US2217960A - Pumping apparatus - Google Patents

Description

Oct. 15, 1940. w AY R 2,217,960

PUMPING APPARATUS Filed March 21, 1938 a sheets-sun 1 Oct 15 1940- w. F. MAYER 2,217,960

PUIPING APPARATUS Filed latch 21, 1938 3 Shoots-Sheet 3 Patented Oct. 15, 1940 UNITED STATES 'PATENT OFFICE 2,217,960 v PUMPING APPARATUS Application March 21,

Claims.

This invention relates to reciprocating pumps actuated directly by pressure fluid, and is particularly useful in connection with pumps of that type in which both the actuating and pumped 5 fluids are liquids. I

In a pressure fluid actuated reciprocating pump of the simplex type, the flow of motive fluid and of pumped fluid is necessarily intermittent, the pumping action being interrupted during the reversal of the stroke, unless some provision is made for continuing the flow during reversal of the pistons.

Ina copending application of Aladar Hollander and Waldemar F. Maiyer, Serial Nor 197,140 filed concurrently herewith, there is disclosed a simplex hydraulic pump of the type referred to, in which excessive fluctuations in the motive and pumped liquid is avoided by providing a surge piston and cylinder which moves during the reversal of the main pistons to maintain substantially continuous flow of motive and pumped liquid.

In simplex pumps it is necessary to have valves for controlling the inlet and discharge of pumped liquid and also for admitting the actuating liquid successively to opposite sides of the pistons to move them successively in opposite directions.

In the aforementioned application, the operation of the reversing valve for controlling the admission and exhaust of actuating fluid is controlled by the movement of the main pistons and piston rod.

An object of the present invention is to provide a pump of the general type referred to and described in detail in the aforementioned application, in which the reversing valve is positively and accurately actuated to control the admission and discharge of actuating fluid, without mechanical connection between the valve and the main pistons or piston rods. It is desirable to eliminate such mechanical connection because it involves the employment of rods, shafts or other mechanical elements extending through walls restraining fluid under pressure, which must be packed to make them fluid-tight.

Still another object of the invention is to provide a practical actuating mechanism for a pump of the type described, in which the main reversing valve can be actuated directly, thereby eliminating the use of a pilot valve without at the same time incurring the possibility of the reversing valve stalling in dead center position or failing to be shifted the full extent of its stroke.

The first object mentioned is attained in accordance with the present invention by utilizing 1938, Serial No; 197,141

the motion 'of the surge piston to actuate the reversing valve. i

The manner in which the second object is attained, together with other minor objects and features of the invention, will be'explained by {i describing in detail certain preferred embodiments of the invention with reference to the accompanying drawings in which Fig. l is a plan view of one form of the pump;

Fig. 2 is a side elevation;

Fig. 3 is an end view;

Fig. 4 is a transverse section taken substantially on line IV-IV of Fig. 2;

Fig. 4a is a detail horizontal section through the pilot valve shown in Fig. 4; l

a Fig. 5 is a partial vertical longitudinal section taken substantially on line VV of Fig. 1;

Fig. 6 is a transverse section similar to Fig. 4, showing a modified form of the invention; and

Fig. '7 is a vertical longitudinal section, taken g0 substantially on line VII--VII of Fig. 6.

The particular pumps disclosed in the drawings are similar to those disclosed in the aforementioned copending application of Aladar Hollander and Waldemar F. Mayer, in that they 25 each comprise a pair of relatively long cylinders secured in coaxial relation on opposite sides of a central valve body with a piston in each cylinder secured to the adjacent end of a common piston rod extending through a partition in the 30 central valve body separating the two cylinders. Liquid to be pumped is admitted to the outer end of one cylinder, while pumped liquid is forced out of the other cylinder by the reciprocation of the piston. Motive liquid is admitted alternately 35 to the two cylinders on the inner sides of the pis-' tons to cause reciprocation thereof.

This arrangement constitutes in efiect a single cylinder double-acting pump pumping alternately from opposite ends thereof. An outstanding fea- 4o ture of this pump is the establishment of approximately equal pressures on opposite sides of the piston, with the pressure of the motive liquid slightly in excess of that of the pumped liquid, making it especially adapted for handling at high 45 pressures liquids of an abrasive or corrosive nature.

