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Publication numberUS1128089 A
Publication typeGrant
Publication dateFeb 9, 1915
Filing dateMar 17, 1913
Priority dateMar 17, 1913
Publication numberUS 1128089 A, US 1128089A, US-A-1128089, US1128089 A, US1128089A
InventorsJohn Astrom
Original AssigneeFort Wayne Engineering And Mfg Company
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Differential pump.
US 1128089 A
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Description  (OCR text may contain errors)




Patented Feb. 9, 1915.




Application led March 17, 1913.

T0 aZQ/ war/,n 'it may Concern.

Be it -tnown that I, JOHN ASTROM, of Fort Wayne, Indiana, have invented a Differentia Pump, of which the following is a specification.

-The present invention relates to pumps,

more particularly pumps of that class which are on single action as regards the intake but :i 3 action as regards the discharge, 1g. in other werds, reciprocating pumps which discharge Water at each stroke but only take it in at every other stroke. Such pumps are commonly called differential pumps.

The'object -of my invention is to improve the design of this class of pumps. more particularly for small pumps of this class, by making them simple and easy to construct `and giving them a high efficiency.

I further aim to rovide means for equaliaing the flow of t e intake-water into the pump, 'thereby reducing sudden variations in velocity superinduced by the fiuctuation in the intake.

My invention consists in the constructions and combinations hereinafter more particularly described and set forth in my claims.

For the better understanding of my invention I have illustrated the same in its most improved form in the accompanying drawingswherein- Figure 1 is a longitudinal section of the oompletepump, and F ig..2 a transverse section thereof on the plane Q.

The piston-rod and pipes are shown in part eievation in Fig. 1 and the dischargepipe in Fig. 2.

The Vreference letters refer each to the same part in each figure of the drawings.

The `pump comprises a generally cylindricai barrel or casing A, preferably made in, a single casting; a pistonB reciprocating in said vaazrcl and carrying a hollow head if" on its lewer end, preferably formed integra? therewith; a. cup-shaped Ivessel C into tile upper end of which the barrei A deits and tc which it is secured in an airi j; ether elements v. Between the bard H inserted a (t fits the barrel place therein.

.if de- Specification of Letters Patent.

Patented Feb. 9, 1915.

serial No. 754,680.

sired. by means of a cup-leather E held in place between the bottom end of the pistonhead and the flange f5 of the valve Fwhich screws thereinto as shown. The piston-head b is a substantially cylindrical shell connected to the piston B by radial spokes b2, of which there may be any number (three are shown in the drawing), thus leaving ports b3 between them through which the water passes in going to discharge which is en the upper side of the piston-head.

ln the lower end of the barrel A is fitted the intake-valve G, which is screwed into the bottom-flange a2 thereof as shown. Both the intakeand discharge-valves open upward and may be of any preferred type adapted'to the purpose, those shown being ordinary pump-valves having rising and falling closure-disks f"and g held in place by springs f2 and g2' which rest against heads f3 and g3 screwed on to the central posts f* and g* of the valves.

Near its .upper end the liner D is formed with a plurality of apertures or ports d', which open into an annular chamber or recess a, formed on the inside of the barrel A, and herein'termed the dischargechamber. On one side of this chamber is an opening a, into Which screws the discharge-pipe H, into which pipe the water is delivered.

The intake-pipe I is screwed Vinto the lower end of the cup-shaped vessel C which an intake of less than atmospheric pressure,

a threaded aperture c4 which is closed by a screw-plug c, under which may be a sealing-gasket c. This plug c5 is termed the priming-plug for reasons which will presently appear. The upper end of the liner D is closed by a bushing J which has a tiangej extending over said upper end, the bushing itself fitting inside the liner. Over this is placed packing K. which is pressed into place by the gland L fitting into the upper end of the barrel A and pressed down by the gland-nut M.

