US1929451A - Pump - Google Patents

Description

Oct. 10, 1933.

lill/l B. F. SCHMIDT Filed July 7. 1930 5 Sheets-Sheet 2 By Jiffy Oct. 10, 1933. B. F. SCHMIDT` PUMP Filed July 7, 1930 3 Sheets-Sheet 3 piston to eiect intake and discharge of a liquid piston in its lowermost position;A

Patented oct. 10, 1933 UNiTED STATES PATENT OFFICE ticularly pertains to a pump of the U PUMP Benjamin F. Schmidt, Los Angeles, Calif.

Application `Iuly 7, 1930. Serial No. 465,835

19 Claims. (Cl. 1031-204) This invention relates to pumps and more parplunger type embodying a reciprocal piston arranged in a cylinder and operable on lreciprocation of the or fluid.

An object of the invention is to provide a pump of the above character in which the contiguous surfaces of the piston and cylinder are protected against wear due to the presence of sand or other gritty or abrasive particles conta liquid being pumped.

ined in the Another object of this invention is to provide a pump in which the liquid being pumped is prevented from contacting the piston liquid being pumped from during pumping operations.

Another object is to provide a means whereby a uid seal will be aorded between a pump piston and the liquid being pumped whereby the latter will be effectively prevented from passing beand its entween the piston and its encompassing cylinder.

Another object is to provide a construction in the pump whereby the fluid seal will be maintained in proper relation to the piston throughout the stroke thereof, and also whereby the sealing uid will be eiectivelyk confined against escape so as to insure proper functioning thereof for protracted periods.

A further object is to provide a pump which while being of extremely durable construction, is adapted to be readily repaired and in which replacement of parts may be easily acc A further object is to provide a means in a pump of the above character whereby a body of lubricant may be maintained between opposing bodies of sealing iluid.

With the foregoing objects in vi with such other objects and advantages as may omplished.

ew, together subsequently appear, the invention resides in the parts and in the combination, construction and arrangement of parts hereinafterv described and claimed and illustrated by way of ex ample in the accompanying drawings, in which:-

Fig. 1 is a View in vertical section of the pump illustrating one embodiment of the invention and showing the partsas arranged wit h the pump Fig. 2 is a sectional view of the pump constructed as shown in Fig. 1, illustrating the piston in its uppermost position;

Fig. 3 is a view in cross section taken on the line 3--3 of Fig. 1;

Fig. 4 is a view in cross section as seen on the line 4 4 of Fig. 1;

Fig. "5 is a view in section taken on the line 5*--5 lof Fig. 1;

Fig. 6 is a view in vertical section of the pump 65 illustrating another -form of the invention;

Fig. 7 is a view in cross section as seen on the line '7-7 of Fig. 6;

Fig. 8 is a view in cross section taken on the line 8 8 of Fig. 6. Y y

Fig. 9 `is a View in Vertical section of a pump showing another embodiment of the invention;

Fig. 10 is a view in cross section as seen on the line 10'-10' of Fig. 9; i

Fig. 11 is a view in vertical section depicting 75 a further modied form of pump construction embodying the invention;

Fig. 12 is a view in section and elevation of the upper portion of the pump shown in Fig. l1, illustrating the parts disposed in an alternative posi- 80 tion;

Fig. 13 is a view in cross section and plan as seen on the line 13 of Fig. 11;

Fig. 14 is a view in cross section taken on thel line 14-14v of Fig. 12;

Figs. 15 and 16 are details in cross section showing the piston as tted with a cup leather and a piston ring, respectively.

In the form of the invention shown in Figs. 1 to 5 inclusive, a pump cyunder A is provided 90 in which is mounted a reciprocal piston B; the cylinder A being connected at its upper end to a tube C leading to discharge and being tted at its lower end with a tapered plug 16 formed with an opening 17 constitutinga liquid or fluid in- 95 take and which is designed to be submerged in the liquid or fluid to'be pumped. The piston B is tubular, is open at its lower end to the cylinder A and has its'upper end equipped with a cap 18 to which is afixed a pump rod 19 through which the piston is reciprocated from any suitable source of power. The cap 18 is formed with openings 20 which aord an outlet communication between the interior of the pump cylinder A above 105 the piston and a valve chamber 2l carried by the piston and equipped with a normally closed valve 22 here shown as comprising a ball which'normally gravitates to a seated position on the margin of an opening 23 formed in the bottom 110 of the valve chamber 21 and leading to the interior of the piston. 7

