US2156326A - Expansible chamber motor - Google Patents

Description

May 2, 1939. w, H. WINEMAN 2,156,326

EXPANSIBLE CHAMBER MOTOR Filed Sept. 28', 1936 g QM I MWM.

a? g g Patented May 2, 1939 UNITED STATES EXPANSIBLE CHAMBER MOTOR Wade 'H. Wineman, Coolspring Township, La

Porte County, Ind., assignor to Sullivan Machinery Company, a corporation of Massachusetts Application September 28, 1936, Serial No. 102,989

16 Claims.

My invention relates to motors, and in certain aspects thereof more particularly to pumping motors. g

A very successful form of pumping apparatus,

used where the stratum pressure is'inadequate to raise the oil to the, surface, is employed for pumping oil Wells, using a central source of motive fluid and employing a number of expansible chamber motors actuated by the fluid supplied from said central source. A very satisfactory form of this system employs a central air compressor plant delivering the air at, say, a pressure from two to- 7 three hundred pounds per square inch and taking back air in the return lines from the pumping motors at a pressure of, say, fifty to one hundred pounds per square inch. The individual pumping unit at each oil well comprises a single-acting expansible chamber motor having fluid-actuated valve mechanism. Under the force of incoming motive fluid, the pumping motor piston raises for a substantial distance a sucker rod line connected to a pump plunger in a pump down in the Well. At the end of the up-stroke the motive fluid which has done its work is discharged to the re- 5 turn line, which is maintained under a back pressure, as above indicated. This back pressure is sufficient to provide appropriate retardation of the downward movement of the pump motor piston, the sucker rod line and the pump plunger. Such devices are extremely effective. Long pumping strokes are possible. Speed control to accommodate substantially any reasonable rate of oil flow is possible. The apparatus is completely automatic. No attendance at each individual well 5 is necessary. Substantially only one serious problem is encountered in the use of such devices, and that problem is capable of easy and effective solution.

It is always possible with any packed pump plunger, for the packing to blow out. Occasionally, moreover, after long periods of use, usually, sucker rod lines may break. Either of these con ditions, or events, may result in a very rapid and relatively uncontrolled upward movement of the pump'motor piston and all or a part of the rod line, unless appropriate control devices are provided. Such devices are commonly applied in the form of dash-pot cylinders constituting an extension of the motor cylinder, and entered by the 50 motor piston upon overtravel of the latter. These dash-pot cylinders in conjunction with the motor pistons efiectively cushion the upward movement of the motor piston when a packing blows out or the sucker rod line breaks, but since the motor 55 pistons and. the attached portions of the sucker if upon the first occurrence of an up-stroke of the motor piston which is at an excessive speed, means for interrupting the normal functioning of the motor by interrupting further fluid supply to the pumping motor cylinder is provided, the chances of injury will be markedly reduced. It is possible to shut down the motor by interrupting admission to it, and this I have provided for in the structure disclosed in my Letters Patent 2,004,145. More compact mechanism can be used, however, when a different approach to this problem is made, and I have found that by interrupting the movement of the fluid distribution mechanism and the holding of the valve mechanism forming a portion of the pumping motor in a position to cut off supply and establish continuous exhaust con ditions, a very effective arrangement is possible.

