US2665901A - Lubricating system for units operated by compressed air - Google Patents

Description

Jam 1954 E. w. PATTERSON LUBRICATING SYSTEM FOR UNITS OPERATED BY COMPRESSED AIR Filed Aug. 15, 1949 ro ues- Patented Jan. 12,,1954

1 UNITED STATES",

LUBRICATING SYSTEM FOR UNITS OPER- ATED BY COMPRESSED AIR Edgar W. Patterson, Downey, Calif. Application August 15, 1949, Serial No. 110,357

1 This invention relates to means for automatically replenishing the lubricating and sealing oil inpres'sure operated units such as air balanced pumping units. 1 'Such' an air balanced oil Well pumping assembly'w'as shown in my United States Patent No. 2,293,916, and is described in my co-pending application,'Serial No. 758,127, for a Pressure Control System for Air Balanced Pumping Units,

nowaba'ndoned. v

Due to defects in manufacture or otherwise the space between thepiston and cylinder in my unit becomes great enough to cause leakage and this leakage is prevented by supplying sealing oil of a suitable quality. This oil is dipped upfrom a reservoir located at the'bottom or" the air balancing cylinder and whenthis reservoir is filled sufiiciently to enable the -oil pump to take up suflicient quantities of this oil the sealing is e e a- However, due to one reason or another, this oil reservoir sometimesbecomes depleted and the seal isbroken. H A g It is an object of my present invention to proe vide means whereby this oil is constantly pro-v vided to the surfaces to be sealed and will not become depleted or insuilicient. Other objects and advantages of this invention will be apparent from the following description and claims, the novelty consistingin the features of construction, combination of parts, the unique relations of the members and the relative proporr tioning, disposition, and operation thereof, all as is more completely outlined herein and particularly pointed outin the appended claims. Q a In the accompanying drawings, forming a part of this present specification, Figure 1 is a side elevational view of a pump: ing unit embodying the present invention. Figure 2 is a detail sectional view of. one embodiment of my present inventio taken along the lines 22 in Figure 1.. g ,1. Figure 3 is a vertical sectional view showing the piston, its cylinder and one embodiment of my present invention for assuring sufiicient' sealing oil between the piston and the cylinder.

Figure 4 is a vertical elevation along 'the lines 4-4-'in-Figure 3. e

Figure 5 is a detail view of another embodiment of my present invention, and

Figure 6 is a detailview taken along the lines 3-5 in Figure 5. 'Reierring to the drawings I will now describe: the general features of the usual air balanced 13 Claims. 01. 267-1) 2 pumping unit which has been used as an i1lus-. tration of my invention.

The pumping unit is mounted on a base It],

, which supports a Sampson post I2, its attached walking beam l4 and horsehead IS. The hanger strap l8, carrier bar 20 and polish rod 22 are shown and actuated in the same manner that is fully described in my above patent and application. Cylinder 24 is raised and lowered by the action of walking beam M to which it is connected by connector 26. This cylinder 24 moves up and down, over and with respect to a piston 28 which is mounted on the mechanism afiixed to base In, so as to be relatively immovable, excepting for slight oscillatory movement, in its relation to base 10. Piston rings 30 are mounted at suitable intervals on piston 28 to act as a seal between piston 28 and the inner wall of cylinder 24.

To assure this seal I provide a sealing oil reservoir 32 in the upper part of this piston 23, the bottom of said reservoir being formed by a radial piston wall 33. This reservoir 32 has ducts 34 leading from the bottom of the reservoir to an annular space between piston 28 and the inner wall of cylinder 24. These ducts 34 feed the oil from the reservoir 32 to the inner wall of the cylinder 24 in sulficient quantities to assure a seal between the inner wallof the cylinder 24 and piston 28.

My present invention relates to the means for maintaining the oil in this reservoir 32 to provide this seal and I have shown several alternative means for assuring the replenishment of this oil.

I will first describe the means shown in Figures V: 3 and 4 hereof.

