US2654326A - Constant delivery pump - Google Patents

Description

Oct. 6, 1953 Filed Oct. '7. 1948 R. T. sHEEN ETAL 2,654,326

CONSTANT DELIVERY PUMP 5 Sheets- Sheet l Oct 6, 1953 R. T. SHEEN ET AL CONSTANT DELIVERY PUMP Filed Oct. 7. 1948 5 Sheets-Sheet 2 @AQ-SMA LIZ.

Ro @www/ Oct. 6, 1953 R. T. sHEl-:N ET AL 2,654,326

CONSTANT DELIVERY PUMP Filed oct. '7. 194e I 5 sheets-sheet 5 INVENTOR 6 eeid Oct 6, 1953 R. T. SHEEN ET AL 2,554,326

CONSTANT DELIVERY PUMP Filed Oct. 7. 1948 5 Sheets-Sheet 4 v 'A/ l l l A NQ A w1 '4 i b 8m u *tg A` E :l I O l gmk-" S V' Sr INVENTORS.

Patented Oct. 6, 1953 CONSTANT DELIVERY PUMP Robert T. Sheen, Wyndmoor, Pa.,l Royal Bartlett Saalfrank, Gulfport, Fla., and John W. Welker, Jenkintown, Pa., assignors to Milton Roy Company, Chestnut Hills, Pa., a corporation of Pennsylvania Application October '7, 1948, Serial No. 53,232

(Cl. 10B- 170) Z Claims. 1

The present invention relates to constant delivery pumps of the character which will produce a uniform or constant output throughout the pumping cycle.

A purpose of the invention is to simplify the design, construction and maintenance of constant delivery pumps particularly with respect to the cams which are employed.

A further purpose is to accomplish change in the pump delivery by change in speed Without change in the constant level of the delivery throughout the pumping cycle.

A further purpose is to design the constant delivery pumps so that cam calculations can more Areadily be made for differences in pressures, viscosities, speeds and volumes.

A further purpose is to permit the control of the output of a constant delivery pump by speed change, while providing corrections for one pump with respect to another in the constant delivery pump assembly, so that the delivery at one level will be constant throughout the cycle.

A further purpose is to reduce the number of Vparts and particularly to reduce the number of connections and the amount of lost motion possible in the operating mechanism of a constant delivery pump, while at the same time obtaining less frictional loss and greater eiiiciency, particularly avoiding the production of vector components of motion Which are not directly useful in the pump operation.

A further purpose is to arrange the operating mechanism to and including the cams in straight line -relation along a plane which includes the centers of the lines of motion of the pumping elements' so as to obtain maximum effectiveness -particularly at high pressures and at high speeds of operation.

A further purpose is to mount the cams on a cam unit which extends through the interiors of yokes which interconnect with the pumping elements, the yokes desirably being supported and guided at both ends of the bifurcated portions.

A further purpose is to drive the cam unit through a Worm wheel forming part of the cam unit and desirably to operate the Worm wheel from a worm unit consisting of a Worm, shaft and bushings capable of being removed as a unit. A further purpose is to provide great accuracy of support of the cam unit by turning it on a shaft supported at opposite ends of the cam unit comparatively remote from the center, and preferably to use a stationary shaft on which the cam unit turns with bearing support being provided by a bushing.

Further purposes appear in the specification and in the claims.

In the drawings we have chosen to illustrate a few only of the numerous embodiments in which our invention may appear, choosing the forms shown from the standpoints of convenience in illustration, satisfactory operation and clear demonstration of the principles involved.'

Figures 1 Iand 2 illustrate one embodiment of the invention.

Figure 1 is a sectional plan View of a constant delivery pump in accordance with the invention, the section being taken on the line I-l of Figure 2.

Figure 2 is a sectional side elevation of Figure 1, the section being taken on the line 2-2 of Figure 1.

Figure 3 is a view corresponding to Figure 2 illustrating a variation.

The preferred embodiment of the invention is illustrated in Figures 4 to 6 inclusive.

Figure 4 is a sectional plan view of this embodiment, the section being taken on the line 4-4 of Figure 5.

Figure 5 is a vertical section of Figure 4 on the line 5 5.

Figure 6 `is a vertical section of Figure 5 on the line 6,-6.

Figure 7 is a front elevation of a further embodiment of the invention.

Figure 8 is a diagrammatic circuit diagram of va speed changer which may be employed in the invention. y

In the drawings like numerals refer to like parts throughout.

Describing in illustration but not in limitation, and referring to the drawings:

Efforts have been made in the past to obtain vectors are introduced. These prior art designs have not been capable of suiiicient structural support of the moving parts to permit safe operation at high pressures and have not been susceptible of suiiicient balance to permit operation at high speeds. Frictional losses in the prior art `forms lhave been high and efficiencies have accordingly been low.

The present invention is designed to overcome these diiiculties and to produce a much simplified and less expensive form, which will have fewer moving parts and particularly fewer cams, fewer points of interconnection and therefore less danger of inaccuracy from lost motion, less frictional loss and greater efficiency. In the present invention a straight line relationship is maintained at the point of cam force application, so that no motion component is introduced which is only partially applicable (through a resultant) to the motion of the pumping elements.

