US1032113A - Method of regulating pumps of certain types for the pumping of liquids. - Google Patents

Description

H. M. & T. M. CHANGE.

METHOD OF REGULATING PUMPS OF CERTAIN TYPES FOB. THE PUMPING 0P LIQUIDS.

APPLICATION FILED MAR. 22, 1911.

Patented July 9, 1912.

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H. M. & T. M. CHANGE.

METHOD OF BEGULATING PUMPS OF CERTAIN TYPES FOR THE PUMPING 0F LIQUIDS.

APPLICATION FILED MABHZZ, 1911.

Patented July 9, 1912.

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HENRY lvL CHANGE AND THOMAS M. CHANCE, OF PHILADELPHIA, PENNSYLVANIA;

METHOD OF REGULATING PUMPS OF CEBJTATN TYPES FOR THE PUMPING OF LIQUIDS.

Application filed March 22, 1911.

To all whom it may concern:

Be it known that we, HENR M. CHANCE and THOMAS M. CHANGE, of the city of Philadelphia, county of Philadelphia, anl State of Pennsylvania, have invented a new and useful Method of Regulating Pumps of Certain Types for the Pumping of Liquids, whereof the following is a specification, reference being had to the accompanying drawings, which show forms of apparatus adapted to carrying out our method.

By the term liquids, we mean to include not only simple liquids, but also mixtures of liquids, mixtures of liquids and gases, and such mixtures of liquids and solids as are capable of being pumped.

The types of pumps or compressors to which our method is applicable are those in which as an incident to the pumping operation, energy stored in an accumulator during the power or out-stroke of the pumping element, is employed to effect or aid the return stroke. A method of pumping in which this method of regulation may be employed, is described in an application filed by us simultaneously herewith, being Serial No. 616,080, but our invention is not limited to the method set forth in said application.

The characteristic feature of our present invention may be explained as follows hen a confined body of liquid is acted upon by a power impulse applied to one end and by its movement effects pumping, and also at what may be termed its other end transmits energy to an accumulator, which power is utilized in efi'ecting the return movement of said body of liquid, a definite time is required for each complete cycle comprising a power or out-stroke and a r turn stroke. This time element is fixed by certain conditions among which are the volume and length of the body of liquid, so that a normal period of oscillation of said body may be said to exist. Thus, the number of cycles per unit of time may increase if the power is increased, or if the body of liquid be reduced in length, or increased in cross sectional area, and vice versa. In order to obtain desired conditions of operation of the prime mover, it is important to regulate the action of such a moving body of liquid actuated from the prime mover, but regulation by modifying one or more of the above described factors involves relatively large changes in the operative conditions, in

Specification of Letters Patent.

Patented July 9, 1912,

Serial No. 616,079.

* order to effect relatively small changes in the frequency of the cycles. Thus, to re duce the speed of a given body of liquid one-half, the power must be reduced to about one-fourth, or the body of liquid must be increased in length about four times, or decreased in cross sectional area to about one-fourth. It is evident that these methods are not well adapted to regulate such pumping operations, and to at the same time preserve conditions favorable to high efliciency, for if the prime mover be designed to Work with maximum eiiiciency for a certain power, velocity and amplitude or stroke, changes in any of these will be attended by loss in efficiency.

Our invention consists in a method of regulating the pumping action by alternately greatly retarding or even actually stopping actuation, and again starting it at some selected point in each cycle, the time interval between such stopping and starting being thus added to the time required for the completion of each cycle. The point selected for such stopping and starting is preferably at the commencement of the return or iii-stroke of the body of liquid, the condition of equilibrium existing throughout the system at the moment of reversal being favorable to the operation of the apparatus, which are conveniently employed for carrying out the method.

Our method of regulation may be carried out by a great variety of mechanical contrivances of the escapement type acting upon the oscillating body of liquid in such manner as to control its movement. These appliances for instance, comprise valves, cocks, piston-controlled ports, ported pistons or other devices, in common use, for controlling the flow of liquids, as well as mechanical escapements operative-ly connected with the oscillating body of liquid.

In the accompanying drawings, Figures 1, II, III, IV, and V, illustrate elementary devices of the first class just mentioned, and Fig. VI, illustrates a device of the second class. In said drawings, Fig. I, is a vertical longitudinal section through that portion of a pumping apparatus of the type just mentioned, in which the devices adapted to carry out our method are located. Fig. 11, is a sectional detail viewed on an enlarged scale, illustrating the combined check and regulating valve shown in Fig. I. Fig. III, represents modified form of apparatus,

and is a vertical longitudinal section through that portion of the apparatus which comprises the device for carrying out our method. Fig, IV, is a vertical longitudinal section showing another modified form thereof located in the pump chamber of the pump, said figure also showing the adjunctive parts comprising a conduit accumulator and discharge main which constitute a type of the apparatus in its entirety. Fig. V, is a vertical longitudinal section showing another modified form thereof. Fig. VI, is a vertical longitudinal section, showing the essential portion of an apparatus oi the second class above mentioned.

