US2821933A - Self-lubricating pump lunger - Google Patents

Description

Feb. 4, 1958 J. R. BRENNAN SELF-LUBRICATING PUMP PLUNGER Filed April 15, 1957 INVENTOR. JOHN R. fi/efN/vA/v ATTORNEY United States Patent 9 P SELF-LUBRICATING PUMP PLUNGER John R. Brennan, Long Beach, Calif., assignor to Fluid Packed Pump Company, Los Angeles, Calif., a cor 'poration of California Application April 15, 1957, Serial No. 652,710

' tiClaims. (Cl. 103-479) This invention relates to the plunger construction of rod-drawn andcomparable pumps, particularlyforuse inpilwells...

...=The primary object of the invention is to reduce wear between such plungers and the barrel in which they reciprocate., ;.1, I

.;Another object of the invention is to provide a pump plungerthatseparates the most eflicient lubricating portion or fractionof the flow or discharge of an oil well and utilizesthe same to lubricate between said plunger and the cylinder or barrel in which it operates.

.,In wells, where the water cut is high and which also may contain sand and other abrasive foreign particles, the eflicient life of both the plunger and barrel of a stationary barrelpump is materially shortened by wear induced by the low-lubricating properties of the Water, or both the waterand sand, if the latter is present. High water-cut wells frequently deliver a combination of water and oil which the water has five times the volume of the oil, ninetyv percent water and ten percent oil not being unusual. Under such conditions, the production, even though it, contains oil, nevertheless, does notefiiciently lubricate between the plunger and barrel of a pump. If, however, the oil in the production may be separated out withinthe pump and the same is directed so as to form a filrnbetween the plunger and the barrel, eflicient lubrication will result and the above faults will be obviated. I

Accordingly, another object of the present invention is to provide a self-lubricating pump that automatically produces lubrication vby the oil component of a we1l-produc tion flow, the same utilizing the diflerence in specific gravity between such component and the other component or componentsof the flow to effect such separation. A still further object of the invention is to-provide a self-lubricating pump which utilizes the pressure differential between the well and the production to not only insure flow of lubricant to the walls of the plunger and barrel but also to insure that the abrasive portions of the production are kept from said walls.

The invention also has for its objects to provide such means that are positive in operation, convenient in use, easily installed in a working position and easily disconnected therefrom, economical of manufacture, relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of construction and novel combinations and arrangements of parts, which will more fully appear in the course of the following description. However, the drawing merely shows and the following description merely describes, one embodiment of the present invention, which is given by way of illustration or example only.

In the drawing like reference characters designate similar parts in the several views.

Fig. l is a semischematic longitudinal sectional view of a well pump embodying the present improvements and shown in operative position with a well casing.

Fig. 2 is a longitudinal sectional view of the plunger of 2,321,933 Patented Feb. 4, 1958 ice 1 said pump, the same being shown in a preferred structural form.

The well casing 5 is conventional, the same receiving, from beneath, the fluid that comprises the well production. The normal level of said fluid may vary, all of the white spaces or annuli of Fig. 1 representing such well fluid, the same being under well pressure which, for the present purposes, will be termed low pressure.

In the present case, a pump 6 is shown disposed within casing 5 and in position to remove said fluid upwardly.

The pump shown is of the stationary barrel type. The same comprises generally, a barrel 7 loosely disposed in the casing, a standing valve 8 carried by the lower end of the barrel and, in the usual manner, opening upwardly to allow flow from the well or casing upward therepast into the lower end of the barrel, a plunger 9 reciprocative in the barrel by means of a string of sucker rods 10 operated from above, a traveling valve 11 carried by the lower end of said plunger, the same being open during the downstroke of said plunger to pass well fluid within the barrel into the interior of the plunger and closed during the plunger upstroke to displace said fluid upwardly, and a discharge 12 from the interior of the plunger into the pump barrel 7 above the plunger. The fluid that is thus upwardly displaced is shown in Fig. l by horizontal broken lines interspersed with dots. This fluid is the well production and, because the same is under a head pressure substantially greater than the well pressure, the same is high-pressure fluid or production.

The above describes a generally conventional stationary barrel pump. The present invention comprises means 15 for separating a part of the oil component of the production for use by said oil to lubricate between the barrel and the plunger. The oil thus separated is shown in the drawing by horizontal broken lines. Said means 15 is disposed above the traveling valve 11 and receives the fluid of the well from a passage 16 above said valve.

The means 15 comprises an inner tube 17 that is preferably concentrically disposed in the hollow of plunger 9 and is connected by its upper end to a fitting 18 to which the upper end of the plunger is connected. Said tube 17, at its lower end, terminates somewhat above the upper end of the passage 16. The outer size of tube 7 is smaller than the inner size of the plunger. Thus, there is provided between said tube and plunger an annular chamber 19 that is preferably larger, diametrally, than passage 16. It will be noted that chamber 19 is of substantial length, the longer the plunger, the longer the chamber.

