US2870717A

US2870717A - Pressure generating means for deep well pumps

Info

Publication number: US2870717A
Application number: US374004A
Authority: US
Inventors: John E Dube; Roger W Schoen
Original assignee: Alco Valve Co
Current assignee: Alco Valve Co
Priority date: 1953-08-13
Filing date: 1953-08-13
Publication date: 1959-01-27
Anticipated expiration: 1976-01-27

Description

Jan. 27, 1959 J. E. DUBE ET AL 2,870,717

PRESSURE GENEEATING MEANS PoE DEEP WELL PUMPS Filed Aug. 15, 195:5

KNEE /s PRESSURE GEERATING MEANS FOR DEEP WELL PUMPS John E. Dube, Chesterfield, Mo., and Roger W. Schoen,

Mineral Wells, Tex., assignors to Alco Valve Company,

The present-invention relates to the pressure generating components of deep well pump apparatus of the type wherein the'operatio'n -of a pump at the bottom of a well is caused by the controlling application of fluid pressure lin a column of power fluid leading down from the surface lto the pump. p

In suchfapparatuses there is a prime mover such as a gasoline or gas engine, a pump such as a vane pump which delivers primary oil under pressure, a hydraulic piston motor reciprocated by the primary oil pressure, and a hydraulic piston pump having a piston reciprocated infa hydraulic cylinder connected to the power oil tubing' leading to the bottom of the well and the pump thereat. Reciprocation of the piston produces the pressure in the power oil required to operate the pump. Sometimes `this pressure alternates high and low; other times, such asin the following explanation, a substantially constant pressure is maintained in the power oil tubing.

The so-called primary oil normally is circulated from the vane pump through a four-way valve alternately to the opposite ends of the power cylinder, whence it is exhausted back to the vane pump, in a closed system. The power oil tubing leads from a suitable supply tank at the surface through the power oil cylinder of the pump and down tothe bottom of the well. Finally, there is a production oil line to conduct production oil (combined with exhaust power oil) back up to the surface and into appropriate separators and storage tanks.

Heretofore there has been a problem in this type of pumping arising because of the generation of heat in the primary oil in the closed circulatory hydraulic motor system. Such oil tends to heat, and if it has any vaporizable fractions in it which do vaporize, a vapor lock can occur in the pumping system.

It is an object of the present invention to overcome the heating problem in the primary oil. It is a more specific object to overcome the heating problem by the use of cooling mediums that are immediately available at the point of use so as to minimize the expense of building and operating the heat exchange arrangement.

Specifically, it is an object of the present invention to arrange a heat exchange device in the primary oil system which has one pass to'receive the primary oil and another pass to receive some other cooling medium which is either the production lluid coming up from the well or is the power oil that is going down to the well. In the preferred construction, the cooling fluid is the production oil coming up from the well.

In the description to follow, reference will be made to deep well pumping of oil. It will be understood that the invention is applicable to other fluids than oil.

ln the drawings;

Figurel is a schematic view of the surface components of'an `oil well pump involving the present invention and wherein the cooling medium consists of the production oil being pumped;

ICC

Figure 2 is a similar view wherein the cooling oil is the power oil;

Figure 3 is a vertical sectional view through the heat exchange device showing the two passes therein; and

Figure 4 is a horizontal section through the heat eX- change device taken on the line 4-4 of Figure 3. .l

` Referring first to Figure l1, a cased oil well is indi` cated at 10. It is here shown with the well tubing 11 bringing the production oil up for delivery through a surface pipe 12. There is also a power oil pipe 13 leading to a hydraulically operated pump at the bottom of the well. l

The type of pump herein involved finds many different embodiments, but a typical embodiment is that shown in the MacDougall Patent No. 2,478,410, dated August 9,1949. Other types are operated by `a substantially constant pressure in the power oil line, and the pres ent description will be such a pump system.

The surface apparatus lincludes a prime mover 1S which is hereshown as a gas or gasoline engine. This motor operates a vane-type primary pump 16 which rotates to deliver liquid lunder pressure from an intake pipe 17 to an outlet pipe 18. The pipe 18 passes through a four-way valve 19, whence it branches by a pipe 20 or a pipe 21, the two pipes leading into opposite ends of a primary oil, hydraulic motor cylinder 22. The cylinder 22 contains a piston 23 on a piston rod 24. The piston rod passes through a packing gland and reciprocates in a power oil pump piston 25 ina power oil pumping cylinder 26. This power oil pump may be referred to as a secondary pump.

