. This pressure of the well oil prevents the rubber tube 51 from expanding. In this action of the short lift of the compressed air pipe 49 which unseats the

plugs

82 and 88, there is no movement of the confining cylinder 35, this being rigidly held in position by the heads 24 and 81.

In view of the fact that the lower plug 98 and also the split bushing 89 have a sliding or working clearance in the perforated confining cylinder 35, it is in reality only necessary to elevate the air pipe .54 with its attached perforated section 56 in order to break the tapered joint at the seat member 4|. The compressed air therefore forces any condensed water or other liquid outwardly through the check valve "and this will rise in the confining cylinder 88 until it may flow out of the lower perforations. Any

liquid which is trapped below such bottom row of the perforations is forced upwardly when the lower plug 6-3 is again seated on the lower seat member 4|.

In the construction shown in Fig. 4 I make provision for pumping in stages, that is, from a bottommost pump to one next above and so on to the top of the well. In this illustration 9. well casingis'indicated by the numeral 89. In

Figs. 1, 2 and 3, the pump is assembled at the top of thewelland lowered in the well casing case that the confining tube 99, the plugs 9| Air is then forced down. under pressure through the pipe 45 and the-lower actual construction the casing is usually tapered fromthe top to the bottom of the well. In the illustration a lowermost pump II is shown and a pump 82 next above but it will be understood that there may be a series of these pumps. Deal- 8 ing first with the construction of the lower pump. 8|, this has a pump barrel 99 with a standing intake valve 84 at the bottom; A combination head and seat 88 is located above the standing valve and has a seat 88 and oil passages 81. An 19 upper combination head and seat .88 is also secured to the pump barrel and has a sloping seat 89. The perforated confining cylinder 99 is secured at itslower end to a lower plug 9|, this seating on the seat surface 88 of the lower head 15 88 which may be similar to that shown in Fig.

4 and have a plug at the bottom. The plug 9| has a blow-oi! valve 92.

The air pipe 98 has a lower perforated section v 94 and is connected at the bottom to the plug 89 9|. The rubber expander has beads 98 at its opposite ends and is confined by the split bushings 91 at the bottom and 98 at the top. The bushing 91 is secured to the plug 9| and the bushing 98'is shown as secured to an upgn' 29 plug 99. The conflningtube 99-is illustrated as connected at I99 to the plug 99. This upper plug has oils ducts |9| with non-return check 'valves I92 at the top. It will be noted in this and 99, the bushings, the perforated section 94 of the air pipe and the rubber expander tube 95 form an assembly which may be completely removed in a manner hereinunder described without disturbing the pump barrel 88.

A string of oil tubing II9 extends upwardly from the barrel 9| of the lower pump and if .desired may be the same diameter as this barrel.

A packer between the upper portion of this oil tube and the well casing slightly below the 40 upper pump 82 separates the easing into different lengths so far as the pumping of oil is concerned. Above the packer there are perforations 2 leading from the inside of the oil tube to the annular space between such tubing and the casing.

The upper pump 82 is quite similar in design. to the lower pump, having a pump barrel II5. In this case a coupling head I I6 may be used for coupling the upper end of the oil tube III! and the 50 lower end of the pump barrel I I5 or these may be coupled in anysuitable manner. This head H9 functions as a lower head for the upper pump and is providedwith a seat I I1, oil passages I I8, each having a check valve II9 andthe air pipe 99 is 55 connected through the head H6. The upper head I29 is similar to the'head 88 having a sloping seat |2|. In this case the lower plug I22 which is provided with a compressed air passage I23 and doesnot have any blow-off valve, seats directly on the seat 1. Theconfining tube I24 is connected directly to the plug I22. The perforated section I25 of the air pipe I26 is connected to the plug I22. The rubber expander tube I29 having end beads I21 is confined by a split bushing I28 connected to the plug I22 and the upper bushing I29 is connected to theupper plug I39 and also to the upper end I3I of the confining ,tube I24. The upper plug I39 is illustrated as the same as the plug 99 of the lower pump 8|. The 70 all leads upwardly above the plug I39 through an upper string of oil tubing I32 and thus leads to a succession of pumps if necessary or to the topof the well.

