US2951447A - Impeller pumps with magnentic drives - Google Patents

Description

Sept. 6, 1960 J. P. cAsAssA IMPELLER PUMPS WITH MAGNETIC DRIVES 2 Sheets-Sheet 1 Filed July 31, 1958 nl l w [JV VENTOR.

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United States Patent O M 2,951,447 JMPELLER PUMPS WITH MAGNETIC DRIVES Joseph P. Casassa, Clio, Mich., assignor to G eneral Motors Corporation, Detroit, Mich., a corporation of Delaware Filed July s1, 195s, sei-.Na 752,323

6 claims. (Cl. 10s-s1) This invention relates to pumps and more particularly to pumps of the impeller type for handling limited or varying quantities of fluid such as engine fuel.

Impeller type fuel pumps have been installed heretofore in engine fuel tanks with the pump intakes immediately abovel the bottoms of the tanks. Annular magnets have also been employed in transmitting a driving torque from a power source to a given pump impeller. Details of construction for a pump of this type are disclosed in the United States application for Letters Patent, SerialNo. 703,142, filed December 16, 1957, in the name of Robert L. Carter.

The pump disclosed in the patent application above referred to performs excellently with a minimum of resistance to the ilow of fluid through the pump inlet. It has become desirable, however, to simplify the pump structure, reduce its cost without impairing the performance characteristics, and to minimize vibratory and sound effects. y

An object of the present invention is to provide an improved impeller type pump of simple construction and A feature of the invention is a pump impeller having a magnetic drive effective through an impermeable nonmagnetic diaphragm, the impeller being rotatable on a pivot pin and preferably with the aid of la bushing of low friction material such as graphite acting asa step bearing.

The above and other important features of the invention will now be described in detail in the specification and then pointed out more particularly in the appended claims. v

In the drawings: v

Fig. 1 is a sectional view of a motor drive and a pump in wnich the present invention is embodied, the rotative elements of the pump being shown in full;

Fig. 2 is an enlarged view of the pump illustrated in Fig. l, the rotative elements being sectioned to show their interior construction and relative location while the pump is not operating; and

Fig. 3 is an exploded view of parts of the impeller and pump drive shown in Figs. 1 and 2, sections being cut away better to disclose the relationship of the parts. in the patent `application above referred to, the pump shown in the present drawings employs annular permanent magnets as driving and driven members. Each magnet could take some other form, but annular rings with sections of alternating polarity arranged about the pump axis are preferred. As in the patent application, the pump is adapted to be suspended from the top Wall of a fuel tank with the pump intake being located immediately above the tank bottom.

The present invention is particularly concerned with the mounting of the pump impeller but it should be understood that a pump drive casing is anged as at 12 for dependence within -a fuel tank 14. A rubber insulator and sealing element 16 is interposed between the casing 2,951,447 Patented Sept. 6, 1960 ICC 10 and a depending flange 18 formed on the tank. A cap 20 is xed to the top of the casing 10 and receives electrical conduit means 22 l.for operating a motor 24. An inverted cup 26 is nested Within the bottom of the casing 10 to hold the motor 24 by means of bolts 28 and nuts 30. The cup 26 bears a rim 32 recessed at 34 to receive the bottom edge of the casing 10 and form a liquid tight seal.

The pump casing comprises a main casting 40 and a bottom wall or plate 42 which cooperate with a brass or nonmagnetic diaphragm 44 in defining a pumping chamber 46. The casting 40 is formed with la spirally expanding recess 48 extending partially around the chamber 46 to a tangential outlet passage 50 formed in a side portion of the casting 40 and closed by an extended portion of the plate 42. A neck S2 is made integral with the casting 40 upwardly to communicate with fuel discharge conduit means generally indicated at 54.

