US2339748A - Pump - Google Patents

Description

3 Sheets-Sheet 1v INVENTOR.

w. P. MUNK PUMP Filed Aug. 19, 1942' Jan. 18, 1944.

Jan. 1s, 1944. w. F. MUNK 2,339,748

. PUMP Filed Aug.` 19, 1942 3 Sheets-Sheet 2 Flc. 3. FIG. 4.

` INVENTOR.

W. P. MUNK PUMP INVENTOR.

5 Sheets-Sheet 3 Jan. 18, 1944.

I 5470 ali Fue.

Patented Jan. 18,1944

UNITED STATES TENT OFFICE This application is led in place of my abandoned application Serial #260,638, led March 8, 1939, which was led in place of my abandoned vapplication Serial #426,973, led February 8,

the frequent shutting down of the pump to make` repairs.

In such pumps, the great Weight of the long column of fluid imposes a heavy load on the rods which actuate the pump, necessitating the use of rods having large cross section to lift their own weight plus the weight of the oil or uid. Therefore, a primary object of this invention is to provide a reciprocating pumping means in which a plurality of pumps are used to divide and raise a column of oil or iluid in a plurality of stages, thus securing reduction in pressure exerted by the column of oil or fluid being raised.

Another object of the present invention is to provide a reciprocating pumping means, in which a column oi oil or iluid is raised during the downstroke, as well as during the upstroke, of the pumping means in order to allow the weight of the reciprocating pump parts to be used for actuating the pumping means to raise oil or fluid during the downstroke of the pumping means.

A further object of my invention is to provide a reciprocating pumping means in which the v downward movement of the rods is restrained during the downstroke'of the pumping means,

thepumping means acting to use the weight of.

the rods during the downstroke to vraise oil or fluid.

Another object of this invention is to provide storage space for, and for surging movement of,

f a reciprocating pump, of the type employing a pump column in a well, which will permit the Withdrawal of the parts from the pump column at any time for the purpose of repair or replacement. v

A still further object of my invention is to provide a kreciprocating pump which allows the draining of oil or fluid from the pump column before pulling the removable cylinders and various pump parts therefrom.

Another object of this invention is to provide for the separation of gases from liquids in the pumping operation.

Other objects and advantages of my invention will appearas the specification proceeds.

For a better understanding vof my invention, reference should be had to the accompanying drawings, in which:

Figures 1, 2, 3 and 4 illustrate consecutively the continuous column of a two-stage pump of my invention in a deep well; the pump and the well being shown in vertical section and the pump parts inthe middle of an upstroke;

l Figure 5 shows the completed two-stage pump of Figures l, 2, 3 and 4, assembled in a well, the well being shown in vertical section;

Figure 6 shows in vertical section a modified form of that portion of the pump shown in Figure 3;

Figure '7 is an enlarged fragmentary vertical 4 section of portions of the pump shown in Figures 1 and 2; v

Figure 8 is an enlarged fragmentary vertlcal section of portions of the pump shown in Figures 3 and 6;

Figure 9 is an enlarged horizontal section taken along the line IX-IX of Figure 1; and

Figure 10 is a diagrammatic view to illustrate the operation of the pump; the pump being shown spirit of the invention.

Attention is being now directed to the Figures 1, 2, 3, and 4 of the drawings, wherein a conventional deep oil well is shown'having the usual well casing, designated by the numeral l, which extends from the ground surface to the bottom of the well and which is provided with the per- `iorations 39 (see Fig. 4) near the bottom to enable the oil or iiuid to enter the casing l and to Vrise until the natural fluid or oil level has been established.

Within the well or casing I is positioned the pump column within which the pump structure is to be assembled, the pump column being threadedly connected through and suspended from a conventional casing head member 3 (see Fig. 1) which is suitably supported from the top of casing I.

The pump column reading downward from top to bottom comprises the following members, each of which follows successively in the respective order and is threadedly connected to and suspended from the preceding member.

Belonging to the second stage: (see Fig. 1) are the aforementioned casing head member 3, the

pipe 29, coupling 30 and the member 4|, whichY terminates the second stage and commencesthe rst stage.

Belonging to the i-lrst stage `but being parts of the second stage pump (see Fig. 1) are the afore mentioned member 4|, pipe 42, coupling I'I, pipe 68, vcoupling 59 having the spacing arms 53 extending"upwardly'into'pipe 98, pipe .35v (see Fig. 2), coupling 'I0 which is provided with the spacing arias 's3 extending upwardly into 'pineta pipe 'I I; reducer ycoupling r'I2` and' .tlicylinden I3 (S Fgigj... K.. And belonging to the first stage ,are coupling I'I, pipe 8 (see Fig. 3) and'thepar'ts belonging to the'rststage pump '(sfeelilig. @are coupling 9, jcket"|2, coupling B9 andthe meiiiberl, at vthe bottom of the pump columnandbelow thenatural 'oil' or uid levelv in" theY well,havingV the tapered bred seattl'ierin for receiving the tapfered 4and'hollow oilor fli'lidfinlet'meniber 'I. "The rst stage pump hash'ollow'piston 5 slidably positioned in a stationary cylinder 4 'sej Thehollow and tapered fluid inlet member 'I (Fi'gfl) of Ithe first"V stage pump has Vaffo'ne-way or' inlet valve v6 I lenclosed in an operi"cagewhich, with valve 6| andthe member 1, form's'the conventional'stan'ding'valve which is provided with the`Garbutt yrod I4 havingT-head B loosely retained bythe bushing II Yin the"'hollow"piston 5.'"M"Il1is inno way restricts thel normal reciprocalnovement of piston 5 when the member 'I of. the standing valve is seated, sealed, and vsecurely but releasably'retained in the member I9, but upon upward pull of the piston S'beyond its normal reciprocal range by rod` I0, .theT-head 6 on G arbutt rod I4 engages with bushingV II to pull the standing valve member 'I. free from its seat and to allow the valve 6| to be vi'rithdrawn fromth'e pump column for the purposefof. repair or replacement.

Inftlie second-stage pump it will be noted by reference to FiguresrZ' and 3 :of the drawings that the duplingv 69, in addition to"meinbers 5.3, is also provided with a tubular downward extension of reduced diameter from which a'tubular assembiyvcomprising the jacket 56,'coupl'ing 51, spadei 5.8,` and parts 59, V31'1 and B3, issuspngu mme pipe' 5,5; f'

A'k stationary cylinder 28 (Fig. l2) for a hollow pist-onw25 i'senc1oS`ed'-Wtliin t-lrewjaeket 56,'and is securely clamped therein couplings 99 mn? f, ""Thesaid tubular. assembly is xed in the pump coltulmn'by. .the tubular'extension of coupling 69 (see :2), and 4isfheld in 'concentric' relation tofltbe pump column by the tubular extension of coupling' B9'and byf the spacing'arms' 93 of coupliiijgiiu, fsee'Figfa)- space' formedbetween the said tubular assembly and pipe"55 communicates lat 4its'upper end, by way of ports 8i in the member 99, with 4the interior of the pump column, and communiy mit surging movement of oil or iiuid between the storage spaces 54 and 5| indicated in Figures 2 and 3.

The part 63 is of less inner diameter than the tubular assembly to provide a seat for a cylinder removably positionedA in the tubular assembly. This cylinder is comprised of an assembly of parts consisting of a cylinder 22, a jacket 38 for same and two end members 52 (see Fig. 2) and l'I4 (see Fig. 3) threadedly received in the jacket 38 to seal and make secure the cylinder 22 in.