The replenishment means shown in Figures 3 and 4' consists in an oil pump which pumps oil from a source of supply to a point above the piston 28, permitting it to fall down past bafile plate 36 into sealing oil reservoir 32. In my preferred embodiment the source of this oil supply is compartment 40 located in cylinder 24 and this oil passes through supply line 42. This oil also passes through an input check valve 44, which permits the oil to go only in the direction'of entrance into the oil pump cylinder 46. At the top of cylinder 46 is a head 48, which is connected to cylinder 46 by means of a screw threaded connection 50. Sealing rings 52 in head 43 serve to maintain pressure within cylinder 46. A piston rod 54 extends through head 48 and has an .enlarged portion or bumper 56 at the top thereof.

Fixed upon the lower end of this piston rod 54 is a piston head 58, having piston rings 60 to effect a seal against the inner walls of the cylinder 46.

There is always pressure in the chamber of the cylinder 46 below the piston head 58, which causes the piston rod 54 and its bumper 56 to be urged upwardly against the wall 33 of piston V 28 during the part of the cycle when piston 28 is in the lower portion of cylinder 24. This pressure comes from line 62, whichopens into the bottom of cylinder '46 below piston head 58.

Leading from the upper end of cylinder 46 is a feed line 64, having an output check valve Reciprocation of piston head 58 in cylinder 46 is effected by the following means.

Cylinder 24 is connected to walking beam 14 by connector 26 so that every time that the walking beam l4 rises and falls during the pumping operation it raises and lowers connector 26 and cylinder 24.

At the bottom of cylinder 24 a closure 61 is bolted to cylinder 24 by bolts 55.

Oil pump 45 is similarly bolted to closure member 61 by bolts 16.

By this construction the reciprocal motion of walking beam 14 is transmitted through connector 26 to cylinder 24 andits closure member 61 to oil pump 45. Therefore, every time that the walking beam l4 moves up or down oil pump 45 likewise moves up or down, respectively.

However, piston 28 is stationary and when oil pump 45 raises, bumper 56 is in contact with piston 28 due to the pressure on the under side of piston 56 which holds piston 58 against piston wall 33 while cylinder 46 moves upwardly or downwardly with relation to piston 58. In this manner, reciprocating movement between piston 58 and cylinder 46 is eilected and oil is Dumped from the source of; supply through line 42- into cylinder -46and out of cylinder 46 past one way valve 66 into line 64. The upper face of piston 58 has a lesser area than thelower face of piston 58, the differencebeing the cross-sectional area of the'piston rod 54, and therefore it can discharge against a pressure greater than the pressure in the cylinder 24, which is-also exposed to oil pump piston 58. V

1 At the bottom of line 64, which goes through closure member 61, is test valve 12, which can be opened to see if the pump is working, and one way check valve 14, which permits oil to go out. but not come back along line 64..

3 At the opposite side of check valve 14 is line. 76, which is really a continuation of. line 64, and which is connected by an open connection with line 62.

Line T6 has a vertical bend and is led upwardly by an open connection into the interior of cylinder 24 above piston 28 in, itsuppermost position.-

In this manner oil is. pumped from compartment lfl through line 42 into cylinder 45 and out through lines 64 and 16 to the, interior of cylinder 24 above piston 28.. There the oil flows down onto piston 28 and past bafile plate '36 into oil reservoir 32.

In this manner it is automatically assured that the oil in reservoir 32 will be constantly replenished from an adequate source of supply through line 42 and the train described above.

, As a result of its unique design, the oil pump 45 is capable of efficient operation throughout a varied range of stroke lengths;

It is to be understood that the piston 58 of oil pump 45 does not move as great a distance with reference to cylinder-'46 duringone complete cycle of operation as the cylinder 24 of the pumping unit to which it is attached does with reference to its piston 28. Furthermore, it is to be understood that piston 28 may be caused to operate at various pro-determined stroke lengths within the main balancing cylinder 24.