Connecting with the intake opening 17 and leading upwardly within the piston B in telescoped and spaced relation thereto, is a tube 24, 'the upper end of which is fltted with a normally closed valve 425 here shown as comprising a ball which normally gravitates to a seated position on a valve seat 26 whereby the upper end of the tube 24 is normally maintained closed to the interior of the piston B.. The ball valve 25 is confined within a cage 27 to maintain it at all times in operative relation to its seat.

The piston B is formed with an enlarged lower end portion indicated at 28, and a reduced upper end portion 29; the lower end portion 28 having its outer periphery formed to extend proximate to and to effect slidable contact with the inner periphery of the cylinder A and the upper reduced portion 29 being' formed to extend in spaced concentric relation to the inner periphery of the cylinder A to afford a clearance space 30 in which is disposed a quantity of liquid as indicated at 31, and which liquid constitutes a sealing fluid above the enlarged lower end portion of `the piston. The body of sealing fluid thus surrounds the upper portion of the piston and is extended such distance longitudinally of the pis-1 ton as to afford a substantial depth thereof. This sealing fluid may comprise any suitable lubricating fluid of greater specific gravity than the liquid to be pumped and not soluble therein, and may consist, for example, of mercury. In some instances the sealing fluid may consist of an oil, or it may comprise water, according to the character of liquid or fluid to be pumped. The interiorn of the piston B also contains a quantity of the sealing fluid as indicated at 32, which when the piston is in its lowermost position as shown in Fig. 1, has its surface level disposed on a plane spaced above the plane of the top surface of' the fluid body 31 ,exteriorly ofthe piston. The body of sealing fluid 32 affords a seal beneath the piston and lls the space within the cylinder A, below the piston when the latter is in its uppermost position as shown in Fig. 2 and also extends part way into the lower portion of the piston so that the lower edge of the latter will be always submerged in the sealing fluid. The bodies 3l and 32 of the sealing fluid thus extended on opposite sides of the enlarged portion 28 of the piston and collectively form a body of fluid which is trapped or confined in the cylinder A, and in which the piston works.

The piston portion is constructed to have a close sliding contact with the walls of the cylinder A, and accordingly such space as occurs between the piston and its accompanying cylinder is very slight and restricted so that a.` free ow of 'the sealing fluid from one side of the piston to the other during reciprocation thereof, is prevented, and whereby as the piston moves up and down the column of sealing fluid exteriorly of the piston will move substantially coincident therewith. Ordinarily this sliding contact between the piston and cylinder is such asV to obviate the use of mechanical packing piston rings, cup leather and the like-but inl some instances it may bedesirable to provide greater clearance between the piston and cylinder and to then provide a packing ring such as a cup leather a as shown in Fig. 15 or a piston ring b as shown in Fig. 16. Inasmuch as some of the sealing fluid above the piston may slowly work downwardly past the piston and be added to the column of sealing fluid `being equal.

interiorly of the piston means are provided for compensating for such displaced sealing fluid. This means is shown in Figs. 1 and 2 as comprising a duct 33 carried. by the piston, which duct opens at its lower end to the interior of the piston adjacent the lower end thereof and thus communicates with the interior of the casing A below the piston. The upper end of the duct 33 opens through a port 34 to the space 30 above the body 31 of ,the sealing fluid thus affording a communication between the duct and the interior of the casing A above the enlarged portion of the piston and in spaced relation thereto. The port 34 serves to establish the head of the column of the sealing fluidainteriorly of the piston. An upwardly opening check valve 35 is provided in the upper end portion of the fduct 33 and is adapted vto normally close the duct against ingress of fluid to the duct from the pump cylinder above the piston.

In initially assembling the pump, such quantity of the sealing fluid is placed therein that when the piston is in its lowermost position as shown in Fig. 1, the level of the sealing fluid within the main submerged in the sealing fluid as shown in Fig. 2.

