US2153360A - Motor driven fluid pump - Google Patents

Description

I April 4, 1939. c. H. AUGER ET AL 2,153,360

MOTOR DRIVEN FLUID PUMP Filed May 26, 1956 Inventors:

Claude H. Augs by M Their Attorney.

6am uel R. PufFen Patented Apr. 4, 1939 UNITED STATES MOTOR DRIVEN FLUID P Claude H. Auger and Samuel R. Puffer, Saugus, Mass, assignors to General Electric Company, a corporation of New York Application May 26, 1936, Serial No. 81,853

1 Claim.

The present invention relates to motor-driven fluid pumps, more specifically to motor-driven liquid pumps in which the pump and the motor for driving it form a unitary structure with the pump including both centrifugal and positive displacement pump elements, the latter serving primarily for priming the pump.

The object of our invention is the provision of an improved construction and arrangement of such motor driven liquid pumps which may be produced at comparatively low cost, readily assembled and dismantled entirely or in part and which reduce the discharge of air or gas together with the liquid. This last mentioned feature is w of special significance where such pumps are used for conveying certain liquids such as gasoline from a tank to a consumer, for instance, an

automobile. In such cases it is undesirable to have gases such as air together with liquid forced through the metering instrument and consequently have a purchaser receive a smaller quantity of liquid than is indicated on the metering instrument.

For a consideration of these and other features of our invention and for a full understanding of what we believe to be novel and our invention, attention is directed to the following description and the claim appended thereto in connection with the accompanying drawing which forms a part of our specification.

In the drawing, Fig. 1 is a front view, partly in section of a motor-driven fluid pump embodying my invention, Fig. 2 is a sectional view along the line 2-2 of Fig. 1, and Fig. 3 is a modification of a part of Fig. 1.

The upper portion of Fig. 1 illustrates the motor with its appliances and the lower portion shows in section the pumping elements.

The motor has a frame ill with an upper end shield ll forming an upper guide bearing l2 and having secured to it an oil cup IS, an outlet l i for connection to an electric line, and a starting switch B5. The lower end of the motor is closed by a lower end shield l6 which forms a hub ll as for a motor shaft 88 and various channels and chambers for the pump structure, more fully described hereafter. The upper and lower motor end shields have ears or lugs l9 and 20 for receiving bolts 2i securely to connect the motor shields 50 to the frame. The hub ll closely fits the shaft 98 without touching it, to forma seal in case of explosion of vapor in the motor. Vapor may accumulate in the motor whenever the pumping arrangement is used for pumping gasoline. An overhung, reduced portion 22 of the shaft is supported by a bearing, in the present instance indicated as a bell-bearing 23 below the hub II. The ball-bearing is held in position in an annular chamber 24 formed in the lower end shield. A spring 25 disposed in the chamber bears at its 5 upper end against the bearing and at its lower end against a sealing member 26, which latter engages a ring member or spacer 21 forming a cover for the bearing chamber 24. Thus, the bearing chamber is sealed and access of liquid thereto is 10 substantially eliminated, this being desirable to assure proper lubrication of the bearing and also to prevent the liquid to be pumped from being contaminated by lubricant contained in the bearing chamber. In case any liquid should enter 15 the bearing chamber, such liquid is drained by means of a draining channel 28 formed in the casting of the lower end shield. This channel is connected to the bearing chamber below the ballbearing, thus preventing leakage liquid in the go bearing chamber from rising to the level of the ball-bearing.

As stated before, the lower end shield forms a portion of the pump casing, broadly the upper half of the pump casing. This upper half or first 25 casing portion is provided with an outer flange 29 secured to a corresponding flange 29a. of a lower half or second portion 30 of the pump casing by means of a plurality of bolts 3| (Fig. 2). The pump comprises centrifugal and positive dis-- 30 placement pump elements. The centrifugal pump elements have an impeller 32 secured to the lower end of the overhung shaft portion by means including a key 33 and a nut 34. The positive displacement pump elementsinclude an inner 35 rotor 35 secured to the overhung shaft portion 22 intermediate the spacer 21 and the impeller by means of a key 36. The positive displacement pump in the present instance is in the form of a gear pump having an inner rotor, just men- 4 tioned, provided with a number of circumferential teeth and disposed within and engaging an outer rotor 37 provided with internal teeth meshing with the teeth of the inner rotor 35. In a typical arrangement, the inner rotor may have 10 teeth and the outer rotor 11 teeth. This type of positive displacement pump is known in the art and therefore need not be described in detail. Fluid is conducted to the inlet side of the positive displacement pump by a channel 38 and discharged w from the opposite side of the pump through a channel 39. Said channels are formed partly within the upper pump casing and partly within I the aforementioned spacer 21. The outer rotor 37 of the positive displacement pump is surroundtioned disk or dividing wall 4|.

