US2319230A - Centrifugal pump - Google Patents

Description

May 18, 1943 l.. s; HAFeRINGTQN CENTRIFUGALl PUMP 2 Sheets-Sheet lv Filed Aug. 25, 1941 Gftornegs.

Patented May1s, 194s l. 2,319,230

Lester B. Harrington, Salem, reg.,assignor of forty per cent to Reynolds Allen, Salem, and fifteen per cent to Clay A. Itacely, Portland, Oreg. y

Application Augustzs, 1941, serial no. 408,258 l A .6 Claims. (Cl. 10S-262) The present invention -relates to improvements in' centrifugal'pumps, and has for an object to provide an improved pump of this class suitable, for use as a water pump, or for pumping. chemiin the claims appended hereto.-

In the drawings, wherein -like symbols refer to -iikeerconespondirns parts throughout the several views,

Figure 1 is a side elevational view. -with parts broken away and parts fshown in section, of an yimproved'centrifugal. pump constructed in ac cordance withthe present invention.

Figure 2 is a vertical section taken on the line vcalsl or generally as a liquid supply pump. 5 2-2 inFigure 1. y The present application is a continuation in w Figure 3 isan enlarged vertical section through part of my prior co-pending application Serial the-pump casing and rotor illustrating the meth'- No. 334,433, flled May 10, 1940. od of liquid operation, and AAnother object of the invention is to adapt Figure iis a top plan view, with parts -broken the type of vacuum pump disclosed in my prior away, of the rotor'. co-pending applicatiai aforesaid for useasA a '-Referring more particularly to the drawing y water pump in which certain dififculties aregen- I0 designates an electric or other motor suitable. counteredv in introducing water at the inlet side for driving the pump through the amature shaft of the pump, inasmuch as the pump shaft was II which may also be the impeller shaft of the "utilized in the prior construction, the passages I5 pump. v

being necessarily small for water so that. an housing I2 may be used to connect the casobject of the present invention is to redesign the ing of the pump to the housihg of the motor I0, pump construction'with the water intake at the although the pump may be supported in'relation so'called bottom ofthe Pump. namely at the to the motor by any other suitable means. At side of the pump opposite the motor or impeller I3 is shown the packing gland or shaft seal whichv shaft. may contain graphite or other mechanical means A further object of the present invention flows Afor preventing the escape of the water at the directly from the objects stated in the. immedimotor side of the pump. In this instance this ately-preceding paragraph in that the .bottom packing gland I3 and the seal may be of normal intake is unimpeded and uninterrupted from any 25 size and diameterin comparison to a standard shaft structure and is thus of larger cross-secsize diameter of shaft II; 'whereasl these parts tional area accommodating the water in greater would have to be greatly magnified in diameter," volume, contributing to the capacity ofthe pump. with consequent greater frictional losses, were A still further diiiiculty encountered with a the water intake to bef. provided at this side of pump such as that disclosed in my prior cothe pump inasmuch as the ^intake passage is of pending application aforesaid when put to water necessity very large in cross-section in dealing pumping uses is the matter of lubrication, inaslwith water. much as water is a poor lubricant, it is an ob` The pump casing is generally formed of side .'Iect of the invention to maintain the pump and walls I4 and I5, andan end wall I8 which is' o f motor shaft of as small a, diameter as possible, volute form and extends concentricallywith the which also contributes to the graphite seal at rotary impeller or rotor Il. The rotor or imthisvside of the pump and prevents scoringaof peller I1 is connectedto be driven by the shaft the bearing and other disadvantages which would -I I which projects through the end wall I5.- The be encountered if the lshaft and its bearing were intake of. the pump is represented at I Sand is of a large diameter necessitated by the water 40 of enlarged cross-section suitable for the intake intake at the shaft side of the pump;` these difof a water pump; to accommodate the -water in culties being eliminated by the water intake at sufficient volume. The intake I 8 is connected the bottom of the pump namely at the side to any suitable source of water-or liquid supply. opposite the shaft. The outlet ofthe pump is shown at I S'and it A still further object of the invention is to pro- 41 comes 01T the casing at the, largest-radiusfof the vide a centrifugal pump in which the propelling volute end wall I8.' liquid circulates substantially radially through In the intake I8 is a bearing l2Il for the. hollow the rotary impeller passages in an annularchamneck 2I which is a part of the impeller, Arotates ber outside, and preferably concentric with the therewith and forms a continuation of the intake eye or central enlarged water intake of the pump. DQ of the-pump. Thishollow njeck'2I vcommunicates to form a compact and emcient structure and l' interiorly with a hollow. annular chamber 22 at one that will produce a high degree of vacuum, l substantially the center. ofthe impeller body. With the foregoing and other objects 'in view, Leadingfrom vthis'chamber 22 are the ,inlet ports the invention will be morefully described'herev 23. Such -inlet ports vmay be provided in any inafter, and will be more particularly pointed out 5* suitable number in accordance with the number of the pump passagesl in. the impeller. Six such Passages-are shown'in connection with the em- "'bodiment ofthe invention illustrated but vany number of such passages might be used.

