US1973180A - Pump - Google Patents

Description

P. L. SCOTT Sek. 119 E934.

PUMP

Filed oct. 20. 1930 -llill Patented Sept. 11, 1934 UNITED STATES 1,973,180 PUMP Philip Laue scott, san Mateo, Calif., assignmto Super Diesel Tractor Corporation, La Porte, Ind., a corporation of New York Application October 20, 1930, Serial No. 489,737

claims. (ci. 10s-14s) This invention relates to a pump and has for one object to provide a pump capable of handling small quantities of liquid with great rapidity and under high pressure.

Another object is to provide a pump of this type which shall deliver, at great speed and under great pressures, small quantities ofA liquid, irrespective of the total quantity handled or compressed by the pump. A further object is to provide a pump in which the quantity of liquid under high pressure may be kept at a minimum relative to the amount discharged by the pump. Another object is to provide a pump of this type in which. leakage past sliding surfaces is eliminated. Another object is to provide a pump in which there are no relatively sliding parts within the compression chamber of the pump. Another object is to provide a pump which, in its operation, will avoid mechanical shock.

Other objects will appear from time to time in the specification and claims.

In one form this invention is peculiarly adaptable to use for pumping or supplying liquid fuel to the spray nozzle of an oil engine. The particular requirements of this problem are `that relatively small quantities of oil must be delivered positively and with great rapidity at pressures which may be in the neighborhood of 10,000 lbs. per square inch and in some cases may be in excess of this, and with speeds which are of the order of magnitude of .001 of a second. The problem is further complicated by the fact that such pressures may have to be built up from zero to a maximum within .0001 vof a second.

In 'solutions of the problem which have been attempted in the past, it has been common practice to rely upon a plunger pump. The disadvantages of this type are many. It has been difficult to providea reciprocating'joint of sumcient tightness under the high pressures involved. There have been substantial metal masses to be accelerated and stopped and started. Such pumps do not lend themselves easily to the requirement that the total quantity of liquid under pressure shall be at a minimum relative tothe amount discharged at each discharge period. These and other diiiiculties are avoided by the pump of the present invention.

This invention embodies apump which in- 50 cludes va pump chamber having an elastic wall.

" The entire chamber wall-may be elastic or a portion of it may be elastic. 4Since the quantities of liquid to be delivered by the pump are small itl is possible to ilexsuch an-elastic wall or an.

55 entire elastic container an amount sumcient to secure the desired delivery of uid while keeping well within the elastic limit of the material. Since the quantity `of fluid delivered is so small and since the amount of movement is small, the elasticity of the container or its wall or a 00 part of its wall, is so slight that the container or the wall need not be formed as aspring, and,

in the ordinary sense of the word, it is the opposite of a spring. Nothing is done by shape or formation to make it. a spring and, in fact, a typical form of my invention involves va pump chamber in which the walls are of heavy steel and the amount of lexure which they undergo during the pumping operation may be of the order of .002 inches.

My invention is illustrated more or less diagrammatically in the accompanying drawing, wherein- Figure 1 is a longitudinal cross section of one form of the pump;

Figure 2 is a transverse cross section taken at line 2-2 of Figure 1;

Figure 3 is a view similar to Fig. 1 illustratingv a modified form of my invention;

`Figure 4 is a transverse section taken 4-4 of Figure 3.

Like parts are designated by like characters throughout the specification and drawing.

A is a pump body having a laterally oir-set portion A1 in which is provideda threaded cavity A11 in which are seatedan intake and an ex-V haust valve, described below. The pump body` A may have relatively raised portion A3 as i1- lustrated in detail in Figure 2, and upon this may be fastened a cradle A*1 which has an oval or concave groove A5 running along its outer edge.

B is a pump tube. It is threaded into the portion A1 of the pump body at one end and at its lower end is closed by a cap B1 which carries a pairv of ears B2 to which a drive rod B3 is pivoted as at B4. The drive may be accomplished in any suitable manner but its effect is to re' lat line -ciprocate the rod B3 'and to bend the pump tube l on the cradle.

In the modified form illustrated in Figures 3 and 4 the pump body A, A1 and A2 is the same as that shown in the earlier figures.l A cradle C which is generally the same as the cradle A4 is mountedv on'the -part A3 of the pump body A. 105

D is a pump tube .threaded at one end to. the pump body A1 and communicating with the cavity A21 in which are located intake and outlet valves. At its lower end it is closed by a cap D1 similar to the cap B1 and carrying ears D1. Piv- 110 oted to the ears D2 is a connecting rod D3 which is pivoted at its other end to a link D4 which is itself pivoted upon a shaft or stud D5. The link D1 carries a roller Di which contacts a cam D7 having a nose or raised portion D2. The cam is fixed to rotate about a shaft D9.