Referring now to Fig. I, it will be understood that the portion of the apparatus there shown, comprises the end of a conduit adapted to carry out the general method of pumping by the movement of a confined body of liquid, the portion represented in the drawing being the end which is remote from the point of application of power to the body of liquid, and which is adjacent to and connected with the accumulator. T he parts not shown in the drawing may be of any construction adapted to carry out the general method of pumping, but they are preferably such as are described and shown in our application filed simultaneously herewith. In said figure, 1, represents a portion of the conduit adapted to contain the confined body of liquid, and which is in communication at the remote end with means for application of power to the body of liquid, and at some intermediate point with the discharge for the pumping operation. 2, represents the accumulator which may be an air chamber, column of liquid or any equivalent device adapted to be made operative by means of the flow of liquid through the passage 3. 4, represents the piston by which a portion of the energy derived from the movement of the confined body of liquid in the conduit 1, is transmitted to the body of liquid (or air) in the chamber 5, beyond the annular partition 6. The piston 4, operates in a cylindrical casing 7 in which it fits snugly, but so as to be movable freely under the impulse transmitted to it, either by means of the pressure of the liquid in the conduit 1, or by means of the rod 8, which may be connected with a power piston located in said conduit. The casing 7, is provided, upon the side which is to the right of the partition 6, with a plurality of ports 10, arranged at different longitudinal distances from the end of the cylinder, as shown, all of which communicate with the interior of the chamber 5, and is also provided at its extremity with a discharge pipe 11, whose opening is con trolled by means of a valve 12, the details of which are shown in Fig. II. Said valve 12, is mounted freely upon a vertical'spindle 13, whose upper portion is screw-threaded as shown at 14, so as to engage with the corre sponding thread in the block 15, located in the wall of the chamber 5. A hand wheel 16, is mounted upon the upper end of the stem 13, so that the lowest position of the valve 12, with relation to the orifice of the pipe 11, may be regulated. Normally it is so set as to limit the reflux, without permitting closure. As the piston 4, advances within its casing, fluid within the right hand end of the casing 7, is discharged through the ports 10, into the chamber 5, and thence through the passage 3, to the accumulator 2, with corresponding accumulation of pressure therein. As the piston overruns the ports 10, it is increasingly cushioned and after overrunning the extreme port, is still more powerfully cushioned by the resistance to the further outflow of fluid aiforded by the relatively small outlet of the discharge pipe 11., which continues until the piston comes to rest. Thereupon the fluid from the accumulator begins to exert power to effect the return stroke, but the partial closure of the aperture of the discharge pipe 1]., by the valve 12, now in its lowermost position, greatly retards this until suificient fluid has passed by this check valve to move the piston far enough to uncover the ports, after which the return stroke proceeds rapidly and normally.

Referring now to Fig. III, 20, is the end of a conduit adapted to carry out the general method of pumping by movement of a confined body of liquid to which we have previously referred, only that end of the conduit which is remote from the point of application of power to the body of liquid being shown. 21, is an accumulator, the passage of liquid from the conduit to the accumulator being controlled by the interposed check valve 22. 'This valve has a recessed valve stem 23, within which is re ceived a boss 24, on the end of a rod 25,

mounted in the piston 26, which slides within the vertical piston casing 27. The upper end of this piston casing engages with the conduit 20, by two passages, one of which, 28, is controlled by a regulating valve 29, while the other passage 30, is controlled by the check valve 31. The operation is as follows :The column of liquid moving forward in the conduit 20, under the impulse of the power stroke, opens the check valve 22, and accumulates pressure within the accumulator, until equalization of the pressure eflects closure of the check valve, at which time the piston 26, is at its lowermost position, by reason of the pressure upon its upper end permitted by the passage of liquid through the channel 30, and check valve 31. As the pressure in the conduit 20, decreases,

the pressure within the accumulator operatmovement being retarded by the necessary outflow of liquid from the upper end of the casing 27, through the passage 28, subject to the retarding action occasioned by the regulating valve 29, which introduces the desired time interval before contact of the boss 24:, with the top of the valve stem 23, elevates the valve 22, permitting the pressure in the accumulator to drive liquid therefrom into the conduit to effect the reverse stroke.

There is illustrated in Fig. IV, a device similar in some respects to that shown in Figs. I, and II, with the difference that the retardation means are applied directly to the main actuator plunger of the pumping apparatus. Here the plunger ll), operates within the casing d1, having ports 42, communicating with the pumping chamber 4L3, which leads to the conduit lt which is provided with an accumulator 85, and discharge conduit 86. The intake 45, for the pumping chamber is controlled by the check valve 46. In addition to the ports 6L2, the casing 41, is provided with an outlet 4C8, to the pumping chamber, governed by a check valve 49,

and also with an auxiliary passage :7, which is governed by a regulating valve of the construction illustrated in Fig. II, and previously described. In operation, when the actuating plunger reaches the forward extremity of its stroke, it overruns and thus closes the ports a2, and as the return stroke begins the check valve 4L9, also closes, so that pressure in the casing l3, is at first communicated to the actuating plunger only by way of the small passage 47, controlled by the regulating valve now in its lowermost position, which retards such communication of pressure until the successive uncovering of the ports 42, permits free communication between the pumping chamber 43, and the casing 41, to effect the return stroke of the actuating plunger.

