US2265099A - Apparatus for timing well pumps and the like - Google Patents

Description

A 2, 1941- R. L. CHENAULT 2,265,099

APPARATUS FOR TIMING WELL PUMPS AND THE LIKE Filed Dec. 20, 1938 4 Sheets-$heet 1 Q PW V I w WCLRQZZZQ Dew 1941- r R. 1.. CHENAULT ,0

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R. L. CHENAULT APPARATUS FOR TIMING WELL PUMPS AND THE LIKE Filed Dec. 20, 19:58

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ets-Sheet 4 Roy m4, Q wv Patented Dec. 2, 1941 Roy L. Chenault, Penn Township, Allegheny County, Pa., asslgnor to Gulf Research a Development Company, Pittsburgh, Pa., a corporation of Delaware Application December 20, 1938, Serial No. 246,895

12 Claims.

This invention relates to apparatus for timing well pumps and the like; and it comprises a fluid pressure motor, a valve for admitting and discharging fluid pressure to said motor to operate the same, a timing device adapted for operation by said motor, said timing device advantageously comprising a closed, circulatory liquid system provided with differential pressure controlled.

valves arranged to regulate the flow of liquid and with means for creating a substantial differential pressure at points in the system for operation of the valves, and a second. valve operated by a said timing device, said second valve controlling paratus or in timed relation to the happening of a related event is quite usual and numerous devices and methods have been created for accomplishing such operation.

In some instances, it is necessary to use an outside source of power to operate the timing device. This may be a spring wound clock, or a source of fluid pressure such as a gas under pressure or a liquid head.

The present invention is directed particularly to the timing of oil well pumps where use is made of a fluid (gas) under pressure for operating the timing device. Such gas is nearly always available on location in connection with the operation of oil wells and it may be gas produced by the well and under substantial or partial well pressure or it may be well gas artificially compressed as by a pump, or it may be simply compressed air.

The difficulty in using this available compressed gas or air for operation of well pump timing devices is due to the frequent fluctuation in pressure of the gas which'prevents operation of the timing mechanism with a motion constant enough to give satisfactory timing. Heretofore, pressure regulating devices have been used in combination with timing devices for obtaining constant motion, but these regulating devices necessitate operation of the timing mechanism at reduced gas pressures and have not proved satisfactory because of the precipitation of moisture in the regulating device. Precipitation of moisture is especially disadvantageous in cold weather valve, but even in warm weather the water that collects, seriously interferes with satisfactory operation of the valve.

In the present invention, a timing device is provided which will operate efiiciently at the fluctuating gas pressures normally encountered in the sources of compressed gas available around oil well pumping installations and it is an achieved object of the present invention to provide such a timing device that will operate without the use of pressure regulating devices. Other achieved objects of the present invention are: the provision of well timing apparatus operated by fluid pressure but throttled or regulated by means 01' a substantially non-compressible liquid such as oil maintained under controlled circulation in a closed system. Circulation of the oil is definitely controlled, without regard to the pressure of the fluid used to circulate it, by means of manually or automatically variable orifices, which create substantial differences in pressure at points in the system, and automatic diiierential pressure operated valves; and the provision of a fluid pressure actuated timing device operable as a unit, separate and apart from the well pumping apparatus, but which at the same time lends itself readily for operation in connection with such apparatus to control the apparatus in accordance with a given period of time or in synchronism with the delivery of definite quantities oi oil by the pump, or in other relations.

Still other achieved objects and advantages of the invention will be apparent from the following detailed description and accompanying drawings in which,

Fig. 1 is a diagrammatic plan view of the timer showing one arrangement of the same connected for operation of oil well pumping apparatus,

Fig.'2 is a detail sectional view of the timing device, 1

Fig. 3 is a diagrammatic plan view of another arrangement for connecting the timer for operation of oil well pumping apparatus,

Fig. 4 is a detail view, partly in section, of a modification of the timer valve actuating mechanism,

Fig. 5 is a detail view illustrating diagrammatically one arrangement for thermostatically controlling a variable orifice-valve oi the timer, and

Fig. 6 is a detail view of an arrangement for securing pressure control of such orifice.

