US1355982A - Centrifugal pump - Google Patents

Description

H. E. LA BOuR.

CENTR|FUGAI. PUMP.

APPLICATION FILED MAR. 11; I918- RENEWED AUG. 12. I920.

1,355,982. Pamnted Oct. 19,1920.

2 SHEETS-SHEET I.

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7 a7)" Ila/Bear H. E. L A BOUR. CENTBIFUGAL PUMP.

APPLICATION FILED MAR-I1, I918- RENEWED AUG. 12. I920.

1,355,982. 7 Patented Oct. 19, 1920.

2 SHEETSSHEET 2.

u! Z I I} car I. Zia/150L27 UNITED v STATES PATENT I oFFicE.

HARRY E. LA'BOUR, OF CI-IICAGO HEIGHTS, ILLINOIS.

CENTRIFUGAL PUMP.

Specification of Letters Patent.

Patented. 001;. 19, 1920.

Application filed March 11, 1918, Serial N0.;221,644. Renewed August 12, 1920. Serial No. 403,155.

To all whom it may concern:

Be it known that I, HARRY E. LA BoUR, a citizen of the United States, residing at Chicago Heights, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Centrifugal Pumps, of which the following is a full, clear, concise, and exact description reference being had to the accompanying drawin s, forming a part of this specification.

1y invention relates to pumps andmore particularly to pumps of the centrifugal type wherein the liquid is delivered under a head to the impeller, the device being employed in systems for conveying acids or other corrosive liquids or fluids.

Due to the corrosive nature of such fluids,

I contemplate a centrifugal pump constructed in whole or in part of non-corrod-' 'ible material. Particularly the interior parts of the pump are made of material that will not be affected by the fluid conveyed.

One of the disadvantages and difliculties of the prior art devices has been due to the formation of eddy currents and gas pockets )Vlthlll the pump, invariably causing pump to become airor gas bound.

the A fur ther difficulty heretofore encountered in pumps of the class to which myinvention relates has been that of properly balancing the impeller shaft to take up or control the end thrust away from the inlet that is created in pumps of this type, particularly those wherein an admission opening is employed on only one side, due to the impact of the liquid against tyhe impeller at the inlet. I

It is an object of my invention to provide an improved pump of simple and durable construction, wherein all tendency to be come air or gas bound due tp the formation of eddy currents or suction pockets will be absolutely eliminated, consequently providing a pump of greatly increased efiiciency. A furtherobject of my inventionds provision of means for controlling the direction and amount of end thrust created in the pump, the controlling means being provided according to the quantity of fluid to be pumped andthe-speed of rotation of the s impeller. i

I accomplish the control of end .,thrust preferabl by forming a'centralrecess in. the impe ler blades at the point-Where the liquid enters. The edges of the impeller the definingthe sides of the recess are preferably parallel to the axis of rotation of the impeller, and-by making the ,recess of suitable depth I am enabled to control or eliminate end thrust. 1

A further object of my invention is the provision of a pump whereinthe fluid will enter the impeller chamber-with a minimum velocity of whirl which is so essential in pumps of the centrifugal type. d

In the preferred form of my invention I form all the interior parts of the pump of relatively non-corrodible material, such'as lead when conveying sulfuric acid. I provide the pump with a removable head member thereby allowing easy'access to the impeller chamber for clearing out dirt, for repairs and for interchanging impellers according to the speed of rotation and the quantity of fluid to be pumped.

By the term low head pump used in the description and claims I refer to. apump of that class which depends for its action on the maintenance of the continuity of the liquid column, and not on the switches.

I find this construction to be highly ad- Q vantageous as it is simple. reliable and durable. precise construction which I disclose herein, as it is apparent that the embodiment of the invention may, be widely varied.

.I do not intend to be limited to the s In the accompanying drawings forming the plane of line 2-2 of Fig. 3; I

'Fig. 3 is a horizontal sectional view taken on the plane of the line 33 of Fig. 1; v

Fig. 4 is a front elevation with the head member removed; and n Figs; 5 and 6 are diagrammatic views illustrating the method of controlling ,the

end thrust.