The operation of the multiple stag. pump of 78 simultaneously on decrease of the air pressure;

The oil is pumpedby the lower pump upwardly through the tubing I III and as .there is an internal pressure at the same time in the upper pump 82, this oil flows outwardly through the perforations II 2 into the annular space defined by the well casing, the pinnp barrel of the upper pump and the packer I I I. On the contraction stroke or cycle, thehead developed forces oil through the check valves I I9 into the'oil chamber of the upper pump so that on the expansion cycle of this pump such oil is forced upwardly to a third pump and so on or to the top of the well;

In this ,construction the various pumps may be disassembled in a sequence from the topdownwardly for removing the confining cylinder and all of the operating parts connected to the upper and lower plugs of each pump. For instance, these parts of the upper pump, if it requires repair, could be pulled upwardly with the air pipe, thus completely removing this upper assembly except the heads I I6 and I28 from the pump barrel of the upper pump and the oil tubing. It can likewise be re-inserted. If it is necessary to remove the lowermost pump, the upper oil tubing with the upper pump barrel may be removed by disconnecting from the head I I6 or this head may be left attached to the upper pump barrel and disconnected irom the oil tubing IIB. Then a connection can be made to the air pipe 93 and a lower Dump assembly including the confining tube and the lower and upper plugs connected theretoremoved upwardly. In this case where it is desired to blow out condensation from the lowermost pump it is necessary to first remove the upper pumps, make an air connection to the lowermost pump and slightly unseat such pump so that the blow-off valve 92 may be operative.

In Fig.5 I illustrate in a diagrammatic manner a suitable means for developing the pulsations of compressed air in the pump or series of pumps in a well. In this illustration an air compressor is indicated by the numeral I50 having a compressor structure I5I, a rotating shaft I52 with a fiy-wheel pulley or the like I53 connected thereto. The compressed air flows outwardly through a pipe I54 connected to a lead pipe I55, there being a regulating blow-off valve I56. The pipe I55 leads through a suitable valve I51 such as a two-way valve which has a connection I58 to the compressed air pipe leading to the pumps and a waste connection I59. This valve is illustrated as having a stem I60 with a lever I8I connected thereto having a roller I62 on the arm. The arm is normally retracted by a retraction spring I54. A cam I65 is mounted on a shaft I66 and this cam is shown as being driven by a belt or equivalent drive I51 from the shaft I52 or the pulley or the like I53.

In operation of this device, the spring normally holds the valve in its open position, that is, forming a compressed air connection from the pipe I55 to the pipe I58 leading to the well, therefore the compressed air from the compressor is lead to the air pipes in order to build up a pressure in the string of compressed air pipes leading to the various pipes, thus causing expansion of the rubber expander tubes. After a predetermined'period the roller I62 rides on the high part of the cam I85 which turns the valve forming a waste connection from the pipe I58 tothe outlet I59 thus releasing the pressure in thepumps' to atmosphere- During this period the comp s is Still operating but will blow-off through the valve I 56.

In this type of pump of course, a considerabletime period is required to build up the pressure to expand each of the pump elements and also to reduce the 'air pressure for theintake cycle'of the pumps. It is of course necessary that the air be pumped-to the lowermost pump. It is merely necessary to increase or decrease the pressure of air in each of the pumps and hence a comparatively small volume of. air is all that is necessary to operate one or more pumps in a. well, this of course being dependent on the length of the rubber expander-s, the diameter to which they expand and thepressure in the well to be overcome in the lift.

In Fig. 6 I show a modification of the pump structure in which instead of an expansible rubber tube I employ a flexible expansible and collapsible structure similar to a bag'or tube. In this illustration a pump barrel is designated by, the numeral I15 having a lower head with a seat I16 and an upper head I1'I also with a seat. The perforated portion of the air pipe I18 is connected to a bottom closed plug I19 and an upper valve plug I 80. The flexible and to a certain extent foldable tube or bag I8I issecured at its opposite ends I82 between clamping rings I 83 and I85 and held in place at its ends by flared bushings I85. The plugs are seated on the respective heads much the same as in the constructions shown in Figs. 1 and 4. In this case however I omitthe perforated confining cylinder and allow the bag to expand until it contacts the pump barrel I15.