Referring to the drawings in which like numerals indicate corresponding parts throughout because of the ice that forms in the reducing the several views, the numeral i designates an oil well casing provided with a suitably valved vent,pipe 2 and inner concentric strings'of tubing 3 for delivering pressure fluid such as complacement chamber and its displacement from the chamber through pipe 4 to the top of the well by admission of compressed gas into the chamber. The apparatus commonly used to reciprocate pipe 4 consists of a cylinder 5 and a piston 3 connected to the upper end of the pipe by means of piston rod 1. Gas under pressure is applied through a pipe 8 to the cylinder beneath the piston and moves the piston up, lifting pipe 4 with it. The piston and pipe are returned to their lowermost position by gravity upon release of the gas pressure in the cylinder to atmosphere or to storage.

For a further and detailed description of the well pumping apparatus illustrated only in part here, reference is made to my prior Patent No. 1,890,720, dated December 13, 1932; it being sumcient for the present purpose to state that such apparatus operates on the intermittent gas lift or slugger principle and that alternate slugs of oil and gas are delivered to the top of the well in periodic succession. It is the reciprocation of pipe 4 which must be timed in the operation of pumping apparatus of this type and the timing is largely dependent on the conditions prevailing at a particular well. For instance, the displacement chamber in the well may fill with oil quickly, due to its being submerged in a pool of through rod l2.

cylinder to alternately connect the pipes l5 and IS with fluid pressure from pipe I8, as the piston moves from one to the other of its two operating positions. Accordingly, the heads or ends of the valve piston are proportioned to alternately connect pipes l5 and I8 with ports 28 and 28 which discharge to the atmosphere or to a storage tank of reduced pressure.

Movement of power piston II is definitely controlled regardless of the fluid pressure applied to move it, by means of the timing mechanism III. This mechanism, as stated above, consists of a cylinder H in which a piston I3 is reciprocated by means of its connection with piston The ends of cylinder H are connected by means of by- pass pipes 38 and 3| and the entire system is filled with oil so that any movement of piston! in the cylinder displaces the oil ahead of it through one or the other of pipes and 3| to the space in the cylinder behind the piston. A ball check valve 32 in pipe 30 limits the direction of movement of the oil in this pipe from the left to the right hand end of the cylinder while ball check valve 33 limits movement of the oil in pipe 3| in the reverse direction.

The quantity of oil passing through these pipesper unit of time is controlled by differential presoil in the oil formation and relatively speaking,

when this occurs, it may be desirable to time the pump so as to give a constant load of oil in the tubing. This gives a constant discharge of oil at the top of the well and prevents over-loading of the apparatus. Then again, the displacement chamber may fill with oil slowly and it is necessary that the reciprocation of pipe 4 be timed to permit this to occur.

The present apparatus for timing the operation of the pump consists of a lower cylinder 3 and a closed circulatory liquid timing system designated generally by the numeral III. A piston. N (Fig. 2) in the power cylinder is connected by means of a piston rod 2 to a second piston l3 in cylinder H of the timing mechanism. Fluid pressure is admitted to and released from the power cylinder at the ends of the cylinder through pipes l5 and I6 respectively, which communicate with a piston type slide valv adapted to be connected to a source of compressed gas through pipe l8. The slide valve consists of a cylinder l9 in which. reciprocates a dumb-bell or spool type piston 20. Valve H is adapted to be operated by means of valve'rod 2| connected at its other end to a fluid pressur responsive device consisting of a cylinder 22 and piston 23. A pipe 24 communicates with one end of cylinder 22 for delivery of fluid pressure to move piston 23 in one direction and a coil spring 25 surrounding the valve rod and positioned between theouter end of cylinder l3 and a collar 26 on the valve rod, forces the piston in the other direction on release of the fluid pressure from the cylinder. I