` place in the jacket 39, the end member 'I4 (see Fig. 8) also being tapered to it a correspondingly tapered bore included with part 63 and thus form a seal'therewith. Parts 63 and 74 also serve to hold the lower end of the cylinder k2:2 in concentric relation to vthe tubular assembly'.

The Y,en dmember 52 is thickened'in Vitsmiddle part toengage the member 59 and acts therewith to hold the upper end of the cylinderY 22 assembly in concentric relation to the tubular assembly and to forml a seal therewith to prevent accumulation ofv sandv in the space between the cylinder 22 and the tubular assembly'which would prevent the removal of the cylinder assemlo'lyl from the tubular assembly'. "The end member 52 also has an extension received in a. coupling for 'and having IanI annular 'series of spring leaves or pawls I5 rising therefrom, which are adapted to be expanded into the recess 'I6 formed in the face of the part 59 (see Fig. 2), by a Aring 'I,'I, to latch the cylinder A22 in position in the tubular assembly. Thela'tterring slides into place from above (with the pumping mechanism) and Ais retained irrposition on the memberl 52 by the'tongue and g'roovearrangement shown in Figure 7. The recess 1,6, the ring 'I'I and the spring` leaves or pawlsl 'I5 form a latch and, when the spring leaves o r pawls 'I5 are expanded-'in'to recess'm by ring 1'I, they serve to prevent accidental loosening or unseating and unsealing of the cylinder 2,2.

Another assembly of parts provides cylinders removably suspended from the member 4| (see Fig. 1). This assembly of parts includes two cylinders |99 (see Fig. 1) and 2| (see Fig. 2) (the latter being of larger inner diameter), a jacket A35 for the cylinder |99, and couplings 13 and 86 threaded into the jacket for holding the cylinder |99 in place in the jacket, the cylinder 2| being suspended from coupling'. The coupling 'I3 is threadedly secured to the member 88 which in turn is seated in and sealed against the member 4| and is latched in position by spring leaves or pawls 'I8 and latch ring 19 in the manner previously described.

The cylinder 2| is surrounded by the gas chamber 92 (see Fig. 2.) `'and'its bottom vend is positioned in concentric relation toy the pump coiumn by the s pacing'arms 53 of the coupling 99 which allow of free intercommunication betweenmthe chambers`92 and 5,4. 'The fit between the cylinder 2| and member 61 is gas tight so as to` allow gas or air to be trapped in the chamber 92.A

The cylinder |99 (with its jacket) is also surrounded by a chamber 9|, 'whichcom'municates at its lower. end, through port 99 with chamber $3 inside' Qi vlinder 21, and ai its, upper'end through ports 8|, with the space outside the pump column.

The pump column discharges through the horsehead 40 (see Fig. 1) which may be suitably connected to a storage tank or pipe line (not shown). I

The reciprocating element of the two-stage pump oi' my invention, reading from the bottom to the top in Figures 4, 3, 2 and 1 may be described as follows:

The hollow piston 5, which has limited freedom of sliding motion relative to the standing valve, has an open cage secured to the top thereof which holds the outlet valve 62. The open cage is connected, by rod IB, with the guide I3, the rod having a head I5 slidable in the guide but adapted to bear against the inner bottom of open cage I6 at the lower end of the guide. The latter thus has a certain freedom of downward motion relative to the rod.

An open cage 44 is attached to the upper end of the guide I8 and has the rod 20 rising therefrom which latter is connected to the piston by the open cage 48 and the head 64 slidable in the open cage.

The rod 2B carries a cross 27 below the cage 48 and has an extension 65 above the head 64, the extension being used tozpush the valve 5i! oi its seat for draining purposes during removal operations later described herein. The housing or closed cage enclosing the one-way or inlet valve 58 forms a shoulder 30 with the piston 2B which latter is hollow throughout the length thereof and has an open cage at its upper end.

A rod 49 arises from cage 45 and connects, by head 32', with open cage 33 suspended from the hollow piston 25 which carries the one-way or outlet valve 41. The rod has a cross 3l secured thereto below cage 33 and has limited freedom of sliding motion relative to the cage 33. An extension 46 of the rod is adapted to unseat valve 4l under certain conditions for drainage purposes.

The hollow piston 25 is directly connected (as to form a continuous central iiuid passage) with a hollow piston 24 directly connected with a hollow piston 23, which connects, by open cage III), with the rod 36 attached to the walking beam 43.

The rod Se carries a cross 85 near its lower end.

It will thus be noted that the piston 5 operates in cylinder 4, the guide i8 in cylinder I3, the piston 28 in cylinder 22, piston 25 in cylinder 28, piston 24 in cylinder 2|, and piston 2'3' in cylinder IUS.

There is a clearance space commencing at member 3 and following all the way down between the pump column and the casing and the chamber 9i connects with this space through ports 8l. I'he latter chamber connects also, through ports 9G, with chamber 93 above piston 24.

A passage (not shown) through casing head 3 may be employed to connect the clearance space with the atmosphere or the usual gas pipe line (not shown), as will be readily understood.

The gas chamber 92, surrounding cylinder 2l, connects, through spaces between the arms 5S, with the storagespace 54 above piston 25, and the latter space connects, through ports 8l, with the passage 82 surrounding the struc-ture depending from member 69. The latter passage connects, through spaces between the arms 83, with the chamber 5I which connects, through guide I8,

.with the chamber 34 above the first stage pump.

The entire pump column is suspended from the casing head 3 and, in'normal operation, the entire reciprocating mechanism is suspended from the walking beam 43.

, One of the` purposes of the guide I8 is to centralize the reciprocal parts of the pump below hollow piston 26, especially when the two stage pump is employed to pump oil or fluid in 01T- vertical or crooked wells. In such cases if the guide I8 were not used, flexing of the portion of the piston 26 moving into and out of the cylinder 22, during reciprocation of the pump, would occur, which would hasten the wear of the piston 26 and cylinder 22. The guide I8 thus assures alignment of the reciprocating pump parts relative to the stationary pump parts at the lower end of the second stage pump. Another important feature will appear, however, in connection with the installation of pump structure in the pump when the pump is used in off-vertical wells, is

largely avoided. By avoiding exing of the cylinders and pistons galling of such members,-which would hasten wear, is largely avoided.

Before installation, the parts of thefirst-stage pump and the second-stage pump are assembled on the surface of the ground and adjusted to assure that they are properly proportioned for length of pump stroke and also to assure that the latch rings TI and 'iS and the ball valve dislocators 45 and 65 will function properly.

It might be said here that the usual log of the well is kept, measurements as to length and relative position of the members forming the pump column being taken and recorded, so that a log of the pump column is available when the pump column is assembled and completed within the casing I.

The parts it, Sil, I2, 4 and 9 of the rst-stage pump as a. unit are now inserted in the casing vI and other parts are added as they are fed down the well to complete the pump column up to member I'l. Connection is now made between the coupling I'I andthe cylinder I3 of the second stage pump (as a unit), after which the remainder of the pump column (pipe 29) is added and assembled and pipe 29 is now connected to casing head .3, which latter is then connected to casing I.

It may be said, that in actual practice when my invention is used in an oil well, the length of the pump column for each stage of the two stage 'pump may be many hundreds of feet, the iirst stage pump being disposed near the bottom of the well and the second stage pump occupying some twenty or more feet in about the middle portion of the well, but may be above or below this point if desired.

The pump column, being properly assembled and completed within casing i, is now ready to receive the reciprocating element of the two-stage pump together with the standing valve and Gar- 'butt rod i4 and also the removable cylinders and their latch rings to complete the two-stage pump.