By the construction shown in Fig. 1, the valve 22 and 25are arranged comparatively close together when the piston is in its lowermost position which is desirable where the pump is employed in pumping gases to minimizethe quantity of gas confined in the pump below the valve 22.

In the operation of the form of the invention just described, assuming theA pump to be positioned in a body of the liquid or fluid to be pumped, upward movement of the piston will induct liquid or fluid through the pump inlet 17, and through the tube 24, past the valve 25 and into the space within the piston above the sealing fluid, and beneath the valve 22. The pump piston in moving upwardly, carries the body 31 of the sealing fluid therewith and also raises such column of the fluid being pumped as may be 'contained within the pump 'casing above the piston by reason of the valve 22 being closed. On down stroke of the piston, the liquid or fluid previously delivered into the space above the sealing fluid within the piston being entrapped therein by the valve 25, will be caused to pass above the piston by flowing past the valve 22 in the manner common in the operation of reciprocalw pumps.

The'piston B, in moving downwardly, displaces the sealing fluid therebeneath, which displaced sealing fluid will be confined within and beneath the piston, it being prevented from passing the exterior of the piston by reason of the restriction .of the clearance space between the piston and the pump cylinder andalso by reason of the pressures on the columns 3l and 32 of the sealing fluid then In event the volume of the column of sealing fluid 32 be increased by the addition theretoof a portion of the body of sealing fluid 31which might occur during upstroke of the piston, such increase will, when the piston reaches its ylowermost position, cause an increase in the height of the column of the sealing`fluid inthe duct 33,

thereby eifecting opening of the check valve and thereby permitting a quantity of the sealing fluid to discharge from the duct through the port 34 into the space 30 until the level of the column 32 of the sealing fluid falls suiciently to permit the valve 35 to resume its seat. The valve 351s of such character as to oat to its open position in the sealing fluid and to gravitate to its closed position.

In the form of the invention illustrated in Figs. 6, 7, and 8, to which reference is now had, the pump includes a cylindrical casing D and a reciprocal piston E carried on a rod F; the piston E being cylindrical and of uniform outside diameter throughout its length and the pump cylinder being formed with aireduced internal diameter at its lower end such that when the piston is in its lowermost position, the lower portion of the piston will slidably contact the inner periphery of the pump cylinder and the upper portion of the piston will be spaced from the inner periphery of the pump cylinder `to provide a chamber 36 in which is placed a body of sealing uid.

The lower end of the pump cylinder is closed by a plug 38 formed with a central intake opening 39 from which projects upwardly into' the tubular pistona tube 40, the lower portion of which is equipped with a foot valve 41. This construction permits the use of a large foot valve where desired. The upper portion of the piston is provided with a normally closed, upwardly opening valve 42.

A column of sealing fluid 43 is provided within the piston and lower portion of the pump cylinder the normal level of which, when the piston is in its lowermost position, is above that of the sealing `fluid exteriorly of the piston. As a means for maintaining an established relation between the bodies 37 and 43 of the sealing fluid, the pump cylinder is formed with a duct 44, the lower'end of which opens to the interior of the cylinder be: neath the piston E and the upper end of which opens to the space 36 through a normally closed check valve 45, which valve is normally maintained in a seated position under the urge of a spring 46 and which spring serves to hold the valve 45 against floating in the sealing uid. The spring 46 is of such strength as to prevent iioating of the valve, yet to permit the valve being lifted whenA the column of sealing uidinternally .of the pistonexceeds the height of the column of the sealing-fluid externally of the piston.

The operation of the pump thus constructed,

is substantially the same as that described with` reference to the form of the invention shown in Fig. 1, excepting that the maintenance of the body of the sealing uid 37 exteriorly of the piston is maintained through the duct 44 in the pump cylinder wall instead of through v a duct carried by the piston.

and 10, the pump comprises a pump cylinder G having a reduced lower end portion H in which is reciprocably mounted a piston I having its lower portion slidably contacting the pump cylinder portion H and having its upper portion spaced from the pump cylinder to provide a` space 47 in which is disposed a body of sealing fluid 48. The lower end of the pump cylinder is tted with a plug 49 having a central opening 50 formed with an inclined wall on which is loosely seated a tube 51 formed with an intake 52 tted with a foot valve 53 and which tube is positioned within a tube 54 afxed to the plug 49 and extended upwardly into the tubular piston H. A body of sealing uid 55 is provided within the lower end portion of the pump cylinder and extends around the tube 54 and within and beneath the piston I, the level ofwhich fluid normally extends to the level of the body 48 of the sealing uid when the piston I is in its lowermost position. Carried by the piston I is a duct 56, the lower end of which opens adjacent the lower end of the piston and the upper end of which communicates through a port 57 with the` space 47 through a normally closed check Valve 58; the

valve being normally maintained in its seated position under urge of a spring 59.

