US2065912A - Pump construction - Google Patents

Description

Dec. 29, 1936. E. G. sTAuDE PUMP CONSTRUCTION Filed June 6, 1932 0h mm mm NV INVENTOR. EDW//Y G.v TAUDE BY l @J 12J/4M l ATTORNEYS.

Patented Dec. 29, 1936 UNITEDfsTATEs PATENT ori-ICE 2,665,912 PUMP CONSTRUCTION Edwin G. Staude, Minneapolis, Application June 6, msaseriai No. 615,622 "6 claims. (c1. 10a-126) This invention relates generally to improvements in iluid pumps, and is particularly concerned with means for controlling pumping volume.

An importanty object is to provide mechanism for controlling the volume by controlling the pumping seal and to so control the seal as to progressively vary the pumping volume conformably lto pumping requirements.

Another object is to provide a construction such that when the pump gears rare idling, as for instance when no now or pressure is required, the pump gears will be practically running in a bath of oil and consequently there will be little, if any, heat generated, whatever the speed ofk rotation of the pump gears. l

This invention is related to the inventionsfof my copending applications kfor Power amplifying devices, respectively bearing Serial Numbers 615,621 led June 9, 1932 and 615,620 iiled June 6, 1932,'now Patent No. 2,047,898,l inthat the present application relates to the pump structure per se, while the inventions of said copend-f ing applications relate partly to the manners of controlling the pumping seals, with relation to other controlled mechanisms.

It is an important object of this invention to provide means wherein the lag or delay in starting, is entirely eliminated, due to the fact that no vacuum is established in the fluid conveying passages of the pump. Tests have proved that in the practice of this invention, there is no lag or delay in the establishment of the pumping force, and it 4has been further proved that .the circulationpressure is reduced more than eighty per cent directly on motion of the volume control means in appropriate man'- ner. Moreover, there is no noise whatever as the result of free iiow of fluid around the pump gears, and there is no heat Whatever the velocitt7 of the pump gears.

As exemplified in the above mentioned copending applications, the present invention finds val-r uable application in conjunction with auxiliary power devices for automobiles in which the pump is constantly driven. Attempts have heretofore been made to obtain a reduction in volume by the use of a valve located on the intake side of the pump, but this device causes serious lag or delay in pumping action due to creation of vacuum in the pump line, torwhich vacuum nuid must be suppliedlbefore full pumping pressure is available. Owing to the large volume of uid in f continuous circulation at high car speeds, the amount 'of heat generated by these continuously rotating gears has presented serious obiections to the use of gear pumps. There is no limitation intended, however, by the statement that' there is a nominal, continuous circulation maintained because an important feature is the use of an element which is movable with respect to the pumplng means to instantly render such means inoperative or operative, or to progressively increase the pump volume, all in such manner as to conserve power, make for pumping efficiency and avoid generation of heat.

An important featureof the invention relates to thefconstruction for by-passing fluid at the meshing point of the 'pumping gears from' the pressure side to the opposite side. Features of the invention include all details of lconstruction shown, along with thebroader ideas of means in-v herent in the disclosure.

Other objects, features andV advantages of the invention will appear from the description of the drawing forming a part of this application, and in said drawing Figure 1 is a horizontal section on line I-I of Figure 2 through the intersecting pitch lines of the pump gear, and shows the volume control in the open position;

Figure 2 is a Vertical section on line 2-2 of Figure 1; v

Figure 3 is a vertical transverse section on line 3--3 of Figure 2;

Figure 4 is a verticalv transverse section on line 4-4 of Figure 1;

Figure `5 is an enlarged horizontal section of a portion of the volume control shown in `Figure 1, with the control in closed position, or with the by-passage obstructed and the pumpconditioned for delivering fluid at the maximum pressure; and

Figure 6 is a detail vertical section taken on line 3f-ly of Figure 2.