Each passage is formed of three components,

namely a central oriilce 24, an abruptly enlarged chamber 25 and a long distal portion 26. 1The inner end of the orifice 24 is spaced away'from thezouter part of the neck 2| and communicates with an annular internal space'21. This internal space -21 extends out radially inall directions between the pump wall I 4 and the adjacent side of the impeller which is spaced from said pump 'wall I4. The space 21 opens at its outercircurnferential portion directly into the volute chamber dened within the end wall I6, such opening being in a plane beside the plane of the impeller disc I1. In other words the 'circumferential mouth of the annular space 21 opens into the casing alongside the discharge mouths of the im' peller passages.

The pulling eiIect in the distal portion 26 will 20. The propelling part of the pump casing when dischargedi'rom the impeller back through the internal space 21 to the inner ends of orifices 24.

The propelling liquid entering an orifice 2 is moved outwardly therein. 'I'he orifice will be so restricted as to cross-sectional area as to form a vena contracta in the liquid. This vena contracta will be projected outwardly beyond the outer end of the orice 24 and into theV chamber- 25. The vena contracta thus forms a low pressure annular space within the chamber 25 at a point where the inlet port 23 communicates with the chamber 25. I'hus the vena contracta will act to draw in Water, gasoline or other liquid through the intake I8, hollow neck 2|, central chamber 22, port 23 and\into the space within the chamber ,surroundingsthe .vena contracta.

' The intake liquid will thus be entrained with the propelling liquid moving outwardly in the impeller. passage.

The liquid, both propelling and entrained, which meets in the vena. contracta is moved out in the pump passage. Due to the enlarged diameter of the chamber 25 and distal end 26, the velocity bi' the liquid at the vena contracts. is converted to pressure and the liquid expands out'- wardly against the wall of the distal portion 26 in all directions at right angles to the axis of the passage, or in other words radially of the passage. Such action creates a largevolume of liquid in the distal portion 24 which-seals such distal portion and prevents atmospheric or other .higher pressure from moving backwardly through the distal portion 26 into the chamber 25 which constitutes the low pressure area. Consequently this low pressure area is sealed bythe body of liquid in distal portion 26 from breaking the high. degree 'of vacuum formed about vthe yenscontracta.

thus act to pull the liquid, both propelling` and intake. through the impeller passages from va point downstream of the vena contracta. y Thus I am ena-bled to dispense with the use of pressure or head at the inner ends of the passages which would tend to push the liquid through such passages.

'Ihe orifice 24 will be of such length and crosssection comparatively to the cross-section of the distal portion 26 to feed sufiicient liquid through the vena contracta to form a sealing volume of liquid in the distal portion 26 which will move outwardly with a suction action.

'Ihe propelling liquid in the pump'is caused at the center to'acquire a high velocity through thev action of the oriiice 24 in order to form a Avena contracta. Thereupon by reason of the enlarged diameter of the chamber 25 and distal portion 26 the liquid is allowed to lose its velocity in favor of -pressure which will have a sealing effect. After the liquid is 4discharged from the distal portions 26 of the passages it enters the casing 'which is ofvolute form toward the outlet I9, thus having a further tendency to convert velocity of the liquid into pressure and enabling the quiet discharge of the liquid from the pump casing.

The distal portion 26 is of the. major length of the axis of the passage to emphasize the pulling effect of the liquid therein.

It will be appreciated that the intake I8 and its neck 2| may be constructed of large diameter l without any modifications of the shaft or its sealing member I3 and moreover the internal bores of such parts may be unimpeded and uninterrupted, thereby allowing a great capacity iiow of'intake water or other liquid to the pump.

Due to the construction where the annular internal space 21 is at one side of the hollow neck 2| and the intake I8' at the other side, no particular packing will be needed at the bearing 20 because the pressure of the recirculated liquid in the annular intern-alspace 21 will offset any pressure of the water or other liquidentering through the inlet I 8.

The discharge of liquid at the periphery of the rotary impeller alongside space 21 makes for an easy cycling of the propelling liquid' back through the space 21. this internal space 21 there will be low pressure due to the movement of the liquid centrifugally outward in the impeller. The reduction of velocity attributable to the voluteV casing/enables this` discharged liquid to more easily come under the influence of this low pressure and be drawn back into the central part of the annular internal space 21 to again feed the orifices 26. It will also be appreciated that lubricant probu lems are not increased by a pump of this charof by a standard sealing member I3; this all Moreover this great .body 'of liquid moving out the distal portion 26 'under the iniiuence of cen-j trifugal force is accelerated. This acceleration will be felt in the low pressure space of chamber 25 about the vena contracta. In other words the o pumped liquid will communicate directly and imheilig secured by the intake I8 being located at the opposite side ofthe pump.

