US2061252A

US2061252A - Plunger pump

Info

Publication number: US2061252A
Application number: US64189A
Authority: US
Inventors: Clifford M Peters
Original assignee: Individual
Current assignee: Individual
Priority date: 1936-02-17
Filing date: 1936-02-17
Publication date: 1936-11-17
Anticipated expiration: 1953-11-17

Description

Patented Nov. 17, 1936 UNITED STATES PATENT OFFICE 2 Claims.

This invention relates to hollow plunger deep well pumps of that general type in which the seal between the plunger and pump barrel is accomplished by a plurality of stationary tubes 5 and movable tubes nested therewith, which tubes provide a labyrinthine path through which fluid must travel before it can pass the plunger and by means of which labyrinth leakage or slip is reduced.

It further relates to a pump assembly which may be lowered into the well and/or removed therefrom through the discharge pipe, and to the means by which the said assembly is sealed to the pipe when so lowered and seated.

Pumps of this general type have been previously known. Ordinarily however, in such pumps the cylinder has consisted of an outer tube or barrel and an inner tube supported at the bottom of the barrel and extending upward, and a plunger of two tubes, both secured to a plunger head and extending downward, the inner within and the outer between the two tubes of the barrel. Such construction has proved inefiicient in that the pocket so formed in the upper end of the plunger and the similar pocket at the lower end of the barrel, both trap and compress the fluid being pumped on the downward stroke of the plunger, which stroke is accomplished solely by gravity, seriously shortening the stroke except at excessively slow speeds, and greatly reducing the capacity of the pump.

In an attempt to obviate this situation so far as the lower pocket is concerned, the outer wall of the cylinder has been moved away from contact with the outer of the plunger tubes, and that part of the labyrinth abandoned; and openings have been made through the inner wall of the plunger to relieve the resulting compression and shortening of stroke caused by the other pocket. To make this latter construction efiective two valves have been found necessary in the plunger itself.

In such construction also, the plunger forms no support for the cylinder in lowering the pump assembly through the discharge pipe to its seat and additionally provides no means, per se for removing the cylinder portion of the assembly from the well should such removal be found necessary. To obviate this difficulty, threaded 1 means or other disengageable types of coupling means have been found necessary in order to secure the pump and cylinder together for lowering into the well, such coupling means having to be disengaged in some manner, as by rotation of the plunger before pumping is begun. Conversely they have to be re-engaged before removal in case the same becomes necessary. Recoupling particularly is ordinarily accomplished only with considerable difliculty and in addition when accomplished is so close as to allow little if any play, so that a direct pull must be used in breaking loose the seal, rather than a jarring one which would be much more advantageous.

The objects of my invention are:

To provide for a plunger pump, a labyrinthine seal in which the compression pockets formed, are acted on during the mechanically controlled upstroke of the plunger, and therefore cannot alter the length of stroke.

To provide a labyrinthine seal construction in which positive discharge from compression pockets is available to clear sand from the labyrinthine passages and to assist in preventing leakage therethrough.

To provide a labyrinthine seal, pump construction in which fluid is trapped in two opposed interconnected pockets, the pressure in one pocket substantially balancing that in the other thereof, minimizing flow therebetween and rendering substantially all of the fluid trapped eifective to remove sand and oppose leakage.

To provide a pump construction in which the coacting areas of the moving and stationary tubes increase as the effective plunger stroke progresses.

To provide a labyrinthine seal, pump-construction in which the plunger assembly supports the cylinder assembly during lowering into or removal of the pump assembly from the well and in which movement of the plunger is available to establish blows against the cylinder assembly to assist in dislodging the seal from its seat.

To provide in a deep well pump a removable pump assembly placeable and/or removable through a discharge pipe which has a supporting seat at its effective lower end, said pump assembly having at its upper end supporting means adapted to cooperate with said seat, whereby substantially all of said assembly depends below said seat and is not subject to silting up.

The means by which the foregoing and other objects are accomplished and the manner of their accomplishment will readily be understood from the following description on reference to the accompanying drawing, in which,

Fig. 1 is a vertical section of my pump through the discharge pipe and the pump assembly.

Fig. 2 is a fragmentary section showing a modified form of sealing means.