In the drawing, 62 generally indicatesa pump case or block having a pair of pump gears 54 and 55. The pump gear 54 is mounted on the spindle 53-and is driven in any suitable'manner from the clutch arrangement 52; The pump gear 55 revolves freely on a iixed shaft 55.

In order to enclose the face of the pump gears and close the ends of certainv passages to be described, plate 51' is provided, which is securely bolted to the member 62 by bolts 6D.' The plate 51 has a groove 15 located at the intersecting pitch circles of the pumpgears, and opening against said gears. Plunger 31 is slidable inra bore of the plate 51 and is adaptedtokoperate across, and to open or close the passage formed somewhat larger than the width of the passage 15, and eiectually shuts off the passage of the iluid through the passagewhen in the position shown in Figure 5.

In this embodiment, the control member is about the size of alead pencil or-a little larger,V say one-fourth of an inch in diameter and the.

area is about .049 of an inch. It will be understood that the end area of the element 31 may be equal to the area of the passage and A31 may nt passage 15 as a piston.

While a cylindrical plunger has been shown,

A because that is the simplest form for making an oil tight sliding iit, there is no intention to limit the invention to the shape of thev plunger, since it may be rectangular. Other constructions located in the side wall of the pump casing, as

shown in Figure 6, which will' permit the freek l as a stop `.against opposite Walls of the casing or plate 51. vIn order to maintain the member 31 normally in the open position shown vin Figures 1 and 2, a spring 4ll is provided which is adjusted to the correcttension by a castle nut 4l.v A threaded plug 42'provides a bearing 43 for the control member 41, and alsoserves to pocket the spring 40, A cap threaded on the corresponding threaded portion 45 of the plug 42 covers the end of the reciprocating member Referring to Figure 3 and assuming that the device is used on an automobile, and that the.

plunger 31 is positioned as in Figure 5, when the `automobile y is Ymoving lforwardly, gear 54 is Ydriven by shaft 53 in counter-,clockwise direction, which sets up a uid .pressure in` passage 64. Referring to Figure 1, the passage 64 is connected to passage 65 by a short passage 66. 'Ihe passage v61 is connected to the passage 65 by a short passage 68. in the port 64 against the plunger 69 in passage 65, it forces `itrinto the positionY shown in Figures 1 and 4 and thus uncovers the port 10, see Figure 4, which connects with the passage 1I leading into space 12 communicating with Vcylinder 29 vto act against the piston 28.

When the pump gears 54 and 55 Vrevolve in an opposite direction or clockwise, as for in- Stance when the motor vehicle is backing, pressure accumulates in passage 61 and acts against the back of the plunger 69 causing it to move tothe opposite endkof the passage 65 and estab,-

lishing'v communication between passages 61, 68V

and port 10, and passages 1.I and space 12. It

is, therefore, clear that whatever the direction of rotation of` the Vpump gear, effectivel fluid pressure against the piston 28 Vis, always ob- As pressure vaccumulates g 2,065,912 by slot `15. 'I'he diameter of this plungeris a sort of breather space throughwhich gases or fumes may escape if developed as the result of friction due to long continued use, as for instance in the case where the device is used in a braking `system during long continuous brake application.

Assuming that the plunger 31 is in the position shown in Figure 5 and that pressure accumulates at 64, it will reactl laterally against the plunger31. r This might' cause binding of the plunger. To obviate this, Vat surfaces 16 and A11 are provided, and these are connected with the slot 15 at each side of the plunger by cross-` ing ducts or passages 18 and `19. When the pressure accumulates at 64, the uid will be' directed to the passage 18, see Figure 5, which is of equalv area as the exposed surface of the plunger 31 in the passage 15, so'that the lateral pressure is equalized. -If the pressure is reversed and accumulates at `6'I, the i'luid flows through the duct or`passage 19 to the space 16 and acts as back pressure from the opposite side.`

My invention includes the yuse 'of a check `at the intersecting pitchcircles of the pump gearsf located in the passagevr that' connects the di's` charge side of the pump gear withvthe opposite side, which passage is locatedvin the side wall of the pump case.v The 'sizeof `this passage andV the sizeof the mechanism` for checking the fluid depends upon thevolume and capacity of 1 the pump.