Attention is called to the unique combination of functions performed by the single 011 line 16. Connecting as this does with both the upper and lower ends of the cylinder 46 the pipe 16 must not only supply oil under pressure to the bottom of piston 58 to accomplish the upward return of said piston following a downward stroke thereof, but must also conduct oil from pump 45 to and discharge it into the upper portion of air cylinder 24. The manner in which it performs these two functions may be explained as follows:

Considering a reciprocating cycle of cylinder 24 as starting with the latter in its uppermost position, the lower end of cylinder '24 containing the pump 45, then has an elevated position in which said pump has approached close enough to the radial wall 33 of piston 28 so as to cause the pump piston 58 to have been pushed to its lowermost point in the pump cylinder 46, ap

' proximately as shown in Fig. 4. When the cylinder 24 starts downward, the pump cylinder 46 carried thereon moves with it and only the differential pressure applied to the bottom of piston 56 keeps this from moving downwardly with the cylinder 46. This differential is adequate, however, to hold the bumper head 56 pressed upwardly against the radial air piston wall 33 as the cylinder 46 moves downwardly thereby causing a relative movement between pump piston 56 and pump cylinder 46, with the cylinder head 48 approaching said pump piston until it engages the latter which marks the limit of said relative movement between said piston and said cylinder head.

During this relative movement between pump piston 58 and pump cylinder 46, the oil in said cylinder above said piston is forced through the check valve 66, pipe 64 and check valve 14 into oil line 16. At the same time that this is being done, of course, a slightly larger volume of oil is being forced under pressure from pipe "16 through pipe 62 into the lower end of pump cylinder 4 6. Thus there is a net discharge or a given volume of oil from the pipe 16 into the pump 45 during the downward movement of the air cylinder 24. It is thus clear that no pumping of oil by the pump 45 through the oil line It and into the air cylinder 24 takes place during the initial stroke of said oil pump just described.

The upward stroke of air cylinder 24 tov com-' plete the cycle of operation being described. begins with the piston 58 ofv the. oil pump 45 -en gaging the cylinder head 48 thereof, that is, with the piston rod 54 at its maximum point of extension from pump cylinder 4-6, and with the bumper head 56 a substantial distance downward from the air piston wall 33. As the air cylinder 24 rises, the pump 45 rises with this-the preponderance of pressure. against the bottom face stroke, however, as all the oil received in the cylinder 46 below piston 58 in the first stroke thereof above described is, in the second stroke, exhausted through pipe 62 into pipe 16. Check valves 66 and 14 prevent this oil recirculating into the upper end of cylinder 46. Thus, the oil discharged by the second piston stroke into line 18 displaces a sufiicient amount of oil therein to cause a volume of oil equal to that delivered through pipe 64 into line 18 during the first piston stroke to be discharged into the upper end of said air cylinder from the upper end of oil line I will now describe an alternative means of replenishing the oil in reservoir 32 that is shown in Figure 2 of the drawings hereof. Also both means may be used in combination with each other to more effectively seal the piston.

In practice the manufacturing tolerances of the cylinders and pistons vary. In order to meet these conditions it sometimes requires a flood of oil on top of the piston 28. This flood of oil passes down between piston 28 and cylinder 24 and accumulates in compartment 48. As long as there is oilon top of piston 28 it is possible to maintain airpressure in the balancing system. When this oil is depleted air will pass by the piston 28 faster than the compressor 85 can replenish the air in the balancing system, the result being a gradual loss of balance pressure. To overcome this deficiency I have provided a pump in compartment 48 to pick up the oil from compartment 48 and return it to reservoir 32 in pis-v ton 28. In some instances the fit between the piston 28 and the cylinder 24 is close enough that relatively little oil accumulates in compartment 48. However, due to air velocity in piston tube '18, oil is sucked over bafiie plate 36 into piston.

tube 18 and thence through line 96 into'air tank 84 where it comes to rest at point 82. In orderj to return such migratory oil to reservoir 32 in piston 28 I provide an aspirator tube 88 as shown in Figures 1 and 2 or an aspirator tube 88 as shown in Figure 5, which accomplishes the same purpose as tube 88 in Figure 2.