The bottom plate 42 bears several inlet apertures 56 located near the center of an impeller generally indicated at 58. The latter is composed of an aluminum vane portion 60, the curved and radially extending vanes 62 of which are located on the underside of the impeller 58 and the inlet openings 56 are directed toward the inner ends of the vanes. A pivot pin 64 has one end lixed to the plate 42 as clearly shown in Fig. 2, and the upper end of the pin abuts the central portion of the diaphragm 44. Surrounding the pin and rotatable with respect thereto is a bushingV 66 of hardened graphite or equivalent non-frictional material which will serve Vas a bearing and be unaffected by the fuel'to be handled by the pump. The annular upper end of the bushing 66 is so formed as to present a smooth surface to the diaphragm 44 as these two parts come into frictional engagement to some extent yas will further appear. The lower end of the bushing 66 is formed with an outstanding ange 68 which is received in an annular recess 70 formed in the underside of the plate 60. It will be noted that the bushing is of such length that it does not span the complete distance between the diaphragm 44 and the plate 42 as does the pin 64, but leaves a slight clearance. The pump or vane portion 60 is xed tightly to the bushing 66 by swaging as indicated at 72. The vane portion 60 has a threaded hub 74 to lwhich is' joined a threaded disc 76. The latter serves as a lock nut holding an annular permanent magnet 78 against the vane plate 60 as a rigid part ofthe impeller 58.` It will be understood that the impeller '58 with its bushing 66 freely rotates within the pumping chamber 46 on the pivot pin 64.

Enclosed within the inverted cup 26 is a hub member 80 on the underside of which is carried a driving permanent magnet 82 similar to the magnet 78. This magnet 82 is held to the hub driving member 80 by means of a lockring 84 which is similar to the lock ring 76. A threaded hub 86 holds the lock ring and is recessed at 87 to accommodate a hardened steel annular ring 88 and a hardened steel step bearing plate 90. Within the ring 88 and adapted to orbit therein because of the clearance provided is located a steel ball 92. This ball rests upon a hardened steel plate 94 which is retained on the center portion of the diaphragm 44 by an annular ridge 96 lformed on the latter.

An open retainer frame is xed to the bottom side of the pump plate 42 -and maintains a screen 102 in position for clarifying fuel passing to the openings 56. Conventional bolts, not shown, are utilized to hold the retainer frame 100 and the pump parts as Well as the diaphragm 44 to the ange 32 as will be understood.

The motor 24 is provided with a depending drive The driving and driven magnets 82 and 78 are each in the form of a ring with sections of alternating polarity arranged about the ring axis, as heretofore stated. The

magnetiosmaterial of at least the magnet 78 should obviously be such as to be unaffected by the fluid to be handled bythe pump or the heat conditions with which the pump mustcontend. A magnet of this type-is discolsed in the British Patent 758,962, published October 10, 1956, and mentioned in the United `States application heretofore referred to. Thelmagnet 82 is sealed within thevmtotor support casing and, therefore, is not in contact with the fuel being pumped. Y s 4 Assuming'that the'apparatus disclosed is suspended in -arfuel tank with the bottom plate 42 of the pump near the-bottom of the fuel supplytank and the current is supplied to the motor 24, it-Will bel seen'that'the motor shaft 104 `will rotate the driver magnet S2. The motor armature as Well as the driving plate 80 and the magnet 82` will vbe supported by the ball 92Which in turn is supported bythe hardened plate 94, the diaphragm 44 and the pin 64. V f v n 'With `the rotation of the driver magnet 82, the magnet 78 willbe caused to rotate with it by Virtue of the magnetic attraction set upl between the two magnets. The latter should be of sufficient magnetic strength to attract each other so that the work load given to thexpump will not causehthe magnets to fall out of phase. With a rotation ofthe magnet 78,y the vanes 62 will produce Van outward discharge of fluid vthrough the passage 50 and the conduit means 54 as will be understood, the fluid entering the pump from the tank by way of the Yscreen 102 and the inlet openings 5 6. With the operation of the impeller 5 8 in the pumping of uid, the pressureof the latterI on thev underside of the impeller will decrease and the bushing 66 Will bear down against the top side of the plate 42. .The bottom end tof the bushing, therefore, acts as astep bearing and the upper end of the bushing will clear the ydiaphragm 44` when the pump isin operation. Upon shutting off the current to the motor 24, ,the

fluid pressure` on the underside of the impeller 58 will.

increase p as the flow of fluid ceases and the mutual attraction of the two magnets 78 and 82 will then be effective to cause the impeller to assume its raised position as depictedY in Fig. 2; i.e,.,.the upper end of the bushing 66 will come into contact with the underside of the diaphragm 44.