The' reciprocating element of the first-stage pump with Standing valve and Garbutt rod I4 depending through If-head 6 f lOm bushingv II of .the hollowA piston 5 are now `inserted into the pump column land rod Ii) is added and the entire assembly lowered within the pump column, rod IIJ having been adjusted for length before being connected.

The rod Il is of such length that when this rod and hollow piston are in their lowermost position in the pump column and rest on the cage of the standing valve when member 'I is seated in the member I9, the bottom of head I5 will just make contact with its seat in cage I6 when the top of the latter is iiush with the bottom of cylinder I3.

Connection is now made between rod ii) and `cage I6 and the entire chain of the second-stage pump is then lowered. This chain comprises the guide I8, rod Eil, the hollow piston 26,7rcd i9 and the hollow pistons 25, 2d and 23 with rod 35. This chain also carries the cylinder 22 riding on shoulder 8D of hollow piston 25 and its latch ring 'I1 riding on cage 45, and cylinders 2I and IOS as well riding as a unit with coupling 85 on a shoulder provided by hollow piston 22, and also the latch ring 'I9 riding on rod 36. The ring 'I9 is disposed below cross 85 and is tied by a cord to the cross in such a manner that the cross may be freed by a twisting motion of the rod and made to pass through the ring (see Figure 9).

The lowering of the chain is continued until member v88 carrying cylinders IDS and 2l is seated in member 4I. Then cross 85 forces latch ring I9 downwardly inside of spring leaves or pawls 18 until the ring seats in the manner previously described.

To release cross 35, a slight strain is taken on rod 36 to lift cross 85 oii the ring 19, whereupon rod 36 is turned clockwise to break the aforementioned cord tying the ring 'I9 below cross 85, in order to position the cross 85 so that it may pass downwardly through the ring 19.

Next the extension Ill with cylinder 22 will reach its seat in the member 63 and the lowering of rod 33 is continued until cross 3l forces latch ring Il into latched position with respect to the spring leaves or pawls 'I5 as previously described.

During this downward movement the standing valve part 'I will have reached its seat and become securely but releasably retained in its seat while the guide iB has descended sufficiently far with respect to rod ID as to cause the head I5 of the rod I0 to project above the inner bottom of the cage I6 as shown in Figure 6. The entire weight of rod lil, therefore, bears on standing valve member I for seating the same.

Horsehead 4I) is now added to the pump column by connection to the casing head 3, and the reciprocating pump parts, being at rest, as shown partly in Figure 6, are then raised to function within their normal reciprocal range as shown in Figures 1, 2, 3 and 4, the rod 35 being connected to walking beam 53. The two-stage pump is now completed and ready for operation.

Thus it is seen that three operations are necessary to seat, seal and latch the insertable or removable cylinders, and to seat, seal and securely but releasably retain the standing valve part l, of the two-stage pump in positions within the pump column; the insertable or removable cylinders |09 and 2l being seated, sealed and latched in position within the pump column by cross 85 and the entire weight of the reciprocating element of the pump; the insertable or removable cylinder 22 being seated, sealed and latched in position within the pump column by cross 3| and the weight of the reciprocating element of the second stage pump and rod 3,6, while the standing valve member 'I is seated, sealed and securely but releasably retained in position within the pump column by the weight of the reciprocating element of the first stage pump and rod Ill, the last two operations being made possible bythe lost-motion connection with guide I8.

In actual practice in oil wells the distance between the rst-stage pump and the second-stage pump and the second-stage pump and the surface may easily be many hundreds of feet, and therefore, the rods I0 and 36 and the pipes 8 and 29 are made up of many sections. In view of the above and even though the members are carefully measured and proportioned for length, a variation in length of the assembled members is bound to occur so that rod IIl might be longer or shorter than pipe 8. If rod I were directly or threadedly connected to the guide I8, the short rod I0 would be prevented from exerting its weight on the standing valve member 'I to seat, seal and releasably retain the latter in position in the pump column because the short" rod I5 would hang from the latched latch ring TI of the insertable cylinder 22, while .the long rod Iii would prevent the rod 35 from exerting its weight through cross 3l on latch ring 'il to seat, seal and latch cylinder 22 in the'pump column because the long rod il when at rest on piston 5 and the standing valve member 'I would hold the cross 3| and rod 36 upwardly and oi latch ring 'Il and cylinder 22. Therefore, it is seen that by proviidng the lost-motion connection with guide I8 compensation for variation in the length of rod I0 is provided, and the proper positioning of the standing valve member l and of the cylinder 22 in the pump column is assured. Compensation for variation in length of the pump parts between insertable cylinders Ita and 2 I, and the insertable cylinder 22, is secured by the operation as described earlier herein, in connection with the seating, sealing and latching of the insertable cylinders (cylinders E59 and 2l being seated, sealed and latched by cross when above the top of the normal pump stroke and cylinder 22 by cross 3l when below the bottom of the normal pump stroke), this operation assures the proper positioning or seating, sealing and latching of the insertable cylinders in the pump column.

When'it is desired to withdraw the reciprocating element of the two-stage pump with attendant parts for the purpose of repair or replacement, the rod 35 is first disconnected from walking beam i3 and allowed to descend until it comes to rest. Guide I8 moves downward on rod IIl and cross 2'I with rod 25 comes to rest on shoulder 84 of cylinder I3. Cage i3 comes to rest on cross 21 and ball valve 5i) becomes dislodged from its seat by rod end 65 (see Figures 3 and 6) Thereafter, cross 3l with rod 49 comes to rest on ring 7l, and cage 33 descends to come to rest on cross 3|. Ball valve All is dislodged from its seat by rod end 45, after which, hollow piston 2li moves downwardly so as to pass completely out of cylinder 2I to form a continuous passage. The latter permits the oil or uid in the pump column of the second stage to be drained downwardly through hollow pistons 23, 24 and 25, and also through chamber 665 and hollow piston 25, and upwardly through passage 82 and between pist0n 2d and the pump column, and further, between insertable cylinder 2i and piston 23 to and through port in cylinder 2l, and by way of the trap space 9i to and through port 8l in the gesch-1s* member 4 I, and downwardly in the space between casing and the pump column to the bottom of the well, thus relieving the parts of the secondstage pump of the weight of the oil or fluid, and thereby enabling rod 36 to pull the reciprocating element and the insertable cylinders of the twostage pump from the pump column with less stress to avoid the straining of rod 36. n

It might be said here, that while I have shown the cylinders of the two-stage pump all of equal length in the drawings, in actual practice the cylinders, as well as the pistons, may vary in length to suit the individual requirements; for example, in the case of the cylinder 28 and the hollow piston and the cylinder |66 and the hollow piston 23: the cylinde1`28 and piston 25 are subject to the pressure of the oil or iiuid during the downstroke only, while the cylinder |09 and piston 23 are subject to the pressure of the oil or fluid during the upstroke as well as the downstroke.` Therefore, the hollow piston 23 and cylinder I 69 should be of greater length than cylinder 28 and piston 25 so as to enable the pistons and cylinders to wear more evenly, and thus maintain an effective oil or :duid seal for a nearly equal period of time, as is well understood.

In actual practice the hollow piston 24 is of very reduced length so as not to require the lowering of the reciprocating element of too great a distance beyond the normal reciprocal range during the drainage of the oil or fluid because of the undesirable gas compression which might occur Vin the chamber 66, and guide I8 should be of such length,relative to the piston 24, as to provide suicient clearance for head I5 and rod l during the seating of the cylinder` 22, or during the draining of the iiuid.

