US1550110A - Pump-operating mechanism - Google Patents

Description

3 2 Sheets-Sheet 1 Aug. 18, 925. y

J. E. SHUTT 'PUMP OPERATING MECHANISM Filed March-20. 192

Aug. 18, 1925. 1,550,110

J. E. 'SHUTT PUMP OPERATING MEGHANISM Filed ual-cn 2o. 1923 2 sheets-sheet a Patented Aug. 18, 1925.

UNITED STATES JOHN EDWARD SHUTT, 0F STUTTGART, ARKANSAS.

PUMP-OPERATING MECHANISM.

Application filed March 20, 1923. Serial No. 626,370.

To all whom t may concern:

Be it kno-wn that I, JOHN E. SHUTT, a citizen of the United States, residing at Stuttgart, in the county of Arkansas and State of Arkansas, have invented a new and useful Pump-Operating Mechanism, of which the following is a specification.

This invention relates, in general, to mechanism for translating rotary motion into reciprocating motion, or vice versa; but has more specific reference to mechanism of the said general character which is intended principally for use in the operation of pumps, and particularly those of the deepwell, double-piston type.

In the operation of such pumps, it is manifestly desirable that their rate of delivery shall be as nearly uniform as may be possible; and it is also extremely important that the volumetric rate of discharge, for a given depth of well and with a liquid of a given specific gravity, shall be the greatest possible in proportion to the piston displacement and to the power expended, and that variations in the power utilized shall be as slight and as uniform as possible, instead of there being a suddenly-encountered peak load at some point or points in the stroke of the pistons, and particularly at a point or points in the cycle where the power of the driving shaft is less effectively applied than at other points, to the production of piston movement. i

When the piston rods of a pump are crank-driven in the usual manner, the power of the driving shaft is applied least effectively at the beginning and end o-f the stroke, during the peak load, when the speed of the piston is least, and during reversal of the direction of movement of the piston; and, as the load decreases after the pickup, due to increase in the .speed and momentum of the piston and the liquid then being moved thereby, the effectiveness with which power is applied to the movement of the piston increases, and, after reaching its maximum at or near the middle of the stroke, in turn decreases as the other end of the stroke is approached and the speed of piston movement decreases. Also, the discharge of the pump is jerky or intermittent, and the average flow is small in proportion to the piston displacement and the maximum and average power utilized.

An important object of my present invention is the provision of mechanism adapted for the operation of double-piston pumps, and which will maintain a higher degree of uniformity of delivery, and more highlyeflicient output per unit of piston displacement and per unit of energy expended, than any mechanism utilized heretofore for a similar purpose; will render the power employed the most effective upon each piston when the load thereon is greatest, and less effective upon either piston during the greater portion of its stroke in one direction than upon the other piston which is moving in the opposite direction at the same time, and thereby minimize both the power required at peak load and the variations in the load imposed upon the power-supply unit; and in which the change in the direction of movement of either piston takes place during move-ment of the other piston in the direction to which such change is made. Other objects are to so design and arrange the parts of the pump-operating mechanism that the means for applying power to piston movement shall be relatively the most effective when the speed and momentum of the piston and the liquid being moved thereby are least; that, whether the reciprocating members be driven from the rotating member, or vice versa, there shall be no dead centre in the complete cycle of operation; and that the two pump-rods shall be guided independently of each other in their reciprocatory movements.

The operation of my improved pump-operating mechanism, and the manner in which the foregoing and other objects are accomplished thereby, will readily be understood from the following description of the accompanying drawings, in which- Fig. l is a side elevation of the pump-operating mechanism, with the crank-shaft and the fulcrum shafts shown in section;

Fig. 2 is a sectional view, taken substantially on line 2 2 of Fig. l;

Fig. 3 is a sectional view, taken substantially on line 3--3 of Fig. 1; and

Fig. 4 is a sectional view, taken substantially on line 4.-4 of Fig. 1.

1n the preferred form of my invention as illustrated in the drawings, a guide rod l is shown, as constituting means, effective upon the pump-rods, independently of each other, for opposing or restricting lateral movement of said pump-rods, relative to each other or to the well-casing (not shown) but it is to be understood that the substitution of different forms, arrangements, or locations, of the means for accomplishing said purpose, falls within the scope of my invention.

Slidably mounted upon the guide rod 1, are two similar split collars or sleeves, numbered 2 and 3 respectively, each of which has a projecting flange 4, which terminates in a collar or sleeve 5, provided with oppositely-disposed trunnions 6. Said trunnions arev mounted in split bearings 7 one of which is located. at one end of each of links 8, a pair of such links being provided for each of the collars or sleeves 5, and each link has its other end forked, as shown at 9, so as to embrace the respective legs 10 of the forked end 11 of a bell-crank lever. Two similar bell-crank levers are employed, in superposed arrangement, and oppositely-disposed, as indicated at 12 and 13, and each of said levers is pivotally mounted upon a fulcruin shaft 14C, projecting from a suitable support, as 15. Those arms of the two bellcrank levers which are remote from the arms 11, and which have similarly-shaped slots 16 therein, are arranged in superposed position, and a roller 17, cairied by a crank-shaft 18, which preferably forms part of a driving shaft located in a plane passing through the centre lines of the fulcrum shafts 14, and equidistant therefrom, is embraced by both of said slots. Thus, when the crank shaft is rotated said roller will be moved in said slots to rock the two bell-crank levers, and thereby to impart reciprocating motion to the links 8. The forked ends 9 of links 8, which are pivotally'connected with the respective parts of the forked ends 11 of the bell-crank levers, may be secured thereto in any suitable manner, as by engagement of split bearings 19 on the forked ends 9 with pins 2O extending through said forked ends 11.