It is obvious that various changes and modications may be made in the details of construction and design of the above specifically described embodiment of this invention without departing from the spiritthereof, such changes and modi- 1. In-a centrifugal pump, an impeller havingy i passages therein of generally radial disposition but curved at their outer ends to radii of thel At the central portion of ,to said enlarged chambers, a-hollow neck communicating internally with said inlet ports and extending off one side of said impeller and forming a journal therefor, a casing for the impeller having a liquid intake at one side in communication with the internal space of said hollow neck,

a bearing in said casing for said hollow neck,

said hollow neck spaced from the inner ends of said passages, said impeller being of a width substantially less than the width of the casing to provide an internal space within the casing beside said impeller communicating both with the inner and outer open ends of said passages, means for driving said impeller, said casing having a volute outer wall, and an outlet for the casing at substantially the largest radius vof said volute outer wall.

2'. In a centrifugal pump, an impeller having a passage therein constructed and arranged for producing a vena' contracta with the inner and outer ends of the passage opening at the inner and outer edges of the impeller, a hollow neck on the impeller spaced from the inner end of the passage and communicating interiorly with the vena contracta, a pump casing having side and end walls with the end wall extending in a substantially volute curve concentrically outward of the impeller and having an outlet at its widest portion,\a liquid intake through one side wall to the internal space of the hollow neck, said casing having a recirculating space beside the impeller communicating with both the inner and Outer ends of said passage.

3. In a centrifugal pump, a pump casing having an intake at one side and a peripheral discharge, an impeller mounted to rotate in said casing, drive means for the impeller connected through the side of the casing opposite said intake, said impeller having a passage therethrough comprising orifices for forming a vena contracta projecting from the other side of said impeller and journaled in said bearing in position to receive fluid centrally through said intake, said neck forming an internal chamber substantially y concentrically of said impeller, said impeller having a passage substantially concentric with said chamber and composed of an orificeat the inner portion of the passage, an abruptly enlarged chamber outwardly of the orice anda distal portion extending from the enlarged chamber to the periphery of the impeller and being `of progressively enlarging diameter cutwardly,`said impeller having ducts `connecting the central neck charnber with the enlarged passage chamber, said impeller having an inner annular'wall in which said'orice is formed, said annular wall being f spaced concentrically outward of said neck to at the inner portion of the passage, an abruptlyy enlarged chamber surrounding said vena contracta, and a long distal portion leading from the chamber to the rim of the impeller, a fluid inlet communicating with the intake and with said enlarged chamber, said casing having an internal space beside the impeller provided with a portion lying radially within said orifices, through which space the propelling liquid may be recirculated from the discharge of the distal portions4 to said vena contracta, a hollow neck extending from the impeller oppositely from the drive shaft having a bearing in the casing at the intake side thereof, said neck lying within the portion of said space which lies inwardly of said vena contracta.

4. In a pump of the character described, a pump casing having spaced side Walls and a peripheral end wall connecting said side walls, one of said side walls having a narrow-diameter opening, a drive shaft projecting through said opening into the interior of the pump casing, 'an v impeller having a closed side wall with a bearing to receive said drive shaft, the other side wall of said casing having a large diameter fluid inlet opening at its central portion and a bearingln said inlet opening, a large diameter hollow neck form an annular chamber withinvsaid annular Wall and outwardly of said neck leaving the orifice open at its inner end to receive recycled ,neck rotatably mounted in said bearing in alignment with said intake and having an internal nuid chamber therein, a drive shaft extended through the opposite side Wall substantially coaxial With said neck, and an impeller supported at one side lby said neck and at the other side by said drive shaft, the internal chamber in said neck extending concentrically into said impeller, said impeller having ducts radiating out from said neck chamber, said impeller having passages therein -opening at the rim of the impeller and composed of orifices at the inner ends of the passagesvdistal portions of progressively increasing diameter outwardly and chambers between .said orices and distal portions which are abruptly enlarged with respect to said orifices, said ducts leading into vsaid enlarged chambers,

. said impeller having an internal wall in which said orifices are made spaced from said neck and communicating at one side with the internal space within the casing alongside said impeller to receive and-recycle. the fluid discharged pe- Arecycling passage for fluid in the casing at the side of said impeller, a hollow neck substantially carrying said impeller in open communication with the intake and .iournaledin said bearing, said impeller having an annular internal wall concentricwth and outwardly spaced from the inner portion of said hollow neck and providing therewith an annular space communicating with thel side space in saidcasing, orices in said annular wall communicating with the rannular space, abruptly enlargedcharnbers in said impeller communicating with and outwardly of said orifices, passages in the impeller leading outwardly from said cham-bers throughthe rim of the mpellerand being of progressively increasing diameter outwardly, said impeller having ducts placing the interior space ofthe hollow neck in communication with said enlarged chambers. LESTER B. HARRINGTQN.

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