Referring to the drawings, the pump of my invention comprises a casing 1 and a head member 2, provided about'their pe-' ripheries' with flanges 3 and 4 respectively. The casing 1 and head member 2 are adaptf ed to be clamped together by means of the bolts 5, with a suitable gasket gripped there between to in sure a tight joint. A bed plate or base 1 member 6 is provided preferably integral with the casing -1, the casing being provided with a suitable bore substantially in the center thereof for the reception of an impeller shaft 7.

The casing 1 is provided with a boss 8 preferably formed integral therewith and.

projecting therefrom, which is recessed or counterbored to form a stuffing box in which i is lodged the packing 9 for forming a tight ends being engaged by-the nuts 15 by means integr-ally therewith and projecting therefrom on either side of the boss 8. The lugs or wings 11 and 12 serve to carry the gland".

adjusting eye bolts 13 and 14, the eye portions of which'are adapted to be secured between the lugs 11 and 12 as by suitable bolts or otherwise. The free threaded ends of the adjusting bolts 13 and 14 project through" suitable openings provided in the flanged portion of the gland 10, their outer of which the gland 10 is readily manipu lated to adjust or compress the packing 9.

The head member 2 is provided with a suction or admission opening '16, the axis of which is adapted to substantially aline with .the axis of the impeller shaft 7 when the casing 1 and head member 2 are bolted to- I gether. The admission opening 16 is surrounded by a suitable flange 17 for con-. necting to a pipe line. The inner face of the head member 2 is provided with an annular channel which is adapted to cooperate, when the head member 2 is bolted to the casing' 1, with a similar channel provided in the inner face of the casing 1, thereby forming an annular discharge passage 18 about the periphery of the pump. The discharge chamber 18-is not made with the usual variable cross se -tion area as in pumps of the volute type. but is of a uniform cross sec-..

tion area throughout. J

A delivery or discharge opening 19 is provided at the topmost point of the pump, as there is less danger of air accumulation in the top of the pump, which must be considered foremost as air pockets would lose the priming of the pump and 'stop operation I of the same. As shown in Fig. 4, the "discharge opening 19 has an equal angle of approach from either side of the pump, each v of the side walls 2;) and 21, ofthedischarge neck being substantially tangentto the outer periphery of the discharge chamber 18. The width of'the passage 22 which affords communications between the discharge chamber 18' and the discharge neck is reducedto considerableless than the diameter of the discharge'chamber,

thereby forming a restricted throat portion integral with a center bossor may be otherpreferably made of n'on-corrodible material such as lead when sulfuric acid is to be con clamped together.

hasbee'n found to admirably provide for the N therewith It will beseen that the cross current pockets between the pressure chamto eflectively prevent the formation of eddy current pockets within the discharge neck. The casingv 1 and head men1ber.2 are provided with suitable flanges which, when the casing and head member are bolted togethery form a continuous flange 23 about the upper end of the discharge opening, 19 to facilitate connection with a discharge pipeline. I

An open type impeller 24 is mounted upon f the inner end of the impeller shaft 7 and '75 may be driven by any rotative motive power such as the motor 25 shown in Fig. 1. The freedom from end thrust which I am able to secure by this construction is of particular importance in permitting the impeller shaft to be coupled directly to the motor shaft. No thrust or axial bearing is required in addition to the regular motor bearings. The blades or vanes of the impeller 24 may be wise rigidly secured'upon the impeller shaft 7, 1t belng understood that the impeller as well as the interior-parts of the pump are veyed. .The blades of the impeller 24 are I recessed adjacent the admission opening 16, as shown. at 26, it being'a pparent that the total depth of the impeller blades from the flat inner face 27 of the casing 1 to the admission opening 16 is greater than is ordinarily found in pumpsof this type, this is toallow therecess26 to be formed of a sufficient depth. It is preferable that the di-. ameter of the recess 26 be substantially equal to the diameter of the admision opening or suction opening 16, the axis of the admission v opening alining-With the axis of the recess when the caslng and head member are This form of impeller admission of fluid into the-pressure chamber witha minimum velocity of whirl. wThe blades or vanes .ofthe impeller 24 aper in depth as shown in'Figs. 2and 3, their greatest depth being at therecess 26,

as has been explained, from where their front edges'taper toward the periphery of the impellerwhere they reach their least 1 forms the inner wall of the pressure chamberin which the impeller24 is adapted to. rotate, the outer wall thereof being, formed by the cooperation of thehead member 2 sectional area of: the pressure chamber is greater at theadmissio'n open ng than at the periphery 1 or point of discharge, thereby effectively preventingthe formation of eddy v ber and the discharge chamber 18 v In Figs; 5 and 6 I have diagrammatically illustrated the method I' employfor contro ling the direction and amount of end thrust;

