US3499324A

US3499324A - Dynamometer for well pumps

Info

Publication number: US3499324A
Application number: US601641A
Authority: US
Inventors: Josef Wenisch
Original assignee: OEMV AG
Current assignee: OEMV AG
Priority date: 1965-12-22
Filing date: 1966-12-14
Publication date: 1970-03-10
Anticipated expiration: 1987-03-10
Also published as: GB1106448A; AT281741B; FR1510203A

Description

a o i a 1 c-noss REFERENCE SEARCH 800 March 10, 1970 J. WENISCH 3,499,324

DYNAMOMETER FOR WELL PUMPS Filed Dec. 14, 1966 3 Sheets-Sheet 1 ATTORNEYS March 10, 1970 J. WENISCH DYNAMOMETER FOR WELL PUMPS 3 Sheets-Sheet 2 Filed Dec. 14, 1966 PRESSURE RECORDING MEANS March 10, 1970 J. WENISCH 3,499,324

DYNAMOMETER FOR WELL PUMPS Filed Dec. 14, 1966 3 Sheets-Sheet 5 FIG.4

INVENT OR Josef \A/entsch ATTORNEYS US. Cl. 73-141 3 Claims ABSTRACT OF THE DISCLOSURE A low-pressure, high-displacement pump is connected to a cylinder 'for quickly and easily moving a piston into engagement with the force transmission path of a deep well pump. A second high-pressure, low-displacement pump is also connected to the cylinder and once the piston is brought into engagement, the second pump causes the piston to support the weight of the pump rod, so that the weight of the rod can quickly be determined.

Dynamometers for Well pumps serve the purpose of determining whether a pump located at great depth is working properly by measuring the force transmitted to the pump rod. For this purpose the dynamometer must be interpositioned in the transmission path of the driving force to the well pump. Existing arrangements are adapted for temporarily interposing a dynamometer between the head of the polish rod and the cross-headfdepending from the so called horse head, so that the desired measurements can be effected.

The invention herein is related to a dynamometer for well pumps which is provided with a hydraulic pistoncylinder arrangement, which is adapted for being linked into the force transmission path of the pump rod between the upper end of said pump rod and the suspension means thereof, whereby said piston and cylinder 'lare brought into the operating position by a main pump and, in the operating position, the pump rod is via the hydraulic'pistoncylinder-arrangement connected with its suspension means. For interpositioning the hydraulic piston-cylinderarrangement into the force transmission path it is necessary to lift the upper end of the pump rod from its suspension means with the aid of said piston-cylindernrrangement. Prior to this lifting it is necessary to bring the dynamometer into contact with the upper end of the pump rod and its suspension means and this in turn makes it necessary to overcome a certain amount of dead-stroke. The arrangement according to the invention is especially suitable for rapidly elfecting said dead-stroke.

An embodiment of the dynamometer according to the invention is schematically illustrated. FIGURE l shows the overall construction, FIGURE 2 shows the suspension of the head of the polish rod on the cross head, FIGURE 3 is for the purpose of illustrating the interposition of the dynamometer and FIGURE 4 is a side cross-sectional view of the spring pre-tensioning means for

levers

20 and 21.

In the arrangement according to FIGURE 1 on the post 1 a beam 2 is pivotally supported at axis 3. There is further provided a counterweight 4, a motor 5 together with a crank mechanism and the connecting rod 6. On the so called horse-head 7 there are attached two ropes 8, which are connected by a cross-head 9. From this cross niged States Patent 0 3,499,324 Patented Mar. 10, 1970 ice,

As is shown in FIGURE 2 the polish rod 10 rests on a plate 13 of the cross-head 9 with its thickened head 12. This thickened head 12 is provided with a cross-head 14 which is given a cylindrical bottom face 15.

In FIGURE 3, the essential parts of the piston-cylinderarrangement of the dynamometer are illustrated, which parts are arranged within a housing not shown. The dynamometer is interpositioned between the cross-head 14 and plate 13, whereby the dynamometer is inserted by swivelling it approximately around the axis of the cylindrical bottom face of cross-head 14. When inserting the dynamometer the cross-head 14 must be lifted, requiring the expenditure of a large amount of energy. The dynamometer is secured in its position only when the pistoncylinder-

arrangement

16, 17 is in engagement between the plate 13 and the cross-head 14. For rapidly securing said engaged position a low-pressure cylinder 18 together with a piston is provided. The piston rod-19 of saidcylinder is acted upon by a spring (see FIGURE 4), which is pretensioned by a lever 20. When the piston-

cylinderarrangement

16, 17 is in its correct position between the plate 13 and the cross-head 14 a disengaging lever 21 is actuated, which in turn releases the piston rod 19. By the pressure exerted by the spring, the piston within the cylinder 18 is forced in lefthand direction and supplies to both of the cylinders 17 such a pressure that the piston-cylinder-

arrangement

16, 17 is clamped between the plate 13 and the cross-head 14. This pressure thereby is supplied via

