US3003583A

US3003583A - Polished rod lubricator

Info

Publication number: US3003583A
Application number: US841194A
Authority: US
Inventors: William B Thomas
Original assignee: Individual
Current assignee: Individual
Priority date: 1959-09-21
Filing date: 1959-09-21
Publication date: 1961-10-10
Anticipated expiration: 1978-10-10

Description

Oct. 10, 1961 w. B. THOMAS 3,003,583

POLISHED ROD LUBRICATOR Filed Sept. 21, 1959 BEA INV EN TOR. Wm L/:4M 5. T-xoMA 5 3,003,583 POLIEiHEl) ROD LUBRICATOR William B. Thomas, Rte. 2, Wellston, Oldm, assigno of fifty percent to Herman Thomas, Shawnee, Okla. Filed Sept. 21, 1959, Ser. No. 841,194 8 Claims. (Cl. 184-65) This invention relates to improvements in lubnicators for oil Well polished rods.

As it is well known in the oil industry, the majority of oil wells requiring pumping means for removing oil from the well utilize a reciprocating-type pump supported in the lower portion of the well and operated by a string of rods extending from a prime mover at the surface. Such pumps are commonly known as sucker rod pumps and the uppermost rod of the string of rods is a specially constructed, smooth-surfaced rod which is commonly known as a polished rod. The polished rod extends through a stufiiing box at the well head which is designed to prevent leakage of the oil at the well head and to direct the pumped oil through a flow line from the well head to suitable storage facilities.

During anormal operation of a sucker rod type of pumping installation, the oil being produced from the Well is present directly below the stufiing box, and the polished rod is moved in and out of this oil as it reciprocates through the stufiing box. The crude oil is normally at a substantially constant temperature, and therefore retains the polished rod at a SubStantiallycOnstant temperatur as well as providing lubricationfor the packing rings in the stufling box. However, the crude oil contains an appreciable portion of foreign matter which invariably enters the stufiing box when the polished rod is not otherwise lubricated, and provides an increased wear of the packing rings, also, the crude oil is not ordinarily the best lubricant for the packing rings. Therefore, operating personnel must frequently visit a producing well and tighten the packing rings in the stufiing box to prevent a leakage of the crude oil through the stufiing box and onto equipment around the well head.

Many oil wells do not have sufficient capacity for a sustained operation of the sucker rod pump, such that all of the available oil in a well is frequently removed by the pumping installation before the pump is shut down by operating personnel. When no crude oil is available in the upper portion of the well for contact with the polished rod, the polished rod becomes dry and substantial friction is encountered during reciprocation of the polished rod through the stuffing box. As a result, the polished rod will burn out the packing rings in the stuffing box in a relatively short period of time and will then come in contact with metallic portions of the stufiing box to cause grooves or dents in the polished rod, which in turn reduces the efficiency of the polished rod for subsequent pumping operation, and frequently requires replacement of the polished rod. Another situation which is frequently encountered is a parting of the sucker rod string during a pumping operation. In this latter event, the prime mover at the surface of the well will normally operate at an increased speed to reciprocate the dry polished rod through the stufiing box and result in damage both to the stuffing box and the polished rod, substantially in the same manner as when the pump is operated with the well in a 'dry condition and as described above.

Prior workers in the art have designed variousdevices for lubricating a polished rod, but none have been widely accepted in the oil industry. Generally speaking, these prior devices utilize a container supported on the upper end of the stufling box in such a manner as to provide a continuous flow of lubricating oil to the polished rod. When the container is of a practical size, it requires a United States Patent ice frequent resupplying of the lubricating oil to provide an effective lubricating operation.

The present invention contemplates a novel lubricating devices which is adapted for attachment to a polished rod above the stuffing box and which provides lubrication of the polished rod in accordance with the temperature of the polished rod, thereby minimizing the supply of lubricating oil which must be retained in the device, and assuring that the polished rod will remain lubricated in the event the well pumps dry, or in the event the sucker rods part. Broadly stated, the present invention may be defined as a device for lubricating an oil well polished rod in accordance with the temperature of the polished rod, comprising a body formed out of a heat conducting material, said body having an upper end and a lower end and having its inner face curved to mate With a portion of the periphery of the polished rod, said body also having an aperture extending transversely therethrough and a groove in the inner face thereof extending from said aperture to the lower end of the body, means for clamping the body to the polished rod, a container carried by the body having an outlet in the lower portion thereof, a supply of lubricating oil in the container characterized by having its viscosity change in inverse relation with respect to its temperature, a horizontally extending conduit connected to the body and the container providing communication between said outlet and said aperture and being formed out of a heat conducting material to retain the temperature thereof substantially equal to the temperature of the polished rod, and a restriction in said conduit for-med of a heat conducting material and having an orifice therein of a size to control the flow of the lubricating oil therethrough in accordance with the temperature of the polished rod.