, Referring to Figs. 1 to 5, the pump comprises generally a pair of alined cylinders I and 2 mounted on a base 3 and connected to opposite 5o sides of a'central body 4. The base 3 is hollow, as shown in Fig. 4, and serves as a suction reservoir for liquid to be pumped. For convenience, this liquid will be termed mud, since the pump is particularly adapted to handling drilling mud 5s used in connection with drilling deep wells. A mud suction inlet 5 on one side of the hollow base 3 is connected to a source of mud. A suction connection 6 is provided at each end of the base 3 and forms a supporting connection between the base and the outer ends of the respective cylinders I and 2, as well as establishing communication between the interior of the base and a valve head I secured to the outer end of each cylinder. An inwardly opening suction valve 8 and an outwardly opening discharge valve 3 are mounted in each valve head, for controlling the admission of suction mud to the respective cylinders and the discharge of mud under pres-- sure therefrom. A discharge pipe i0 extends from each valve head to a centrally disposed common discharge pipe ll leading to the point of use.

A piston 15 is reciprocable in each cylinder l and 2, the two' pistons being connected together by a piston rod i6 extending through a partition H in the central body 4. A stufling box I8 seals the piston rod in fluid-tight relation to the par- .tition.

A motive liquid under pressure is alternately admitted to the cylinders I and 2 on the inner sides of the pistons l5, to cause reciprocation of the latter. The admission of motive liquid to the cylinders is controlled by a main reversing valve, generally indicated at 2|. The valve is a balanced, four-way valve and comprises a pair of valves 22 and 23 connected by a stem 24. Motive liquid is supplied from a suitable source to an inlet pipe 25 communicating with a central chamber 26. Valve 22 controls communication between the chamber 26 and a port 21 leading to cylinder 2, and also controls communication between port 21 and a discharge port 28 leading to a discharge pipe 29 for spent motive liquid. In a similar manner, valve 23 controls communication between chamber 26 and a port 30 leading to cylinder I, and between port 30 and a discharge port 3| connected to discharge port 28.

In the position shown in Fig. 4, the valve is inits right-hand position, admitting motive liquid from the chamber 26 to port 30 and thence to cylinder I, causing the pistons l5 to move to the left. Valve 22 closes communication between chamber 26 and port 21, but establishes 'communication between port 21 and discharge port 28, whereby spent motive liquid is vented from cylinder 2.

In the form-of the invention illustrated in Fig. 4, the reversing valve is actuated hydraulically by a pilot valve, generally indicated at 35. Secured to the outer side of valve 23 is a piston rod 36 attached to a shuttle .piston 31 reciprocable in a cylinder 38. Motive liquid under pressure is alternately admitted to cylinder 38 on opposite sides of piston 31, through a passage 40 leading from central chamber 26, a branch passage 4i, and either of two passages 42 and 43. The admission of motive liquid to cylinder 38 is controlled by the pilot valve 35, comprising a balanced, four-way valve similar to the main reversing valve. In the position shown in Fig. 4, pressure liquid is admitted to'passa-ge 42 and vented from passage 43 to a passage 44 (Fig. 4a) communicating with discharge port 3|. When the pilot valve is shifted to the left, pressure liquid will be admitted to passage 43 and vented from passage 42, thereby causing the shuttle piston and the main reversing valve to move to the left. When this occurs, pressure liquid will be cut off from cylinder l and admitted to cylinder 2 to cause the pistons l5 to move to the right.

In the aforementioned application of Aladar Hollander and Waldemar F. Mayer, the reversing valve is actuated by a pilot valve which is in turn actuated through suitable mechcanism by the main piston at the end of .each stroke. In the present instance, however, there is no mechanical connection between the pilot valve and the main pistons or piston rod. Instead, the pilot valve is actuated by a surge piston simliar to that shown in Figs. 1 to 4 of the aforemen-' tioned application. A surge cylinder 5! is mounted in a horizontal bore in the central body 4 and extends transversely of the main cylinders. One end of the cylinders is in open communication with the mud discharge pipe Ii, and the other end communicates through a passage 52 with passage 40 leading to the central chamber 26. A surge piston 53 mounted in the surge cylinder is thus exposed on opposite sides 'to the discharge mud pressure and the motive liquid pressure. A

piston rod 54 connected to the motive liquid side of piston 53 extends through a stufling box 55 to the exterior of the body 4.