The, foldable inflatable bag or tube may be made of afabric material somewhat as employed in the manufacture of balloons only of heavier weight. This does not stretch in the manner of a rubber tube but when collapsed will fold in an irregular manner around the perforated air tube I18. Then when the compressed air is forced downwardly ,in theair tube the bag or flexible tube expands and in its expansion forces the oil between the tube and the pump barrel upwardly. The flared bushings support the end portions of the expandible flexible tube preventing any sharp or angular bends. The bushings are close enough to the pump barrel to prevent any pinching of the bag but still allow an upward flow of the oil as it is displaced by the bag.

Various changes may be made in the details of the construction without departing from the spirit or scope of the invention as defined by the appended claims.

I claim:,

1. A pump comprising in combination a cylindrical pump barrel having an intake standing valve at the bottom, a. lower and an upper head,

each having a seat, the lower head having passages for liquid, an air pipe having a. perforated section with a plug at the bottom forming a closure, an upper plug adapted to engage the upper seat, a resilient expansible ,tube mounted 9,196,998 .the upperand lower plugs with the bushings being removable through the upper head by elevat ing the air pipe.

3. In a deep well pump, the combination oi a well casing, a lower pump having a pump barrel,

an oil tube connected thereto, a packer between the upper part of said tube and the 'well casing, said oil tube being perforated above the packer, an upper pump having a pump barrel with an upper oil tube connecting thereto and leading upwardly in' the well, the lower oil tube being connected to the upper pump, a common air pipe leading downwardly through the pumps, each pump having a perforated section of the air pipe with an expansible and collapsible flexible member connected thereto, means at each pump forming an oil chamber with inlet and outlet valves, each chamber surrounding the flexible member, the outlets for each valve communicating with the oil tube thereabove.

4. In a deep well pump as claimed in claim 3, each pump having a lower and an upper head with a seat and having lower and upper plugs connected to the perforated section 01' the air pipe to seat on said heads, the plugs of the upper pump with the air pipe connected thereto being first removable and then the oil tube and the pump barrel of the first pump being removable and the plugs with the air pipe of the lower pump being then removable.

5. In a deep well pump the combination of a well casing, a lower pump having a pump barrel, a lower oil tube connected thereto, an upper pump having a pump barrel with an upper oil and leading upwardly in tubeconnected thereto the well, means adjacent the upper oil pump to trap oil pumped upwardly by the lower pump through the lower oil tube, means connecting the lower oil tube to the upper pump, a common air pipe leading downwardly. through the pumps, each pump having a perforated section of the air pipe with an expansible and collapsible flexible member connected thereto, means at each pump forming an oil chamber with inlet and outlet valves, each chamber surrounding the flexible member, the outlets for each valve communicating with the oil tube thereabove.

6. In a deep well pump as claimed in claim 5, each pump having lower and upper plugs connected to the perforated section of the airpipe with means on which said plugs seat, the plugs of the upper pump with the air pipe connected thereto being first removable and then the lower oil tube and pump barrel of the upper pump being removable and the plugs with the air pipe of the lower pump being then removable.

'1. In a deep well pump the combination of a well casing, a lower pump having a pump barrel, a lower oil tube connected thereto and extending upwardly, an upper pump having a pump barrel with an upper oil tube connected thereto and leading upwardly in the well, means connecting the lower. oil tube to the upper pump barrel, means surrounding the upper pump barrel and having communication with theupper portion of the lower oil tube'to receive oil pumped upwardly by the lower pump, a common air pipe leading downwardly through the pumps and the pump barrels, each pump having a perforated section of the air pipe with an expansible and collapsible flexible member connected thereto, means at each pump forming an oil chamber with inlet and outlet valves, each chamber surrounding the flexible member, the outlets from each outlet valve communicating with the oil tube thereabove.