The horsehead is uncoupled in the usual way from the member 3 and the reciprocating element of the two-stage pump together with the insertable Acylinders and their latching rings, and also the standing valve, may now be withdrawn from the pump column in the following order:

The standing valve member l being pulled from its seat in the member i9 by Garbutt rod |4 when T-head 6 engages bushing to follow upwardly with the reciprocating element.

AThereafter latching ring i1 is unlatched and pulled froml within spring leaves l5 by cage 45 to enable spring leaves I5 to contract to normal position (see Figure 7) so as to allow the spring leaves 'I5 to become disengaged from the beveled annular recess 16 to enable extension 'I4 with insertable cylinder 22 to be pulled free from its tapered bored seat in the member 63 and upwardly with the reciprocating element by head 80 of hollow piston 26.

And thereafter latching ring and pulled from within spring leaves 'i8 by cage ||0 of hollow piston 23 or cross 85 on rod 36, to enable spring leaves 'i8 to contract to normal position so as to allow the spring leaves 'I8 to become disengaged from beveled annular recess 'i6 to allow extension 88, with and from which insertable cylinders 2| and |09 depend, tov be pulled free from its tapered bored seat in the member 4| and upwardly with the reciprocating element by hollow piston 24 engaging the coupling 36, the part 'l being pulled first, the latching ring Il being pulled next, and then the latching ring 'i9 being pulled next, then insertable cylinders 2| and |69 followi g next, and finally insertable cylinder theorder shown hereaboveand not all at oneY 'i6 is unlatchedA 22, the parts being pulled in time so as not to strain vrod 36, this being im-i portant in view of the reduced cross sectionof rod 36, as will be shown later herein. y

To explain the operation of the pump, reference is had to Figure 10, it being assumed, for the purpose of illustration, that the pistons have the following relative areas: piston 23 equals 1.8; piston 24 equals 4; piston 25 equals 6; piston 26 equals 2; and piston 5 equals 4. The guide I8 has been omitted from Figure 10,` to simplify the diagrammatic view.

The pump being full of oil and making anA upward stroke, valver6| being open and valve, 62 being closed, a charge of oil is drawn, by piston 5, in through valve 6| into workingpump chamber 2, which increases in volume to the extent of i parts. Valve -56 isopen and valve 41 is closed and the latter, in conjunctionwith piston 23, discharges oil through the horsehead 40 proportional tothe extent of 1.8 parts, the area of piston 23.

At the same time chambers 54 and 34 are decreasing in volume and a volume of o'il to the extent of 2 parts is moved downward throughl passage 82 to mix with and increase thejvolume of oil to the extent of 4 parts, coming from chamber 34, to a total of 6 parts, but chambers 5| and 66, during the upstroke, are increasing in volume and 2 parts of the 6 parts are taken inv 'r by chamber 6| which increases in volume to that extent, and the remaining 4 parts passV through open valve 56 and are-taken inV by chamber 66 (which increases in volume to that extent).

On thedownstroke of the pump, valves 6| and 66 are closed and valves 62 and 41` are open. The column of oil below valve 56 is restingjon' valve ly and the hollow piston 5 descends@ through the oil, causing 4 parts of'oi1 4to pass 40 from working pump chamber 2 into chamber 34, which increases in volume to that extent and which freely communicates with chamber 5|. Valve 56 is closed and the oil in chamber 5|,to j the extent of 2 parts is transferred upwardly' through passage S2 into chamber 54, which ncreases in volume to that extent.

At the same time working pump chamber 66 y is decreasing in volume and moves oil upward for discharge through horsehead 4|). The' amount thus discharged is equal to the effective area of working pump chamber 66 (area ofy piston 25 less area of piston 26, or 6 minus 2 equals 4) minus the area of pistonv 23 (1.8), leaving a` net discharge in vvolume to the extent of 2.2. parts.' It should be obvious from the description of the pump and its action that the hollow piston 26 obviates troublesome rod diiculties encountered in multi-stage .pump

construction, and, together with the piston 25 volume during the downstroke, enables reduction of oil or fluid load during the .upstroke and l also enables the weight ofthe rod l0 to be .uti-y lized to lift oil or iiuid duringA the downstroke. '1"hejhol1owpiston 24 is packing and valve The above described the piston 23, which utilized with'tn'e pump mainly when'short strokes'are employedland also when viscous oil is being= pumped, and may be dispensed with in long stroke pumps, the fluid or oil rising and surging in the chambers abovethe working pump chamber 65, the head thus created being sufficient to assure movement of the oil or fluid from the first stage into the `working pump chamber 65 of the secondk stage to and through port 8| in the member 4|, and

downwardly between casing and the pump column tothe bottom of the4 well.

The gas chamber 92 serves to prevent piston hammer during the movement of the oil or fluid betweenv the chambers positioned between pistons and 24, and also serves as a storage. chamber to Astore leakage oil or fluid leaking from the fluid elevating members of the second-stage pump during thevdownstroke of the pumping means until the leakage oil or` fluid has an op,- portunity to k:fe-enter the working pump chamber 66 or hasv had time to escape by relatively loose-fitting hollow piston 24.

Inthefexample chosen, I have shown the rststage pump as being a single-acting single-stage pump; however, the first-stage pump (Figure 4i) is in reality a double-acting4 single-stage pump acting to raise a lmajor fractional volume of oil or fluid during the upstroke of the pumping# means and to raise a very minor fractional volume of oil or fluid during the do'wnstrokeV of theA pumping means. l

With the first-stage pump acting to raise fluid` duringthe downstroke aswell as during the upstroke ofthe pumping means, and with chamber 66`of the second-stage pump increasing in volume during thelupstrokeof the pumpingV means and'decreasing in volume duringthe downstroke o f the pumping means, and with valve 50 of the second-stage pump open during the upstroke of 'the' pumping means and closed during the downstroke of the pumping means, it will be seenthat some provision must be made for theA minor fractional volume of fluid being raised by the first-stage pump during the downstrok'e of the pumping means.v This condition may be met' by increasing the differential area between the hollow pistonsn25 and 21| (by reducingthe diameter ofhollow piston 24) so that the volume of chamber 54'is large enough to store or receive a volume of fluid proportional to that of chamber 5| plus a volume of uid proportional tothe minor fractionalvolume of-fluid being raised by the rst-stage pump during the downstroke of' urvrrefof,v fluidloreingV stored in chamber 5l whilethe other fractional volume of fluid (equal tc the minor fractional volume raised by the first, stage; pump during the downstroke) is` being added to the, major fractional volume of iiuid being raised bythe first-stagev pump, the combined fractional volumes of fluid received in chamber 56 being equal to the volume of fluid drawn in through open inlet valve 6| intoY chamber 2. Thus it is seenl thatthe second-stage pump may be used with either a single-acting, singlestagel pump. or a double-acting single-stage pump` for the first stage, and this is made possible by varying the differential area between hollow pis.- tons ,25 and 24 as disclosed hereabove.

During the reciprocation of the pumping means. the chamber 93 will increase4 in volume duringz the downstroke of the pumping means andi-williy decrease in volume during the upstrokef of the pumping means and when no, fluid is present inthe chamber 93 (this being possible when the pumpingA means is new and is pumping fluid` to the extent of only a fraction of itsvcapacity, the` column of fluid in the wellbeing pumped downV so that` all the fluid entering the two-stage-pump` by way of inlet valve Sl is elevated in the pumpv column to the ground surface so that no fluid accumulates in the chamber 93), gas or air willf surge back and forth between. the space formed between the pump column and. thecasing byI Way of port 8|, trap space 9| and the port 90 in insertable cylinder 2|, thus preventing thepump from becoming gas-locked.