Referring now to the drawing in which the various parts are indicated by numerals, II? is a discharge pipe, I l a coupling, and I2 a casing section depending below the coupling II and enclosing the pump. The coupling I I is bored out at I3 to loosely fit the exterior of the pump and is counterbored to form an annular shoulder I I to support the cylinder assembly. I5 is a head for the cylinder assembly. This head is provided with an outwardly extending annular flange I6 which overlies the annular shoulder M of the coupling II. I! is a seal, preferably of lead disposed between the shoulder I4 and flange It to support the cylinder assembly and seal the same to the coupling II and discharge pipe. This seal is preferably secured to the cylinder head I5 by tinning the exterior of the head and casting the lead ring therearound. I V

Depending from the head I5, is an outer tube I8 forming the outer wall or barrel of the cylinder and shorter inner tube I9 spaced therefrom. The barrel I8, at its lower end, supports a valve seat 29. 2| is a ball valve cooperating with this seat and 22, a pin limiting the travel of the ball valve 2 I.

The plunger comprises a head 25, provided with the usual threaded shank 26 for attachment to the pump rod (not shown). The head 25 is provided with the usual annular valve seat 21 and ball valve 28, the upper portion of the head forming a cage for the valve 28 and being provided with openings 29 through which discharge of pumped fluid is effected into the discharge pipe IE3. Secured to and depending from the head 25 is a tube 30 lying within the inner cylinder tube and having a working fit therewith. At its lower end the tube 35 is secured to and carries a head 3I which is shown as a thickening and enlargement of the tube, but may be otherwise formed. 32 is a hollow valve seat secured inthe head ill. 33 is a ball valve and 34 a pin limiting movement of this valve. Secured to the head 3| and extending upwardly therefrom, is a second and shorter plunger tube 35, spaced outwardly from the tube 35, the surfaces of this tube having a working fit with the interior of the cylinder barrel I8and the exterior of the cylinder tube Ill. The tubes It and 35 are both shorter than their respective related barrel and plunger tubes, leaving pockets 35 and 3'! in the barrel assembly and plunger assembly respectively.

When assembled and nested, as shown, the cylinder and plunger tubes form a labyrinth seal surrounding the hollow plunger and valve construction, the provision of four tubes and the resulting two pockets substantially balancing the pressures along the contiguous surfaces of the two shorter tubes and creating along such surfaces a minimum, if any, leakage flow.

It will be seen that the lower head 3! of the plunger and the tube 35 supported thereby underlie the tube I9 and head I5 of the cylinder assembly so that the cylinder'assembly is supported by the plunger and can be lowered or removed thereby.

It will particularly be noted that the depending cylinder assembly lends itself to the placingof the seal at the top of the cylinder and in position where any deposit of sand is minimized by agitation due to movement of the plunger and discharge therefrom, such packed sandbeing one of the most serious troubles encountered in removal of pump barrels.

In Fig. 2 the pump assembly is supported in the coupling I IA and sealed thereto by a seal comprising seating cups AIL-4| held in place by retaining rings 62, 43 respectively and secured by a retaining nut M.

Operation supports the cylinder assembly, the weight of the assembly compressing the link I! to seal the cylinder head I5 tothe coupling II and com- "pleting the installation.

In thus lowering the pump assembly into the well the plunger assembly supports the cylinder assembly, the lower head SI of the plunger and the tube 35 thereof underlying the inner tube I9 and head I 5 of the cylinder assembly.

To operate the pump, the plunger assembly is lowered and raised in usual manner by well known apparatus at the top of the well, such as is now in general use. Descent of the plunger is largely accomplished in this operation by gravity since the long plunger rod ordinarily used is too flexible to impart a direct thrust. Raising of the plunger however is by direct pull of the rod and therefore the upper limit of the plunger stroke is definite. During the down stroke fluid within the cylinder barrel is trapped by the foot valve 2i and enters the plunger barrel through the lower valve 33 thereof. On the up stroke this fluid is raised by the plunger and additional fluid drawn into the cylinder through the foot valve and the operation continued in usual manner to accomplish pumping. During this action the barrel 30 and tube 35 of the plunger slide within and against the tube I9 and barrel I8 of the cylinder. On the down stroke fluid is drawn upward between the outer wall of the plunger tube 35 and the inner wall of the cylinder barrel I8 into the pocket 36, and similarly fluid is drawn downward along the outside of the plunger barrel 30 and between such tube and the inside of the cylinder tube I9 into the lower pocket 3?. Also flow may occur from or to the pocket 36, to or from the pocket 31 along the contiguous surfaces of the cylinder tube I9, and the plunger tube 35, but the pressures in the two pockets are substantially equal and such flow or movement is not usually material.

On the up stroke fluid within the pockets 36 and 31' is forced therefrom, substantially all of this flow from the pocket 36 occurring between the inside of the cylinder barrel I8 and the outside of the plunger tube 35, and from the pocket 31 between the inside of the cylinder tube l9 and the outside of the plunger barrel 3!]. If the fluid being pumped is a true liquid, such as water with substantially no entrained gases, this flow in both the upper and lowered pockets must be in direct proportion to the area of the pockets and the plunger stroke. If however, the fluid to be pumped is a fluid such as oil containing a large proportion of entrained gases, the pockets need neither fill completely nor empty completely, owing to the compressibility and expansibility of the entrained gases, and therefore the flow of fluid from and to the pockets in such case would be largely reduced from the corresponding flow where a true liquid is pumped.