Reduced portion 21 of piston 20 of the valve is arranged with respect to the location of the connections of pipes l5, l6 and It with the valve sure operated valves 34 and 35, respectively. As shown, these valves consist of diaphragm chain bers 36 in which are mounted diaphragms 31. Valve stems 38 connected to the central portions of the diaphragms are adapted to engage with valve seats 39 when fluid pressure is applied to the diaphragms as by means of pipe 40 (to valve 34 and pipe 4| to valve 35) Valve springs 42 in the body of the valves engage with the casing at one end and with pins 43 at the other end and exert a slight pressure on the diaphragm to lift the stems from their seats and normally maintain the valves open. A pressure differential for operating the valves is created in the system by means of orifice members 44 and 45 located respectively in pipes 3|! and 3| between the valve 34 and the connection of pipe 40 with pipe 30 and valve 35 and the connection of pipe 4| with pipe 3|. Returning to the structure of valves 34 and 35, diaphragm chambers 36 are supported on the body oi the valve by means of tubular shaped casing members 46 which surround the valve stems and springs. Perforations 41 in the body of the valve on the pressure side of the seat and perforations 48 in the bottom of the diaphragm chambers allow entry of oil from the system into the diaphragm chambers to exert back pressure on the diaphragms. This back pressure also tends to open the valves, and, as

. will be readily seen, the valves are balanced in any one position when the differential pressure across the orifice times the diaphragm area equals the tension on the valve springs.

The entire timing system is maintained filled with oil by means of reservoirs 49 and 50 con-- nected through pipes 5| and 52 respectively with pipes 30 and 3| respectively, as shown. The feed of oil from these reservoirs to replenish the system with oil that has been lost through leakage or otherwise, may be by gravity. The reservoirs also provide for expansion and contraction of the oil due to changes in temperature.

Movement of timed piston rod |2 to either of its extreme positions activates 'a pilot piston slide valve 53. This is accomplished by means of a collar 54 secured to rod l2 and adapted to engage with shoulders 55 and 56 of pilot valve shifter 51. The pilot valve shifter ls-simply a yoke shaped member attached to the piston rod of the valve. As shown, movement of the pilot valve is not continuous with the movement of rod i2 but occurs only when the rod approaches its extreme positions. The pilot valve alternately connects pipe 24 with a source of fluid pressure through port 56 or with the atmosphere as by means of port 66.

Referring more specifically to Fig. l, where there is illustrated one method of operating well pumping apparatus by means of the timing device, pipes 6 and 24 are joined together as at 60 so that fluid pressure is simultaneously delivered to the pump lifting cylinder 6 and to the cylinder 22 for operation of slide valve l1. The fluid pressure in cylinder 5 will then lift well tube 4 and hold it in raised position until pilot valve 56 is shifted again by the timing mechanism. In this method of operation, fluid pressure for actuating the timer and for operating the well pump is obtained from the well along with the oil pumped and delivered to a combined oil and gas separator and storage tank 62. Oil and gas enter the tank near the top through pipe 63 which is flexibly connected to the pump delivery pipe 4, as shown. In the tank, the oil separates from the gas and may be continuously bled away by means of valve 54 in the bottom of the tank. The gas which separates from the oil may be maintained under suitable pressure in the tank so that the well can be operated under back pressure. The amount of this back pressure is determined primarily by the conditions sur-' rounding the delivery of oil and may vary from a few pounds to many pounds per square inch. Its object is to prevent emulsiflcation of the oil due to a sudden release of pressure and also to provide for a more uniform and smooth operation of the pumping apparatus. Gas collecting in the tank is continuously withdrawn through pipe 65 by compressor 66 and most of it is recycled down the well through pipe 61 and well tubing 3.

A small portion of this gas, however, is used to operate the timing mechanism and lift pipe 4 to shift the valves of the pumping apparatus.

on the pressure drop across the orifice and this will be constant for a constant rate of flow.

Since the regulating valve is adjusted automatically by differential pressure only, the absolute value of the liquid or oil pressure which varies with the varying pressure of the gas in power cylinder 6, is or little significance as long,v

' 66. Pump piston 6 and well pipe 4 will then fall Suitable connections for accomplishing this result are made through a pipe 66 communicating with pipe l8 of the timer piston valve and port 58 of the pilot valve.

