US1418951A - Controlling apparatus for piston pumps - Google Patents

Description

F. MARTIN.

CONTROLLING APPARATUS FOR PISTON PUMPS.

APPLICATION FILED 0cT.4,1920.

1A18,95 1 a a e e une- 6, 1922.

2 SHEETSSHEET 1 F. MARTIN.

CONTROLLING APPARATUS FOR PISTON PUMPS.

APPLICATION FILED OCT. 4. 1920.

1,418,951 0 Patented June 6, 1922,

2 SHEETS-SHEET Z.

UNlTED STATES PATENT OFFICE.

FRIEDRICH MARTIN, OF ESSEN, GERMANY ASSIGNOR TO FRIED. KRUPP AKTIEN- GEELLSCHAFT, OF ESSEN-ON-THE-RUHR, GERMANY.

1&18351.

Specification of Letters Patent.

Patented June 6, 1922.

Application filed October 4, 1920. Serial No. 414,690.

To all whom it may concern:

Be it known that I, Fmnnmcrr MARTIN, residing at Essen, Germany, a citizen of the German Republic, have invented a certain new and useful Improvement in Controlling Apparatus for Piston Pumps, of which the following is a specification.

The present invention relates to regulating devices for piston pumps with shaft drive and variable stroke-length, in which a starting or regulating piston, intended to adjust the stroke-length of the pump piston during the operation of the pump, is influenced by the fluid pressure, generated by the pump, and also by a power source counteracting said pressure; so that the fluid pressure tends to set or adjust the starting piston in the direction of a diminished stroke-length. When the greatest piston stroke-length in pumps of known art is selected for mean water consumption, it will be necessary to use an accumulator which delivers the additional quantity of water during greater water consumption. The object of the present invention is to provide a regulating device, so that the contents of the accumulator may be utilized to the greatest possible extent.

One embodiment of the present invention is illustrated in the accompanying drawing, showing in Fig. 1 a side elevation, partly in section, of a regulating device, together with appurtenant parts of the pumping plant and Fig. 2 on a larger scale a similar view of means for varying the stroke length of the pump. And this embodiment also shows how it is possible to provide a very gentle transit of the starting piston from its position, corresponding to the greatest strokelength, into the position corresponding to a diminished water consumption; in case the water consumption is diminished from a quantity in excess of the greatest production of the pump to a quantity which is smaller than this production.

A is the casing of the piston-pump, to which suction pipe a and pressure pipe (1 are connected. The pump is provided in the usual way (Fig. 2) with several stationary cylinders A, arranged parallel to their drive shaft B. In each cylinder A is guided a plston L. which is connected by a rod Q with a cam disc R, which in turn is connected wlth the casing A by a cross comprising two pairs of pins 1" and S, arranged at right angles to each other. The axes of the two palrsof pins 1" and S intersect in a point 0, formlng the center of the cross, and lying in the axis of the shaft B. Cam disc R bears through a ball bearing T on a hearing member B, which is so adjustably mounted on a disc B rigidly connected with the shaft B, that it can turn relatively thereto about an axis which stands at right angles to the axis of the shaft B in the center point 0 of the cross 1", S. To adjust the bearing member B, a sleeve C is provided, which is slidable but not rotatable on the shaft B, driven, for example, by an electric motor of constant speed. The sleeve C is provided on both sides of the shaft B with rack bar 0 which engages a gear sector U. Each of the sec tors U is rotatably journalled on a bridge rigidly connected with the disc B and meshes with a gear segment 6 mounted on the bearing member B, so that the latter can be turned relatively to the disc B rigidly connected with the shaft B. by a displacement of the sleeve C about its axis passing through the point 0. By this displacement of the sleeve C a variation of the length of the stroke of the piston L can bebrought about in a known way, and a shortening of the length of stroke takes place when the muff C is displaced in the direction of the arrow w. With a stud (1' one arm of the bellcrank D engages a groove 0' in the muff C, the arm being pivotally attached to the housing A of the pump. The other arm of the bell-crank D is, by means of an intermediary link E, connected with a single-armed lever F, which is pivotally secured on the housing A. This lever is positively connected with a piston rod H, of a starting piston H running in a cylinder A, through the intermediary of a sliding piece G, hinged to the lever and running in a slot in the piston rod H.

Every position of the starting piston H corresponds then with an exact position of lcad qftnsstcumulator pist on;

the mud C, and, as a consequence, with an exact stroke-length of the pump piston. The starting or regulating piston is representedon the drawing in a position corre- 5 spondin to the greatest stroke-length, in which the production of the pump is equal to the mean water consumption in the pressure conduit." The 'dirction in which the piston H moves during a' diminntion of the strokeinder A stands in connection with the pressure conduit a through a, pipe of, which is attadh edto"thh right' end of the cylinder,. Where the piston rod H extends. The left end of the cylinder A is, by means of a,

pipe J,- connected with ap-ressure tank shown) acting as power SO'lilI'dGl" j The accumulator is provided with a-z-disk piston K, havingapiston rod on*ohe side (not rod K'- gees through; the cylinder Mis connected with the'pressu'rcconduit a3, through a passage m, and at "its lower end; through J whic leads'tothev shown).

The active pressure area of the piston K,

at the' end nearest the pressure-tank,'-is denotedby R; and the smaller activearea at trlnediary ofa pressure plate N surrounded by a cap '7??? when the piston has reached within a certain small distance from the bottoinof the cylinder M, as shownby dotand-dash lines onthe drawing. When" the piston gets still closer to tlie'botto'ni" of the cylinder, the spring'beromes compressed and W tends to lift the 'iston.