It is an object of my invention to provide an improved motor apparatus. It is another object of my invention to provide an improved pumpoperating motor apparatus having improved. controlling means. It is a further object of my invention to provide an improved motor having associated therewith improved means for interrupting the operation of the distributing mechanism of said motor in the event that certain derangements of said motor occur. It is still another object of my invention to provide an improved motor having associated therewith improved means operative upon overtravel of the motor piston element to interrupt the operatic-n of the fluid distribution means forming a portion of said motor, and thereby to shut down said motor. It is yet a further object of my invention to provide an improved pumping motor having improved distributing valve mechanism forming a part thereof and having associated therewith improved means for rendering said distributing valve mechanism inoperative in exhaust-effecting position upon overtravel of the motor piston. More specifically, it is an object of my invention to provide an improved expansible-chamber-motor type pump-actuating system having improved arrangements incorporated therewith for interrupting fluid supply to the pumping motor and connecting the same, with respect to the working spaces thereof, continuously to exhaust, in the event that the pumping motor loses its load. Still a further object of my invention is to provide an improved pumping motor operable with a relatively 1 uniform stroke during normal pumping operation, but having provision permitting overstroking thereof and cushioning of the over-stroking thereof in the event that the pumping motor loses its load; and to provide with such motor a controlling means therefor operative in the event that such over-stroking occurs to move the distributing means for said motor to a position in which supply of fluid to the motor cylinder is interrupted and the working space within the motor cylinder continuously connected with ex haust and so maintained until a deliberate operator intervention and restarting of the motor takes.

place. Other objects and advantages of my invention will hereinafter more fully appear.

In the accompanying drawing, in which for purposes of illustration one embodiment which my invention may assume in practice has been shown:

Fig. 1 is a view in' front elevation showing a pumping motor of the character hereinabove mentioned incorporating my invention in its illustrative form.

Fig. 2 is a vertical section on a plane corresponding to the section line 2-2 of Fig. 1, some parts being shown in elevation,

Fig. 3 is a section on a further enlarged scale on ,a plane corresponding to the section line 3-3 of Fig. 2, showing details of the distributing valve mechanism and the automatic control therefor.

Figs. 4 and 5 are views on an enlarged scale through the automatic control device associated with the distributing valve, these sections being taken on a plane corresponding to the plane of Fig. 2 and showing the automatic control device in respectively its normal position and the position which it assumes when a predetermined overtravel of the motor piston has taken place.

Fig. 6 is a fragmentary section on the plane of the line 6-6 of Fig. 3.

Now referring to the drawing, it will be noted that a suitable support I has pivotally connected thereto at 2 an upper head element 3 of a pumping motor generally designated 4, said pumping motor including, in addition to the upper head 3, a lower head 5, a cylinder 6 having a bore I, a piston 8 reciprocable in said cylinder, a piston rod 9, and a fluid distribution mechanism generally designated I9.

The motor cylinder 6 comprises a portion 6 within which the piston 8 is reciprocable during normal pumping operation, and an alined cylinder portion 6 which constitutes a dash-pot cylinder. A suitable automatic relief valve device II is associated with the dash-pot cylinder and is efiective during normal operation of the pumping motor to preclude the building up of a material back pressure against the motor piston upon its upward movement, but effective to prevent discharge of air from above the motor piston without throttling or to interrupt its discharge as may be preferred, in the event that upward motor piston movement at above a predetermined desired maximum rate takes place. Obviously by providing a long enough pump cylinder in the well it is possible to permit the piston rod 9 to impart to the pump plunger (not shown) pumping strokes of considerable length during normal pumping operation and to move further upward the pump plunger, without damage should a pump packing break, far enough for a cushioning and bringing to rest of the motor piston 8.

' I5 in which there are formed a fluid supply space IS, a fluid exhaust space H, and an intermediate space I8 connected through a port I9 with the lower end of the cylinder bore '1. Fluid may be supplied, desirably, to the space It, as through a connection 26, at a pressure of say two hundred to three hundred pounds per square inch, and fluid may be exhausted by way of a connection 2i from the exhaust space I! against a substantially constantly maintained back pressure of per.- haps fifty to one hundred pounds per square inch, depending upon the depth of the well and other factors. A suitable bore 23 is formed within the projecting portion I 5 of the lower head 5 and receives the liner and valve-chamber-forming member 24. An upper head 25, engaging the in position by suitable tension elements 26 holding the head 25 in position. A lower head element 2'! is secured in position to close the lower end of the bore 23 and has a projecting portion of reduced diameter 28 which fits into and closes the lower end of the bore of the element 24. Element 24 has a stepped bore formed therein, the lower longer portion of which is designated 30 and the upper, shorter and larger portion of which is designated 3I. A clearance at 32 around the lower end of the member 24 and a passage 33 formed in the member 2! provide a continuous communication between the space I! and the lower end of the smaller bore 30. The larger upper bore 3I is provided with means for connecting it with the bore 1 of the cylinder 6, as will shortly be described. A distributing valve 35 is reciprocable within the bore'of the member 24 and has an upper relatively short larger head 36 fitting the bore 3| and reciprocable therein, an intermediate head 3'! spaced by a reduced portion 38 from the head 36, and a lower head 39 spaced by a fluid supply groove 40 from the head 37, heads 31 and 39 fitting the bore 30.