The piston I is carried on a pump rod J and is iitted at its upper end portions with an upwardly opening valve 60 and connecting with the piston is a'stem 61 which projects downwardly through the tube 54 and into the tube 51; the lower end of the stem 61 being provided with a ange 62 which is adapted on upward movement of the piston I to a point beyond the termination of its upstroke to ,eifect engagement with the upper end of the tube 51 whereby the latter with its valve 53 may be lifted from the pump on 1 withdrawing the piston I from the pump cylinder. The upper end of the tube 51 is formed with openings 63 affording a communication between the tubes 5,1 and 54.

The pump as shown in Fig. 9, operates in substantially the same manner as that previously described, but by the construction and arrangement shown in Fig. 9, the foot valve 53 is rendered removable from the pump casing on withdrawing the piston from the latter. In this construction the tube 54 being securely attached to the plug 49 serves to entrap the -sealing Iiuid within the pump cylinder when the piston is removed from the pump casing. After the piston has been removed, it may be replaced by merely lowering it in the casing to its lowermo'st position, whereupon the sealing iiuidl will seek its proper levels.

Where the clearance space between the piston and cylinder is provided in the cylinder wall as shown in Figs. 6 and. 9 the column of the cylinder fluid exteriorly of the piston extends to a height greater than the length of the piston stroke to prevent the portion of the piston, which slidably contacts the cylinder when the piston is in its lowermost position, from being exposed to the liquid being pumped kwhen the piston is in its uppermost positionthus insuring against any grit being carried by the piston through the sealing fluid and into the joint between the piston and its cylinder.

In the construction shown in Figs. 6 and 9, the piston moves relatively to the outer column of the sealing uid as distinguished from that shown in Fig. 1 in which the outer column of the ,i sealing uid moves with the piston and rela- In the form of the invention shown in Figs.9

tively to the cylinder; `the column of fluid around the piston in the latter instance being of a height greater than the length of the piston stroke so that the surface of the piston contiguous the cylinder walls will not overlie on the upstroke of the piston `any portion of the cylinder which has been ex- In the construction shown in Figs. 11, 12, 13,

well casing. In this instance the well casing indicated at K is formed at its lower endl portion with a tapered seat 65 surrounding an inlet 66 and the pump is formed with a pump cylinder L having a tapered lower end portion 67 adapted to seat on and effect close connection with the tapered inner surface of the seat 65. The pump cylinder is designed to be lowered into the well casing and to be demountably secured thereto and as a means for efectuating a connection be-Y tween the pump cylinder and the well casing the latter is formed with an inwardly projecting flange 68y which is inclined on its upper and lower surfaces and mounted on the pump cylinder is a series vof radially slidable catches 69 adapted to be moved in and out of engagement with the under side of the flange 68, and arranged in the upper portion of the pump cylinder in slidable, telescoping relation thereto, is a sleeve 70 having a tapered lower end 71 adapted to effect wedge engagement with the slide catches 69 to force the latter outwardly into engagement with the under side of the flange 68 as shown in Fig. 11. The catches 69 are here shown as comprising circular discs formed with transverse slots c and engaging the slots is a split, resilient ring d which serves to hold the catches in place. The sleeve 70 is formed with a collar 72 projecting beneath an inturned projection 73 on the upper end portion of the pump cylinder; the collar 72 being adapted to engage said projection 73 on lifting said sleeve '70.