Because the interior of tube 17 is vertically aligned with passage 16, the same will normally receive all or most of the flow from said passage. In order to insure ample flow entering the chamber 19, the lower end of tube 17 is provided with a restriction 20 that is smaller than pas sage 16. Thus said end, in the form of a flow-dividing fitting 21, divides the flow from passage 16 in such manner as to insure flow into annular chamber 19.

Part of the flow into chamber 19 is returned to the interior of tube 17 as by means of holes or ports 22 in the lower end of said tube above the fitting 21. The remainder is trapped in chamber 19 which, because its upper end is closed by the fitting 18, constitutes a flotation or settling chamber, the longitudinal extent of which is between the uppermost holes 22 and said fitting 18.

Near the upper end of the plunger 9, the same is provided with a set of ports 23 that open into chamber 19 somewhat below its uppermost end. A manifolding groove 24 is formed around the outside of the plunger, said ports discharging into such groove.

Since the oil component of the production is of lighter specific gravity than the water or water and sand in the production, the same will rise in chamber 19 and thus float on the fluid in the lower part of the chamber. At the same time, sand, if present, will settle downwardly from both the purer oil component in the upper portion of the chamber and the fluid in proximity to holes 20 and 22. Thus, such settling matter will be drawn off with the production through the interior of tube 17 and outwardly of discharge 12 into the barrel above the plunger.

It will be clear that on each upstroke of the plunger, the traveling valve 11 will close due to the greater pressure of the fluid thereabove than is in the well. Since this high pressure is manifested throughout the interior passages, holes and ports of the plunger, oil from the upper portion of the flotation chamber will be forced through ports 23 to lubricate between the plunger and barrel. Such lubricating flow is but immaterially resisted by the low pressure in the well. Since the pressure within the plunger is as great as the pressure above the plunger, this flow from the lubricating ports resists any tendency of the productionoil and water or oil, water and sand-from entering between the plunger and barrel.

In the above manner, the pump is efliciently lubricated and its useful life extended.

Since some wells pump water for a period of time before oil enters the suction or discharge, in practice, the flotation chamber of the present pump, before the pump is lowered into a well, is filled with grease. The same supplies lubrication, as above, until gradually used up and displaced by oil from the well fluid.

The grooves 25 are provided for the usual purposes and in the usual way, the same serving to collect impurities to minimize wear between the plunger and the barrel.

While the foregoing has illustrated and described what is now contemplated to be the best mode of carrying out my invention, the construction is, of course, subject to modification without departing from the spirit and scope of the invention. It is, therefore, not desired to restrict the invention to the particular form of construction illustrated and described, but to cover all modifications that may fall within the scope of the appended claims.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In a pump for fluid that contains both oil and a livery stroke of the plunger and a traveling valve in the lower end of the plunger closing to support the fluid in the plunger during said delivery stroke, the improvement that comprises a tube within the hollow of said plunger defining an annular chamber between itself and the plunger, the lower end of said tube being open and valveless and in direct communication with the chamber at all times whereby both tube and chamber receive fluid entering the plunger past the traveling valve, and ports in the plunger in spaced adjacency to the otherwise closed upper end of the chamber and constituting a passage for fluid trapped in the upper portion of the chamber to the area of sliding engagement between the plunger and the barrel.

2. In a pump according to claim 1, a set of holes adjacent the lower open end of said tube and constituting return passages to the interior of the tube for fluid entering the annular chamber, the annular chamber above said set of holes constituting a flotation chamber in which oil in the fluid is trapped and exists through the mentioned ports.

3. In a pump according to claim 1, the lower end of said tube being provided with a restriction that accepts part of the flow past the traveling valve, the remainder of the flow being diverted by said tube end to the annular chamber.

4. In a hollow pump plunger having a fluid-lifting traveling valve and a fluid passage above said valve, a tube within the hollow of said plunger and having a lower end terminating above said passage, the adjacent end of said tube being smaller than said passage, an annular chamber defined between the tube and the plunger and open at the lower end thereof to flow from said passage, means closing the upper end of said chamber whereby the same traps flow entering from below and divides the fluid thus trapped from the fluid within the tube, and ports in the barrel in spaced relation below the closed end of the chamber for discharging the fluid in the chamber outwardly of the plunger.

5. In a hollow pump plunger according to claim 4, said tube, above the lower end thereof, being provided with holes constituting a connection between the lower end of the chamber and the interior of the tube whereby fluid filling the chamber above said holes is separated out of the flow that moves in the interior of the tube.

6. In a hollow pump plunger according to claim 4, the flow receiving end of the tube being provided with a flow divider that diverts part of the flow past the valve into the annular chamber.

References Cited in the file of this patent UNITED STATES PATENTS

Images