From a point 40 uncovered by'the lower end of the upwardly moving piston 8 adjacent the end of the desired up-stroke of the latter there extends a connection 4| downward to the upper head element 25 of the distributing valve mech anism. -Within this head 25 there is provided, as it were, a check valve mechanism 32 comprising a ported valve element 43 which is adapted, when in seated position, to prevent flow in either direction between the space above the head 36 in the bore 3I and the cylinder bore. The valve 43 is spring-seated as at M and has a projecting stem 45 which is engageable by the upper end surface of the head 36, when the distributing valve 35 is in its top-most position, so that the valve 43 is then unseated and permits communication between the space within the cylinder 1 and the space within the bore 3| above the valve head 36. When, however, the distributing valve is in the position shown in Figs. 2 and 3, the valve 43 is seated and flow can take place neither from the cylinder to the space within the bore 3! past the valve 43, nor in the opposite direction, as the spring 44 is of such strength as to prevent any normal pressure occurring within the space 3| unseating the valve 43.

Another point in the motor cylinder 6, this time a point designated 50, so located that the upper end of the piston 8 will pass below it adjacent the lower desired limit of the piston travel, is also connectible with the space within the bore 3| under certain conditions as hereinafter described. The connections include tubing 5|, a space 52 within a novel mechanism 53, hereinafter more fully described, tubing 54, and a valve-seat-providing tubular element 55 secured centrally in the head 25. Member 55 provides a valve seat 55 and the head of the distributing valve carries a resiliently mounted valve element 5'! which in the upper position of the distributing valve cooperates withthe seat 56:and prevents flow in either direction between the space within the bore 3| and the point of communication with the cylinder bore I. No pressure normally present in the cylinder bore 1 can unseat the valve 51 when the distributing valve is in its upper position. When, however, the distributing valve is moved to a position to move the valve 51 from engagement with seat 56 free communication between the bore of cylinder 6, at point 50 therein, and the bore 3! is established.

The mode of operation of the apparatus so far described will be readily apparent. Let us assume that the parts are all in the positionv illustrated in Figs. 2 and 3. It will be evident that the motor piston 8 has not yet in its downward travel uncovered the point 5!] for a Sllfficiently long period at least for the fluid to pass from the space within-the bore 3! above the valve head 35 and allow the constant back pres sure acting upon the lower end of the head 39 of the distributing valve to raise the latter. It

will, of course, be understoodthat at the instant represented by the position of the parts in Figs. 2 and 3 there prevails in the space within the bore 3| above the head 36 approximately the same pressure as is acting on the lower end of the head 39. Now when the motor piston 8 has its upper end pass below the connection point 50 the fluid within the bore 3! above the head 35 of the distributing valve will pass through the connections 54, 52 and 5| into the portion of the motor cylinder above the motor piston, a. portion in which substantially atmospheric pressure prevails by reason of the presence of the relief-valve device H. As soon as the pressure above thehead 36 is released, the pressure acting on the lower head 39 will raise the distributing valve, and the groove 40 in the latter will connect the space !6 and the port 19, and motive fluid willbe supplied beneath the motor piston 8 to raise the latter. When the motor piston 8 starts upward its lower end will pass above the connection point 50, but nothing will happen as the valve 51 will then be engaged with the seat and prevent any flow of fluid at cylinder pressure through connections 5|, 52 and 54 into the distributing valve chamber. The motor piston will then continue to rise until it passes above the connection point 43, at which time fluid will pass through the element 41 and pass the then unseated valve 43 to act upon the upper head of the distributing valve and force the latter downward. The pressure passing the valve 43 will merely start the distributing valve, and