A cycle of operation of the arrangement above described and illustrated in Figs. 1 and 2 is sub'- stantially as follows:

With parts in the positions shown, fluid-pressure is conducted from the compressor 66 to the righthand end of power cylinder 9 driving piston II and connecting rod l2 to the left. Piston l3 in the timer i0 is thus forced to the left displacing oil from the left side to the right side of the piston through pipe 30, orifice 44, valve 34 and check valve 32. When there is no flow through this circuit, valve spring 42 holds the valve in wide open position, but when the fiow starts, the differential pressure across the orifice is applied to the upper side of diaphragm 31 opposing the force of the spring and tending to close the valve. Valve stem 36 is thus forced downward toward seat 36, reducing the flow of oil through the valve and orifice. on the lower side of the diaphragm and when this pressure, plus the force of the spring, equals the oil pressure on top of the diaphragm, the valve will be in a balanced partially closed position. The amount of valve opening will depend Oil pressure immediately increases by gravity to their lowermost position and spring 25 will force piston valve rod 2| and pistons 26 and 23 to the left, thus admitting fluid pressure from the compressor 66 to the left end of power cylinder 6. Piston II is then caused to be moved to the right-hand end of the cylinder and accordingly oil in the timing device I6 is displaced from the right end of cylinder l4 through bypass pipe 3! orifice 45, pressure differential valve and check valve 33 to the left end of the timer. Speed control ofpiston l3 from the right to the left-hand end of the cylinder by means of valve 34 and orifice 44 operates on the same principle as its movement from the left to the right Just described.

As timer piston l3 approaches the right-hand end of its stroke collar 54 engages with shoulder 56 of the valve shifter and moves the valve to the right to again connect cylinders 5 and 22 through pipes 24 and 8 with fluid pressure from the compressor 66 through pipe 68 and port 56. Thus, pump power piston 6 and well pipe 4 are again raised and valve l1 shifted tothe right to begin another cycle of operation.

Another arrangement for operating well pumping apparatus with the timer, is shown in Fig. 3. In this arrangement, piston valve I! is caused to be actuated directly by the raising and lowering of well tube 4. A conical surfaced cam 66 engages a. follower I6 attached to the valve stem for forcing the valve to the right, while a coil spring II, acting on an extended portion of the valve stem, forces the valve to the left.

Pilot valve 53, in this showing, is arranged to be moved to the right by means of a differential pressure operated diaphragm mechanism I2. This latter mechanism is disposed for operation across an orifice opening 13 in well delivery pipe 4. Attached to the diaphragm of the mechanism is a push rod I4 adapted to engage the piston of pilot valve 53 to move the valve to the right. Coil spring 15 on the push rod returns the rod to its left position in the absence of sufiicient differential pressure across the diaphragm. The piston of pilot valve 53 is moved to the left by means of push rod 16, which, in this instance, is simply an extension of the timer and power piston rod l2. Thus the pilot valve in this case is essentially a floating valve in that it is alternately pushed toits two positions and left there.

The fluid pressure connections for operation of the well pump andtimer are essentially the same as in Fig. l with the exception that operation of piston valve I1 is by means of cam 66 and spring H rather than by the individual fluid pressure operated motor 22 and spring 25 used in the device illustrated in Figs. 1 and 2. Pipe 61, as in Fig. l, is connected to a gas or air compressor not shown. Since the timer and pumping apparatus careful adjustment of the speed of the timer piston I! in its two different directions of travel.

With the parts in the position shown in Fig. 3, the operation of the device is substantially as follows:

Fluid pressure from pipe 81 is delivered by -means of valve 53 to pump power cylinder beneath piston 6 to move it to the top of the cylinder. This releases cam 89 from follower 10 and allows spring 'I I to shift piston valve II to the left. Fluid pressure is thus conducted from pipe 61 through pipes 60 and I8, valve l1 and pipe I! to the left end of the timer power cylinder and moves the power piston II and timer piston I; to the right-hand ends of their respective cylinders and relieves push rod 16 from the end of the piston rod of the piston in the pilot valve 53. Assume at this 'time that a slug of oil has just been delivered to the top of the well, and the tail end of the slug is passing through orifice ll in delivery pipe 4, a substantial difference in pressure is thus created across the orifice due to the sudden increase in velocity of the oil at this time and this difference in pressure is sufiicient to force the diaphragm in mechanism 12 to the right. When this occurs, push rod H connected to the diaphragm moves the piston in pilot valve 53 to the right. In this position, the fluid pressure in cylinder 5 is exhausted through pipe 8, pilot valve 53 and exhaust port 59 to the atmosphere, and