When uid is present inthe chamber 93- (this being possible when the pumping means has becomeY worn and the fluid elevating members of the second-stage pump leak so-that fluid leakage by hollow piston Zrlvalso takes/place, asdescribed earlier herein) the fluid will surge backand'forth between the trap space 9| and chamber 93 by way of port 90, the fluid rising and falling,` in the trap space 9| and the excess leakage fluid being spilled through overflow port 3| at the completion of each upstroke of the pumping means thus preventing the pumping means from becoming liquid-locked.

It'will be observed thatthe surging and mixing,

.ow throughiport 8| or through horseheadlllll atthetop of the pump column andthereby-be prevented from lodging in any particular spotv in the pump to cause excessive wear, orto restrict the movement of thereciprocating pump parts.

In actual practice, the second-stage pump .will be positionedsubstantially in the middle portion of the pump column, andthe two pumps will act to divide the column of oil or fluid into two`- stages,rthe pressure .of the column ofl oil orv fluid in thersecondrstage beingy alternately takenv by the.v valves 50 and il of the second-stage pump' duringthe upstroke and downstroke of the twostage pumping means. Therefore, at no time, is the rst-stagepump subjectedl to the pressure exerted by the entire column of oil or fluid, and it will be readily seen-that each individual pump is less subjected to wear.

During-the `upstroke of the two-stage pumping` means the rods ||land-3l6 will lift a load equal to the-weight of the column of Aoil or uid'being raised through the first stage plus a load equal to the weight of the fractional volume of oil or fluid being raised through the second stage, and during the downstroke of the two-stage pumping means the second-stage pump will act to move the remaining fractional volume of oil or iiuid upwardly, the weight of rod lil and attendant pump parts aiding in this operation.

With the primary pump or the conventional single-stage pump (Figure 4) being used as the first-stage pump to raise a volume of oil through a first stage only, it will be seen that a reduction in oil load imposed on the first-stage pump is secured and the rod I may therefore be of smaller cross section and of less weight than heretofore.

With the double-acting multi-stage pump (Figures 1, 2 and 3) being used as the second-stage pump to raise a volume of oil through the second stage during the downstroke as well as during the upstroke, a fractional Volume during the upstroke and the remaining fractional volume during the downstroke to equal the volume raised by the rst-stage pump, it will be seen that a reduction in oil load imposed o-n rod 36 by the second-stage pump is secured and this together with reduced weight of rod lil, secured as above described, enables rod 35 to be of smaller cross section. And with the second-stage pump elevating a fractional volume of oil during the downstroke, by employing the weight of rod Il! to pull the second-stage pump downwardly, the rod 38 is relieved of the weight of rod l0 during the downstroke and rod 35 will therefore be subjected to less stretch or elongation.

Because of reduced loads imposed on the rods, and therefore less tension, there Will be less vi- .bration of the mechanism, and where wells are crooked, as is usually thercase, there will be less friction and wear on the rods and the pump column.

While I have shown my apparatus as particularly applied to an oil well and have shown but two stages of pumping, it will be understood that the conventional single-stage pump for the first stage (Figure 4) may be used with any number of double-acting multi-stage pumps (Figures 1, 2 and 3) for the successive stages to pump oil from a deep well in any number of stages in order to obtain even greater all around efficiency, and fluids other than cil may be pumped with equal facility by my invention.

I desire, however, to emphasize the importance of pumping in a plurality of stages and of also employing the weight of the rods and pump parts below the pumps for the successivestages to actually pull the pistons of the pumps for the successive stages downwardly, thereby forcing o-il from the pumps for the successive stages upwardly, to raise oil through the successive stages.

I do not limit myself to the particular form of latch means shown with the insertable cylinders. The latch means may be adapted for use with the rings 'I'I or '19 Xed to the insertable cylinders, if desired, in which case the spring or resilient action of the pawls or leaves i8 and i5 to engage same with their respective recesses may be relied upon to releasably retain the inserta-ble cylinders in place in the pump column.

The pump hereinabove described may be used as a gas and oil pump, in combination with the conventional gas and oil separating means (not shown) disposed below the pump. The ports 8l in that case serve as vents for gas rising with the oil.

Under certain conditions, during operation 4oi the pump inanvoil well, fluid may rise in the clearance space to and above ports 8i, in which` occur in chamber 9i, such separated gas venting itself out. through ports 8i and back into the clearance space, and such separated liquid mov ing downward through the chambers and passages eventually to find its way into the second stage pump, which in this case may operate as the prime pumping medium. In the pumping operation, especially when piston 23 and piston 24 as well, are not employed with the pump (ports 87 also being omitted and port 8l being placed through and adjacent to the upper end of pipe 55) separation of the gas from the oil may occur in the annular chamber formed between pipe 55, member 69, cylinder 28, parts 58, 59, 63 and 83 and cylinder 22.

When the second stage pump employs a packed rod lll or its equivalent and an inlet valve on the cylinder 28, as a substitute for hollow piston 23 and valve 50, and the pump used for the rst stage is a single-acting pump, the hollow piston 24 may be retained, and in this case its outer diameter will remain equal to that disclosed in the example given earlier herein, but piston 25 (there being no piston 26 and therefore no chamber `5l which would require the chamber 5ft for surging movement of fluid as disclosed earlier herein) is therefore reduced to an outer diameter equal to the displacement area of the piston of the first stage pump. In the above mentioned case piston 5 retains the same area, as in the example disclosed earlier herein, or 4 units, piston 25 is made equal to 4 units, piston 2li equals 4 units, and piston 23 equals 1.8 units. When a double acting first stage pump is employed with the above disclosed second stage pump the outer diameter of piston 2d should be less than that of piston 25 to provide a space of variable volume (chamber 5d) to receive for storage the oil or fluid displaced upwardly by the rst stage pump during the downstroke of the pumping means.

By increasing the displacement area of the piston 23 to equal that of the piston of the rst stage pump during both the up and down strokes, the second stage pump may be made to act as a single-acting pump, if desired.

Making piston 26 of an outer diameter equal to or greater than that of piston 5 enables use of a stationary cylinder instead of an insertable cylinder for piston 2E, yet facilitates withdrawal of the pump parts for repair or replacement, this being accomplished by varying the displacement areas of pistons 25 and 2li as disclosed in the example given earlier herein. In this case the piston 2S may be made to extend upwardly through cylinder 22, the cage 31 being directly connected to cross 3 I. This last mentioned condition may also be accomplished without increasing the outer diameter of piston 26, by use of a modied latch, disclosed earlier herein.

And nally, while I have here shown certain of the cylinders in the pump stationary or xed within the pump column and certain of the cylinders removable with the rods from the pump column, I wish that it be understood that the twostage pump may be modified so that cartridge type pumps for the first and second stages, wherein all of the cylinders may be made removable with the rods, may be employed, if desired,

I claim:

l. 1n a pump' column for use in a well, a twostage pumping mechanism comprising: a first stage pump having a first inlet valve and a first piston means and a first outlet valve and a first working pump chamber between said first piston means and said first valves, a second stage pump having a second inlet valve anda second piston means and a second outlet valve and a second workingpuinp chamber betweenv said second piston means and said second valves, and means b'etween and to actuate said first and said second stage pumps in series; means providing a reservoir adapted for supplying fluid from and raised by said first stage pump to said second stage pump, and means including a lateral port through said pump column substantially on a level with the top of said second stage pump providing an overow passage placing said reservoir in communication with the space exterior to said pump column.