An important object of this invention is to decrease the manual attention required for servicing oil Wells, and particularly the servicing of oil well stufiing boxes.

Another object of this invention is to increase the service life of stuffing box packing rings. 7 T

A further object of this invention is to increase the service life of oil well polished rods.

Another object of this invention is to provide lubrication of a polished rod in accordance with the operating temperature of the polished rod.

A still further object of this invention is to provide a polished rod lubricator which has no moving parts, for simplicity of construction; requires no source of energy 'for operation, other than heat from the polished rod;

will have a long service life, and may be economically manufactured.

Other objects and. advantages of the invention will be evident from the following detailed description, when read in conjunction with he accompanying drawings which illustrate my invention.

In the drawings:

FIGURE 1 is a top view of a lubricator constructed in accordance with this invention illustrating the lubricator installed on a polished rod, and with the polished rod shown in section.

FIGURE 2 is a sectional view as taken along lines 22 of FIG. 1, with the polished rod and the clamping means for holding the lubricator on the polished rod being removed for simplicity of illustration.

FIGURE 3 is a front elevation view showing the inner face of the body of the lubricator which is clamped onto the polished rod.

FIGURE 4 is a sectional view similar to a portion of FIG. 2 and illustrating a modified construction.

Referring to the drawings in detail, reference character 10 generally designates a lubricator constructed in accordance with this invention and which includes a body 12 adapted to be clamped around the polished rod 14 of a well pumping installation by means of a U-bolt 16. The body 12 is formed of a heat conducting material, such as bronze, and is constructed in the shape of a saddle, with its inner face 18 curved to mate with the surface of the polished rod 14. It may also be noted that the body 12 is of a width to extend slightly less than half way around the polished rod 14. Apertured flanges or ears 2% are formed at the opposite sides of the body 12 to receive the end portions of the U-bolt 16, such that the body 12 may be calmped onto the polished rod 14 upon tightening of the nuts 22 which are threaded onto the end portions of the U-bolt 16 into contact with the flanges 20. As previously indicated, the body 12 is clamped onto the polished rod 14 above the stuffing box (not shown) of a well pumping in stallation a sufficient distance that the body 12 will not contact the stufiing box during reciprocation of the polished rod 14.

As shown in FIGS. 2 and 3, an aperture 24 extends transversely through the central portion of the body 12 to provide a passageway for lubricating oil to the polished rod 14, as will be described. Also, a vertical groove 26 is formed in the inner face 18 of the body 12 and extends from the aperture 24 to the lower end 28 of the body to conduct lubricating oil from the aperture 24 downwardly along the polished rod 14. Additional grooves 30 are also preferably provided in the inner face 18 of the body 12 extending at an angle from the aperture 24 downwardly and outwardly to the lower end 28 of the body on opposite sides of the groove 26 to further distribute the lubricating oil around the polished rod 14.

A coupling 32 is formed on the outer face 34 of the body 12 in such a position that the bore 36 through the coupling communicates with the aperture 24. In the preferred embodiment, the aperture 24 is positioned at the upper end portion of the bore 36, for purposes which will be hereinafter described. A restriction 38 is secured in the outer end portion of the coupling 32, as by threads, and is also secured in the outer end of a conduit 40 extending from the lower end portion of a container 42. The restriction 33 is also formed of a heat conducting material, such as bronze. An orifice 44 extends longitudinally through the center of the restriction member 38 to control the flow of lubricating oil through the aperture 24, as will be described.