Each of the forms of my pump is provided with an intake and an outlet valve. They may be positioned so as to communicate with the cavity A2. The discharge valve is mounted in a housing E which is removably positioned in the portion A1 of the pumpbody. The housing E is provided with an opening E1 about which is formed a seat portion E2. A valve member E3 may be seated on the seat portion and is normally held seated by a spring E4.

F is an inlet valve housing positioned in the portion A1 of the pump body and communicating with the cavity A2. Within it a valve body Fl is mounted for reciprocation. It may be seated on a seat portion F2 of the valve body. A spring F3 tends normally to hold it in the 'seated position.

G is an air vent communicating with the cavity A2 in the pump body. G1 is a valve member carried on a valve body G2 which is mounted in a threaded perforation G3 and carries projections or handles G4 by means of which it may be readily rotated. The threaded portion G2 has a seat portion G5 in which the valve G1 may be seated. The valve G1 may be manipulated to open or close the air vent. Such manipula'- tion will normally be manual and will be carried out whenever it is necessary to free the system from air or gas.

It will be realized that whereas I have herewith shown and described a practical operative device, nevertheless many changes might be made in the size, shape, number and disposition of parts without departing from the spirit of my invention and I wish therefore that my showing be taken as in a sense diagrammatic. Particularly the form of pump chamber and the flexing mechanism might be almost infinitely varied. The entire chamber need not be made exible and need not be exed. The major portion of the pump chamber might be rigid and only a small portion might be iiexible. The air vent might be" omitted.

The use and operation of my invention are as as follows:

In the form shown in Figures 1 and 2 a steel tube is used. It is substantially straight and in normal position it is of oval cross section as shown in Figure 2. The upper end is xed and the lower end is free and by-means of the drive which is indicated diagrammatically in Figure 41, the lower end is oscillated or moved. The

particular form of driving mechanism will cause the oscillation to take place generally at right 'angles to the axis of the tube. This, however, is not an essential feature and for some purposes it Will be sufficient so long as the tube is bent in any fashion. As illustrated in Figure 1, the tube will be bent or drawn down to one side against the cradle and as its bending increases it is somewhat ilattened, the major axis being slightly increased and the minor axis being slightly decreased. T he bent position is indi cated in dotted lines. The decrease in cross sectional area decreases the volume of the tube content and increases the pressure within the tube, thus unseating the outlet valve and permitting discharge of a portion of the contents of the tube. When the drive mechanism moves in the reverse direction the tube is released from its bending or distorting load and tends to return to its original straight form. As this takes place, its elliptical.cross section increases in the minor axis to its original size, the volume of the tube again increases and thus the pressurelis reduced. Th'e inlet valve is forced open and a suction stroke occurs and liquid is drawn into the pump again. v

As illustrated in Figures 3 and `l the pump is initially bent. When the shaft D9 rotates the nose D8 of the cam Dr1 will contact the roller D6 and thus through the movement of the link D4 and the rod D3 the tube is moved in a straightening direction. This straightening movement of the curved or bent tube increases the volume of the tube, suction is developed, the intake or inlet valve is opened and Huid is drawn into the pump. Thus a suction stroke occurs. When the cam D8 passes beyond the roller the tube is free and moves or snaps back to its original bent position, thus decreasing its volume, raising the pressure within, forcing open the outlet or discharge valve and dischargingy uid. Thus a compression stroke occurs.

In each of the forms of the invention it is the pumptube or pressure chamber thewalls of which are exed. The amount of flexure is extremely slight and the tube itself is approximately rigid. It is not in any accepted sense to be considered as a spring or a spring form and it is given no particular shape to increase or accentuate any spring action.

The pump tubes of my invention, of any form, are subject to strains well within their elastic limit. This is accomplished without the necessity of corrugating, fluting or otherwise specially forming the elastic metal wall. The pump chamber is enclosed by walls, wholly or in part approximately rigid, capable of yielding minutely and of returning to their original position of their own elasticity when free to do so. If parts of the wall are not approximately rigid, they are rigid.

It will be understood that the degree of move ment or the amount of movement indicated for the tubes in the drawing is intended only to be diagrammatic and is exaggerated, and that the amount of movement of the tubes asshown is greater than it would normally be in practice.

I claim:

1. In a pump, a tubular member, intake and outlet means communicating with said tubular member and means for movingit, and a supporting member, contacting a portion of said tube and adapted to be additionally contacted vby the tube when it is moved.

cating with said tubular member and means for'v moving it, and a supporting member, contacting a portion of said tube and adapted to be additionally contacted by the tube .,when it is moved.

3. In a pump, a tubular member, intake and outlet means communicating with said tubular member, one end of the tube being rigidly held, the other being free for limited movement and means for moving it, and a supporting member, adapted to be contacted by the tubular member in its movement.

4. In a pump, a tubular member, intake and outlet means communicating with said tubular member, one end of thetube being rigidly held,

being rigidly held, the other being free for limited movement and means for movini it, and a curved supporting member provided with a groove, generally in axial augment with the tube and o! a cross sectional shape different from that of the tube.

PHILIP LANE SCOTT.

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