2. In combination with a pump column for use in a well, a two-stage pumping mechanism having pump structure in said pump column'comprising 'a first stage pump having a first inlet valve and a first piston means and a first outlet valve' and a first working pump chamber between said first piston means and said first valves, a second stage pump having a second inlet valve 'and a second piston means and a second outlet valve and a second working pump chamber betweenl said second piston means and said second valves, a first rod connecting the reciprocal portions of said first and said second stage pumps, anda second rod connected to the top oi the reciprocal p0rtion of said second stage pump and extending substantially to the top of said pump column and adapted to actuate the two-stage pumping mechanism, and said two-stage pumping mechanism also having other pump structure comprising means providing a reservoir adapted for supplying fluid from and raised by said first stage pump to said second stage pump, and means providing an overflow passage placing said reservoir in communication with the space exterior to said pump column, and said second Working pump chamber being adapted to increase in volume and to decrease in Volume during the upstroke and downstrole, respectively, of the two-stage pumping mechanism; said second stage pump also having a hollow piston, and 'a cylinder for said hollow piston, said hollowpiston and said cylinder being positioned above and adapted to convey iiuid from said second working pump chamber into the secondstage, and said hollow piston and said cylinder having a fluid displacement ar'ea less than that of said second working pump chamber whereby fiuid is raised in the second stage during the downstroke as well as duringthe upstroke of the two-stage pumping mechanism, to enable the weight of the reciprocal parts of the two-stage pumping mechanism to be utilized to actuate said second stage pump during the downstroke, in order to reduce stress on said second rod during the upstroke and the downstroke of the two-stage pumping mechanism.

3. In combination with a pump column for'use in a well, a two-stage pumpingmechanism having pump structure in said pump column comprising a first stage pump having a rst inlet valve and a first piston means and. a first outlet valve and a first working pump chamber between said first piston means and said rst valves, a second stage pump having a second valve cntrolled inlet and a second pistonmea-ns 'and a secessere a-waive conduits sauerland :..seoria working' pcmpfciijaab'er bawsisaiiusecd piston sans and said second valve controlled inlet and said second'v'al'v'er controlled outlet, and operating rod means between 'and toV actuate said rst and said second stage pumps in series, and said two-stage pumping mechanism also having other pump structure comprising-'means providing a reservoir adaptedfor supplying fluid from and raised by said first sjt'ag'e'pump to said second stagepum'p, andfi'n'eains providing an overow passage' placing said reservoir in; cor'ifimunication with the space exterior to said pump'colum'n; said second piston means comprising a first piston, a second piston above and of different fiuid displacement area than said first piston, said pistons being connectedto operate in series, and a cylinder for said first piston and a cylinder for said second piston, adapted to cooperate with and form a chamber between said pistons and said second valve'controlled inlet and said second valve controlled outlet and of variable volume during actuation of the pumping mechanism, for providingV the second working pump chamber to advance the flow of iiuid from the' first stage to the second stage in the pump column.

4; in combination with a pump column for use in a well, a two-stage pumping mechanism having pump structureA in said pump column comprisinga` first stage pump having a first inlet valve and a first piston means and a rst outlet valve Iand a first working pump chamber between said first piston means and said first valves, a second stage pump having a second inlet valve and a second piston means and a second outlet valve and a second working pump chamber between said second piston means and said second valves, and operating rod means between and to actuate said first and said second stage pumps in series, and said two-stage pumping mechanism also having other pump structure comprising means providing a reservoir adapted for supplying uid from and raised by said first stage pump to said second stage pump, and means providing an overflow passage placing said reservoir in communication with the space exterior to said pump co1- umn; said second piston means comprising a first hollow piston, a second hollow piston above and of different fluid displacement area than said first hollow piston, said hollow pistons being connected to operate in series, said second inlet valve being associated with said first hollow piston, said second outlet valve being associated with said second hollow piston, and a cylinder for said first hollow piston and a cylinder for said second hollow piston, adapted to cooperate with and form a chamber between said hollow pistons and said second Valves and oi" variable Volume during actuation of the pumping mechanism, for providing the second working pump chamber to advance the ow oi fiuid from the first stage to the second stage in the pump column.

5. An inserted pump adapted to be positioned in a pump column for use in a well, comprising: a first cylinder, a second cylinder above said first cylinder, a first hollow piston in said first cylinder, a second hollow piston in said second cylinder, operating rod means between and to lactuate said hollow pistons in series, means actuated respect to said pump column, the two meansV seating and sealing and releasably retaining said cylinders in respect to said pump column also enabling said cylinders to be spaced apart by said pump column; and a lost-motion connection in said operating rod means adapted to compensate for variations in length of the portions of the pump column and the pump related to said cylinders, in order to assure actuation of the two means, for seating and sealing and releasably retaining said cylinders in respect to said pump column, by said operating rod means.

6. An inserted pump adapted to be positioned in a pump column for use in a well, comprising: a rst stationary cylinder sealed and secured in respect ot said pump column, a second cylinder positioned above said i'lrst stationary cylinder, a first hollow piston in said rst stationary cylinder, a second hollow piston in said second cylinder, a standing valve below said iirst hollow piston and adjacent to the lower end of said rst stationary cylinder, operating rod means between and to actuate said hollow pistons in series, means actuated by said operating rod means seating and sealing and releasably retaining said standing valve in respect to and adjacent to the lower end of said first stationary cylinder, and means actuated by said operatingr rod means seating and sealing and releasably retaining said second cylinder in respect to said pump column and enabling said second cylinder to be spaced apart by said pump column from said rst stationary cylinder and said standing valve; and a lost-motion connection in said operating rod means adapted to compensate for variations in length of the portions of the, pump and the pump column related to said second cylinder and said standing valve, in order to assure actuation of the two means, for seating and sealing and releasably retaining said second cylinder and said standing valve in respect to said pump column and said first cylinder, respectively, by said operating rod means.

7. An inserted pump adapted .to be positioned in a pump column for use in a well, comprising: a rst cylinder, a second cylinder above said rst cylinder, a rst hollow piston in said rst cylinder, a second hollow piston in said second cylinder, operating rod means to actuate said hollow pistons in series, means actuated by said operating rod means seating and sealing and releasably retaining said first cylinder in respect to said pump column, and means actuated by said operating rod means seating and sealing and releasably retaining said second cylinder in re,- spect to said pump column, the two means seating and sealing and releasably retaining said cylinders in respect to said pump column also enabling said cylinders to be spaced apart by said pump column; and means for compensating for variations in length of the portions of the pump and the pump column related to said cylinders, said compensating means comprising the combination of a shoulder with one of said two cylinders and an arm with said operating rod means, the combination being arranged so that said arm engages said shoulder to permit the actuation, by said operating rod means, of the means seating and sealing and releasably retaining said one of said two cylinders in respect to said pump column and the combination also being arranged so that said arm disengages said shoulder to permit the actuation, by said operating rod means, of the means seating and sealing and releasably retaining the other of said two cylinders in respect to said pump column',

CII

in order to assure actuation of the two means, for seating and sealing and releasably retaining said cylinders in respect to said pump column, by said operating rod means.