A piston rod 30 also projects oppositely from the piston 23,'outside the cylinder 22 and has a head 31 at its end.' This head operates trip mechanism 32 connected with a pilot valve 33 which is designed to reverse the four-way valve 19. Since the pilot valve is notpart of the present invention, it is not necessary to explain in greater detail the operation of the pilot valve and the four-way valve. A mechanism that may be used is that shown in the MacDougall patent. The head 31 operates the trip mechanism to reverse the pilot valve and cause reversal of the four-wayvalve, each time the pistons reach either end of their stroke.

In one position of the pilot valve 33, and hence of the four-way valve 19, the pressure fluid from the pump through the line 18 passes through the line 20 to the left side of the piston 23, driving the piston to the right, which is made possible because the line 21 is ported to exhaust by the four-way valve. In the other position of the pilot valve 33, and of the four-way valve 19, the high pressure fluid from the pump16 passes through the line 21 to the right side of the piston 23 while the line 20 is ported by the valve 19 to exhaust so that the piston then moves to the left.

It will be noted that the line 13 connects into the pumping cylinder 26 by two

pipes

36 and 37. These two pipes contain

check valves

38 and 39 that admit only outflowfrom the cylinder 26 into the line 13.

The cylinder 26 is also connected by two

pipes

40 and 41 to a pipe 42 that leads from a power oil supply tank 43. The two

branches

40 and 41 are controlled by

check valves

44 and 45 that admit flow only from the line 42 into the cylinder 26.

A heat exchanger 50 contains two separate fluid flow passages. It has an outer casing 51 having a top 52, a bottom 53, and a pair of

headers

54 and 55. A plu- -rality of tubes 56 connect through the two headers,

thereby connecting a top space 57 and a bottom space 58 and separating them-,from an intermediate space 59 surrounding the several tubes.

The pipe 12 enters thespace 59 which constitutes one pass of the heat exchanger, and a pipe 60 leads from the upper end of this pass 59. The pipe 60 leads to a Separator 61 from whence another'pipe 62 leads to an oil storage tank.

,There is ;a low pressureprimary oil pipe ,63 leading from the'fourlway valve r19 and 'entering the 'heat exchanger 50 at the top. It passes centrally d own through the heat exchanger' andrthen opens below a baie'64 vin the bottom space 58 of the 'heat exchanger. The baffle 64 ensures a spreading of the fluid. The iluid may then rise'through the tubes 56 to the top space 57, whence it may emit through the pipe 17 that constitutes the intake to the vane pump. The spaces 57 and 58 and lthe' interior of the tubes 56 constitute the other pass of the exchanger.

Operation In general, the operation of the prime mover 15 and the liquid pump 16 need hardly be described since they are Well lknown in the art. See the patent to MacDougall, No.72,47.8,4l0, dated August 9, 1949. Sufce it tosay at this point that the engine rotates the pump 16 and causes it to draw liquid through the .pipe 17 and discharge it under pressure through the pipe 18 tothe four-way valve 19. That valve is shifted by the pilot valve 33 which, in turn, -is shifted each time the piston 23 reaches an extreme of its stroke, all as described in the MacDougall patent. The shifting of the pilot valve 33 alternately causes the four-way valve 19 to `deliver high pressure oil from the pump 16 through the pipe Ztl, or to deliver such high pressure oil through the pipe 21 at the opposite side of the piston 23. Each time one of these two pipes and 21 is connected to high pressure, the other will be connected by the fourway valve 19 to the return line 63. u 1

The primary oil in each case returns from the fourway valve 19 to the pipe 63, whence it enters the heat exchanger Sil, flowing axially therethrough to below the baille 6ft. Spreading around the baffle, it rises through the tubes 56 and nally flows out the pipe 17 back to the pump 16 for recirculation to the four-way valve and hydraulic motor.

As shown, high pressure primary oil is being introduced from the four-way valve 19 through the line 20, and the piston 23 is moving to the right, approaching its` rightwardextreme, and causing corresponding movement of the pump piston 25 in the cylinder 26. Owing tothe presence of the

check valves

38 and 39, the rightward movement of the piston 25 in the cylinder 26 drives the oil through the line 37 past the check valve 39 into the power oil line or tube 13. Meanwhile, the check valve prevents the egress of ltheaforesaid oil back into the supply line 42. Appropriate relief means against excess pressure in the pipe 13 may be provided.

Rightward movement of the piston 25 also draws oil in from the supply line 42 past the check valve 44, and bythe pipe di) to the left side of the piston 25. During this, the check valve 38 prevents the drawing of oil from the pipe 13 to the left side of the piston.