the complete throwing and holding of the distributing valve will be effected by the pressure which will flow through the valve'seat 55, through the connections 53, 5|, 52 and 54, as soon as the valve 51 is unseated. As the upper end of the motor piston, on the downward travel of Y the latter, moves below the connection point 40, there will be no escape of fluid from the space above the distributing valve piston 36 because the valve 43 will then be seated and the distributing valve will remain in the position shown in Figs. 2 and 3 until the upper end of the piston 8 passes below the connection point 50, at which time upward movement of the distributing valve to a position for readmission of fluid to the motor cylinder will take place as above described. This mode of operation will be carried on continuously as long as no derangement takes place and fluid is supplied continuously to the distributing valve mechanism and an appropriate back pressure is maintained.

Now let us consider whatwould occur if the pump plunger packing blew out, or if the rod linebroke during the up-stroke of the motor piston 8, which is obviously the time when such a breakage would occur, if it occurred. It will be understood, of course, that pumps of this character may work for many months without any difiiculty whatever, but ultimately, due to certain peculiarities of the phenomena which attend pumping,,rod lines are likely to break; and now we shall consider what will take place when breakage occurs. freed of a substantial part of its load. The pressure acting beneath the motor piston, which is calculated to provide for the desired speed of upward motion of the motor piston under full load, will obviously be much in excess of that necessary to raise the piston under the reduced load condition. The motor piston 8 will therefore move up at a much accelerated rate and will pass its normal upward limit of travel, notwithstanding the fact that the conditions for a relief of the working fluid beneath it will be produced as soon as the upward movement of The motor piston 8 will be the piston carries it above the connection point then again move up under the admission of line fluid effected by the reversal of the position of the distributing'valve as the motor piston gets to bottom positionj Obviously the speed of upward movement will be undesirably rapid, and if the cushion pressure built up is very high the downward speed of the movement may be .too,

rapid, and damage would be likely to result very shortly.

To prevent this possibility of further damage, I have provided improved means for interrupting the operation of the distributing valve 35 and preventing movement of the latter out of exhaust establishing position, as soon as the abnormal operation of the motor 4 begins to take place. previously described and certain connections which I shall now explain. An additional connection point with the cylinder bore will be provided at such a point that it will be uncovered by the lower end of the upwardly moving piston 8 only when the latter makes such an extended up-stroke, as will occur in the event of a This mechanism includes the device 53' breakage of the sucker rod line or the blowing out of one of the packings on the pump plunger.

This connection point 68 will be connected by a suitable tube 59 with a space 62, the supply of fluid to which will render the automatic shut down device 53 effective. Now considering the structure of the shut down device 53, it will be observed that a valve casing 64 is provided with alined bores 55 and 66, of which the latter is somewhat the larger. propriate seat 6'! is formed at the junction of the bores 65 and 66. The connection enters the bore 65 near the upper end of the latter and the connection 5 5 communicates with the bore 65 at a point somewhat below the point of communication of the connection 5! with the bore 65. These points of communication are respectively designated herein 68 and 69. 'A valve element H3 is reciprocably mounted in the bores 65 and 66 and comprises a lower head H fitting the bore 65 and a larger head i2 fitting the bore 56, a conical portion 73 adapted to cooperate with the seat iil, and a reduced portion 74 surrounded by a groove-like space '55 for purposes later explained. Within the bore 65 there is arranged a lower head l? of a manually operable plunger.