"If the recess26 were formed of too great a 130 if depth, for the speed of rotation and quantity i for the incoming liquid to change its direc-- of liquid to be pumped, as shown in Fig. 5, the incoming liquid, the flow of which is indicated by the dotted lines and arrows, upon entering the impeller recess, would change its direction of flow, that is, would receive a centrifugal motion too far in front of the face 28 of the impeller 24, and atmospheric pressure on the shaft would produce a suction pocket, as shown at 29, the tendency of which would be to pull the impeller 24: toward the incoming liquid as indicated by the arrow.

In Fig. 6 I have illustrated the result of making the recess26 too shallow. Inthis case sufficient space has not been allowed tion of flow, upon entering'the impeller recess 26, consequently a portion of theliquid,

the amount of which-obviously depends upon the depth of the recess, strikes the face 28, thereby producing a thrust along the impeller shaft 7, away from the incoming liquid, asindicated by the arrow. I therefore make the depth of the recess such that" the, impact of the liquid at the-inlet and the atmospheric pressure on the shaft balance each other, eliminating all end thrust.

In determining the depth of recess for any particularuse or installation, I proportion it to the speed of the impeller, the pressure of the liquid at the point of inlet, the but in any event I liquid to be pumped,

than the width of the make the recess deeper peripheral discharge. I do this because the longitudinal depth of the liquid is greater at the point where it crosses the longitudinal edges of the cut-out portions of the blades than it is at the relatively long peripheral outlet. By this I mean that the unobstructed peripheral area of the recess formed by cutting the blades as shown is greater than that area required by the liquid at the point of passage. through said unobstructed peripheral area of the recess, and

at the velocity imparted to it by the im-- i peller.

By unobstructed peripheral area is meant the area between adjacent cuts in adjacent blades. I't isobvious that in an impeller constructed as described, only the edges of the blades of the impeller receive the impact of the'liquid, therefore presenting a minimum of surface to receive such impact of the flowing liquid, and that any pressure on the impeller parts resulting from such impact must ,be for the most part radial and not longitudinal, and that in consequence of this I am enabled to produce a pump of this character in which the end thrust on the impeller shaft is controlled or entirely eliminated. I Centrifugalpumps only possess the tepdency to produce thrust toward the incoming liquid when lifting from a point below the repairing and interchanging impellers,

level of the pump, which is not a condition of normal operation for low head centrifugal pumps, such as the present invention. In such pumps the liquid is almost. always delivered to the pump,

the exposedarea of the impeller. is that which lies at an acute angle to the direction of nate such an area peller blades to form the recess described.

in connection with systems wherein acidsflow of the liquid and I elimiby the cutting of theimand the thrust is: dues to thevelocity of impact of the liquid against This area Although I havedescribed my invention so It is now apparent that under a head, a pressure chamber, a casing I forming the inner wall of said pressure I chamber, ahead member forming the outer wall thereof, a shaft carrying .an open im; peller adapted for rotation in said pressure chamber, the blades or vanes of said impeller being recessed at the axis thereof,

said head member being provided with an,

admission opening. adjacent the recessed portion of said impeller blades, a discharge.

chamber surrounding saidcrusher chamber, a radial discharge throat the side walls of which approach a discharge opening substantially tangent to the outer periphery of said discharge chamber and a. discharge passage connecting saiddischarge chamber and 'saiddischarge throat, the depth of said pas sage being less than the diameter of said discharge chamber.