With the simplified construction as above described, it will be seen that the inlet passages for the fluid by Way of theopenings 56 are clear and not obstructed and that large bearing surfaces are provided for rugged support of the vimpeller 58. It will also be noted that the support of the central portion of the diaphragm 44 is rm and that drumming or vibratory noises are, therefore, not to be encountered under heavy service.

I claim:

1. A pump including a casing, an impenneable diaphragm of nonmagnetic material cooperating with said casing in defining a pumping chamber, a first permanent magnet arranged Ioutside said chamber on one side of said diaphragm and adapted to be power rotated, an impeller in said pumping chamber opposite said first magnet and including a second permanent magnet facing said diaphragm, radially extending varies on said impeller, said casing having an inlet nearthe center of said impeller tand directed toward said vanes, lan outlet in said casing leading from the periphery of said pumping chamber and impeller, a pivot pin fixed lto" 4said casing, a bushing of lowY friction ,material rigidly. fixed to .said impeller .and rotatable with the'latter on and with respect to said pivot'pin, and saidbushingbeing adapted to contact said diaphragm,` and said ;casing.` l. ..1

' 2. A pump including a casing, an impermeable diaphragm ofnonmagnetic material cooperating with said casing in defining a pumping chamber, magnetic drive means including a -magnet rotatable'ina plane parallel with said diaphragm and outside said chamber, a pump impeller in said chamber within the magnetic lield of said magnet 'and including radial vanes, said casing having gan inlet directed toward Vthe vinnerend of one of said vanes and an outlet, directed from theperiphery of said chamber, a nonrotatablepivot pin having one end contacting thepumping` chamber side of said diaphragm .and` its length extending from saidv diaphragm to said casing, Vand said impeller-beingrotatable on-said pivot pin. Y g

3. A pump including la casing having aV bottomfwall with an inlet opening, an impermeable nonmagneticdiaphra-gm cooperating with said casing in defining apumping chamber, said wallpartially defining a discharge pas-` sage leading from said chamber, a pump impeller with radial vanes mounted in said chamber, said yvanes extending in arplane adjacent to said Wall, a .nonrotatable pivotpin extending between said bottom wall anddiaphragm andY abutting the latter, said impeller being rotatable on said pivot pin, and magnetic driveY meanszar, ranged .to rotate said impeller by magnetic flux eective through said diaphragm. g g 4.4.A pump. such as set forth in claim ELtheY magnetic drive Ymeans including a driver magnet and an orbiting ball step bearing resting on the diaphragm. f. g' n 5. A pump including a casing adapted to be immersed in iiuid and including anonmagnetic, impermeable diaphragm and a bottom wall, said diaphragm and wall being parallel todetermine apumping chamber betweenthem, an inlet and an outlet in said casing and communicating with said chamber, a nonrotatable pivot pin extending upwardly from vsaid wall to and in .contact with said diaphragm, a pump impeller journaled directly on said pin, and` magnetic drive means associated -withsaid pump vto transfer torque to said impeller by magnetic linx eifective through said diaphragm. z;

6. A pump including a casing, an, impeller, anda pivot pinasset forth in claim 5, and said impeller including a bushing journatled on said pivot pin, said bushing being ofnon-friction material `such as graphite and being adapted to act las a step bearing.

References Cited in the -tile of this patent UNITED STATES PATENTS 2,429,114 Whitted oct-14,f.1'947 2,592,752 Shenstone Apr. 15, 1952 2,779,513 Dickey Jan. 29, 1957

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