conduits

22, 23 which are provided with

back pressure valves

24, 25. With the pressure-cylinder-

arrangement

16, 17 being clamped in its position the dynamometer is not yet linked into the transmission path for the head 9 the polish rod 10 is depending. The well casing forces from the motor to the polish rod because the pressure within the low pressure cylinder 18 is insufiicient for bringing the head 12 of the polish rod out of contact with the plate 13. For this purpose a high pressure cylinder 26 is provided, the piston of which is actuated via its piston rod 27 by means of a hand lever 28. By means of said high pressure pump'26, pressure is supplied to the pistoncylinder-

arrangement

16, 17 such that the head 12 of the polish rod is brought out of contact with the plate 13, linking the pistoneig'ylinder-

arrangement

16, 17 into the force transmission i iath and the pressure of the pressure fluid within the cy lnder 17 is an exact measure for the load of the polish rod 10. A load diagram can be recorded, for instance on a drum-recorder or the like, as shown generally at 60.

By opening the release valve 29 the piston-

cylinderarrangement

16, 17 is set free and can then be removed.

FIGURE 4 shows the spring-loaded piston rod 19, the lever 20 and the disengaging lever 21 in greater detail. The low pressure cylinder 18 is formed by a sleeve 30 inserted into a bore of the dynamometer body 31 and sealed thereto by a sealing ring 32. Within the low pressure cylinder 18 a piston 33 is slidably mounted, said piston being connected to the piston rod 19, which in turn is urged by means of a compression spring 34 towards the left-hand end of the cylinder 18. The spring 34 abuts with its one end against the rear end of the piston 33 and with its other end against a shoulder 45 of a bore 36 of a member 37 fastened to the dynamometer body 31 by means, not shown, for instance screw bolts or the like. Within the bore 36 the piston rod 19 is guided, said piston rod on its upper face being provided with a rack 38 cooperating with a pinion 39 rotatably mounted by means of an axle 40 within the member 37. Axle 40 is fixed to the lever 20, andlever 20 can be turned in the direction of the double arrow 41.

The rear end of the piston rod 19 on its lower side has arecess 42 into which is engaged a nose 43 of a plate 44 pivotally mounted within a slot 46 of the member 37 by means of a pin 45. This engaging lever 21 is fixed to plate 44, and plate 44 has a hole 47 into which engages the one end of a compression spring 48, the other end of which engages with a hole 49 of a plate 50 screwed to the member 34. As shown in this figure, the device is in its tensioned and secured position with nose 43 engaging recess 42. The lever 20 has been turned to its left-hand position so that the compression spring 34 is compressed. When it is desired to release the device, the disengaging lever 21 is turned in the direction of the arrow 51 so that the nose 43 slides ofi? the recess 42. When the piston rod 19 is released, the piston 33 is forced by the spring 34 towards the left-hand end of the cylinder, so that the hydraulic fluid contained in the cylinder 18 is forced out through conduit 22. When the piston 33 moves to the left, the lever 20 is turned in a clockwise direction about the axle 40.

If it is desired to retension the device, the lever 20 is turned in a counter-clockwise direction, so that the pinion 39 is rotated moving piston rod 19 to the right as shown in FIGURE 4, thereby retensioning the spring 34. When the piston 33 has reached the position shown in FIGURE 4, nose 43 can enter into recess 42 holding rod 19 in the position shown in FIGURE 4.

I claim:

1. In a dynamometer comprising a hydraulic pressure unit including a cylinder means and a piston means adapted to reciprocate in said cylinder means and a pressure recording means operatively connected with said hydraulic pressure unit, said hydraulic pressure unit being adapted to be interposed in the force transmission path, which is defined by a generally vertically reciprocating pump rod of a deep well pump, said pump rod being operatively carried by a first cross-head member connected to said deep well pump, said pump rod having in addition a second cross-head member longitudinally spaced from said first cross-head member in the direction of travel of said pump rod, said piston means and said cylinder means being interposed between said first and second cross-head members, the improvement comprising:

a low-pressure, high-displacement pump, communicating with said cylinder means for hydraulically driving said piston means into extension from said cylinder means and into engagement with one of said cross-head members after said cylinder means is placed in an abutting relationship with the other of said cross-head members, a high-pressure, low-displacement pump communicating with said cylinder means for hydraulically further extending said piston means thereby separating said cross-head members and causing the force on said pump rod to be transmitted to said first cross-head member through said piston means, and means for selectively actuating said low pressure and high pressure pump.

2. The dynamometer defined in claim 1 wherein said low pressure pump comprises a second cylinder and piston means, and additionally comprises a compression spring connected to said second piston means and releasable means for holding said spring in a compressed state until released whereupon said spring will displace said second piston and will operatively displace said piston positioned between said first cross-head member and said second cross-head member.

3. The dynamometer defined in claim 1 additionally including a check valve between said low-pressure pump means and said cylinder means, said check valve opening in the direction of said cylinder means.

References Cited UNITED STATES PATENTS 3,004,426 10/1961 Lodynski 73-141 2,741,915 4/1956 Renken et al. 73-151 X CHARLES A. RUEHL, Primary Examiner US. Cl. X.R. 73-151