element E8 whose stem portion 79 extends through an opening 80 in the upper head 8! which closes the top of the bore 66, A manual pressure applying portion 82 is secured to the stem 79. A spring 84 is arranged between the enlarged portion 12 of the valve element Ill and the head l1. A latch device'86 is movable between positions shown respectively in Figs. 4 and 5 and has a head 81 adapted, in the position of Fig. 4;, to hold the head Tl in such a position that the spring 84 will hold the valve 70 in the position shown, notwithstanding the pressure which may act upon the lower end H thereof. A piston 88 reciprocable in a bore 39 formed in the member 64 is movable upon the supply of 7, pressure through the connection 6! to withdraw the latch 8? and release the plunger element 78 for upward movement, thereby relieving the valve ii! of the holding pressure exerted by the spring 84. It may be noted that the connection 5| communicates at 90 with the space 62 formed within the cylinder bore 89, to the inside of the piston 88. A connection 9| leading from the live pressure space 56 in the valve chest opens into the bore 55 below the piston ll. This type of fluid supply to the space beneath the piston 1| of the valve 70 is particularly desirable, althoughnot necessary, .as it is sufficient merely to insure the availability of some pressure which shall make certain the maintaining of the valve nection even with the back pressure line of the pump, having in mind the larger size of the head 35 of the distributing valve, would of course provide a sufficient pressure, but be less instantaneous in operation. 7

Now the mode of operation of this apparatus will be very readily followed from what has been said. In the normal position of the controlling device 53, the parts will be as shown in Fig. 4; the valve element it in its lower position with the portion 13 thereof seated on the seat 61 and with the annular space 75 surrounding the reduced portion M of the valve Til establishing communication between the ports 68 and 69, and with the head 'li preventing the flow of live pres sure through the connection 9|. Now let us imagine that the rod line breaks and that the motor piston moving rapidly upward in an ex- A conical or other ap 8? and free the plunger 78 for upward movement,

with the result that the compression of the spring 84 will be released. Of course the dis tributing valve 35 will have already, in all probability been moved to exhaust effecting position and so will merely need to be held there. If, however, it had not yet moved to exhaust establishing position, it would be so moved as a result of what occurs when'the shoulder "H is unlatched. Obviously the live pressure acting upon the lower end of the piston 1! will immediately move the valve 10 up to a position where the-head ll will seal port 68 and will uncover the port-69. The live fluid from the space l6 will immediately then pass through connection a position shown in Fig.4. Fig. 5 shows the parts in the position they assume after the upwardly moving piston has uncovered the connection point 60.

When the necessary repairs have been made, the operator will apply pressure to the portion 82, force the plunger 18 downward, will move the latch 87 in, to hold the sition shown in Fig, 4; and will have been moved down to its position shown in Fig. 4, will there be maintained, and the operation of the motor can then be recommenced in a normal manner. a

It will be evident from the description which I have given that I have provided an improved and very eifective apparatus for interrupting the operation of a pumping motor when a certain derangement thereof takes place, such as the breaking of the connection between the motor piston and its load. It will be noted that the motor is automatically shut down on the very first stroke thereof by permanently connecting the working space thereof with the exhaust. It will be observed that the apparatus may be very readily'reset when desired; and that it is made absolutely efiective by reason of the abundant pressure differential provided for bringing about its op eration. It will be noted that it is simple, comprises no parts capable of derangement under any normal conditions, that if the spring 84 were to break, the device would shut down, and that accordingly the only rupturable element present could not make the deviceinefiective should an emergency arise even were it to break.

While in the accompanying drawing I have disclosed and in the foregoing specification de-' scribed one species which my invention may assume in practice, it will be understood that the same may be modified and incorporated in various other embodiments without departing from collar 11 in the pothe spirit of the invention or the'scope of the apthe valve 10, which tributing functions, and means operable automatically upon a predetermined derangement of said motor to remove the control of said distributing valve from said first mentioned means and maintain said valve in exhaust-conditionestablishing position.

2. In combination, a single-acting motor having a piston and a. distributing valve which controls the motor exhaust, valve holding means rendered inoperative during normal operation of said motor, and means operative automatically upon overtravel. of the motor piston in a working direction to release said valve holding means and to effect a holding of said distributing valve in exhaust-establishing position.