In ordinary pumping the fluid is often accompanied by considerable quantities of sand. So far as actual pumping is concerned, sand drawn in through the foot valve 2| passes upward into the plunger, is raised thereby and largely passes with the fluid directly to the surface and is discharged therewith. There is a tendency however for some of the sand to follow the fluid drawn along the sealing surfaces of the tubes and into the pockets. In both cases however, the tendency of the sand is to follow the freer flow of the fluid pumped and a minor quantity only is drawn along these sealing surfaces toward the pockets. On the up stroke the fluid within the pockets is definitely forced out by the up stroke of the plunger and clears or tends to clear all of this sand from these surfaces, the evacuation of fluid from the pockets ofiering a definite resistance to the plunger stroke. In the present case this resistance is overcome by the definitely fixed movement of the plunger raising mechanism, and therefore irrespective of the speeds must be fully accomplished at each stroke, whereas the evacuation of the pockets were these pockets inverted would be accomplished only by gravity and even at normal speeds evacuation of the pockets would not be complete and the capacity of the pump would be greatly lowered.

After continued use of the pump, it is often found necessary to remove the same for overhauling and/or cleaning, and such removal requires dislodging the seating seal and also dislodging of any sand which may have packed over and around such seal. In the instant device, particularly where oil containing entrained gases has been pumped, it is possible by slightly lowering the pump rod and thereby separating the ends of the tubes l9 and from the bottoms of their respective pockets, to accomplish by sharp upward movement, a blow or jar which is effective to dislodge the seal I! from its seat and thereby permit the removal of the pump assembly from the well.

It will again be noted, that at all times portions of the plunger assembly underlie portions of the cylinder assembly so that they are definitely locked together at all times, making it possible not only to use this jarring stroke to release the seal between the pump assembly and its support, but also making the plunger assembly inherently effective for the subsequent removal of the cylinder assembly and thus obviating the difliculty often unsurmountable of coupling these parts together as a condition precedent to the removal of the cylinder assembly.

What I claim is:

1. In a pump having a discharge pipe with an annular seat adjacent its lower end; a cylinder assembly and a plunger assembly reciprocably cooperating, said cylinder assembly comprising an annular head having annular supporting and sealing means cooperating with said annular seat,

-a barrel and a tube spaced inward therefrom,

both secured to and depending from said head, said tube being shorter than said barrel, and a foot valve carried by said barrel; said plunger assembly comprising a working valve, an annular upper head, a barrel secured to and depending from said head within said cylinder tube and having a working fit therewith, an annular lower head carried by said barrel and a tube shorter than said barrel spaced outward therefrom secured to and extending upward from said lower head, said plunger tube lying between said cylinder barrel and cylinder tube and having a working fit with said barrel, said cylinder barrel and tube and said plunger barrel and tube forming together a labyrinthine passageway interrupted by upper and lower pockets both decreasing in volume on the upstroke of said plunger and having discharge escape only along the respective working surfaces between said barrels and their cooperating tubes; whereby leakage downward along the pump barrel due to the pressure of the fluid column during the pumping stroke is opposed by upward discharge flow from the lower pocket augmented by counterbalancing pressure from the upper pocket.

2. In a pump having a discharge pipe with an annular seat adjacent its lower end; a cylinder assembly and a plunger assembly reciprocably cooperating, said cylinder assembly comprising an annular head having annular supporting and sealing means cooperating with said annular seat, a barrel and a tube spaced inward therefrom, both secured to and depending from said head, said tube being shorter than said barrel, and a foot valve carried by said barrel; said plunger assembly comprising an annular upper head carrying a working valve, a barrel secured to and depending from said head within said cylinder tube and having a working fit therewith, an annular lower head carried by said barrel and a tube shorter than said barrel spaced outward therefrom, secured to and extending upward from said lower head, said plunger tube lying between said cylinder barrel and cylinder tube and having a working fit with said barrel, said cylinder barrel and tube, and said plunger barrel and tube, forming together a labyrinthine passageway interrupted by upper and lower pockets both decreasing in volume on the upstroke of said plunger and having discharge escape only along the respective working surfaces between said barrels and the cooperating tubes; whereby leakage downward along the pump barrel due to the pressure of the fluid column during the pumping stroke is opposed by upward discharge flow from the lower pocket augmented by counterbalancing pressure from the upper pocket.

CLIFFORD M. PETERS.