It isk possible, by the practice of this invene tion, to have the areaA of the plunger whichis exposed to pressure be quiter small, so that the" proportional back pressure onthe plunger' at five hundred Vor more pounds pump pressure perV invention is particularly lvaluable where it is, re-V quired that the revolution ofthe pump gears be e i continuous, because 4the pump v can deliver `fluid' with full fluctuation from maximum volume and velocity to zero volumeand velocity.

It is noted that thisinvention provides means moving independently oi' the pumping means for controlling the volumeand/or seal, and also Aprovides volume control` means which, in the case of a gear pump, movesindependently of the pump gears; also the volume control means is operable in the wall of the pump. y

I 'claim as my inventionr k1. A gear pump comprising a walled having a pump chamber, meshing lpump gears inthe chamber, a groove in the ixmer face of one of the'walls and opposing thegears at their 1meshing' point, and adapted to by-passV the pump fluid, a -plungerreciprocable in the wall across the'groove to control 'by-pass flow and having an end Aengagea'ble with the side face of the gears to stop by-pass fiiow through the groove, a spring normally holding the plunger in aposition to permit full uid flow through the by-pass groove, and means for movingthe plunger, against the actionfrof said spring.

- 2. A gear pump comprisingaa `walledcasing casingv having a pump chamber, meshing pump gears in the chamber, a groove in 'the inner face oi' one of the walls and opposing l13h@ Sears' at their meshing point, and adapted to by-pass the pump fluid, a plunger reciprocable in the wall across the groove to control by-pass iiow and having an end engageable with the side face of the gears to stop by-pass iioW through the groove, a spring normally holding the plunger in a position to permit full fluid flow through the by-pass groove, means for adjusting the tension of the spring and accessible at the outside of the pump casing, and means for moving the plunger, against the action of the spring.

3. A gear pump having a circulating system including a gear chamber having therein meshing pumping gears, a cover closing the chamber, a groove in said cover opposed to the meshing point of the gears and adapted to by-pass the entire volume of fluid from the pressure and suction side of the system, a pumping pressure control plunger reciprocable in thetcover and traversing the groove to block passage of fluid therethrough and adapted to abut the gear faces at their meshing points, a swinging arm cooperating with the plunger for controlling it, a spring against the action of which the plunger is moved to increase pumping pressure and adapted to normally move the plunger away from the gears, and

' means for adjusting the tension of the spring.

4. A circulating system including a gear pump having a casing and pump gears and having .at the meshing point of the gears a by-passage of suicient size to by-pass the entire volume of the liquid around the gears from the pressure to the suction side, a piston plunger yieldable to the liquid pressure reciprocable across said pasof the last mentioned means to prevent any bypassing of liquid.

5. A circulating system including a gear pump having a casing and pump gears, and having at the meshing point of the gears a luy-passage of sufficient size to by-pass the entire volume of the liquid around the gears from the pressure to the suction side, a plunger reciprocable across said passage toward and away from the side vfaces of the gears to completely open and completely close the passage, yieldable means for holding the plunger to permit by-passage of all the pumped liquid, means acting on the plunger to forcibly and rapidly move it against the action of the last mentioned means to prevent any by-passing of liquid, and means limiting motions of the plunger in opposite directions respectively to permit full capacity by-passing and to prevent any by-passin'g.

6. A circulating system including a gear pump to forcibly and rapidly move it against the actionV y' having a casing and pump gears, and having at the meshing point of the gears a by-passage of suii'lcient size to by-pass the entire volume of ,y

the liquid around the gears from the pressure to the suction side, a plunger reciprocable across said passage to completely open and completely close the passage, yieldable means for holding the plunger to permit by-passage of all thev

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