It will be readily seen that the reciprocatien of the piston B causes the Water to pass upwardly through the valve F at each downstroke of the piston, While the valve G remains closed, and at the same time. to deliver part of said water, corresponding to the volume of the increased portion of the piston B within the cylinder, into the 'discharge-chamber a3 and thence through the discharge-pipe H; while on .the up-stroke the valve F remains closed, discharging an additional volume of water into the chamber as and pipe H, and at the same time drawing Water inwardly through the valve G from the vessel C. The volume of water delivered on the up and down-strokes will be equal or unequal according as the area of the piston is equal or unequal to half the area of the piston-head, as is true of differential pumps in general. y

The action of the vessel C is to equalize the flow of the intake by providing an aircushion or air-chamber 07. Where the flow of the water is under pressure it will, of course, flow into the chamber C above the lower end of the barrel A until it has compressed the air in the chamber c to a volume corresponding with the intake-pressure, i'f the pump is at rest, and the increased draft of water into the pump on the up-stroke of the piston will draw on this extra supply of water and not force it to flow at a high speed through the pipe, thereby avoiding unnecessary frictionloss ofy power which would occur in a small pipe. Where the pump is to be used for suction, this will also be true, as the pum will first draw from the chamber c" venoug- V air to effectively seal the lower end of the bai-rel A with water, consequently the pump is to a certain extent, self priming; but it may als'o\be specially primed by removing the plug 05 and after partially filling the chamber c with water, replacing said plug so as to seal the chamber. The air in the chamber c1 will then work under a vacuum corresponding with that of the suction.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is: I 1. The combination of an u right pumpbarrel providedl with a bore o uniform size from end to end and having in its upper portion an annular recess around the bore thereof and a discharge passage leading from said recess, a cylindrical liner fitting in the bore of said barrel and extending above said recess so as to cover the latter and having one or more ports or apertures formed therein to pass the water therethrough, an upwardly discharging intake-valve closing the lower end of said barrel, a piston reciprocating coaxially in said barrel and smaller than the bore of said liner and carrying a hollowhead having the same diameter as the bore of said liner, an upwardly discharging valve mounted in said head, a stuffing-box closing the upper end of said barrel, and a cup-shaped vessel into which thelower end of said barrel depends; said vessel being connected in an air-tight manner to said barrel and having a water-intake passage- Way at its lowei end and an air-aperture at its upper end, said air-aperture being provided with an air-tight closure.

2. In a differential pump, the combination cfa single-piece barrel having a straight cylindrical bore of uniform diameter throughout extending from end to end except for an inturned flange at the lower end7 and having at an intermediate point near the top an annular recess provided with an outlet; in combination with a straight cylindrical liner fitted neatly in said bore, and having ports opposite said recess forming in conjunction therewith an annular receivingchamber, the lower end of said liner resting against said flange; `an inwardly opening vah'e fitting within said flange and yclosing the bottom of 'said barrel; a piston carrying a hollow head and containing a valve and operating within said liner, a' closure-block bored to receive said piston and resting upon the upper endy of sald liner, and a stufiing box disposed within the upper: end of said barrel and restingupon saidv closure-block.

In-witness whereof I have hereunto set my hand in the presence of two witnesses.

JOHN' As'rRoM.



Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3340818 *Jun 28, 1965Sep 12, 1967Tuthill Pump CoReciprocating plunger type pump
US3469532 *Mar 25, 1968Sep 30, 1969Mcneil CorpPump
US3966360 *Jan 27, 1975Jun 29, 1976Greene James LContinuous-flow fluid pump
US4003297 *Mar 28, 1975Jan 18, 1977Du-Al Manufacturing CompanyHydraulic cylinder
US4009971 *Aug 27, 1974Mar 1, 1977Binks Manufacturing CompanyElectric motor-driven, double-acting pump having pressure-responsive actuation
US5407424 *Feb 24, 1993Apr 18, 1995Scimed Life Systems, Inc.Angioplasty perfusion pump
WO1981001445A1 *Nov 18, 1980May 28, 1981Bionostics SaDouble acting continuous flow system type pump
U.S. Classification417/543, 277/525, 92/142, 417/549, 92/171.1, 92/168, 92/163
Cooperative ClassificationF02M59/14, F04B11/0025