The flow of air past the open ends of tubes 88 or 88 sucks oil from these tubes and atomizes the same so that the particles of oil thus formed are entrained in the air stream and thus carried into the air cylinder 24 above the piston 28 as this cylinder rises in its upward stroke. The aspirated oil accumulates in cylinder 24 above piston 28 and runs down the side walls of cylinder 24 into reservoir 32 of piston 28. In this eombination if oil leaks by piston 28 to compartment 48, or if the oil blows over baffle plate .38 down tube 18 into reservoir 82 it is returned to reservoir 32 in the manner above described. Thus the oil seal is maintained at all times 'on pistoni 28 to efiectively seal it against airloss. Both systems are effective to maintain an oil seal on piston 28. However in the combination of the aspirator and the oil pump it is only necessary to fillthe system with oil once as the oil is sealed in the unit andeannot escape to the atmosphere 18 into cylinder 24. The aspirator functions on the up stroke of cylinder 24. Aspirator tube 88,v

' toward bore 18 and prevents return of the oil or outside the unit. If only the aspirator is used oil can leak by thepiston and into compartment 48 and finally overflow and escape from the system. If the oil pump is used as the sole lubri-. eating means oil may be blown over into tube 18 a t o zs i oi 'v wh re. it cannot .be .returned to reservoir 32, requiring the addition of oil to compartment 48 at frequent intervals to insure proper lubrication to piston 28 and cylinder walls 24.

In Figure 2 the piston rod 38 has a hollow bore 18 leading to the interior of cylinder 24 above piston 28. Oil is fed through this hollow bore 18 to the interior of cylinder 24 above piston 28 through line 88.

The oil that is thus fed through line 88 into bore 18 comes v from reservoir 82, located in the bottomof'tank 84.

Pressure is maintained in the balancing system and tank 84 by compressor 86 and the usual connections, which are not shown.

hollow piston rod 18 and line 96 to reservoir 84. This is on the down stroke of the beam. On the up stroke of the beam, air moves from reservoir,

84 through line 96 and through hollow piston red.

as shown in Figure 2, is directed into pistontube 18. As air passes by aspirator tube 88 going to cylinder 24 the velocity of this air picks up oil. from reservoir 82, as shown in Figure 1 Check valve 94 prevents the return of oil through line 88 to the reservoir 82 on the down stroke of cylinder 24. 7

Check valve 94 opens only in the direction after it has passed valve 94. In this manner oil from reservoir 82 is constantly fed through bore I8 to the walls of cylinder 24 above piston 28,

whence it drops down past baflle plate 38 into oil reservoir 32. In this manner the permanent reservoir 82 supplies the oil to the lubricating reservoir 32 in piston 28. I will now describe the other alternative method of supplying oil to reservoir 32 that is shown in Figures 5 and 6,

hereof.

The bottom of tank 84 is provided with the."

same oil reservoir 82 and a line 88 drops down into this oil. Near the bottom of this line is a one way check valve 98 that permits the oil to be removed from reservoir 82 but prevents it from returning thereto. At the bottom of cylinder 84 is a drain plug 92, present both in Figure 5 andin Figure 1, for draining off any water that may accumulate in the bottom of reservoir 82, as it is heavier than the oil.

A spider 94', as shown in Figure 6, is provided adjacent the port in tank 84 and a flexible line 96 that can compensate for the oscillatory movement of the piston tube 38 is similarly provided. The action of the. air

This carries valve 98. surging back and forth between the balancing cylinder 24 and the tank 84 will cause oil to be picked up out of the reservoir 82 in the bottom of tank 84. This oil is then fed through line 88 to bore .18 in piston rod 38 to the interior of cylinder 24 above piston 28 and thereafter the action is the same as in the variation hereof shown in Figure 2.