ed by a ring 40 which is held between the spacer 21 and a wall member or disk 4|. The latter is secured to the upper pump casing by a plurality of bolts 42 projecting through openings in the ring 49 and screwed into holes in the upper pump casing. The heads of the bolts are disposed within an annular groove 43 in the lower surface of the disk 4|. The disk 4| forms a lower end wall with regard to the positive displacement pump and at the same time it forms an upper wall with regard to the centrifugal pump. Thus, broadly, it constitutes a dividing wall between the two pumps. The common dividing wall of the two pumps provides for a compact arrangement. The ring 40 is slightly thicker than the rotors 35 and 31 to permit free rotation of the latter. The impeller 32 forming a part of the centrifugal pump is disposed within an impeller chamber deflned between the lower casing and the aforemen- The impeller chamber has an axial, centrally arranged inlet 44 which is screw-threaded for connection to an inlet conduit leading to a source of supply, not shown. Fluid forced into the impeller chamber is pumped into. an annular chamber or scroll 45 by the action of the impeller 32. In order to mcrease the pressure in the chamber 45, a part of the velocity energy of the fluid leaving the impeller chamber is converted into pressure energy by means of a diffuser 45, in the present instance shown as a ring diffuser intermediate the impeller chamber and the discharge chamber 45. The

ring difluser is formed between a portion of the inner surface of the lower pump casing and a surface of a ring 41 centered with and secured to the upper pump casing by a plurality of bolts 48. The pump chamber has an outlet 49 for discharging fluid to a. receiver, which may be a metering device, in case the pump is used for conveying gasoline. The discharge chamber, as will be readily noted, is lower on the left-hand side of the i'lrawing than on the right-hand side, its height rising gradually from a minimum to a maximum, as indicated by the dotted line 59.

The inlet channel 38 for the positive displacement pump is connected to the discharge chamber 45 by a radial channel 5| at a point at which the height of the discharge chamber 45 is a The channel 5| is formed in the process of manufacture by a radial hole drilled into the casing. The outer end of the hole is closed by a plug 52.

The discharge channel 39 for the positive displacement pump is connected through channels formed by a radial bore 53 and an axial or vertical bore or bores 54 to an opening 55 in the lower casing. The opening 55 is threaded for connection to a conduit to return fluid discharged by the positive displacement pump to the supply tank. However, it may be desired in certain cases to have a continuously rising path for this discharge and this connection may be made at the point where the plug is shown, instead of at 55.

During operation, rotation of the motor when connected to a source of electric energy causes simultaneous operation of both pumps, the priming pumpand the centrifugal pump. The priming pump having an inlet connected to the discharge chamber of the centrifugal pump removes from such chamber and the inlet of the centrifuto the source of supply. As far as the priming action'is concerned, it is immaterial where the fluid is discharged by the priming pump but whenever the arrangement is used for pumping gasoline there is a distinct advantage in returning the fluid conveyed by the priming pump to the source of supply because this fluid ordinarily contains a substantial amount of air. In' order to remove all of the air or, from another viewpoint, in order to prevent air from being discharged through the outlet 49, for instance to a gasoline meter, the inlet channel 5| for the priming pump is connected to the chamber 45 at a point where the chamber has a maximum height. When the chamber is partly fllled with gasoline or other liquid, the air or other, gases collect at the surface, that is, in the upper portion of the chamber 45, whence such gases are withdrawn by the priming pump. For a like reason the discharge opening 49 which may be connected to a asoline meter is connected to a lower portion of the chamber 45, which portion is usually filled with liquid. Thus, broadly speaking, the discharge outlet 49 is connected to the liquid space of the chamber 45, whereas the inlet channel 5| for the priming pump is connected to the gas space of the chamber 45. The provision of a chamber which has an inclined ceiling assures thecollecting of all gas at the upper point of the ceiling which connects to the inlet of the priming pump. Another reason for providing the inclined ceiling is to reduce the necessary space for the discharge chamber or scroll of the centrifugal pump to a um.

