US2475703A - Automatic pump control - Google Patents

Description

My 12, 1949. A. J. GRANBERG AUTOMATIC PUMP CONTRO 2 Sheets-Sheet 1 Filed Dec. 27, 1943 INVENTOR A586??? J arm/awe ,0 ATTORNEY July M, 1949 A. .LGRANBERG Mmm AUTOMATIC PUMP CONTROL Filed Dec. 27, 19-45 2 Sheets-Sheet 2 n 5;; I e m Patented July 12, 1949 FFl-Gg AUTOMATIC PUMP EQNQRQII. Albert J- Granberg, Oakland; Galifi, assignor to Granberg; Equ pment, Inc:,

Oakland; Califr', a:

corporation of California ApplicationrDecember 27, 19.48; SflifilrgNl15I538r48i- 2. Claims. 1.

Mvvinventi mrelates to: p mps; and; ore. p ticularly to" pumps of F the variable displacement type.

Among; thehobjectslof my invention. are:

1. Toprovidea new and improvedzpump sWhOSE capacity range may; be; adjusted; in conformity with-.the loadxto be handledby thepump;

2.. To provide anew and'improved.pumpwonthe variable displacement type whose capacity range may: be r adjusted without? resorting to. an; interchanging of control springs;

3. To, provide anew and improved pump: capahlelofs automatically adjusting its output capace ity; inaccordancelw-ith, changing demands on. the pump.

4! Touprovide anewand improved':pump of' 'the variable displacement type, capable of meeting load demands thereon without by-passing; churning of liquid, or-waste of power.

5. 'Ioaprovidea new and improved pump: capable of automatically adjustingits output in accordancewith changing; demands 0n the pump andawhich is-protected against excessive surges without :reliance upon surgetanks;

Additional objects of my invention will be brought :out. in the following descriptioneoifalpre ferredembodiment of' the same, taken inconnection with: the accompanying drawings wherein:

Figure 1' is atop planviewrof a pump of my inrproved type;

Figure; 2is aside elevationalview; partly in section, exposing some ofi'the internaliconstruction;

Figure 3 isaviewin section in the planet-3 0i Figure: 1;.

Figure 4a is a view in section .in the 1 plane; 4&4 of: Figure 1;

FigurewSi. is anfragmentary section through i the valve and piston. chamber of Figuret, takenlon the: line 5.-5 of saiclfigure;

The. present invention is an improvementeupon the type; of pump disclosed. in. mysPatent No. 2,260,8051of Oct; 28; 194-1; and exceptsfor' theimprovement features constituting: the present invention, .the. structure of the two pumps :couldvbe identical.

Incommon withthe pump of. mysprion patent, my improved pump compriseswa casing i=1 having a. substantially spherical interior chambeniflprovided with an inletpassage SutheretaandJa dis- :hargepassage therefrom.

The interior working elements of thepun1pinzludegaa. discoidal piston. 9: hingedly connected to r. spherical. segment: I l both thevdiscoidal piston ind the; spherical segment-being rotatablyrdriven 2; through; a. corresponding spherical segment. (not exposed); connected toanend of adrive shaft. 13 and.hingedly. connectedto the discoidal-piston 9 attright, an lesto, the hingeaxis ofthe driven spherical segment... I II The. capacity. of. such pump is determined by the relative angularrelationship between the axes of. the spherical segments. With such axes in line, ,the-.pistom9 will rotate in a fixed plane, and theloutputzof. thenpump willbezero. As 50011 as one of: these sphericalsegments, however, is vangularly displaced with respectto .theotherspherical segment, thfirx discoidal. piston M will. be. caused; to wobble out of. its.aforementionediplane aslit, ro-- tates; thus-pausin the chambers between the piston; and: spherical; segments; to. alternately in?- orease andrdecreaser involume, whereby thepump will; take'in liquid;through the.- inlet passage 5 andr discharge the same through the; discharge passaget 'h Thevcapacitybf the. pumpwill increase as the an r-ularapositiontof one of the spher ical; segments; is: increased with respect to the Qtherrspherical';segment then IJHmDr'Ofa my: earlier patent previously referreda to;.the;'drivenspherical' segment is fixed at: that: angular: position whichdetermines the maximum outputiofm theapump; and. a: return bypass; valve; is: provided'ztowrecirculate, such excess dischargefas; is'rnotfi'demanded :by. the loadon the pump.