It is to be understood that the form of my invention herein shown and described is my pre- In the movement of cylinder 24 over piston 28 air is moved from the interior of cylinder 24 through between said cylinder and said piston and means to replenish the sealing oil to said reservoir including a sealing oil collecting reservoir located beneath said piston and in the lower portion of said cylinder so that oil leaking past said piston drains into said oil collecting reservoir and pump means associated with said reservoirs and operable by the relative motion between said cylinder and said piston to continuously transmit sealing oil from said collecting reservoir to said reservoir in said piston.

10. In an oil sealing mechanism the combination of: a cylinder, a piston movably mounted in said cylinder, a sealing oil reservoir in said piston, there being a duct leading from said reservoir to the outside of said piston whereby said sealing oil can flow from said reservoir through said duct to the space between said piston and said cylinder to effect a seal between the exterior of said piston and the interior of said cylinder, means forming a passageway connecting a source of air under pressure to the interior of said cylinder above said piston, the interior of said cylinder above said piston communicating freely with said sealing oil reservoir, a sealing oil storage reservoir, an aspirator tube connecting said storage reservoir to the interior of said passageway and a check valve in said aspirator tube limiting flow in said tube to flow from said storage reservoir to the opening of said tube into said passageway.

11. In an oil sealing mechanism the combination of: a cylinder, a piston movably mounted in said cylinder, a sealing oil reservoir in said piston, there being a duct leading from said reservoir to the outside of said piston, a sealing oil storage reservoir, means forming a passageway connecting a source of air pressure to the interior of said cylinder above said piston, the interior of said cylinder above said piston communicating freely with said sealing oil reservoir, an aspirator tube having an opening in said passageway, a source of oil supply for said aspirator tube, a check valve in said aspirator tube preventing a reverse flow of oil therein towards said source of supply, and pump means to transmit sealing oil from said oil storage reservoir to said reservoir in said piston.

12. In an oil sealing mechanism the combination of: a cylinder, a piston movably mounted in said cylinder, a sealing oil reservoir in said piston, there being a duct leading from said reservoir to the outside of said piston, and means to replenish the sealing oil in said reservoir including a sealing oil storage reservoir, pump means to transmit sealing oil to said reservoir in said piston, a source of oil supply for said pump means, means forming a passageway connecting a source of compressed air to the interior of said cylinder above said piston, the interior of said cylinder above said piston communicating freely with said sealing oil reservoir, an aspirator tube connecting said storage reservoir to the interior of said passageway, and a check valve in said aspirator tube limiting the flow of oil therealong to a flow from said storage reservoir to said passageway.

13. In an oil sealing mechanism the combination of: a cylinder, a piston movably mounted in said cylinder, a, sealing oil reservoir on said piston having a duct leading to the space between said cylinder and said piston whereby said seal ing oil can move from said reservoir to the space between said piston and said cylinder to efiect a seal between the exterior of said piston and the interior of said cylinder, and means to replenish the sealing oil in said reservoir including means forming a passageway connecting a source of compressed air to the interior of said cylinder above said piston, there being a communication between the interior of said cylinder above said piston and said sealing oil reservoir, an aspirator tube opening into said passageway, a check valve in said aspirator tube limiting the flow of oil in said tube to a flow towards said passageway, a source of oil supply for said aspirator tube, pump means to transmit sealing oil to said piston reservoir and a source of oil supply for said pump means.

EDGAR W. PATTERSON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 707,284 Wagner Aug. 19, 1902 1,602,536 McElroy Oct. 12, 1926 1,819,381 Palmer Aug. 18, 1931 1,984,144 Laugaudin Dec. 11, 1934 2,098,290 Hinkle et a1 Nov. 9, 1937 2,223,700 Norgren Dec. 3, 1940 2,464,710 Patterson Mar. 15, 1949 2,486,705 Corey Nov. 1, 1949 FOREIGN PATENTS Number Country Date 535,599 France Jan. 27, 1922

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