3. In combination, a motor having a piston and a fluid-actuated distributing valve which controls the motor exhaust, and means operative automatically on overtravel of the motor piston and governed by the movement of the latter beyond its normal limit of travel to release a supply of pressure fluid to maintain said fluid-actuated valve in exhaust-establishing position.

4. In combination, a motor having a cylinder containing a piston and afluid-actuated distributing valve, and means including a connection-with the motor cylinder at a place beyond the normal travel of said motor piston and pressure fluid actuated devices supplied with pressure upon the uncovering of said connection for interrupting the operation of said distributing valve on overtravel of said motor piston.

5. In combination, a motor having a motor cylinder containing a piston and a fluid-actuated distributing valve, and means including a connection with the mot-or cylinder at a place beyond the normal travel of said motor piston but within the potential travel thereof and means including an element supplied with cylinder pressure upon the passage of the motor piston beyond such place for interrupting the operation of said distributing valve upon predetermined overtravel of said motor piston.

6. In combination, a motor including a piston and a fluid-actuated distributing valve, said fluidactuated distributing valve having a throwing connection leading thereto and a plurality of sources of supply for said throwing connection, one normally operative and the other rendered operative automatically in the event of overtravel of said piston.

'7. In combination, a motor having a cylinder and a piston recip-rocable therein and distributing valve means of the fluid-actuated type which controls the motor exhaust, and means operable automatically upon overtravel of said motor piston, by cylinder pressure, for causing said distributing valve meansv to be held in exhaustestablishing position by line pressure.

8. A single-acting motor comprising a cylinder, a piston reciprocable therein, and distributing means, and means operable by sup-ply pressure and controlled by cylinder pressure admitted upon overtravel of said motor piston for precluding readmission of motive fluid to said motor cylinder, automatically, after a predetermined overtravel of the motor piston takes place.

9. In combination, a motor having a distributing valve, valve holding means normally rendered inoperative, and means operable upon loss of load by said motor for releasing said valve holding means for automatically holding said distributing valve in' a predetermined position.

10. In combination, a motor having a distributing valve, valve holding means normally rendered inoperative, and means automatically operable upon loss of load by said motor for releasing said valve holding means for automatically holding said distributing valve in one of its extremes of position.

11. In combination, a motor having a distributing valve, valve holding means normally rendered inoperative, and means operable automatically upon loss of load by said motor for releasing said valve holding means for holding said distributing valve in a position to shut down said motor.

12. In combination, a motor having a distributing valve, and means operable upon loss of load by said motor for automatically establishing a pressure fluid force efiective to hold said distributing valve in a position to shut down the motor.

13. In combination, a valve casing having supply and delivery connections between its ends and a further supply connection at one end, and valve means operative in one position to effect connection of said two connections first enumerated and in another position to effect connection of said delivery and third connections,

vmeans for latching said valve in said first named position, and means operative on abnormal operation of a device for which said valve constitutes a control, for releasing said latching means.

14. In combination, a motor having a cylinder, a piston, and an automatically actuated distributing valve, means operative on fluid supply thereto to transfer the control of said valve from its normal automatic control and to move said valve into and to maintain said valve in a position to interrupt motor operation, and controlling means for said first mentioned means having means whereby it may be set manually for.

operation and controllable by motor piston movement.

15. In combination, a motor having a cylinder, a piston, and a fluid actuated distributing valve having a cylinder-connected throwing passage, a source of throwing pressure independent of said cylinder, and automatic means responsive to pressure transmitted thereto upon overtravel of said piston for switching the connection of said throwing passage from said cylinder to said independent source.

16. In combination, a motor having a cylinder, a piston, and a fluid actuated distributing valve having a cylinder-connected throwing passage, a source of throwing pressure independent of said cylinder, and automatic means responsive to pressure transmitted thereto upon overtravel of said piston for switching the connection of said throwing passage from said cylinder to said independent source, said automatic means having resettable control means for normally holding it in a position to maintain said throwing passage connected with said cylinder.

WADE H. WINEMAN.

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