Ina accordance with the: present invention, instead:of maintainingsuchrangularaposition-fixed, Iiautomaticallyradjusttheangular :positionzofthe driven lspherical segment inaccordance withthe .loadedemandiorntheapump, wherebyethe pump will be causeditosdischarge orrly soxmuchqliquid' as. the loadrcalls-ibr.

'Iloraccompli'sh this. ,Icprovidegthe driven sphereica-llsegment; H with: a: stubshaft; l5' extending throughran opening -I1: in: the: pump casing, and apply; axdownwardaforcesto thisxshafti in, response tm-existingr pressures at, the discharge end; of; the pump; it being notedxthat. the; pressureon the dischargersidetofzthevpump willptend to rise as-the demanmonz; thes pumndecreases below: the full capacity of: thelpum'p- Aahousingr l,9,-.,having an open side is attached tovtheacasing. Iv, thelopenqside being closed by a wall-whore. piston-block .23r'bolted thereto. The

. stub; shaft lfirisr'surrounded by abearing 25.113;-

ing parallelsidesadapted to engagethe walls of the housing in sliding relationship theretmthe housing serving; to guideethe permissible movementlofithe driven segment LlIandstub shaftl5 inava; fixed; plane:

ance with the rise in pressure.

The stub shaft bearing is formed with an integral laterally extending stud 2T journaled in a bearing 29 carried by a piston iii in the piston block 23, such bearing extending into an elongated opening 33 through the wall 2! of the piston block.

The piston Si is hollow, and is biased by a coil spring 35 disposed in the piston block and urging the piston to its uppermost position.

The calibration of this spring is such as to be just sufficient to raise the stub shaft 55 and its associated spherical segment H to'its position of greatest angularity with respect to the drive shaft i3 and its associated spherical segment, during stationary or non-operating periods of the pump. Any pressure against this piston 31, therefore, will tend to reduce the angularity of the stub shaft and associated spherical segment toward a position of reduced capacity for the pump.

A passage 36 from the interior of housing IQ through the casing i to the suction side of the pump exposes the rear of the piston 3| to the suction line pressure thereby providing for quick response of the piston when the piston is exposed to pressures against its work surface.

This piston is exposed by Way of a pressureresponsive shut-off valve 31 and a passage 39 through the casing i, to the pressure conditions existing at the discharge end l of the pump, the piston thereby being made responsive to such pressures above that pressure at which the shutoff valve may be set to open;

Such shut-off valve is enclosed Within a valve housing M mounted on. the upper end of the piston block and having communication with the interior of the piston block by way of an opening 43. The valve is disposed horizontally, and is maintained in proper alignment with its valve seat in the housing by means of guide fins whose edges contact the inner walls of the housing on the intake side of the valve.

The valve 37 is biased to seating position by a coil spring 41 disposed between the valve and an adjustable back-stop 49 slidably supported within the valve housing by an adjusting screw 5| threaded therethrough. By means of this adjusting screw and back-stop, the effective calibration of the spring may be altered to change the opening pressure of the valve at will, within the limits permitted by the spring.

The opening pressure of the valve is preferably set at a value approaching the pressure in the discharge of the pump when operating at substantially full capacity. Under these conditions, the valve will be open for practically all periods of operation during which the demands on the pump are below a predetermined full load value. Below such discharge volumes, the pressure on the discharge side of the pump will tend to rise and this in turn will tend to reduce the angular position of the stub shaft and associated spherical segment with respect to the drive shaft in accord- Such reduction in angular position will, in reducing the capacity of the pump, tend to reduce the pressure on the discharge side, and this in turn will tend to relieve the pressure somewhat on the piston 3 l. Accordingly, one effect compensates the other and the stub shaft and associated spherical segment will assume a position of stable equilibrium at an angle to the drive shaft in accordance with the load demands on the pump.