In Fig. V, there is shown a conduit 50, with a cylindrical extension containing a piston valve 51, which controls the port 52, in the bypass 53, of the conduit, which leads to the extension 54, and accumulator 55. The piston valve is cushioned between the opposing springs 56, and 57, which normally keep it in central position closing the port 52. The power impulse of the pump driving liquid in the conduit 50, operating upon the end of the piston valve 51, drives it against spring 57, and uncovers the port 52, the liquid beyond it passing into the eX- tension 54, by way of a passage 58, controlled by a check valve 59. As the velocity of the moving liquid decreases, and the column comes to rest, the piston valve 51, returns to its central position under the influence of the springs, closing the port. The check valve 59, having also closed, the pressure within the accumulator can only operate to move the piston 51, and again open the valve by means of the communica tion afforded by the passage 60, controlled by the regulator valve 61, which retards the fiow of liquid sufliciently, and thus prevents the reverse stroke, until the piston has again uncovered the port, when the unrestrained pressure of the accumulator permits liquid to fiow freely back from the accumulator as the liquid in the conduit 50, makes its full return stroke. At the end of this stroke, the cushioning springs again bring the piston valve 51, to its central position.

Fig. VI, shows an actuator plunger 67, working in a pump chamber 68, a piston rod 69, and cross-head 7 O, cross-head guide 71, a latch 72, in said cross-head, operated by latch-spring 73, a latch releasing push rod 7st, push-rod guide 7 5, a piston-rod 7 6, connected to a piston 7 7 working in a cylinder 78, a check valve 7 9, and regulating valve 80, placed in an outlet overflow 81, in connection with a tank 82; and a connection 83, between the cylinder 7 8, and pump chamber 68. When the plunger 67, moving from right to left completes its power stroke, the latch 7 2, is in contact with the push-rod 7 41, and suction developed in the pump chamber 68, acting through the connection 83, upon the piston 77, causes the piston 77 and pushrod 74t, to fall, and enables the spring 73, to push down the latch 72, engaging with the slot in cross-head guide 71; after the end of the suction period reaction pressure from the accumulator acting through the pump chamber 68, through the connection 83, upon the piston 7 7 tends to force it and the pushrod 74, up against the latch 72, and raise this to a point where it is no longer engaged in the slot in cross-head guide 71, but this action is delayed by the time necessary for liquid in one end of the cylinder 78, to es cape through the regulating valve 80.

The construction shown in Fig. VI illustrates a type of apparatus wherein the return stroke of the body of liquid is controlled by the movement of the pump plunger 67. In carrying out our method by means of apparatus of this type, we do not confine ourselves to the employment of the particular organization thus shown, but said figure is intended to represent typically any apparatus wherein control of the plunger is the means used to effect the regulation characteristic of our method.

In using our method of regulation it is best to employ devices which except initially have small etiect upon the velocity of the return stroke, and this can be accomplished by actually stopping the oscillating column, or by so shutting off the accumulator pressure that the body of liquid moves very slightly for a definite time interval at or about the commencement of the return stroke, and at the end of this period quickly &

removing the obstruction to movement so that the return stroke proper is made with practically its normal velocity. By this method of regulation pumps may be operated at a small number of strokes per minute without appreciable loss in efiiciency, for the conditions under which the power stroke is made are not changed by thus varying the speed of operation.

Having thus described our invention, we claim 1. The hereinbefore described method of regulating pumps, wherein power oscillation and return oscillation of a body of liquid are utilized to absorb and supply energy; which consists in restraining the return oscillation at or about its commencement and increasing the time interval between the completion of each power oscillation of the body of liquid and the completion of its return oscillation, whereby the cyclic frequency of operation is decreased.

2. The hereinbefore described method of regulating pumps, wherein power oscillation and return oscillation of a body of liquid are utilized to absorb and supply energy; which consists in restraining for a limited time the commencement of the return oscillation and increasing the time interval between the end of each power oscillation and the commencement of the return oscillation, whereby the cyclic frequency of operation is decreased.

The hereinbefore described method of regulating pumps, wherein the momentum of a moving body of liquid is utilized to draw any liquid after the direct action of the driving medium has ceased, and in which said body of liquid is driven in a return stroke by energy stored during the power stroke; which consists in restraining said return oscillation during an interval of time after the end of the power stroke and thereby decreasing the cyclic frequency of operation.

In testimony whereof, we have hereunto signed our names, at Philadelphia, Pennsylvania, this twentieth day of March 1911.

HENRY M. CHANGE. THOMAS M. CHANCE.

WVitnesses JAMES H. BELL, E. L. FULLERTON.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C.

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