A tubular stem 74 is connectedto the upper end of the sleeve 70 and leads to discharge at a suitable point in the well casing and through which projects a pump rod 75 connegted at its lower end to a pump piston M which latter is here shown as constructed in the manner disclosed in Fig. 1, being formed with an enlarged lower end portion 76 which slidably contacts the pump cylinder L and has a reduced upper end portion to provide a space 77 in which is placed a sealing fiuid 78. A tube 79 is carried by the lower end of i the pump cylinder and projects upwardly within.,

the piston with its lower end opening to the intake 66 and with its upper end fitted with upwardly opening foot valve 80. The upper end portion of the piston M is equipped with an upwardly opening valve 81 and the lower portion of the piston is fitted with a by-pass duct 8 2 affording a communication between the lower portion of the piston and the space 77. The pump mechanism in this instance operates in the same manner as that previously `describedwith reference toFig. 1.

In assembling the pump shown/in Fig. 1'1, the

vpump cylinder L issuspended from the tube 74 as shown in Fig. 12, and lowered into the well casing until the lower end thereof seats on the lower end of the well casing, whereupon the slide catches 69 are positioned to extend beneath'the flange 68 so that von further lowering of the stem 74 relatively to the pump cylinder, the tapered lower end 71 thereof will act to force the slide catches into engagement with the well casing as shown in Fig. 11. ated as before described. When it is desired to remove the pump from the well casing, the ,stem 74 is withdrawn thereby moving the collar 72 into engagement with the projection73 and the tapered end portion 71 re-disconnected relatively to the slide catches 69 so that on effecting an upward pull on the pump cylinder, the slide catches 69 will ride inwardly out of engagement with the The pump may then be operfiange 68, whereupon the pump cylinder may be withdrawn from the well casing. The weight of the sleeve 70 and tubular stem 74 acts to maintain the tapered end of the sleeve in wedge engagement with the catches 69.

An important feature of the invention derived from the construction of the piston and the arrangement of the sealing fluid as set forth is the maintenance at all times throughout the reciprocal movement of the piston of a film of the sealing fluid in such clearance space or spaces as may occur or be present between the outer periphery of the lower end portion of the piston and the contiguous inner periphery of the pump cylinder, which serves to effect lubrication of the wearing -surfaces .of the piston and cylinder and which coupled with the provision of a substantial body ofthe sealing fluid both above and below the proximate surfaces of the piston and cylinder, insures against any liquid or iiuid being pmnped from passing from one side of the piston to the other.

It will be noted that in the several applications of the invention, as here shown, the pump piston is maintained in a fluid seal throughout its stroke; and that the sealing fluid is so entrapped as to prevent its escape from the pump.

It -will also be observed that in each of the pumps shown I have provided a pump cylinder equipped with a piston and a standing intake fitted with a foot Valve, in which the piston and the standing intake are surrounded by a sealing fluid of a specific gravity greater than the fluid being pumped, and insoluble therein and to such heighth or depth that the substance being pumped will be prevented from contacting the surfaces of the piston or the cylinder which contact each other during pumping operations; and that I also provide a means for maintaining the bodies of sealing fluid above and below the piston at'predetermined and constant levels in relation to each other. M

By the provision of the upstanding intake tube, equipped with the foot valve, with the intake tube opening above the column of sealing fluid, loss of the sealing fluid through the-intake is prevented, and passing of the liquid being pumped through the sealing fluid is obviated and consequent emulsication of the sealing uid is prevented.

In some instances it may be desirable to afford lubrication of the piston and cylinder other than will be effected by the sealing fiuid. This may be accomplished by the provision of spaces e and f bodied in the pump as a. sealing fluid, its funcf tion is not limited to a sealing action as the bodies of this fluid serves primarily as a shield or barrier to protect the contiguous surfaces of the piston and cylinder against the passage of grit. The fluid also acts to displace liquid or fluid being pumped and further serves as a lubricant.

A pump constructed to embody the invention is applicable to many uses, but is especiallysuitable for use in pumps employed in pumping liquids containing solid particles of abrasive character as the fluid seal will float the solids and prevent their working past the piston. However, the pump may be employed in pumping various liquids, and may be used in pumping gases. f

It is to be understood that the manner of carrying the invention into effect is herein specifically set forth to enable those skilled in the art to make and use the same and is to be considered as illustrative and not in a limiting sense; and that various changes may be made in the parts and in their construction and arrangementrwithin the meaning of the terms and scope of the appended claims without departing from the spirit of the invention.