8. In a deep well pump the combination of a tubular means to suspend a pump barrel in a well, said barrel having the standing valveat the bottom opened for flow of oil by the pressure in the formation and having check. valves at the top open for upward flow of oil through the tubular structure by pressure developed between the standing and the check valves, an expansible structure positioned in the pump barrel, means forming an internal support of the expansible structure, a closure means for opposite ends of said expansible structure, an air pipe connectin from the expansible structure to the top of the well, means to produce an increase and a decrease of air pressure in the air pipe and hence expand and permit contraction of the expansible structure, means to separate the tubular supporting structure from the pressure in the well on the standing valve whereby such pressure in the well normally fills the pump barrel outside of the expansible structure between the standing and the check valves, the expansible structure on increase of air pressure in the pipe being expansible to force the oil upwardly through the check valves, the pressure of.the well fluid operating by a fiow through the standing valve being operative to collapse the expansible structure on decrease of air pressure whereby on periodic changes of increase and decrease of air pressure, the oil is pumped upwardly in the well.

9. In a deep well pump the combination of an oil conveying tube having a pump barrel connected thereto, the said tube extending to the top of the well, said pump barrel having a standing valve at the bottom for inflow of oil from the formation, an upper head, a plug seated on the upper head, check valves in said plug, a lower head having ports therethrough, a plug seated on the lower head, the lower plug being of less diameter than the upper plug to pass therethrough, an air pipe extending downwardly from the top of the well and connected to the upper and lower plugs and having a perforated section between the plugs, a flexible foldable collapsible and expansible tube attached to the pipe and the plugs and enclosing the perforated section, an air flow means at the top of the well to periodically increase and decrease the air pressure in the air pipe: whereby on increase of pressure the flexible tube becomes expanded and thereby displaces oil trapped between the standing and the check valves upwardly through check valves and whereby on decrease of air pressure, the pressure and flow of the oil from the well through the standing valve is adapted to collapse the said toldable tube whereby the pressure of the oil from the formation fills the pump barrel between the standing and the check valves and surrounding the ioldable tube, the said perforated portion of the air pipe forming a means to interiorly support the foldable tube when collapsed.

10. A pump comprising in combination a pump barrel with a standing valve in thebase thereof, a compressed air pipe'having a connection centrally to an expansible tube mounted on a section of the air pipe, such section being perforated,-a foraminous confining cylinder held in a fixed position between the tube and the pump barrel, the space between the barrel forming a liquid chamber with an inlet at the bottom above the standing valve and an outlet at the top having a non-return valve, the said tube being adapted to expand on internal air pressure in the perforated air pipe to force liquid in the said chamber upwardly through the outlet and the nonreturn valve, the pump barrel having a lower and an upper head, each with a seat, the air pipe having lower and upper plugs seated thereon, the lower plug having a blow-off valve whereby on elevating the'perforated air pipe the blow-off valve may operate to discharge liquid from the perforated pipe. I

11. In a pump, a hollow expansible structure, meansto support said structure internally, the said structure having means for inflation with air from the top and means to prevent the leakage of air from the lower part of said structure, means forming a liquid chamber on the outside of the expansible structure, valves for in and out flow of liquid to and from said chamber where by on decrease of air pressure in the expansible structure said structure collapses to engage the internal support and causes the liquid chamber to be filled with liquid and on inflation .of the said expansible structure such structure expands and forces liquid from said chamber, the said expansible structure having a flexible and foldable wall whereby when the structure is collapsed the wall may have a series of folds-and when expanded the wall becomes unfolded without stretching the material forming the wall.

12. Ina pump, an expansible structure having a flexible and foldable wall whereby when the structure is collapsed the wall may have a. series of folds and when expanded the 'wall becomes unchamber on the outside of the expansible struc-' ture, valves for in and out flow of the liquid to and from the chamber whereby on inflation and deflation of the expansible structure, liquid is pumped through the said liquid chamber.

13. A pump comprising in combination a compressed air pipe having a section thereof with perforations and a resilient expansible" tube mounted over the perforated section, means forming a liquid chamber on the outside of the said tube with an inlet and outlet, each having a valve, means to increase and decrease the air pressure in the pipe whereby the tube becomes inflated and deflated to expand and to again contract the tube whereby on expansion of the tube liquid is forced from the liquid chamber outwardly through the outlet, the air pipe having a plug below the lower end of the expansible tube, said plug having a valve therein, a seat for said plug whereby the valve and the plug is rendered inoperative during the expansion and contraction of the tube in pumping, the said plug being adapted to be elevated on its seat whereby the valve of the plug may become operative for blowing liquid out of the air pipe.

JOE H. KIDDE'R.