US1157240A - Balanced centrifugal pump. - Google Patents

Description

M. B. MACNEILL.

BALANCED CENTRIFUGAL PUMP.

4 APPLICATION FILED FEB. 28. 1913.

1,157,240. Patented t.19,1915.

, Z0 Z2 33 32 L. m '36 33 72 3 v 73 5 M M I 565. fiverzZaw' UNITED STATES PATENT ornion.

MARTIN B. MACNEILL, OF BELOIT, WISCONSIN, ASSIGNOR TO FAIRBANKS, MORSE &

\ COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

BALANCED CENTRIFUGAL PUMP.

Specification of Letters Patent. I

Patented oa. 19, 1915.

Application filed February 28, 1913. Serial No. 751,220.

To all whom it may concern.

Be it known that I, MARTIN B. MAONEILL, acitizen ofthe United States, residing at Beloit, in the county of Rock and State of Wisconsin, have invented a certain new and useful Improvement in Balanced Centrifugal Pumps, of which the following is a specification.

This invention relates to centrifugal and similar pumps, blowers and the like. It is especially applicable to vertical or horizontal shaft centrifugal pumps of the single or multi-stage type. j

The object of the invention is to provide means adapted to automatically adjust the pressure existing on the two sides of the impeller wheel of a pump of this class so that the wheel runs freely in the casing without being impeded by friction against either Wallof the case. I

The invention consists in a device for carrying out this object which can be very easily and inexpensively made and installed, which operates efficiently and is not readily liable to get out of order, and particularly one in which no parts are required other than those ordinarily used in a pump of this class which is not equipped with an automatic balance, and in which the power of the pump is not wasted in operating auxiliary pumping vanes. and devices of similar character, or vacuum chambers in the impeller proper.

More particularly the invention consists in the use of pressure chambers on opposite sides of the impeller formed between the impeller and the case or pump shell, the pumpable liquid in one chamber being regulated in amount and consequently in pressure by the axial position of the impeller with reference to the case with the result that the impeller is axially moved in proportion to the pressure in said chamber.

More in detail the invention consists in the construction and arrangement of parts herening position. In such a pump the impeller may be placed vertically, as shown in the drawing, or horizontally without departing from this invention.

In this drawing is shown an ordinary pump casing or shell 2 having an intake port 4 and a discharge port 6. In this case is journaled a shaft '8 carrying an impeller wheel 10 having within it a plurality of ducts 12 adapted to receive liquid through passage 13 from the receiving chamber 14,-

fed by port 4, and deliver it into the usual volute passageway 16 leading to' the discharge port 6.

Broadly speaking, the parts thus far described are old in the art, and the object of'the invention is to so balance the impeller disk 10 between the walls 18 and 20 of the case that the normal end thrust of the shaft 8 on the impeller 10 is automatically neutralized and counteracted so that the impeller runs freely between the Walls Without materially frictionally containing either Wall or parts projecting therefrom. v

The result desired is accomplished by providing on one side of the impeller an annular pressure chamber 22 communicating with and receiving liquid from the passageway 16, said chamber having a relatively large pressure surface 28 upon the adjacent side of the impeller 10. In the particular case here illustrated, this chamber 22 is on the side of the impeller away from the shaft 8 -or on what would ordinarily be the bottom side of the impeller when the pump is a vertical one, but it may be located on either side of the impeller without departing from the invention. In 'case any liquid from chamber 22 passes through the annular opening 24 which is ordinarily about one sixtyfourth of an inch wide, it enters the vacuum chamber 26 from which it is immediately pumped through the agency of the suction created in the spaces 13 by the water driven through the impeller openings 12. Under this pumping action it passes through the passageways 28 into the liquid flowing from the chamber 14 to the passageways 12. The only liquid pressure tending to move the impeller 10 to the right as viewed in the figure,

- is',{u1fen, that-produced by the liquid in the said chamber 22 and is a constant quantity.