The container 42 is provided to retain a supply of lubricating oil 46 therein which is characterized by having its viscosity change in inverse relation with respect to its temperature. In other words, when the temperature of the oil 46 decreases, the viscosity thereof increases, and vice versa. The lubricating oil 46 is discharged from the container 42 through an outlet 48 in the lower end portion of the container. The conduit 40 is suitably secured to the container 42 concentrically around the outlet 48. It may also be noted that the outlet 48 is preferably positioned slightly above the bottom 50 of the container 42, such that any foreign matter which may be in the lubricating oil will settle out into the extreme lower end portion of the container and will not flow with the oil through the outlet 43. Finally, a suitable cap 52 is secured over the upper end of the container 42 in any desired manner, such as by the use of threads 54. However, the cap 52 should not be secured air tight over the upper end of the container 42, since the oil 46 gravitating through the outlet 48 must be easily replaced by air, as will be readily understood by those skilled in the art.

Operation As previously indicated, the device is clamped to the polished rod 14 a sufficient distance above the stuffing box, such that the device 10 will not contact the stufiing box during reciprocation of the polished rod. When the device 10 is first secured on the polished rod 14 and the container 42 is filled with the lubricating oil 46, or when the polished rod 14 is not operating and is at normal atmospheric temperature, a portion of the lubricating oil will fiow through the outlet 48, conduit 40, orifice 44, bore 36 and aperture 24 into

grooves

26 and 30 to provide an initial lubrication of the polished rod 14.

During a normal operation of the polished rod 14, the polished rod will run at a substantially constant temperature, as previously indicated. Since the body 12, coupling 32 and restriction member 38 are constructed of a heat conducting material, the temperature of these components will be substantially equal to the temperature of the polished rod 14. The size of the orifice 44 and the characteristics of the lubricating oil 46 are preferably selected such that either no oil, or only a minimum amount of oil, will flow through the orifice 44 when the polished rod '14- is operating in a normal manner. For example, the oil 46 may be a conventional 30 weight engine lubricating oil, and when the orifice is .016 inch in diameter, the oil will either not flow through the orifice, or will only drip slowly through the orifice, when the oil is at a temperature corresponding to the operating temperature of most polished rods 14. It will be apparent that when no oil is flowing through the orifice 44, no oil will be supplied to the bore 36 in the coupling 32 which forms a reservoir between the orifice 44 and the aperture 24. However, this reservoir is initially filled with oil, as previously described, such that a small quantity of lubricating oil will be immediately available for discharge through the aperture 24 in the event the temperature of the polished rod 14 begins to rise. As the temperature of the polished rod 14 increases, the oil standing in the reservoir 36 is heated and will expand to flow through the aperture 24 into the

grooves

26 and 30. As the temperature of the polished rod 14 either 0ontinues to increase, or stay at an increased temperature, the restriction member 38 is also gradually heated up to heat the oil congealed in the orifice 4'4 and provide a flow of the lubricating oil through the orifice 44 for continuous discharge through the aperture 24.

Any oil flowing through the aperture 24 will gravitate through the

grooves

26 and 30 to the respective portions of the polished rod 14. As the polished rod 14 is reciprocated through the stuffing box, this lubricating oil will come in contact with the upper end of the stufiing box and will be adequately distributed around the entire periphery of the polished rod 14 to maintain lubrication of the polished rod in the stuffing box packing rings. Therefore, the packing rings will not become burned through the lack of lubrication, and will have an increased service life.

As an alternate construction, and as illustrated in FIG. 4, the coupling 32 may be formed concentrically around the aperture 24 and the restriction member 38 may be threaded completely into the coupling 32 to abut the outer face 34 of the body 12. In this construction, the orifice 44 is aligned with the aperture 24 to transfer lubricating oil directly between the orifice 44 and the aperture 24 when the temperature of the restriction member 38 is raised sufiiciently for a flow of the lubricating oil through the orifice 44. It may also be noted that the aperture 24 may, in this embodiment, be formed the same size as the orifice 44, since no oil will flow through the aperture 24 until the oil also flows through the orifice 44. FIGURE 4 also illustrates that only the groove 26 may be used in the inner face 18 of the body 12 to conduct the lubricating oil downwardly along the polished rod when the oil flows through the aperture 24. In all other respects, the embodiment shown in FIG. 4 is the same as the embodiment shown in FIG. 2.