One of the collars or .sleeves 5 is suitably secured upon a tubular pump-rod 21, while the other of said collars or sleeves is secured upon another pump-rod 22, which is adapted to reciprocate within said rod 21, and which extends between the links of one of the pairs, which are connected with said rod 21, and is connected with the other pair of said links, as indicated at 23.

From the foregoing description, it readily will be seen that the rocking movement of the two bell-crank levers, which results from movement of roller 17 on the crank-shaft 18, within the two slots 16, imparts reciprocating movement, through the links 8, to the pump-rods 21 and 22, the greater part of the movement of one of said pump-rods in either direction being accompanied by similar movement of the other of said rods in the opposite direction, and the pistons (not shown), intended to be secured upon said rods, respectively, being correspondingly moved.

During each revolution of the crankshaft 18, the following conditions are created, successively :-Starting to follow the cycle from the position of the crank-.shaft shown in Fig. 1, the lever arm 13, connected with pump-rod 22, is at the termination of its downward movement, and in position to commence its upward movement, at its minimum speed, while the lever arm 12, connected with pump-rod 21, is approaching the termination of its upward movement, with its speed gradually decreasing. Upward movement of rod 22 is now initiated, at gradually-increasing speed and with maximum effectiveness of power-application, and upward movement of rod 21 continues until the crank-shaft is at right angles to the slotted arm of the bell-crank lever 12, whereupon downward movement of rod 21 is initiated, at minimum and gradually-increasing speed, and with maximum and gradually decreasing leffectiveness of power application. lVhen the crank-shaft reaches the limit of its downward movement, and therefore its centre lies within a plane passing through the centre lines of the two fulcrum shafts 14, the two slots 16 are concentrically superposed; rod 21 is approaching the iniddle of its downward movement, and is moving downward at the greatest speed attained by it at any time in its upward-and-downward travel; and rod 22 has passed the middle of its upward stroke, and is moving less rapidly, and with greater effectiveness of power-application, than rod 21, but at increasing speed and with decreasing effectiveness of power-application. As the crank-shaft now moves toward the pumprods, and upward, rod 21 approaches the termination of its downward stroke, at decreasing speed and increasing effectiveness of power-application, while rod 22 approaches the termination of its upward stroke, at increasing speed and with decreasing effectiveness of power-application. As the crank- .shaft passes the position in which it is at right angles to the slotted arm of bell-crank lever 12, downward movement of rod 21 changes to upward movement of said rod, at decreasing speed and increasing eectiveness of power-application, and upward movement of rod 22 continues, at decreasing speed and increasing effectiveness of powerapplication, until, when the crank-shaft is at right angles to the slotted arm of the bell-crank lever 13, upward movement of rod 22 changes to downward movement thereof. It is not thought necessary to describe in detail the movement of the respective rods during the remainder of the cycle, since the same mechanical principles apply aS during the half-cycle just described.

Thus, it will be noted that reversal of the direction of movement of the two rods does not take place simultaneously, but, for a short interval near the beginning and termination of the movement of either rod in either direction, the two rods move in the same direction; the rods do not reach the middle of their respective strokes at the same time; they at no time move at the same speed, or with the same effectiveness of power-application, except for the infinitesimal period between movement of the two rods in the same direction and the change in the direc-tion of movement of the first of them to make such change, the effectiveness of the power-application to the rod initiating its upward movement being at this instant substantially at its maXimum; the average power required for movement of either rod in either direction is the same as that required for its movement in the opposite direction; and there is no dead centre in the complete cycle of operation. Furthermore, in the preferred form of the invention, as illustrated in the drawings, the increase in the effectiveness of the power-application to, and in the rate of movement of, the upward-moving piston, immediately following the initiation of such movement, is greater and more rapid than is the case at the initiation of downward movement.

Changes in minor details of my improved pump-operating mechanism will doubtless readily suggest themselves to those skilled in the art to which it appertains, and I therefore do not desire to limit my invention to the exact construction shown and described.

Having thus described the invention, what is claimed is In pump-operating mechanism, the combination with a crank shaft, of a pair of bell crank levers fulcrumed on opposite sides of said shaft, one arm of each of said levers having an elongated slot to receive said shaft, the other arm of each of said levers being forked, links connected to said forks, a cross head connected to each pair of links, a hollow piston rod connected to the lower cross head, a piston rod connected to the upper cross head and extending through said lower cross head and said hollow piston rod, a guide rod arranged adjacent said piston rods, and sleeves carried by sail cross heads and surrounding said guide ro In testimony that I claim the foregoing as my own, I have hereto affixed my signature.

JOI-IN EDWARD SHUTT.

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