I claim:

1. In a pump, a pump cylinder, a reciprocal piston therein, a body of fiuid on each side of said piston arranged to prevent a liquid being pumped from contacting adjacent slidably contacting surfaces of said cylinder and piston, an upwardly extending intake tube in the pump cylinder projecting above the body 'of iiuid below said piston, a valve in said tube, said iiuid being of greater density than a liquid to be pumped, and valve controlled means for maintaining said bodies of fluid in relatively proportional volumes on each side of said piston. l

2. In a pump, a pump cylinder, a reciprocal piston therein, `having a portion thereof slidably contacting said cylinder, a iiuid in said cylinderl eifecting a seal immediately above and below,r the slidably contacting portions of said piston and' cylinder and affording a film of the iiuid between the piston and cylinder, an upwardly extending intake tube in the pump cylinder projecting above the'body of fluid below said piston, avalve in said tube, and valve controlled means for effecting delivery of saidrfluid from below said slidablycontacting portions toabove said portionsaw 3. In a pump, a pump cylinder, a vertically reciprocal piston therein, there being a clearance space affording a working t between said piston and cylinder, a shielding fluid entrapped in saidcylinder at each end of said clearance space and lling said space, an upwardly extending intake tube in the pump cylinder projecting above the body of fluid below said piston, a valve in said tube, and valve controlled means for maintaining said uid in substantially relativeproportions of volume at each end of said space.

4. In a pump, a pump cylinder, a vertically reciprocal piston therein having a lower end portion slidably contacting said cylinder, a chamber between the upper portion of said piston and said cylinder, a sealing fluid in said chamber adapted to ow downwardly between said piston and cylinder, a column of sling uid-in said cylinder beneath said piston in which the lower portion of said piston is submerged throughout the stroke of the piston, an upwardly extending intake tube in the pump cylinder projecting above the body of fluid below said piston,a valve in said tube, and valve controlled means for eiecting delivery'of uid from said columnthereof to said chamber.

5. In a pump, a pump cylinder, a vertically reciprocal piston therein the lower portion of which extends contiguous the walls of said cylinder and the upper portion of which is spaced from said cylinder, a sealing fluid in the space between said piston and cylinder, said piston being tubular and open at its lower end to said cylinder, a. column of sealing iiuid in said cylinder extending internally of said piston, means for conveying pumped uid from beneath said column of sealing uid to a point thereabove, a duct carried by said piston leading from the lower portion of said piston in open communication with said cylinder beneath' the piston and communicating with the umn of sealing fluid entrapped beneath said piston, a duct formed in the cylinder wall affording a communication between the interior of the cylinder beneath the piston and the chamber extending between the cylinder and piston, and a normally closed check valve in said duct.

7. In a pump, a pump cylinder having an intake at the lower end thereof, a tube leading from said intake and extending into the pump cylinder in spaced relation thereto, said tube forming a communication between the pump intake and the pump cylinder, a foot valve in said communication, a tubular piston in said pump cylinder having its lower end inopen communication with said cylinder and being arranged in telescoped, spaced relation to said tube, a passage leading from the interior rof the upper portion-of said piston to said pumpv cylinder, an upwardly opening valve in said passage, va column of liquid entrapped in said pump cylinder extending upwardly in said piston in which the lower portion of said piston travels throughout the length of stroke'of the piston, a second body of liquid surrounding the upper portion of said piston apart from the aforesaid column of liquid, a duct leading from said column of liquid to said body of liquid, and an upwardly opening check valve in said duct.

8. In a pump, a pump cylinder having an intake at its lower en'd, a reciprocal tubular piston in said cylinder having an open lower end, a tube connected to said intakeand extending upwardly in said cylinder and within said piston, a valve housing demountably seated in said tube, a foot valve in said housing, a connection between said piston and said valve housing for effecting the removal of said housing and Valve on withdrawing said piston from said pump cylinder, a column of liquid surrounding said tube interiorlyy of said piston, a column of liquid surrounding said piston apart from the column of liquid invlteriorly thereof, a duct through which liquid may be delivered from the column of liquid interiorly of the piston to the column exteriorly thereof and acheck valve for preventing back ow of liquidfrom the exterior of said piston to the interior thereof.