piston 8, carrying cam 69 falls by gravity to the bottom of the cylinder. Cam 69, engaging follower 10, moves the piston of valve II to the right again. This movement of valve i1 causes fluid pressure from pipe 61 to pass into the right-hand end of cylinder 9 by way of pipes 68, ll, valve I1 and pipe l8. Movement of power piston H to the left end of th cylinder is definitely timed as above explained by the adjustment of the variable orifice 11 in by-pass 30 of the liquid timing mechanism. It is to be noted here that the stroke of piston I3 is considerably greater than the stroke of the piston in the pilot valve so that actuation of the pilot valve piston to move it to the left end of its cylinder does not occur until the timer piston closely approaches the left end of its stroke. Also that immediately the tail end of the slug of oil above referred to' passes entirely through orifice 13, there is adecided drop in pressure differential and spring 15 forces the push rod away fromcontact with the pilot valve piston and returns the diaphragm in mechanism 12 to its left-hand position ready to be acted upon by another slug of oil.

This timed movement of the pilot valve to the left end of its cylinder definitely times the pumping of a fresh slug of oil into well tube 4 for delivery to the top of the well in accordance with the ejection of a slug of oil through the orifice 13. By this means, a constant load of oil in the well tubing 4 may be maintained and overloading of the pumping apparatus prevented.

Other arrangements for connecting the timing mechanism for operation of the pilot valve may be desirable in particular instances. One such arrangement is shown in detail in Fig. 4. Referring to this figure, rod 19 may be an extension of timer piston rod I! on the opposite side of the piston from rod l2, and as shown may be adapted for sliding engagement in a tube or sleeve member connected to the pilot valve -matically instead of manually as shown in Fig. 3.

This may be accomplished in many ways, depending upon the method of control most adapted to the requirements. Figs. 5 and 6 show two methods for thus automatically controlling the size of the opening or orifice in these choke members. In Fig. 5 is shown a thermostat 83 arranged to control the orifice opening in accordance with temperature variations. As shown, the thermostatis made to operate a rheostat 84 in series with a source of electricity such as battery 85 and a solenoid motor 88 attached to the valve. As the temperature increases or decreases, more or less electrical resistance is thrown into the circuit to increase or decrease the electric current to the solenoid thuscausing opening or closing of the valve. The thermostat could also be arranged to operate the valve mechanically as will be readily apparent to one skilled in the art.

ticularly adapted for controlling the operation of oil well pumps, it is also useful to control the operation of such devices as are driven by compressed gases, or by liquids under pressure. The timing mechanism may find particular usefulness in controlling the operation of coal stokers and other feeding devices such as the feeding of fuel oil to burners and the feeding of chemicals. As will be readily appreciated, the source of power for driving the timer is not necessarily limited to a gaseous fiuid under pressure but a liquid may be used with equally good results.

What I claim is:

1. Apparatus for timing the operation of oil well pumps and the like comprising a power developing mechanism adapted for operation by fluid under pressure, valve means for controlling admission and discharge of fluid pressure to said mechanism, a substantially closed circulatory liquid system, orifice means in said system for creating a substantial differential in pressure between parts of the system when the liquid is in circulation, valve means operated by the difference in pressure in said system created by said orifice-for controlling the circulation of liquid in the system, means connected for operation by said power developing mechanism for causing circulation of liquidin said system, and'means also connected for operation by said power mechanism for causing actuation of the valve means controlling admission and discharge of fluid pressure to said mechanism.

2. Timing mechanism comprising a pair of cylinders, pistons in each of said cylinders, a rod connecting said pistons for simultaneous movement thereof, a valve for admitting and discharging motive fluid to one of said cylinders to cause reciprocation of said pistons, a pair of bypass pipes connecting opposite ends of the other cylinder, a liquid in said other cylinder and in said by-pass pipes, check'valves in said pipes for directing the flow of liquid in opposite directions in the pipesalternately, from one end of the cylinder to the other upon reciprocation of said pistons, an orifice member and a diiferential pressure operated valve in each of said pipes, said valves being arranged for operation by the difference in pressure developed across said orifices during the flow of liquid through said pipes, said valves controlling the quantity of liquid passin through said pipes regardless of the pressure of the fiuid applied to move said pistons whereby the moving stream of liquid in the conduits for causing operation of the differential pressure conmovement of said pistons in either direction is timed.