Operation of the impeller causes fluid to be forced through the inlet 44 of the centrifugal pump, whence the fluid is pumped by the action of the impeller and forced through the ring diffuser into the discharge chamber or scroll 45. From the discharge chamber a portion of the fluid, that is primarily the liquid, is discharged through/ the opening 49 and another portion which may contain a small amount of air or gas is removed by the priming pump and returned through the outlet or return opening 55 to the source of the fluid.

The fluid entering the priming pump during normal operation from the discharge of the centrifugal pump or at the full discharge pressure of the centrifugal pump may leave the priming pump at a lower pressure than at which it enters. In this case the priming pump acts as'a motor driven by the fluid from the centrifugal pump. This motoring tendency has the effect of reducing the power required of the electric motor in driving the combined pumping unit. All of the inlets and outlets of the pumps, that is, the inlet 44 and the outlet openings 49 and 55, which are to be connected to conduits are provided in the lower or second pump casing portion. This has a distinct advantage in that it facilitates considerably the assembling and disassembling, more particularly the replacement of certain pump elements. It will be noted that the two pumps, together with the motor, may be completely removed by disconnecting the bolts 3| connecting the upper and lower casing portions of the pump without necessitating any changes as regards the pipe connections with the aforementioned inlets and outlets 44, 49 and 55. Thus, the centrifugal pump or the positive displacement pump or both may be readily replaced without in any way disturbing the pipe connection with the lower pump casing.

As will be noted in the drawing, thedischarge chamber or scroll 45 for the centrifugal pump a arrests completely surrounds the positive displacement pump. As the chamber $5 is normally substantially filled with liquid or containsa body of liquid, it forms together with the liquid a means for dampening the transmission of noise from the positive displacement pump.

The arrangement, as a whole, as regards the flow of fluid through the inlet of the centrifugal pump, the impeller chamber, the discharge chamber and the inlet of the priming pump forms a continuous path rising upward from the inlet of the centrifugal pump to the inlet of the priming pump with the highest point connected to the priming pump. This highest point is located near but above the outlet 49 of the discharge chamber where the maximum amount of gas would most likely be formed. This upward path connected at the highest point to the priming pump reducesin particular the accumulation of a considerable amount of gas in the impeller chamber and thus eliminates the possibility of the centrifugal pump becoming inoperative due to the presence of an excessive amount of gas in the impeller chamber.

The modification shown in Fig. 3 shows an arrangement further to facilitate the flow of fluid carrying trapped gases in a continuous upward path. The arrangement comprises a member 60 which corresponds to the member 41 of Fig. 1

and a lower casing wall 6! corresponding to the second casing portion 30 of Fig. 1. These two elements form the outer portion of an impeller chamber for accommodating an impeller 62. As will be readily seen, the element 60 has a lower plane surface in contrast to the element M of Fig. 1 in order to assure a continuous upward path of the fluid discharged by the impeller and thereby to prevent the formation of gas pockets within the impeller chamber. A continuous upward path for the flow discharged from the priming pump may be accomplished, as stated above, by removing the plug in the bore 53 and discharging the fluid through the plug opening.

Certain features described above form a part of the invention of Sanford A. Moss, covered by the application Serial No; 81,857 filed on the same date and assigned to the same assignee as the present application.

What we claim as new and desire to secure by Letters Patent of the United States is:

A pump arrangement including the combination of a centrifugal pump having an impeller chamber with an impeller, a vertical drive shaft connected to the impeller and a combined discharge and separating chamber surrounding the impeller chamber and forming an outlet opening near the'bottom of the chamber, the discharge and separating chamber having an inclined ceiling reaching a maximum height above the outlet

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