8. An inserted pump adapted to be positioned in a pump column for use in a well, comprising: a standing valve adjacent to the lower end of said pump column, a cylinder above said standing valve, a piston in said cylinder, operating rod means to actuate said piston, means actuated by said operating rod means seating and sealing and releasably retaining said standing valve in respect to said pump column, and means actuated by said operating rod means seating and sealing and releasably retaining said cylinder in respect to said pump column, the two means for seating and sealing and releasably retaining said cylinder and said standing valve in respect to said pump column also enabling said cylinder and said standing valve to be spaced apart by said pump column; and means for cornpensating for variations in length of the portions of the pump and pump column related to said cylinder and said standing valve, said compensating means comprising the combination of a shoulder with said cylinder and an arm with "said operating rod means, the combination being arranged so that said arm engages said shoulder to permit the actuation, by said operating rod means, of the means seating andr sealing r and releasably retaining said cylinder in respect to said pump column and said combination also being arranged so that said arm disengages said shoulder to permit the actuation, by said operating rod means, of the means seating and sealing and releasably retaining said standing valve in respect to said pump column, in order to assure actuation of the two means, for'seating and sealing and releasably retaining said cylinder and said standing valve in respect to said pump column, by said operating rod means. 4

9. In a pump column for use in a Well, a pump adapted to raise uid in said pump column and having a iirst hollow piston, la iirst check valve associated with said rst hollow piston, a second hollow piston of relatively larger outer diameter than said rst hollow piston and positioned above and connected to said rst hollow piston Whereby said first and said second hollow pistons operate in series, a third hollow piston of relatively less outer diameter than said second hollow piston and positioned above and directly connected to said second hollow piston, a second check valve associated with said second and said third holf low pistons, a rst cylinder forsaid iirsthollow piston, a second cylinder for said second hollow piston, la third cylinder for said third hollow piston, said rst and said second cylinders being connected whereby a rst chamber of variable volume is formed between said rst and said second cylinders and said rst and said second hollow pistons and located between said valves vand serving as la working pump chamber, a second chamber of variable volume formed between said second and said third pistons and said second and said third cylinders, and means enabling formation of a, passage between said second and said third cylinders and said pump column and terminating with a lateral port through said Ipump column, said passage and said lateral port placing said second chamber of variable volume in i communication with the space exterior to sai pump column. i

10. In a pump column for use in a well, a pump adapted to raise iluid insaid pump column and .having "a :rst hollow. piston,4 a vrst check/valve associated withl saidi rstxhollowpistonpa:second .hollow piston :of relativelylargeriouterdiameter than said rst hollow piston and'positionedabove andconnected to said rst'hollow'pistonwhereby :said first and'said second hollow pistonsfoperate in,series,'a third hollow piston oirelativelyless `:outer ffdiameter than saidsecond J hollow 'piston pandpositionedabove and directly connected to said second hollow piston, `arsecond `check valve -associated with said secondgand saidthird 'hollow .'pistons,` alfirst cylinderior. said rst hollow .piston,.a.seoond cylinder for 'said `second hollow piston, 'a third cylinder for said. third hollow piston, said first and saidsecondcylinders being connected wherebya rstrchamber of variable .Volume is formed between lsaidlirstl and said-'second cylinders and'saidirst-.andf said second hollow 'pistons'rand located. between said'va'lves and s serving .I as .a' workingv` .pump chamber, a .second .chamber of-variablefvolumez'partially formed by .,saidirst cylinder .andbyzan'dbelow saidfirst hollow piston, a third chamber .of'yariableavolume formedbetween :said secondzand .said .third hollow pistons and saidv second.` andrsaid fthird "cylinders, and means ienablingi'formationfsof i .a passage `between-said first'andr said second and "said .third :cylinders Aand 'said'pump column, said .passage `connecting said second. and: said third chambers ofvariable volumeand :permitting'fluid to surge `back fand "forth between `said second .and :said .thirdiichamberscof variable volume.

11..Ina pump column foruseiinxa; wellpa pump adapted to raise. iiuid. in said .pump Acolumnzand :having aiirst hollowz-piston, aiirst .check-valve :associated withv said 'iirstzhollow piston, :a second .hollowtpistonof relatively largerfouter diameter -thanffsaidrst hollowrpistonfandzpositioned above ian'dcconnected to' said rsthollow: piston whereby said-l` first-and said secondhollow :pistons operate in series, a third hollowzpistonfoff relatively less outer diametertthan,said seoon'dhollow piston and :positioned above and:l directly. connected to said fsecond fliollow piston, a .fourth hollow :piston yof .reiativelypless outerdiameter than saidsthirdhollovltpi'ston and positioned above andiilrectly conneotedztoz'said thirdy hollow piston, la' second check val-veasso'oiated with said-:secondrzan'd :said4 third :andi said Vfourth lhollow` pistons, a first cylinder forisaidrstfhollow.piston; za. second: cylinder, for said :second vhollow piston, ra third cylinder for -saidthird hollow-piston, .a fourth .cylinder for said' fourth hollowxpiston ,"'sai'd .rst :andl Vsaid :second 'cylinders being :connected lwhereby `a first 4chamberr of variable volume i is f formed .between said: firstpand said secondcylinders::andasaid first Vandffsaifd second hollow. pistonsrian'd located between-said valves and servingfasr aworkingt pump chamber, ra secondftchamber"of-variable `volume partially formed by said i'lrstcylinder` Aand by and belowfsaid rst hollow piston.: aathirjd chamber Aof variable volume :formed :between said; second andfsaid third;cylinders:andsaidsecond and-said third "hollow, pistons, means? enabling: formation 'offfafirst pasage between; .'sa'dirstaridsaidfzsecondf andl said thirdrcylindersxand; said punrpgcolumnsandccnnecting saidsecondvand said third chambers; of variable volume; and permitting: iiuid to surgefback andlfortlr between said second. and .saidr third chambers of4 variable-volume, a fourth chamber. of variable volumeiformedbetween said thirdazand said fourthcylindersandrsaid third and said fourth hollow pistons, and:means .enabling formation-.offra secondpassagerbetween vsaid ,thirdl and said fourth cylinders;- and fsaid pump column and terminating with a lateralport .through said pump column,.said second passage and said lateral port placing said fourth cham- .ber of variable volume in communication with the spaceexterior to said pump column.

. 12. An inserted pump .adapted to be positioned in a pump column for use in a well, comprising: a'rst hollowpiston, a second hollowvpiston of relatively less outer 'diameter than said first hollow piston and positioned above and directly-com nected to said rst hollow piston, a checkvalve associated with said hollow pistons,a lirst cylinder for said rst hollow piston, la second cylinder for. said second hollow piston, said first and said second 'cylinders being directly connected, a chamberof variable volume formed in said cylinders and by said cylinders and said hollow pistons, a iirst lateral port through said iirstv cylinder .and positioned. substantially on a level with .the'1top -of vsaid chamber of variable volume,

-pump column.

13. An inserted pump adapted to' be :positioned in a pump column foruse .in a-well, comprising: a rst hollow'pistonfa second hollow piston .of

i relatively less outer' diameter than sa-id: first hollow piston v'and positioned xabove 'and .ldirectly l. connected tosaid firsthollow pistomfa ii'rstrcylinder provided for said rstihollow;piston,-:a1fsec ond lcylinder provided for,l said-second hollow, pistom-said rst and said: second-.fcylindersbeing directly'connected, a :chamberxiof `variable volume formed in said cylinders; and `bysaid r.' cyl- :inders and said hollowpistons, a rst lateralport ythrough said first 'cylinder andpositionedsub- `stantially on a level'with the topriofsaidcham- 'bei' of yvariable volume, means'rseating said cylinders in respect to said .pump lcolumngmeans sealing said first cylinderinrespeot'to said pumprcolumn, means sealing said selsondicylinder in re- .spectv to said pump column, and `means releasably retaining said` cylinders in 'respectto'said pump column; and-a passageformed` betweenlthe ytwo sealing means .provided for-said cylinders and between said cylinders and said pump columnand connecting'said'rst lateral port with a second lateral port through said pump column,

said passage and. said rst and said second lateral ports` placing said chamber' of Variable volume in communication `with the lspace#exterilor to saidpump column.