'3. The combination with an oil well pump of the intermittent slugger type including a fluid pressure operated pump valve member adapted to be reciprocated to secure, alternately, admission of oil from the well to the pump and then admission of gaseous pressure fluid to the pump beneath the oil for lifting the oil in a succession of slugs to the top of the well, and an oil delivery pipe, of a timing device for securing timed reciprocation of said member, said timing device comprising a fluid pressure operated power developing mechanism, a valve for admitting and discharging fluid pressure to said mechanism to operate the same, a timing mechanism adapted for operation by said power developing mechanism, an orifice in said oil well delivery pipe, said orifice being adapted to create a substantial difference in pressure in the pipe upon passage of a slug of oil therethrough, differential pressure operated means connected across said orifice, a valve adapted upon reciprocation to control the flow of fluid pressure to said pump valve member for operation of the same and to control admission and discharge of fluid pressure to said power developing mechanism, and means whereby said valve is moved in one direction by the timing mechanism and in the other direction by said differential pressure operated mechanism.

4. A timing device comprising a cylinder, a

piston in the cylinder, a by-pass conduit connecting opposite ends of the cylinder, said cylinder and by-pass being filled with liquid, a diiferential pressure operated -valve in the bypass conduit and means in said conduit forcreating a difierential pressure in the liquid in the conduit for operation of the valve upon displacement of the liquid by the piston from one end of the cylinder through the conduit to the other end of the cylinder.

5. The apparatus of claim 4 wherein means is provided for adjustably controlling the flow of trolled valves upon displacement of the liquid by the piston from one end of the cylinder through one of the conduits to the other end of the cylinder.

7. The apparatus of claim 6 wherein means is provided for independently adjusting the flow of liquid through the conduits to provide for different lengths of time for the piston to move in one direction in the cylinder then in the opposite direction.

8. The apparatus of claim 6 wherein said means in the conduits for creating a differential pressure in the moving stream of liquid in the conduits is adjustable.

9. A hydraulically operated timing device comprising a cylinder, a piston in the cylinder, means for reciprocating the piston, a by-pass conduit connecting opposite ends of the cylinder, an orifice member in said by-pass adjacent one end of the cylinder, a check valve in the by-pass inder oppositethe end of the cylinder to which orifice members for independently adjusting the flow of liquid through said by-pass conduits to provide for different lengths of time for the pis-, ton to move from one end of the cylinder to the other.

10. The apparatus of claim 4 in which the cylinder and by-pass conduits are maintained full liquid through the conduit in addition to the automatic control of'flow oi liquid aflorded b said diflerential pressure operated valve. q 6. A timing device adapted for operation from a source 01' power of varying intensity comprising a cylinder, a piston in the cylinder, means connecting the piston with thesource 01 power for causing movement of the piston in the cylinder, a pair of by-pass conduits connecting opposite ends of the cylinder, said cylinder andsaid by-pass conduits being filled with liquid,

check valves and diflerential pressure controlled valves in said conduits, said check valves being arranged to limit the fiowot liquid in one conduit in a direction opposite to the flow of liquid in the other conduit, and means in said conduits for creating a diflerential pressure in the of liquid under pressure of liquid in a reservoir.

11. The apparatus of claim 6 in which the cylinder and by-pass conduits are maintained full of liquid under pressure of liquid in a reservoir.

12. In oil well pumping apparatus of the gas lift type including a tube for delivering oil from the bottom to the top of the well, a source of gaseous fluid pressure, a pump valve in said tube adapted in one position to admit oil in the well to said delivery tube and in another position to admit gaseous fluid under pressure from said source to said delivery tube for lifting the oil in the tube in slugs to the top of the well, and motor means for operating the pump valve, the improvement which comprises a member movable to different positions for controlling the operation of said motor means to move the pump valve from one position to the other, an intermittently operated timing device for controlling the movement of said member to one position,

means actuated by the pressure of a flowing slug

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