Rightward movement of the two `pistons occurs in corresponding manner, upon shift of the

valves

33 and 19. In other words, the piston 25 constitutes a twoway pump which maintains substantially continuous pressure on the oil in the pipe 13. It will be vunderstood that a one-way alternate high pressure and low pressure pumping system may be used where that is the type of deep well pump involved. The present arrangement, however, is used where the deep well pump requires constant high pressure on the power oil.

The deep well pump within the well 10 brings oil up and discharges it through the pipe 12. From this pipe it enters the intermediate pass 59 of the heat exchanger. Being cold, it withdraws heat from the primary oil that is circulating through the tubes 56. The production oil leaves the heat exchanger by the pipe 60, thence moves throughua separator 61 from which i As illustrated in Figure 2,the cooling of the primary oil may also be obtained by passing the power oiliustead of the production oil through the heat exchanger. Figure 2 shows the prime mover 15 and the pump 16 as before. The pump delivers to the four-way reversing valve 19 just as before, and this valve controls -the llow to the hydraulicv piston motor cylinder 22, just asbefore. This motor operates the pump piston, not shown, but contained within the cylinder 26 just as before so .as to maintain substantially constant high pressure on tbe` power oil pipe 13. The production oil pipe 12 brings oil up and, in this case, delivers it directlyto the Separator.

'The heat -exchanger '50 is the same as before. However, the power oil pipe 142 delivers power oil into the intermediate pass of the heat exchanger, and it emits from that pass by the pipe and flows intothe op` posite end of the cylinder 26. In other words, in the present case the intermediate pass of the heat exchanger 50 has been interposed into the pipe leading from lthe -power oil supply tank to theoppositeends of the pump cylinder 26. The other pass of the heat exchanger receives primary oil from the pipe 63, that is the exhaust side of the four-way valve, and it delivers oil ,through the pipe 17 that leads tothe intake side of the vane motor `16, all just `asin Figure 1.

The only diierence of Figure 2 over Figure 1, therefore, is that instead of passing the production oil through the intermediate pass of the heat exchanger 50, as in Figure 1, the power oil fromthe power oil tank is -run through this intermediate pass in Figure 2. The operation of the system is the same as before, save only that the power oil does the Acooling of the primary oil, and'is itself increased in temperature somewhat. This latter is immaterial because the power oil will be cooled when it descends into the earth through thewell;

It willV be seen that in `both exemplications of` this invention the primary oil which is used to operate the hydraulic motor is kept from heating excessively and f perhaps foaming or'vaporizing, because of the presence of the heat exchanger. It'also is apparent that the heat exchanger derives its source of coldfrom an immediately available supply offluid such` as the production oil delivered from the well or the power oil delivered to the well.

vWhat is claimed is: k Y

1. In a well pumping apparatus: a fluid circuitincluding a primary uid pump, a iluid motor, connections between the pump andthe fluid motor so that the iluid pressure produced by `the :pump operates the iluid motor, and connectionsy from' the iluid motor back to the pump whereby the -fluid can be circulated kin a closed system; a fheat exchanger having two passes, one

pass interposed .in one of said connections; a second-k ary pump connected with and adapted to `be .operated by the fluid motor; power uid piping connecting-into the last named pump; power oil vhigh pressure piping leading from the last named pump, ak deep well pump connected to the power oil high pressure piping at the bottom of a well;y a production fluidpiping for conducting production uid from the pump; and connections introducing one of said last named fluid piping's through the other pass of the heat exchanger.

y2. The combination of claim 1,1171 which the production uid piping is the one 'of the pipings lconnected to the heat exchanger.

3. The combination of claim 1, in which the power uid piping is the one of the pipings connected through the heat exchanger.

4. In a well pumping apparatus: a prime mover; a primary hydraulic pump operated by the prime mover; a hydraulic piston motor, a heat exchanger; connections from the heat exchanger to the primary pump; connections from the primary pump to the opposite sides of the hydraulic piston motor, with reversing valve means in said last-named connections alternately to connect one side of the piston to the high pressure side of the primary pump and correspondingly to connect the opposite side of the piston to the heat exchanger; a hydraulic secondary pump connected to and operated by the hydraulic piston motor; piping connect- 15 2,478,410

References Cited in the le of this patent UNITED STATES PATENTS 1,860,137 Carr May 24, 1932 2,033,210 Tennant et al. Mar. 10, 1936 2,429,947 Rose Oct. 28, 1947 2,432,079 Albert Dec. 9, 1947 MacDougall Aug. 9, 1949