Upon shutting down of the pump, the liquid trapped in the valve housing ll and piston block 23 would normally tend to preclude restoration Oil of the piston 3| and consequently the stub shaft l5 and its associated spherical element l l to their normal positions, which they should occupy during non-operating periods of the pump. I take advantage of the presence of such trapped liquid in assuring a relatively slow restoration of these elements to their normal positions, by providing a slight clearance between the piston 3i and the piston block 23 to thereby establish a by-pass for such liquid as the piston is forced upwardly to displace the same.

In connection with different pumps and installations, the amount of clearance between the piston 3! and the piston block 23 would ordinarily have to be changed. To maintain standardization of such parts and avoid the necessity of having to vary such clearance with different installations, I provide a passage 53 in the wall of the piston block connecting the work side of the piston with the interior of housin l9 and adjust its effective cross section by a tapered setscrew 55. Inasmuch as the upward movement of the piston will under these conditions force some of the liquid from the work side of the piston through the passage 53 to the rear of the piston, the rapidity of restoration of the piston to its uppermost position can thus be, to a certain extent, controlled through adjustment of the setscrew 55, thus eliminating the necessity of changing the original clearance to obtain a desired restoration velocity of the piston.

The pump thus far described is admirably suited for operation under conditions where the load demand on the pump may vary over a wide range of output values, such, for example, as would occur in an airport fueling installation, where the pump may be called upon to supply gasoline for the refueling of a single plane or a large number of planes simultaneously.

A problem encountered in such an installation, arises in connection with pressure surges generated by the inertia of the moving parts of the pump and drivin motor at such times as when the demand on the pump is rapidly reduced, and such surges are particularly bad when a number of outlets are shut off simultaneously. Such pressure surges develop within a split second and prior to the ability of the automatic volume control to respond sufficiently to hold such pressure surges down to safe values.

Accordingly, in cooperation with this automatic volume control feature, I provide the pump with a surge valve 51 whose construction may be identical to that disclosed in my aforesaid earlier patent, though its function and purpose are entirely different, in that the operation of the surge valve is cooperatively tied in with the automatic volume control feature as a protective feature whereas in my earlier patent it functions as a sort of discharge or volume control. Consequently while the surge valve 51 in the present inventior. does not necessarily differ in structure from thai disclosed in my earlier patent, its calibration an( operating pressure are correlated to the pressuri characteristics of the shut-off valve 31 and, a: will be pointed out, differ from what v they WOllk be when such valve is employed in the manne: of my earlier patent.

This surge valve is mounted in a valve chambei 53 which spans two openings El and 53 in th upper part of the pump casing I, the opening 6| communicating with the suction side 5 of thl pump and the other opening 63 connecting witl the discharge side 1 of the pump. The valve 57 is mounted in opening 63 which exposes it t the pressures on the discharge side of the pump.

This valve comprises a circular valve head 65 having a frustoconical surface adapted to seat upon a valve seat formed by a circular opening in a seating member 61 resting in the opening 63 on the pressure side of the pump, and retained in place by the valve housing 59 which spans the valve seat member and clamps it to the pump casing.