In accordance with the invention the great simplicity of the design and the support provided for all elements permits operation at high pressures. Likewise the extent of support and the possibility of dynamically balancing permits operation at high speeds.

Cam correction is greatly simplified by the present invention. Not vonly are there fewer corrections since no corrections are necessary for change in angularity of positions of the operating parts, but also those corrections made are simplified.

It will be evident that each of the pumps (two or more) which makes up the constant delivery pump has a cam which is respectively out of phase with the cam of another pump. Thus if there are two pumps the cams will be approximately 180 out of phase. If there are three pumps, the cams Vwill be approximately 120 out of phase. In the preferred practice however this gure is not exact, since there is preferably an overlap at the beginnings of the pumping strokes of individual pumps, so that with two pumps the pumping stroke of each pump will preferably be somewhat greater than 180.

The detailof the cam corrections forms no part of the present invention and has been set forth very fully in Saalfrank U. S. application Serial No. 27,294, filed May 15, 1948, now Patent No. 2,620,734, for Constant Delivery Pump, incorporated herein by reference. Suffice it to say that the cams are corrected so that the total delivery .of all pumps is the same at all points in the pumping cycle, and this remains true notwithstanding change in the volume of delivery- Corrections are made in the preferred embodiment for pressure, viscosity, speed and volume, but the pump delivery will remain constant over a wide variation in capacity once the corrections are applied.

Due to the straight line character of the cam action and the elimination of extra parts, the application of cam corrections for the various factors is greatly simplified, since vectors do not require consideration.

In accordance with the present invention the change in volume of delivery of the pump is accomplished by change in speed without in any wayimpairing the uniformity of delivery at a particular level.

The accuracy of the device is greatly improved by mounting the cams together in a cam unit which turns inside the interiors of yokes, and which is supported at relatively widely spaced points by a cam shaft. The cam shaft is preferably stationary and the cam unit preferably is provided with a bushing on the shaft. Likewise in the preferred embodiment the worm which drives the cam unit is assembled with its components as a separate unit before insertion into the mechanism, thus greatly facilitating assembly.

As shown in the form of Figures l and 2, the constant delivery pump comprises pumps and 2l having a common inlet 22 and a common outlet 23. Each pump has a cylinder 24 and a pumping element 25. The pumping element may suitably be a piston passing through a stuffing box 26. It will be understood of course that the pumping element 25 may be of any suitable typey and the detail of this element is not important to the present invention, the question of whether it be a piston, diaphragm or bellows not being critical.

The pump may be of any of a wide variety of types, but will preferably conform to Milton Roy Sheen U. S. Patent 2,263,429, granted November 18, 1941, for Pump, or U. S. Patent 2,367,893, granted January 23, 1945, for Liquid Pump. The cylinder block 21 has inlet valve passages 28 which contain inlet valves 30 and 3l, preferably of the ball type, and the outlet passages 32 have additional valves 33 and 34 which are also preferably of the ball type. The respective inlet valves are in series and the respective outlet valves are in series. The pumping elements 25 include extensions 35- in the form of plungers which are effectively part of the pumping elements and are united thereto by tubular nuts 36 suitably threaded to the extensions and surrounding enlarged ends of the pistons. The extensions 35 may be comparatively short as shown in the form of Figures l and 2 and of Figure 3, or may be elongated and yoke-shaped as shown in Figures 4 to 6 inclusive.

Ail of the pumping elements are aligned side by side and the center lines of motion of the pumping elements include the center lines of motion of the extensions 35. Thus it will be seen that these center lines of motion lie in the same plane whether there be two pumps or more than two lined up side by side. In this plane is located the center of a follower 31, suitably a rollery pivoted on a pin 3B.

A cam unit 40 operates the followers. In the form of Figures l and 2 the cam unit comprises cams il and 42 having face cam tracks 43. The cam tracks conveniently face towards one another in the case where two pumps are employed, and the followers occupy positions in the cam tracks.

Located intermediately between the cams, coaxial therewith and connected thereto is a worm wheel 413. Spacers 45 suitably occupy positions between each cam and the worm wheel to properly position the cams.

A sleeve or bushing passes through the interior of the cams, spacers and worm wheel, and provides internal bearing for them. The cam unit is united together by bolts 4l extending through the cams, spacers and worm wheel.

The cams are arranged approximately out of phase, as shown in Figure 2, and each includes correction for the other as set forth in detail in Saalfrank application above referred to. Thus with the correction provided there will normally be a slight overlap cf the pumping strokes, (one pump beginning the pumping stroke before the other finishes), but the volume delivered by the pumps in the aggregate will be the same, Whether a single pump is providing the output or a plurality of pumps are at the moment contributing to the output.