The mode of operation of the surge piston is identical with that shown in Figs. 1 to 4 of the aforementioned application. As described more in detail therein, the pressure of the motive liquids is only slightly higher than that of the discharge mud. In order to retain the surge piston in retracted position, as shown in Fig. 4, except during reversal of the stroke of the main pistons, the piston rod 54-is made of sumcient size to reduce the piston area on the motive liquid side of piston 53 so that the total force-exerted As the main pistons approach the end of the stroke, it is desirable to effect a gradual'reduction in piston velocity, and this is accomplished by the provision of a. dashpot. As shown in Fig. 5, a dashpot Si is secured to the end plate 62 of eaclr valve head I. A plunger 63 secured to the outer side of each piston I5 has an outer diameter slightly less than the inner diameter of the dashpot 6i, whereby a narrow channel is formed between the plunger and the dashpot for the slow escape of liquid from within the dashpot as the plunger enters the latter at the end of each stroke. This arrangement causes the main pistons to come to rest gradually, effecting a gradual reduction in the pressure of the discharge mud.

When the discharge mud pressure has decreased to such an extent that the total force exerted by it is less than the force exerted on the piston by the motive liquid, the surge piston will move to the left, forcing mud through discharge pipe ii to compensate for the temporary interruption in discharge from the main cylin rod 54 and the pilot valve stem. As shown in Fig. 4, -a rocking lever. 61 is pivoted at 88 to-a bracket 69 extending laterally from the central body 4, the pivot 68 having its'axis' intersecting the axis of piston rod 54. The lever is pivotally connected at 10 to the stem of pilot valve 35. A cup-shaped cap H is yieldably and rockably mounted on a pin 12 secured'to the outer end of piston rod 54, a spring 13 being interposed between the cap and the end of the piston rod tollrge the cap into a centrally disposed position.

It will be apparent from the foregoing description that at the end of each stroke of the main pistons the surge piston moves to the left and then returns to the right as the main pistons begin their stroke in the opposite direction. This movement of the surge piston causes the cap II to engage one of two rollers I5, 15 mountted on the lever 61 to rock the latter about its pivot 68. Since the pilot valve is hydraulically balanced, spring-means is provided to effect full throw of the lever 61 and hence of the pilot valve. A spring 16 is secured at one end to a pin 11 on the lever 61, and at the other end to a pin 18 on the bracket 69. Upon pivotal movement of the lever 61, the spring is swung from one side to the other of the lever pivot 68 producing the well-known toggle effect. The other position of the lever 61 is indicated in'dotted lines at 61', with the spring pin 11' below the pivot pin 68 and the upper roller 15 in position to be engaged by the cap II on the next stroke of the surge piston. 1

In the form of the invention shown in Figs. 6 and 7, the arrangement is generally similar tothat shown in Figs. 1 to 5. The principal distinction lies in the fact that the toggle mechanism actuates the main reversing valve instead of a pilot valve. Otherwise the mode of operation of the two forms is identical. In Figs. 6 and 7, however, the structural arrangement has been changed slightly. The reversing valve assembly 2! is disposed vertically, instead of horizontally as in Fig. 4. The valves 22', 23' and ports 26', 21, 28' 30,,and 3| correspond to valves 22 and 23 and ports 26, 21, 28, 30 and 3| of Fig. 4. High pressure water is admitted to the upper end ofthe surge cylinder 5| above the piston 53' through passages 40' and 52', and

discharge mud enters the surge cylinders 5! from a chamber ll" communicating with a mud discharge pipe. The toggle mechanism of this form of the invention is identical with that of Fig. 4 and hence will not be described again, except to point out that the toggle lever 61 is pivotally connected at 10' to a link in turn pivotal-1y connected to valve stem 36.

As shown in Figs. 6 and '7 the pistons l5 are in the extreme left ends of their stroke and are reversing. However, prior to reaching the end of the stroke, the left piston l5, as shown in Fig. '7, was decelerated by entrance of the dashpot piston 63 into dashpot cylinder 6|, thereby reducing the pressure of the pump discharge liquid sufficiently to permit the surge piston 53' to move downwardly in response to the greater force exerted by'the motive liquid in passage 40 on the upper end thereof. This movement of the surge piston 53' caused the cap II on the outer end of the surge piston rod 54' to en-- gage the left-hand roller 15 and swing the toggle lever 61' in counterclockwise direction, thereby moving the sliding valve 2i into such position as to connect the motive liquid inlet passage 40 through the port 30' with the cylinder 2 of the pump and connect cylinder I through ports 21'. and 28 with the motive liquid discharge for exhaust-passage 29' thereby applying motive liquid to the right-hand pistonand causing the'two pistons l5 andthe piston rod l6 to move to the right. The pistons l5 quickly accelerate to normal speed, thereby-raising the pressure of the pumped fluid to its normal value, under which condition the force exerted by the pump discharge liquid-against the underside of the surge piston 53' is greater than the force exerted against the top of the piston by the motive liquid, whereupon the piston 53 rises to decelerated to cause a reduction in pressure of the pumped liquid, permitting the surge piston 53' to again move downwardly. This time the right-hand roller 15' is in the path of the cap H on the upper end of the surge piston rod and the toggle lever 61 is oscillated in a clockwise direction to shift the valve 2| to the other end tons. By this arrangement the provision of trip mechanism within the main cylinders iri the path,

