US2612839A - Variable-delivery pump - Google Patents

Description

Oct. 7, 1952 Q H, DENNY Y 2,612,8,39

VARIABLE-DELIVERY PUMP Md; NSMQQM C. H. DENNY VARIABLE-DELIVERY PUMP oct. 7, 1952 SHEETS-SEET 2 Filed Sep\',. 2, 1947 Patented Get. 7, 1952 'Carta-n H. Denny, Seattle, iWaslh., assigner. to Webster-Brinkley Co.; Seattle, Wash., a c0rpo' y ration of Washington Application September 2, 1947, Serial No`.`77l,764

tory connection, and providing means bywhich, one of the two pistons of a, pair may be regulated4 at will from substantially zero to full` WorkingI stroke.

It is a further and important object of the invention to provide a pump for the purpose described particularly designed in a manner `which permits a battery of pumping units to be compactly assembled together and driven from va single power shaft common to all, reserving to each pump, however, complete independence in respect of pumping output.

With the above and other obJects and advantages in View, which will appear and be understood in the course of the following description and claims, the invention consists in vthe novel 4 Claims. (Cl. 10S-38),

construction and in .the adaptation and comr' bination of parts. hereinafter described and claimed.

In the drawings: n Figure 1 is a view partly in top plan and partly in horizontal section illustrating `a battery ,of

four pumping units constructed to embodythe preferred teachings of the present invention.

Fig. 2 is a vertical sectional of Fig. 1; and Figs. 3, 4 and 5 are fragmentary vertical sectional views on lines 3-3 of Fig. 2, if-4 .of Fig. 2, and 5`5` of Fig. 1, respectively. Y Y

According to the present invention there. is provided a suitably driven power shaft lll journaled in bearings ll carried upon the bed plate i2 of a machine frame, and either fixedly secured to or made an integral part of this shaft are one or more concentric hubs 9. Secured, asy

by the bolts E3, to oppositel end faceslo these hubs are eccentrics I4 and I5. The mountingvo,

these eccentrics, which are identicaLis such-that the low point of one coincides with the hghvpoint of the other, and which is to say that `one eccentric is shifted about the axis of the shaft '180 from the other.

As before stated, each pumping unit'is ycorriprised of a pair of reciprocating pistons placed one to the front and the other to the rear of a transverse median line taken through the hub,y and there is provided one such pair of pistons"V at each side of each pair of eccentrics with the pair at one side being directly opposed to the view on line 2--2 pair-at' theother iside. One'eccentric opn'eratesv one piston of each? of the two units while the other eccentric =acts upon the other piston vofeach saiduniti Inasmuchf as the structural nature ofv the'severalpumping units isridentical, it willv suiii'ce vto1d`e`st'zribe"indetail only .a vsingle saidunit. "l .J 1I f" The pistons in question are denoted viandv l1 andxworkwin respective cylinders, as IS antik-I9; bored from fthe inner end of .a single block 2! rigidly bolted to the bedfplate, and also 'provided inthe block `are relatively deep counter-bores, as 2| and 22'.. Piston vrods'23 and 24, rigid with the pistons, extend axially through the counter.

bores, and maderrigid with the outerA ends .of Y

theserods are forkedv'cro'ss-heads 25fjournale'd for end-wise movement in slide-Ways of a guide-1v block 26, the guide-block occupying*v a ,positionv between' the cylinder block andzthe driven'eccenidlyboltedto'thej bed-plate ofwthe machine' frame. Received between the fork-arms of'thei respective. cross-heads is a `rotatively-journaled roller -21 arranged to trackvupon the related ec-`V centric, `andf tojyieldingly urge these-rollers into;

In theinstance of one of thetwo counter@ bores,'=the upper wall is slotted longitudinally forA Y the major, part of .'thelength, l'and' received through and more or less closely fitting vthisslot', which I denote 3i, is an arm formedcasan in-y tegral dependencyof` a traveler-nut 32, the armv having a` iurcate f extremity '33 str'addling the piston-rod at the louter side ofthe collar. 30. Functional to the traveler nut is a feed-screw designated 34 whichffinds a rotary journal atlits two ends 'in bearings 35 and Vlili bolted to .the cylinder block. For turning the feed-screw a-y knurled knob 3l is pinned or."otherwise fixedl'y secured. thereto, and 'acting as a complement g to the Vknobfor resisting endwise thrust transmitted from the pistonrodto the travelernut is a`pinv 38 working in l'a'circumferential'groove of the'y feed-screw.

Induction and eduction pipes have shown these pipes as connecting one'fwth one cylinder and the other with the o-therucylinder of'fa pumpingunit,introducingfto each' said pipe anon-rerum valve; las 42 and In.' J-rfn traer that. 1 `roth the inductionand the @duction 'pipes W111i for. 'the "sume" are indicated by 4t'- andl lil, respectively, andfI' and having both the induction and the eduction pipes connect through non-return valves with..

this manifold. While using simply a ball check as the non-return valve for the induction'side of` the pump, I find it desirable to employla springclosing valve for the eduction side, incorporating a control wheel 46 for regulating the pressureof g the spring.