On the opposite side of the impeller 10 from' the chamber'22 is another annular liquid pressure chamber 32 also communicating with the passageway 16 and having apr ssure surface 33 upon the impeller 10 of less area than the opposite pressure surface 23 in the chamber 22. One-wall of this chamber 32 is formed by an annular flange 34 extending from the surface of the impelv ler in close proximity to an oppositely point' ed annular flange 36 extending from the wall toward the impeller 10.'- These two flanges 34 and 36 are spaced apart slightly, say about one sixty-fourth of an inch, so as to form a circumferential passageway 38 leading from the chamber 32 into an annularsupplemental pressure chamber formed on the same side of the impeller 10 as the chamber 32. 'There is sufficient space within I this chamber 40 so that as the impeller 10 is reciprocated-sidewise, between thewalls 18 and 20, the end of the flange 34 does not strike the wall 20 and thus interfere with this movement. It will be noticed that the passageway 38 is of such acharacterthat it remains ofconstant area regardless of the lateral position of the impeller.

The supplemental pressure chamber 40 has an annular pressure surface 42 on the impellerlO of suflicient area so that when liquid under a given unit of pressure-is applied to this pressure surface and to the pressure surface 33 of the chamber 32, the combined total pressure will slightly overcome that exerted [by liquid of the same unit pressure on the pressure surface 23 of chamber 22, and the impeller 10 will move to the left, but when the volume of liquid in chamber 40 and consequently the pressure of said liquid ull surface 42 is materially reduced, the pressure on surface 23 in chamber 22 which remains constant will be sufliciently great to overcome the pressure of liquidin'chamber 32' and the impeller-1O will move to the right.

Another way of looking at the structure is that chambers 22 and 32 being in communication are in effect one chamber whose effective pressure surface is the difference between the twoand is exerted on the left side of the impeller and this net pressure is less than the maximum possible pressure which can be applied tosurface 40 in the regulating chamber, in the manner hereafter 7 described. I

The chamber 40 heretofore described, communicates-"withthe vacuum existing at the center of'the impeller in space 13 by means ofa relatively large circumferential passageway 44 usua ly about one-eighth of an inch Wide formed between the annular flange 46 of the impeller wheel.10 and an inwardly projecting stationary annular flange 48 adjacent thereto. This passageway 44 is, as

the walls of the case.

stated, of substantially larger area than the passageway .38, and communicates with a passageway 50 formed between the ends of the flange 46 and the portion 20* of'the wall 20 of the case. Flange 48.could be dispensed with without departing from this invention but it is provided herein so that passageway 44 is formed leading into fpassageway 5'0 thereby producing a sharp angle at their juncture which serves to partly discourage the flow of pressure, water from chamber 40 to vacuum space 13 thereby cushioning the impeller against too rapid movement to the right. It is self evident that the area of the passageway '50 varies in width and consequently in size depending upon the relative position of the impeller 10 with reference to impeller is moved as far as it will gotothe right, the end of the flange 46 contacts with this wall 20 and practically closes the passageway 50; while on, the other hand, when the impeller is moved to its extreme For iilstance when the lefthand position, the passageway, 50 will be'considerably larger than itappears in the drawing which shows its area when-the imp'elleris in-its intermediate position.

The forming of the passageway 50 be tween parallel, preferably wide, abutting faces 46 and 20 is very important because wear from sand or other agents may take place on these surfaces, thereby increasing thev size of the passageway 50 without destroying the accuracy of the device for with a larger passageway 50 the impeller simply adjusts itself to a difierent axial position to balance the device, as described. In a versaid passageway 50 is wide open. In other words, the relationship of the passageways 38 and 50 is such in size that when passageway 50 is closed liquid will pass from chamber 32 through. passageway 38 into chamber 40 thereby exerting an increasingly greater pressure on surface 42 and when that pressure becomes great enough to, as described, force the impeller 10 to the left and thus widely open the passageway 50,the suction in'space 13 willdraw or pump substantially all of the liquid from chamber 40, thereby reducing the pressure on surface 42 so that the pressure 111 chamber 22 can, as described,

again force the impeller to the right, there by closing passageway 50-again, and repeating the operation. In practice, the extreme limits of motlon just described should never be reached,-the pressure in chamber 40 varying just enough, first greater then less, to, as described, hold the impeller in substantially intermediate position, shown in the drawmgs. v

