US1798787A - Pump - Google Patents

Description

March 31,1931. D. J. CQQANT PUMP 2 Shets-Sheet l Original Filed Feb. 15, 1926 FIGURE .1

rleune 2 FIGURE F IQURE 5 INViHTOH ATTQRNEY March 31, 1931. D, J CONANT 1,798,787

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Original Filed Feb. 15, 1926 2 Sheets-Sheet; 2

y FIGURE 6 ATTORNEY Patented Mar. 31, 1931 DAVID J. CQNANT, 0F MEMPHIS, TENNESSEE PUMP Continuation of application Serial No. 88,327, filed February 15, 1926. This application flled December 15, 1927. Serial No. 240,316.

In the construction of centrifugal pumps it is common practice to mount the impellers upon a round steel shaft by means of the ordinary gib-head key. In this construction it is necessary to provide a sufliciently large bore in the impeller to permit the shaft to slide freely therethrough, and consequently Also when the load of driving is applied the force acting upon the driving shaft will urge it into contact with the impeller upon one side of the key with a corresponding separation from the impeller upon the opposite side of the key thereby creating an eccentric relationship between the driving shaft and impeller.

This oflsetting of the impellerrelative to the shaft on which it is mounted obviously unbalances the impeller so that balancing of the same is required after the impellers are mounted on the shaft. Also, since the impeller is offset relative tothe shaft it is also offset relative to the axis of the neck of the bowl in which it operates. It is necessary,

therefore, to provide a bowl having a neck somewhatlarger than the impeller to permit the free rotation of the impeller therein.

Because of this somewhat eccentric mounting of the impeller on the shaft considerable hand fitting is required in assembling the parts, and nonsinterchangeable parts must be used. Furthermore, in this construction the shaft should be of steel to carry the load and consequently will rust in the water being pumped. When rusted, the Whole shaft must be replaced.

It is one object of my invention to provide a construction wherein the above men tioned difficulties may be satisfactorily over-- come and the impellers accurately and concentrically mounted in the several bowls and so maintained in concentric relation thereto regardless of whether or not the shaft is concentric with the impellers, thereby eliminating the necessity of subsequent balancing and hand fitting as now required,,or, in other words, to provide a journal surface for the impeller to rotate upon that is entirely separate from the driving means and which will maintainits concentric position with the impeller whether or not the driving shaft is concentric with the impeller.

It is another object of the inventionto provide a structure wherein the pump bowl neck may be made in its normal size and still provide the required clearance between it and the impeller, whereby to reduce leakage.

It is still another object of the invention toprovide a structure wherein a non-corrosive material may be used for that portion of the shaft carrying the impellers and wherein the impellers may be mounted on the shaft withoutthe use of a key if so desired.

Finally it is an object of the invention to provide a structure of the character indicated wherein a means is provided'for spacing the several impellers and supporting the same, and closingthe supporting shaft off from the water being pumped so that materialfor the shaft such as steel maybe used. without danger of corroding.

. In the drawing: 7

Figure 1. is a longitudinal section through a pump structure embodying myinvention. FigureQ is a section on line 2.2 of

Figure 1. a

Figure 3 is a section on line 33 of Figure 1. y

Figure 4 is a sectional view through a portion of a pump structure showing another embodiment of my invention.

Figure 5 is a detail illustration showing a means for securing a positive driving connection between the sleeve and impeller.

Referring more particularly to the drawing, I show at 1 a portionof a shaft hexagonal in transverse cross-section, having one end upset-as at 2 and the other end cylindrical in form as at 3 and threaded as at 1 and 5.

At 6 I show an impeller broached as at 7 to engage the shaft part 1, and having annular shoulders formed in each end thereof and concentrically positioned relative to its axis of rotation as shown at 8 and 9 respectively.

Between each two impellers is shown a sleeve 10. This sleeve 10 is somewhat larger than the shaft part 1 and completely encloses the same, and fits snugly into the opposing shoulders 8 and 9 of the two impellers. A sleeve 10 is also shown inserted between the g upset end 2 of the sliaft part1 and theshoulder 80f the lowermost impeller-{and another sleeve 10 is shown mounted upon the uppermost impeller. On this upper sleeve 10 is seated'a nut 11 which is screwed into place on the threaded part 3 of the shaft.

It'may now be clearly seenthat by providingsleeves 10 of uniform length-the impellers and sleeves are each interchangeable and may be assembled as "they come to hand, and merely slipped on to the shaft without the use of a key of any kind. The impellers and shaft must of necessity rotate as a unit, and they are securely bound together with the sleeves on the shaft by the upset end '2 on shaft part 1 and the locknut 11, this binding together of the impellers and sleeves effecting a positive driving connection between them.

In the construction hereinbefore described rotation of the impeller, but it need not be oversize as in the pumps heretofore constructed.

Since it is, in practical work, necessary to I provide some little spacing between the impeller and the drive shaft in order-to render the impeller slidable on the drive shaft, it

necessarily follows that although the shaft and impeller may be concentric when at rest, when a polygonal shaft of the type described is used, this concentric relationship is immediately destroyed when power is applied to the shaft since it is of necessity forced into contact with the impeller hub at one point and away therefrom at another.

Since the water is entirely shut off from the shaft part 1 it is effectually prevented from rusting, and consequently provides a durable construction.

In the embodiment shown in Figure 4 it is shown that this construction may also be used witha round shaft'if so desired'by using opposite sides of the key. If a key is driven in in such a manner as to secure a tight fit between shaft and impeller then an eccentric relation would be had, but the concentric relation of impeller and bowl would not be destroyed, because the impeller must run true in the journal surface provided in the bowl neck 13. c

The sleeves 10 clearly perform several important functions. They space the several impellers to which they may be secured in any suitable manner. They protect the shaft from the corrosive action of the water being pumped. They maybe made of non-corrosive material and they function as bearings. But their most important function is to cooperate with the bearings and the bowls to maintain the impellers in concentric relation to the bowl necks irrespective of the exact relation between'the shaft-and the impellers. This desired cooperation can only be secured, of course, if a correct driving connection is established between the sleeve and impeller. This connection may be securedas described, or inother ways such as notching the sleeve as at 16 and providing a key 17 long enough to engage the notches. The engaging notch and key construction 1617 is preferably used merely to prevent slippage between the impeller and sleeve.

I It is to be understood, of course, that while bly and operation may be made within the."

I claim: I y

1. In combination, a pump bowl having a bearing therein, a: sleeve revolubly mounted inthe bearing, a-drive shaft passing through the sleeve in spaced relation thereto, animpeller revolubly mounted in the bowl in axial alignment with the sleeve, 9. driving and aligning connection between the impeller and sleeve, and driving means inserted between the impeller and shaft.

2. In combination, a pump bowl having a bearing therein, a sleeve revolublymounted in the bearing, a driveshaft passing'through the sleeve in spaced relation thereto, an impeller revolubly mountedin the bowl in axial alignment with the sleeve and having a 'recess formed in the end thereof in concentric relationto its axis of rotation, one end of the adj acent sleeve 'being' fitted into said recess scopeof the appended claims.

DAVID J. CONANT.

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