of the pistons is avoided. The reversal of the main valve is positive, with no danger of stalling even with the directly-actuated reversing valve.

Having fully described the preferred embodiments of this invention, it is to be understood that I do not limit myself to the exact constructions herein set forth, which may obviously be varied in detail without departing from the spirit of this invention, .but only as set forth in the appended claims.

I claim:

1. The combination with a simplex hydraulically-actuated piston pump having a main cylinder and a main piston therein actuated by motive liquid to displace pump liquid, motive liquid inlet and discharge means, pump liquid inlet and discharge means and a valve' controlling said motive liquid inlet and discharge means and movable to reverse the stroke ofsaid pump, of surge means including a surge cylinder and piston connected to said pump liquid discharge means and movable only during the reversal of stroke of said pump for reducing pressure fluctuation of pumped liquid, and an operative connection between said surge piston and said valve whereby the latter is actuated by movement of said surge piston.

2. A hydraulic pump as defined in claim 1, in which said valve means comprises a sliding valve, and said operative connection includes a spring toggle mechanism.

3. A hydraulic pump as defined in claim 1, in which said valvemeans includes a hydraulically actuated main valve and a pilot valve for actuating said main valve, and in which said operative connectlon includes means actuated by said surge piston for actuating said pilot valve.

4. A hydraulic pump comprising, in combination: a pair of cylinders, a main piston reciprocable in each cylinder, said pistons being interconnected to reciprocate in unison, pump-liquid suction and discharge connections to each cylinder on one side of the main piston therein, valve means for controlling the admission of motive liquid under pressure alternately to said cylinders on the other side of each of said pistons to reciprocate the latter, a surge cylinder, a surge piston therein, fluid connections between opposite ends of said surge cylinder and said motive liquid and said pump discharge respectively, and an operative connection between said surge piston and said valve means whereby the latter is actuated by movement ofsaid surge piston.

5. A hydraulic pump as defined in claim 4, in which said main cylinders are connected in axial alinement, and a common piston rod connects said main pistons for reciprocation in unison.

6. A hydraulic pump as defined in claim 4, in which said valve means includes a hydraulically actuated main valve and a pilot valve for actuating said main valve, and in which said operative connection includes means actuated by said surge piston for actuating said pilot valve.

7. A hydraulic pump comprising in combination: cylinder means, a pair of pistons reciprocable in said cylinder means, said pistons being interconnected to reciprocate in unison, pumpliquid inlet and discharge means, motive-liquid inlet and exhaust means including a valve movable to successively admit and then exhaust motive-liquid from said cylinder means, a surge cylinder, a surge piston therein, fluid connection between opposite ends of said surge cylinder and der and a main piston therein actuated by motive liquid to displace pump liquid, motive liquid inlet and discharge means, pump liquid inlet and discharge means, and a valve controlling said motive liquid inlet and discharge means and movable to reverse the stroke of the pump, 01' surge means including a surge cylinder and piston connected to said pump liquid discharge means and motive liquid inlet means and movable during reversal of stroke of said pump for limiting pressure fluctuation 0! pumped liquid, an operative connection between said surge piston and' said valve, whereby the latter is actuated by movement of said surge piston, said surge pistonbeingmovable in response to drop in pump-liquid discharge pressure relative to motive liquid pressure 'during reversal of stroke of said pump, and means functioning independently of liquid pressures in said pump for decelerating the piston of said pump at the end of each stroke.

9. The combination as described in claim 1, with means for gradually decelerating said main piston at the end of each stroke, whereby the discharge pressure fluctuates to actuate said surge means and said valve.

10. The combination as described in claim 1, with dashpot means within said main cylinder for decelerating said main piston at the end of each stroke, and thereby reducting the discharge pres sure to actuate said surge means and said valve.

WALDEMAR F. MAYER.

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