. 14. An insertedizpump adapted to beY positioned in a pump columni for `use in a 'welL'comprisingz a cylinder and a piston in said cylinder, means witlnn said pump column: and with saidcylinder adjacent toits upper endseatlng and sealing said cylinder inrespect to said. pump colummand an annular recess Within saidl pump column-andpositioned adjacentttothe liirstmentioned' means within said pump column; and resilient means, adapted. forl surrounding said cylindenadjacent to its uppenendandadaptedl for engaging said recess, latching said cylinder in respect to said pump column.

15. An inserted pump adapted to be positioned in a pump column for use in a well, comprising: a cylinder and a piston in said cylinder, means within said pump column and with said cylinder seating said cylinder in respect to said pump column, means within said pump column and with said cylinder adjacent to its upper end sealing said cylinder in respect to said pump column, means within said pump column and with said cylinder adjacent to its lower end sealing said cylinder in respect to said pump column, and an annular recess within said pump column and positioned adjacent to the second mentioned means within said pump column; and resilient means, adapted for surrounding said cylinder adjacent to its upper end and adapted for engaging said recess, latching said cylinder in respect to said pump column.

16. An inserted pump adapted to be positioned in a pump column for use in a well, comprising: a first stationary cylinder sealed and secured in respect to said pump column, a iirst hollow piston positioned in said iirst stationary cylinder, a second hollow piston of relatively less outer diameter than said first hollow piston and positioned above and connected to said first hollow piston whereby said hollow pistons operate in series, a second cylinder provided for said sec-` ond hollow piston, and means seating and sealing said second cylinder in respect to said pump column; and means latching said second cylinder in respect to said pump column.

17. An inserted pump adapted to be positioned in a pump column for use in a well, comprising: a rst stationary cylinder sealed and secured in respect to said pump column; a first hollow piston positioned in said rst stationary cylinder, a first check valve with said first hollow piston, a second hollow piston above and of relatively less outer diameter than said first hollow piston, a second check valve with said second hollow piston, said hollow pistons being connected to operate in series, a second cylinder provided for said second hollow piston, means seating and sealing and releasably retaining said second cylinder in respect to said pump column, and a chamber of variable volume between said cylinders and said hollow pistons and said valves, said chamber of variable volume serving to advance the flow of uid in said pump column.

18. In a well pump, a pump column, a pump located in said pump column and comprising: a first hollow piston, an inlet valve associated with said first hollow piston, a second hollow piston of diierent outer diameter than said first hollow piston and positioned above said first hollow piston, an outlet valve associated with said second hollow piston, operating rod means to connect and to actuate said hollow pistons in series, a rst cylinder for said first hollow piston, and a second cylinder for said second hollow piston, said cylinders being connected and with said hollow pistons form a chamber of variable volume acting as a working pump chamber; said pump also having means providing a lost-motion connection with the operating rod means between said rst and said second hollow pistons and adapted to dislodge said outlet valve from its seat, and means below said irst piston enabling said inlet valve to be dislodged from its seat.

19. An inserted pump adapted to be positioned fil) in a pump column for use in a well, comprising: a cylinder, a hollow piston extending through said cylinder, means seating and sealing and releasably retaining said cylinder in respect to said pump column, and means with and at the top of said hollow piston providing a shoulder engageable with the upper end of 'said cylinder during and to facilitate actuation of the means seating and sealing and retaining said cylinder in respect to said pump column; and means, with and at the bottom of said hollow piston and comprising a closed cage of greater outer diameter than said hollow piston and a check valve in low piston means, an outlet valve, and a first chamber of variable volume in said pump and between said hollow piston means and said valves and serving as a working pump chamber, and a second chamber below said pump and between said pump and said pump column and said closure and communicating at its upper end with Y said inlet valve; supporting means below said retaining means and between said pump and said pump column, said supporting means and said retaining means coasting to substantially prevent misalignment of said pump in respect to said pump column, a third chamber serving as an oil and gas separation chamber positioned between said retaining means and said supporting means and said pump and said pump column and substantially on a level above said rst chamber, and a passage between said supporting means and said pump and said pump column, said passage affording communication between the bottom of said third chamber and the top of said second chamber,l and lateral openings through said pump column and positioned substantially on a level with the top of said third chamber and placing said third chamber in communication with a space between said pump column and vthe well whereby oil and gas entrained in the oil are admitted from said space to said third chamber and gas is vented from said third chamber to said space.

21. In a well, a pump column provided with a closure adjacent to its lower end preventing the downward movement of fluid in said pump column, a pump located in said pump column above said closure and having an inlet valve, hollow piston means, an outlet valve, and a. first chamber of variable volume in said pump and between said hollow piston means and said valves and serving as a working pump chamber, a second chamber below said pump and between said pump and said pump column and said closure and communicating at its upper end with said inlet Valve, a i'st retaining means positioned at the top of said pump to hold said pump in said pump column, and a second retaining means positioned intermediately between the top and the bottom of said pump and between said pump and said pump column, said second retaining means also being provided to hold said pump in said pump column; a first supporting means betweenY said first and said second retaining means ,and said pump and saidpump column, a third chamber servi-ng as an oil and gas separation chamber between said rst retaining means and said'rst supporting means and said pump and said pump column, a Asecond supporting means positioned belowA said second retaining means and between said pump and said pump column, said iirst and said second retaining means and said rst and said second supporting means coacting to substantially prevent misalignment of said pump in respect to said pump column, and a passage between said first and said'second supporting means and said second retaining means and said pump and said pump column, said passage aording communication between the bottom of said third chamber and the top of said second chamber, and lateral openings through said pump column and positioned substantially on a level with the top of said third chamber and placing said third chamber in communication with a space between said pump column and the well whereby oil and gas entrained in the oil are admitted from said space to said third chamber and gas is vented from l said third chamber to said space.

hold said pump in said pump column; supporting means between said pump andl said pump column, said supporting means and said retaining means coacting to substantially prevent misalignment of said pump in respect to said pump column, and a passage between said pump and said supporting means and said pump column, said passage placing said last mentioned two chambers in communication to permit uid to surge back andforth between said last mentioned two chambers.

23. In a pump column for use in a Well, a surge pump comprising the combination of an inlet valve,V hollow piston means, an outlet valve, a rst chamber of variable volume in said pump and between said hollow piston means and said valves and serving as a working pump chamber, a second chamber of variable volume about said pump and vpositioned substantially on a level above said rst chamber of variable volume, a third chamber of variable volume about said pump and positioned substantially on a level below said rst chamber of Variable volume, and retaining means to hold said pump in said pump column; supporting means between said pump and said pump column, said supporting means and said retaining means coacting to substantially prevent misalignment of said pump in respect to said pump column, and a passage between said pump and said retaining means and said supporting means and said pump column, said passage connecting said second and said third chambers of variable volume and permitting surging movement of fluid between said second and said third chambers of variable volume.

W'ILLIAM PAUL MUNK.

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