This valve seat member has integrally formed therewith valve guide means in the form of upstanding posts 69 disposed about the valve seat opening and a depending cylindrically shaped dash pot 1 I, the wall of which adjacent the valve seat being provided with openings 13 therein, enabling the admission of liquid thereto from the discharge side of the pump. The valve head 65 has depending therefrom an integral shank 15 extending into the dash pot 1| and terminating in a circular peripherally grooved flange 11, the flange making a rather snug fit with the inner wall of the dash pot below the openings 13 therein to enable said flange to act as a piston. Such flange 11 has a perforation 19 or a plurality of such perforations therethrough, and such openings are covered by a distortable disc 8|, spring biased against the under surface of the flange by a conical coil spring 83, which itself is maintained in position by a machine screw 85 extending through the center of the spring and threaded into the shank 15. The compression of the conical coil spring may be varied by adjusting the machine screw, thereby altering the pressure of the disc 8| against the under surface of the flange 11. The dash pot 1| is rounded out at its lower end to provide a chamber 81 in the dash pot below the flange.

The valve when closed, is maintained in its seated position by a valve spring 89 which bears at one end against the upper surface of the valve head 65 and at its other end, against the under surface of the lip of a flanged cup 9|. A valve spring adjusting screw 93; threaded through an opening in the housing 59 directly above the Flanged cup 9|, is adapted to enter and engage the Flanged cup and maintain the valve spring 89 inder compression. The degree of compression )1 the valve spring may thus be controlled by nanipulation of the adjusting screw.

With the spring 89 of the surge valve 51 adusted to a pressure just slightly above that of he spring 41 of the control valve 31, the surge alve will remain unaffected by normal pressures reated in the discharge line with varying load. Ipon the generation of a surge in the line, howver, the surge valve will respond immediately s the surge pressure passes the pressure responive value of the spring 41, and with a rapidity uflicient to hold the surge pressure down to a afe value while the automatic control is respondig to adjust the pump in the direction of reduced utput.

Thus, it becomes apparent that my invention ilfills the objects previously set forth. While have disclosed my invention in its preferred )rm and as applied to a particular type of ump, it is apparent that these features of my ivention may be incorporated in pumps of other esigns wherein the capacity of the pump may be varied by altering the position of one of the working elements thereof with respect to other elements of the pump.

Therefore, while I have described my invention in detail with respect to a specific embodiment thereof, I do not desire to be limited in my protection to such specific embodiment, except as may be necessitated by the appended claims.

I claim:

1. A variable displacement pump comprising a casing; Piston means therein including a driven member disposed for angular adjustment with respect to another member and cooperative therewith to effect an intake of liquid at one point in said casing and a discharge thereof at another point in said casing in accordance with the angular position of said driven member; a stub shaft extending from said driven member through said casing; a housing enclosing said stub shaft and providing a bearing guide for angular movement of said stub shaft with said driven member; and control means responsive to pressure on the discharge side of the pump for adjusting the angular position of said stub shaft accordingly, said control means including a piston coupled to said stub shaft and exposable to pressures on the discharge side of said pump, and a shut-off valve between said piston and the discharge side of said pump, set to open at a predetermined pressure on the discharge side of the pump to expose said piston to such pressures above said predetermined value.

2. A variable displacement pump, a casing; piston means therein including a driven member disposed for angular adjustment with respect to another member and cooperative therewith to effect an intake of liquid at one point in said casing and a discharge thereof at another point in said casing in accordance with the angular position of said driven member; a stub shaft extending from said driven member, through said casing; a housing enclosing said stub shaft and providing a bearing guide for angular movement of said stub shaft within said driven member; control means responsive to pressure on the discharge side of the pump for adjusting the angular position of said stub shaft accordingly, said control means including a piston coupled to said stub shaft and exposable to pressures on the discharge side of said pump, and a shut-off valve between said piston and the discharge side of said pump, set to open at a predetermined pressure on the discharge side of the pump; and a surge valve exposed to pressure on the discharge side of said pump and set to open at a value slightly above the opening pressure of said shut-off valve.

ALBERT J. GRANBERG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,148,277 Rose Feb. 21, 1939 2,248,076 Harrington July 8, 1941 2,299,234 Snader et a1 Oct. 20, 1942 2,333,422 Higgins Nov. 2, 1943 2,260,805 Granberg Oct. 28, 1941

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