The cam unit is rotatably supported on a shaft i8 whose center is in the plane above referred to which includes the lines of motion of the centers of the various pumping elements. The shaft is transverse to such lines of motion. Collars 48 center the cam unit on the shaft. The shaft is preferably stationary, and is supported in a housing 50 at two widely spaced supports 5l, so that In operation of any of the forms, it will be seen that once the device is assembled, it is merely necessary to vary the speed adjustment to obtain constant delivery at any output level. The particular type of speed changer used will vary widely to suit the individual installation. The type of arrangement shown in Figure 7 may be employed with particular advantage where a chemical reaction is involved and it is desired to supply several different chemicals by the pumps 10|, 102, |03, but to have the system independent of fluctuations in the electrical source.

It will be evident that in all of the forms shown there is a straight line relation provided between the motion of the 'pumping elements and the cams. Aside from the connection between the followers and the cams, there is no possibility of lost motion. The moving parts which accomplish the main operation are limited to the cam unit, the followers and the pumping elements with their extensions. Very little frictional loss can occur and maximum eiiciency is obtained.

In making the cam corrections, allowance does not have to be made for complicated vectors as in other devices. Corrections can easily be applied to the cams for the different variables which may apply to the individual installation.

The structure is unusually rugged and even in case maintenance is required it can easily be performed. The wide spacing between the points of support of the cam shaft assures accuracy in the cam positions notwithstanding that slight wear may occur. The rear or Outrigger bearing on the 'yoke assures accurate yoke alignment and elimination of any tendency of the yoke to whip or I jump. The installation of the cam unit as a subassembly and the similar installation of the worm unit as a sub-assembly makes it possible to change these units readily at any time, as for example where it is desired to make an inspec.

tion, to replace worn parts, or to change the application of the pump to a different service, and therefore to use a different set of cams having different corrections.

The prase common inlet and outlet, as used in the claims, is defined to include any case where the pumps draw from a common source and discharge into a common system, whether this is by means of manifolding at the pumps or by means of separate -pipes to the source or system.

In view of our invention and disclosure variations and modications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benets of our invention without copying the structure shown, and We, therefore, claim all such insofar as they fall within the reasonable spirit and scope of our claims.

Having thus described our invention what we claim as new and desire to secure by Letters Patent is:

1. In a pump having constant delivery at any setting and variable delivery constant throughout the cycle at various settings, a plurality of pumps aligned side by side and each having an aligned pumping element in parallel relation facing in the same direction and having a common inlet and outlet, a yoke extending in prolongation and secured to each pumping element, having a bearing on either side of a bifurcated yoke portion, the bifurcated yoke portions being arranged side by side in the various yokes, a follower on each yoke having its center in a plane which includes the center lines of motion of the pumping elements, sliding bearing supports for the portions of the yokes at opposite ends of the bifurcated portions, a' shaft extending through the bifurcated portions of the yokes, a cam unit comprising a cam for each follower and cooperating therewith, a gear between the cams, a bushing on the interior of the cam unit journaling on the shaft and connecting means extending through the cams through the bifurcated portions of the yokes and through the gear and uniting the same together to form the cam unit, a stationary cam shaft extending through the bushing, and having support at the opposite ends of the shaft on either side of the cam unit, a

drive having a gear interconnected with the gear on the cam unit and a speed changer on the drive.

2. In a -pump having constant delivery at any setting throughout the cycle and having variable delivery at various settings, a plurality of pumps having pumping elements aligned and extending in the same direction and having a common inlet and outlet, a plurality of yokes each extending in the direction of the line of motion of one of the pumping elements and connected thereto, each yoke having a sliding bearing portion at opposite ends of a bifurcated yoke portion, and the bifurcated yoke portion of the various yokes being arranged side by side, sliding bearings for the yokes engaging the bearing portions at opposite ends of the bifurcated yoke portions, followers on one side of each yoke having their centers in the plane which includes the lines of motion of the pumping elements, a cam unit extending through the interiors of thebifurcatedportions of the yokes and rotatable on an axis in the plane including the lines of motion of the pumping elements transverse to such lines of motion, said cam unit including a cam operatively interconnected with each yoke, the cams being respectively out of phase and having corrections for one another to the extent that the delivery of the pump for any capacity is constant throughout the cycle, said cam unit also having a 'worm wheel interposed between the cams at a position between the yokes, and said cam unit having f astening means extending through the cams and the worm wheel and uniting the cam unit together as a single unit, a, Worm unit including a worm cooperating with the worm wheel, and including a shaft and removable bushings, the worm unit being removably mounted with respect to the Worm wheel, and a support mounting the bushings for the worm unit.

ROBERT T.` SHEEN. ROYAL BARTLETT SAALFRANK. JOHN W. WELKER.

References Cited in the iile of this patent UNITED STATES PATENTS Number Name Date 780,130 Salzer et al Jan. 17, 1905 782,597 Cheshire Feb. 14, 1905 797,742 McCord Aug. 22, 1905 1,005,515 Cooley Oct. 10, 1911 1,018,483 Cousans Feb. 27, 1912 1,748,443 Dawson Feb. 25, 1930 1,766,610 Davis June 24, 1930 1,795,197 Compton Mar. 3, 1931 1,910,636 Pownall May 23, 1933 2,263,657 Towler et al Nov. 25, 1941 2,349,161 Frimel May 16, 1944 FOREIGN PATENTS Number Country Date 679,092 France Jan. 5, 1930

Images