To summarize the operation, it may be stated that the device is first primed or filled with water in the ordinary manner and power is applied to rotate theshaft 8', thereby rotating the impeller 10. ,This rotary.

motion draws water through passageway 1 into chamber 14 thence through passageways 13 past opening 50 into and through passageways 12 from-which the water is de livered via passageway 16 to outlet 6, the discharge water filling chambers 22 and 32 and thus exerting pressure on opposite pressure surfaces 23 and 33 as described. This operation creates the vacuum in space 13, and'consequently in chamber 26 which is in constant and direct communication with 7 space 13 through port or ports 28. The

vacuum in space 13 pulls or pumps out, to a greater or lesser degree, that portion of the liquid in chamber 40 which flows to it through passageway 38 from the chamber 32 as described, thereby, in the manner described, varying the pressure on surface 42 and thus automatically regulating the position of the impeller ,between the walls ofv the case. As stated, the vacuum chamber 13 through the agency of vacuum chamber 26 pumps up and carries away all leakage through passageway 24 thus insuring the pressure in chamber 22 always being of a constant value. v v

The drawing and the foregoing description show only one impeller wheel and a case therefor, but manifestly where more than one impeller wheel is used thedevice may be applied to one or more of the wheels without departing from this invention.

I am aware of Patent No. 997,101 to F.

'W. Krogh which shows my balancing device proper but said Krogh device is-pro- 'vided and necessarilyv so with' auxiliary I pumping vanes which render the device I claim as new and desire to secure by doing very unsatisfactory because the auxiliary vanes leading to the outer periphery of the impeller and discharging such short circuited water as is permitted to enter them causes turbulence in the whirlpool chamber at the outer periphery of the impeller and mate rially reduces the efiiciency of the device. Ha'vingthus described my invention, vghat ters Patent'is: i v

'1. In a centrifugal pump, in combination with a case and a rotatable and axially movable impeller' without auxiliary vanes said impeller beinglocated within the case adjacent to one wall thereof adapted to pump liquid through and out of'the case and in so means tending to move the impeller toward form a vacuum within the case;

said wall of the case, the impeller so fitting the wall of the case that a pressure chamber is formed between the wall and the impeller, having a pressure surface on the impeller opposing said moving means and of greaterpressure capacity than said moving means, and that a relatively small entrance passageway is formed for the entrance of pressure liquid to said pressure chamber which remains of constant area regardless of the axial position of the impeller with reference to the case and that a relatively larger discharge passageway is formed between the end of the face of the impeller perpendicular to its axis and an abutting portion of the case, said last passage varying in size with-the axial movement of the impeller and leading to said vacuum.

2. In a centrifugal pump, in combination with a case and a rotatable andaxially movable impeller without auxiliary vanes said impeller being located within the case adand of greater pressure capacity than said.

moving means, certain of said interfitting parts between the impeller and the case forming a relatively small constant area entrance passageway for the entrance of pressure liquid to said pressure chamber regardless'of the axial position of the impeller and other of the said interfitting parts forming a larger discharge passageway leading to said vacuum, said discharge passageway including at one point a portion of the side wall of the case and a relatively wide abutting endof a hub of the impeller whereby the area of the discharge passageway is automatically varied in size in accordance with the axial position of the impeller with reference to the wall of the case, for the puron the impeller opposing sald' moving means and of greater pressure capacity than said moving means, and that a relatively small lot entrance passagewai is formed for the entrance of pressure liquid to said pressure chamber which remainsof constant area regardless of the axial position of the impeller With reference to the. case and-that a relatively larger discharge passageway is formed between the end of the face of the impeller perpendicular to its axis and anabutting portion of the'case, said last passage. varying in size with the axial movement of the impeller and leading to said vacuum.

.In witness whereof, I have hereunto subscribed my name in the presence of two witnesses.

MARTIN B. MACNEILL.

I Witnesses:

DWIGHT B. OHEEVER, MAX S. RQSENZWEIG.

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