The operation of the pump is as follows:

Assuming that the traveler nut 32 is shifted by operation of the control knob 31 to bring the nut to the end limit of its travel working toward the closed end of the slot 3 I, the collar 30 of the piston-rod 23 will be then responsively retracted to a degree which places theroller 21 of its crosshead 25 radially at or beyond the outermost compass of the eccentric I4, and the result is to immobilize the .piston I6, the piston' I'I meanwhile working through its full stroke, in opposite directions of reciprocation. This working travel draws into the cylinder in each intake stroke a volume of fluid corresponding to the full displacement of the piston, and in the following discharge stroke such volume of fluid is expelled to the eduction pipe. This discharge represents the maximum pumping capacity of the pump. Now assuming that it is desired to reduce the output, the operator simply turns the feed-screw to shift the traveler nut inwardly toward the eccentrics, and the reduction in output will then correspond to the relative degree `to which the immobilized piston is now permitted to move as its related roller 21 is brought into the operating sphere -of the eccentric I3, this permitted movement counteracting a corresponding travel of the other piston I1 and the pumping efficiency being consequently reduced to that amount of fluid which the piston I1 will displace in its remaining travel. Should the traveler now be shifted rearwardly to the full extent of its sliding movement and such, more especially, as to bring the. same into the position in which it is shown in Fig. 2, the related crosshead 25 will then reciprocate through the full degree of its permitted travel and responsively transmit to the piston I6 a stroke travel exactly corresponding but converse to the reciprocal movement of the piston I1, the fluid then simply circulating from the one to the other cylinder with zero pumping output.

-It will be apparent from an inspection of Fig. 1 that each of the multiple pumping units admits of being independently controlled, and a system such as I have here described hence becomes especially advantageous as applied to operations which call for the simultaneous pumping of a severalty of different fluids for delivery in necessary predetermined ratios. The fact of the several pumps each having a common powering instrumentality and working under identical conditions gives positive assurance that the pumping output, relatively speaking, will remain absolutely constant. y

The invention should be clear from the foregoing `description of my now-preferred and illustrated embodiment. Modifications may, however,

4 be resorted to without departing from the spirit of the invention, and I accordingly intend that the hereto annexed claims be read with the broadest scope commensurate with the language used.

What I claim is:

1. In a variable-delivery pump: the combination of a rotary drive shaft; a pair of identical eccentrics iixedly secured in axially spaced relation upon the drive shaft with the high point of one placed to coincide with the low point of the other; a pair of identical fluid pumps placed radial to the shaft in side-by-side relation and each .comprising a cylinder and a reciprocally 'acting piston working in the cylinder and with "the pumping chambers of the two cylinders in constant communication; a guide-block between the pistons and the eccentrics; piston-rods rigid with the pistons and each carrying a forked cross-head slidably journaled in the guide-block; respective rollers arranged to track upon the periphery of the eccentrics and journaled for rotary movement between the fork arms of the cross-heads; springs acting upon the cross-heads to yieldingly hold the rollers against the eccentrics; and adjustable means acting counter to the thrust of one of said springs and operating upon the piston-rod to serve as a stop for variably limiting the stroke travel of the rod.

2. The structure of claim l in which the piston-rods are each provided with a collar arranged to receive'thevthrust of the related spring, and wherein the stop means comprises a feedscrew and a traveller-nut working upon the feed screw and providing an arm extending into the path of travel of one of the collars to interrupt the collar as the latter moves by the thrust of the spring from the high to the low point of the related eccentric.

3. In a variable-delivery pump: a pair of fluid pumps each comprised of a reciprocally movable piston anda cylinder for the piston and characterized in that the pumping chambers of the cylinders are in constant communication, one of said pistons having a constant stroke travel while the other piston admits to adjustment of its stroke travel; means for imparting reciprocatory movement to said constant travel piston; means including ya power-driven eccentric and a counter-acting spring for imparting reciprocatory movement to the adjustable-travel piston, the arrangement; being such that the direction of movement, pumping function considered, is opposite as between the two pistons; and adjustable means acting counter to the thrust of said spring and operating as a stop for the related y piston variably limiting the stroke travel thereof,

said fluid pumps both having an identical maximum uid displaced.

4. In a variable-delivery pump, in combination: a rotary drive shaft; an eccentric secured upon the drive shaft; a fluid pump placed radial to the shaft and comprising a cylinder and a reciprocally acting piston working in the cylinder; a guide-block betweenv the piston and the eccentric; a piston-rod rigid with vthe piston and carrying a forked cross-head slidably journaled in the guide-block; a roller arranged to track upon the periphery of the eccentric and journaled for rotary movement between the fork arms of the cross-head; a spring acting upon the crosshead to yieldingly hold the roller against the eccentric; adjustable means acting counter to the thrust of said spring and operating upon the piston-rod to serve as a stop for variably limit- 5 ing the stroke travel of the rod; a second uid REFERENCES GITED y Pump Which likewise comprises a cylinder and a' The following references are of `record in the reciprocally moving piston working in the cylinme of this patent: der and having its pumping chamber in constant communication with the pumping chamber of 5 UNITED STATES PATENTS the first-named fluid pump; and means acti- Number Name Date vating the piston of said second-named fluid 27,610 Borden Mar. 27, 1860 pump and so operatively interconnected with the 1,388,780 Stanley Aug. 23, 1 921 eccentric as to cause the two pistons to work in 1,502,195 Hicks, Jr July 22, `1924 timed concert but with the direction 0f mOVel0 1,640,509 Lowe Aug. 30, 1927 ment, pumping function considered, being Oppo- 2,32'7,787 Heintz --1 Aug. 24, 1943 site as between the two pistons.

CARTAN H. DENNY.

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