From the foregoing, it will be apparent that the present invention provides a polished rod lubricator which has no moving parts, for simplicity of construction; requires no source of energy for operation, other than heat from the polished rod; will have a long service life, and may be economically manufactured. When the device is constructed to provide a constant application of lubricating oil on the polished rod, a film of the lubricating oil will remain on the polished rod, even though only a minor amount of the oil is used. As a result, a minimum of the crude oil produced by the well will enter the stuffing box and increase the wear of the packing rings, such that the field personnel will not need to adjust the packing rings as frequently as in the present day installations. In this connection, it may be noted that most oil wells are produced only a portion of each 24-hour period, such that additional amounts of lubricating oil will be supplied by the device rather frequently to maintain efiicient lubrication of the packing rings in the stufiing box. Also, if difficult conditions are encountered, the orifice may be of sufiicient size to provide an increased flow of the lubricating oil through the apparatus for increased lubrication of the polished rod. It will also be apparent that the present device provides an appreciable lubrication of the polished rod in the event the polished rod becomes heated, as by the well running dry or by a parting of the sucker rod string. Furthermore, since either no lubricating oil is constantly drained from the present device, or only a minor portion of the lubricating oil is continuously drained through the present device, a minimum oil supply will be required and the container will not need to be filled with lubricating oil, except during trips of the operating personnel to a well for other operations, such as for starting the well pumping installation.

Changes may be made in the combination and arrangement of parts or elements as heretofore set forth in the specification and shown in the drawings, it being understood that changes may be made in the embodiments disclosed without departing from the spirit and scope of the invention as defined in the following claims.

I claim:

1. A device for lubricating an oil well polished rod in accordance with the temperature of the polished rod, comprising a body formed of a heat conducting material, said body having an upper end and a lower end and having its inner face curved to mate with a portion of the periphery of the polished rod, said body also having an aperture extending transversely therethrough and a groove in the inner face thereof extending from said aperture to the lower end of the body, means for clamping the body to the polished rod, 2. container carried by the body having an outlet in the lower portion thereof, a supply of lubricating oil in the container characterized by having its viscosity change in inverse relation with respect to its temperature, a horizontally extending conduit connected to the body and the container providing communication between said outlet and said aperture and being formed of a heat conducting material to retain the temperature thereof substantially equal to the temperature of the polished rod, and a restriction in said conduit formed of a heat conducting material and having an orifice therein of a size to control the flow of the lubricating oil therethrough in accordance with the temperature of the polished rod.

2. A device as defined in claim 1 wherein said restriction is positioned in spaced relation from said body to provide a reservoir between the orifice and said aperture.

3. A device as defined in claim 2 wherein said aperture is larger in diameter than said orifice and is positioned at the upper end of said reservoir.

4. A device as defined in claim 1 wherein said restriction is positioned in contact with said body and said aperture and said orifice are aligned.

5. A device as defined in claim 1 wherein said body also has a pair of slanting grooves in the inner face thereof extending downwardly and outwardly from said aperture on the opposite sides of the first-mentioned groove.

6. A device as defined in claim 1 wherein said lubricating oil is a BSD-weight engine lubricating oil and said orifice has a diameter of approximately .016 inch.

7. A device for lubricating an oil well polished rod in accordance with the temperature of the polished rod, comprising a body formed of a heat conducting material, means for clamping the body to the polished rod for retaining the body at substantially the same temperature as the polished rod, a container carried by the body, a supply of oil in the container characterized by having its viscosity change in inverse relation to its temperature, and means forming a passageway from the container to the polished rod when the body is clamped onto the polished rod which is in heat conducting relation to said body, said last-mentioned means being formed of a heat conducting material and having an orifice therein of a size to control the flow of the oil therethrough in accordance with the temperature of the polished rod.

8. A device for lubricating a reciprocating rod in direct proportion to the heat of the rod derived from its frictional contact with a packing seal through which it moves, comprising a heat-conducting body secured to said rod in heatconducting relation thereto for reciprocation therewith, said body having an orifice extending from said rod through said body of a size to control the flow of lubricant therethrough in accordance with the temperature of the rod; a container having its interior in communication with said orifice; and a lubricant in the container characterized by having its viscosity change in inverse relation to the temperature.

References Cited in the file of this patent UNITED STATES PATENTS 1,162,586 Dutro Nov. 30, 1915 1,446,098 McNamara Feb. 20, 1923 1,712,006 Moore May 7, 1929 2,479,349 Hagg Aug. 16, 1949