In describing t e manner of" operation of the pumpin'g'plant; it will be supposed'that first the'w'ater consumption is greater than the production of the pump,. so that the excess water" consumption must' be compensated for by the accumulator. During the" igndition' of inertia, the accumulator piston the"springfhas be'n liberated by the collar is es" on the piston rod K.

v pressureexistingover thepiston isnow denetewi by 35, while the power sourcepressure under the piston is denoted b 39 The i ugh the length is indicated by an arrowy. The cyl and running nr'an upright -standing cylini-d. derMi At itsfup pe'r endwhere the piston.

a passe m it isconnected with thepipe' pressure) tank (not moveswith uniform'spee'd upwards after The correct fluid ower source pressure, is consequently p F he following equation may now be written On the regulating piston H the fluid pressure now acts, in the direction of the-arrow y,'with' a force of a magnitude and in the opposite direction the power A source pressure acts with a force-of the magnitude p In opposite direction to arrow y 'a renitude As new the proportionis greater than ft n 1n opposlte direction to arrow is always ppsltlve' and becomes so great;

ysuitabl selection of values and thatzthe'reglp" lating'piston" H; in the case under consid-: eration, always adjusts itself accurately-in the position that corresponds to the greatest stroke-length. The re lat'ing. isten camnot therefore, clearly a justitsel in any position' that represents a shorter stroke-length. which by longer continuation of the water consumption in excess of-the greatestproduction of the pump, wouldcause a too' early emptying of the accumulator,

Supposing now, that the water consumption becomes less than the greatest waterroduction'of the pump; the excess quantity" of water produced by the pump then flows throu h the passage m in the accumulator and t e piston K moves downwardly Thefluidpressure existing above the piston K then at first remains practically constant and the regulating piston H- is therefore:

sultan-t force consequently acts of a mag-f F consequently the resultant force-acting.

further held in its position representing-the I greatest stroke-length. This condition remains untilthe collar -10 of the accumulator piston Strikesthe pressure plate N, and the' piston con'sequentl reaches its almost 1owest position. A rther movement of the accumulator piston is now onlyipo'ssibl'e a compression of the spring pressure above the accumulator'piston-and in the pressure conduit must consequently increase during continued compression of the spring. Finally, the force, acting in the direction of the arrow y and generated by the fluid pressure on the regulating piston H, attains an excess over the forces acting in the opposite direction, and the regulating piston H starts now in the direction of a shortened stroke-length of the pump.

By suitable selection of proportions and particularly by correct choice of strength for spring P, it can be easily attained that at the beginning of the movement of the regulating piston H, a sufiiciently greater fraction of the excessive quantity of water enters the accumulator, so that during the ac celeration of the regulating piston H and the other regulating parts which are displaced by the latter, there will be avoided, with certainty, undesirable shocks.

As soon as the regulating piston has an rived in the position wherein the production of the pump is the same as the water consumption in the pressure conduit, the piston comes to a standstill. Then a fluid pressure will occur in the pressure conduit that lies so much above the normal operating pressure p ,.that it equalizes the force acting upon the regulating piston generated by the power source pressure 39 Simultaneously the accumulator piston K comes to rest in its lowest position, when the spring P is compressed so much that the spring pressure and the force exerted upon the piston K by the power source pressure g0, equalize the force exerted by the increased fluid pres sure.

If thereupon a water consumption should take place, that is in excess of the production of the pump corresponding to the greatest stroke-length, then the fluid pressure in the pressure conduit sinks so'that the equilibrium is broken between the force acting against the regulating piston H and the force acting against the accumulator piston K. Both pistons then start to move; the regulating piston H in the opposite direction to arrow 1 or, in other words, in a direction of an increase of the stroke-length of the pump; and the accumulator piston K lit) in an upward direction. As soon as the accumulator piston has risen so hi 11 that the collar has released the spring the correct operating pressure p will again be obtained in the pressure conduit, through -which the force exerted by the power source pressure 1),, upon the regulating piston -H will be in excess of the forces acting in the opposite direction, as has been described hereabove.

Claims.

1. A regulation device for piston pumps with shaft drive and variable stroke-length, comprising an accumulator cylinder connected to the pressure conduit of the pump, a piston in said cylinder and means for controlling the fiuid pressure therein whereby the fluid pressure may be increased when the accumulator piston has been displaced by the fluid pressure to the end of its stroke, a regulating cylinder likewise connected to the pressure'conduit of the pump, a piston in. said regulating cylinder controlling the stroke-length of the pump iston during the operation of the pump,said controlling piston being adapted to be displaced by the fluid pressure in the direction of a diminished stroke-length, and means whereby the controlling piston is automatically operated in opposite direction, said controlling piston being so proportioned that it is held in a position correspondin to the greatest strokelength, before the uid pressure in said accumulator cylinder has been increased by said fluid pressure controlling means.

2. A regulating device in accordance with claim 1, wherein the means for controlling the fluid pressure in the accumulator cylinder are adapted to be actuated by the movement of the accumulator piston when near its extreme position which corresponds to the greatest accumulator contents.

3. A regulating device in accordance with claim 1, wherein the accumulator and the controlling piston are constructed as disk pistons, said pistons having difierent areas on both sides thereof, said accumulator cylinder and regulating cylinder being connected on the side of the. greater area with a pressure tank, the proportion between the smaller and the larger pressure areas of the accumulator piston being greater than that for the controllin piston.

4:: A regulating evice in accordance with claim 2, wherein the accumulator cylinder is provided with a spring, said spring being ositioned so as to be engaged by the accumulator piston, substantially as and, for the. purpose .set forth.

lhe foregoing specification signed at Essen, Germany, this 17th da of June, 1920.

- FRIEDRIC MARTIN.

In presence of Hans Gor'rsmann, JOHANN Dnorsnns.

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