9. In a pump, a well casing having an intake, a pump cylinder demountably arranged in said casing having an intake arranged to communicate with the well casing intake, means for detachably connecting said pump cylinder and well casing, a reciprocal piston in said pump cylinder open at its lower end, a tube leading from the pump cylinder intake into said piston, affording a communication between the pump intake and the interior of the piston, a foot valve in said communication, a valve controlled passage leading from the upper portion of said piston, a column of liquid extending interiorly f the piston relatively to which said piston is movable and in which the lower interior portion of the piston is submerged, a body of liquid encompassing the upper portion of the piston apart from said column of liquid, and means operable on down stroke of piston to effect delivery of liquid from said column interiorly of the piston to the body of. liquid exteriorly thereof.

10. The structure called for in claim 1 including a lubricant trap arranged between contiguous surfaces of the cylinder` and piston for containing a lubricant of less density than the bodies of fluid on each side of the piston. i

11. The structure called for in claim 1 in which the piston is formed with a reduced portion for the reception of a lubricant arranged to afford a body of lubricant between the bodies of fiuid on the opposite sides of the piston.

12. In a pump, a pump cylinder, a reciprocal piston therein, bodies of mercury extending above and below said piston and arranged to afford a shield between the piston and cylinder against a. fluid being pumped from contacting the surfaces of the cylinder and piston which are contiguous throughout the length of stroke of the latter, and means for retaining a body of lubricant interposed between the piston and cylinder and between the bodies of uid above and below contacting portions of said piston and cylinder.

13. In a pump, a pump cylinder, a hollow reciprocable piston therein, an upwardly extending intake tube in said cylinder projecting interiorly of said piston, a valve associated with said tube, a body of protective fluid interiorly of said piston surrounding said tube, a second body of protec- `tive fluid exteriorly of said piston, means associated with said piston and cylinder separating said uid bodies into independent columns through which restricted leakage of fluid from one column to the other in one direction may occur, and means for maintaining said fluid bodies in constant proportional volumes during reciprocationof said piston to compensate for such leakage.

14. In a pump having a barrel and a plunger slidably contacting said barrel, independently en' trapped bodies of protective fluid confined above and below the contactingsurfaces of said plunger and barrel, and means for automatically delivering iiuid from one body of said protective uid to the other to compensate for leakage past the contacting surfaces of said plunger and barrel and to maintain said bodies of protective fluid in constant proportional volumes, and means for conveying pumped fluid from beneath the body of sealing uid below said contacting surfaces to a point above said body of fluid independent of said body of fluid.

15. In a pump, a barrel, a piston therein, independently entrapped columns of protective fluid in which the working surfaces of said piston and barrel are immersed, means for maintaining said columns of protective uid at predetermined levels relative vto said working surfaces, and means for conveying pumped iiuid from beneath said columns of protective fluid to a point above said columns of fluid apart therefrom.

16. In a pump, a barrel, an upstanding valved intake tube in said barrel, a tubular piston telescoping said tube, independently entrapped columns of protective iiuid disposed interiorly and exteriorly of said piston and immersing the working surfaces of said piston and barre1,said protective fluid being insoluble in the uid to be pumped, and means for maintaining said columns at predetermined levels relative to said working surfaces.

17. In a pump, a barrel, an upstanding valved intake tube in said barrel, a ltubular piston telescoping said tube, separate columns of protective uid disposed interiorly and exteriorly of said piston and immersing the working surfaces of said piston and barrel, and means for maintaining said columns at predetermined levels relative to said l working surfaces, including avalved by-pass per, 100

mitting passage of iluid from the interior column to the exterior column.

`18. In a pump, a pump cylinder, a reciprocal piston therein having a wall portion the outer periphery of said cylinder in slidable relation thereto, said piston also having a reduced portion'extending above said wall portion forming a space for the reception of a iiuid; a body of Vperipheryof which extends proximate the inner fluid entrapped in said cylinder above said wall 11g portion, a body ofv fluid entrapped in said cylinder below said wall portion, means for conveying pumped liquid or uid from beneath said last named body of fluid to a point thereabove apart therefrom, said bodies of fluid being of greater density than the liquid or fluid to be pumped, and means for maintaining said bodies of fluid in definite 'relative proportions of volume during 'reciprocation of said piston.

Images