2. In a pump adapted to receive. liquid under 'a head, a stationary pressure chamher, the cross sectional area of said pressure chamber being substantially greater at the admission opening than at the point of ,dis-

charge, a discharge chamber surrounding saidpressure chamber, the cross sectional area. of said discharge chamber being substantially equal throughout and a coin I.

tracted peripheral necting the discharge. chamber with the pressure chamber in communication -.with said discharge chamber.

discharge passage. con- 3. In a pump havingan 'open impelleradapted to receive liquid under a head, a casinghaving an annular channel therein, a head member adapted to be 'clampedfto said casing, said I head member having an charge. chamber, the cooperation of said annular channel adapted to cooperate with; I

' head member with said casingv forming a discharge opening,- a discharge throat the side Walls of which approach said discharge opening substantially tangent to. the outer periphery of said discharge chamber, the

depth of the discharge throat at thedis charge chamber being substantially less than the diameter of said discharge chamber, to form a restricted communication therebetween.

4. In a pump adapted to receive fluid y let, an open impeller on said shaft within said casing, said impeller comprising blades extendlng substantially radially from said shaft to said outlet, said blades being cut away at their inner ends to form a recess substantially equal in diameter to the inlet and of such a. depth as to eliminate axial thrust in said impeller shaft, said pump being adapted to receive fluid from a head.

6. In a pump adapted to receive fluid from a head, a casing, a head member adapted to be clamped thereto, a rotary im peller. comprising a shaft having a plurality ofblades or vanes secured thereto. the

blades or vanes of said impeller being recessed at the axis of the impeller, the depth of said recess being proportioned to the capacity ofthe pump and the speed of the propeller to control the axial thrust in said lmpeller shaft.

7. A rotary impeller for centrifugal pumps comprising a shaftcarryinga plurality of blades or vanes, the blades or vanes of said impeller being recessed at the axis of the impeller, the depth of said recess be ing proportioned to the capacity of the pump and the-speed of the impeller to control the. axial thrust in said impeller shaft.

8. The combination in a pump adapted to receive fluid under a head,-of 'a stationary casing, a head member adapted to be clamped thereto, said casing having ,an in let at the center of said head member and a a. peripheral dischargechamber, a radially rssaesz extending discharge throat communicating with said chamber through a restricted passage and arotatable open impeller in said casing in axial alinement with said inlet, said impeller comprising blades extending radially from said inlet to the outlet, said blades being recessed at the axis of the impeller, the depth of said recess being proportioned to the capacity of the pump and the speed of" the impellerto control the axial thrust in said impeller shaft.

9. In a pump for operation in a continuous fluid column and for'cdrrosive fluids, a body having the interior parts thereof formed of non-corrodible material, said pump and the speed of the. impeller to control the axial thrust in said impeller shaft.

10. A rotary impeller for low head centrifugal pumps comprisinga shaft carrylng a plurality of blades or vanes, the blades or vanes of said impeller being recessed at the axis thereof, the depth ofsaid recess being proportioned to the capacity of the pump and the speed of the impeller to control the axial thrust in said impeller shaft, the greatest depth of said blades or vanes being at said recessfrom where they taper, reaching their least depth at the periphery of the impeller. I

11. Ina pump of the class described, a

substantially closed casing having a central inlet and a peripheral outlet, a rotatable open impeller in said casing in axial alinement with said'inlet, said rotatable impeller having blades extending radially from said inlet, said blades-being cut away at thecenter of the impeller to form an axial recess, the depth of said recess being proportioned to the capacity of the pump and the speedof the impeller to control the axial thrust' in the impeller shaft and said pump adapted to receive fluid from a head.

In witness whereof I hereunto subscribe my name this 7th day of March. D. 19 18.

7 HA RY- E. LA .BOUR.

Corrections in Letters Patent No. 1,355,982.-

It is hereby certified that in Letters Patent No. 1,355,982, granted October 19,

1920, upon the atpplication of Harry E. La Bour,'of. Chico-go Heights; Illinois, for

,an improvement in Centrifugal Pumps, errors appear in the printed specification requiring correction as follows: Page 2,1ineS 46-47, for the word section reed sectional; page 3,.1ine 101, chtinr 1, for the word crusher re'ixol pressure and that the said Letters Patent should be read with these oorrections therein that the sarne Inay conform to thereoord of the ease in the Patent-Ofiice.

Signed andlsealed this 30th day of November, A. D., 1920.

SEALQ L. B MANN, Acting Commissioner-of Patents 01. 253- 206. I

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