US1999163A - Centrifugal pump - Google Patents

Description

April 23, 1935. F B, ALLEN CENTRIFUGAL PUMP Filed June 4, 1929 2 Sheets-Sheet 1 INVENTOR f ATTORNEY 259 F. B. ALLEN CENTRIFUGAL PUMP Filed June 4 1.929v 2 sheets-sheet l2 `57 y v H x g u "I gif-1 I \50 f I I ry BY Y ATTORN EY atented piu 23, 1935 Nrn-:p srA'ras cEN'rmFUGAL PUMP Frank B. Allen, Lower Mex-ion Township, Montgomery County, Pa., assignor to The Allen- Sherman-Hon Company,v a corporation of Pennsylvania Application June 4, 1929, serial No. 36s,2s9

(ci. s-10s) 2 Claims.

This invention relates 'to the art of centrifugal pumps and pumping and is particularly con- 'cerned with a new and improved apparatus for pumping liquid containing substances injurious 5 to parts of the pumps.

Although methods and apparatus for the centrifugal pumping ofv liquid have been in use for a A considerable period of time, they have not been utilized prior to my invention, so far as I am` aware, with any'marked degree of commercial success in the pumping of liquid containing substances having an injurious action on parts of the pump., For instance, attempts with which I am familiar have been made heretofore to utilize the prior art pumps and pumping methods in pumping water containing ash from coal burning -furnaces. These attempts have been unsuccessful commercially for several reasons.

y The ash 'containing water enters the spaces between the impeller andthe impeller casing and causes rapid wear on the vadjacent surfaces. Such wear required highmaintenance cost and had the further serious difficulties that it` permittecl leakage of water from the high pressure chamber of the pump with a corresponding reduction in eiciency of the pump and a limitation on the eifective liquid pressure obtainable at the pump discharge. 'I'his was due to the fact that the ash carrying water wore away the walls between the rotating element and the casing where close clearances were initially provided and as these p'arts Wore more and more the clearances became greater and greater and permitted'the pumped liquid-to escape between the impeller and the side walls of the casing thereby decreasing the available amount of liquid pumped and also limiting the liquid pressure thereof. 1

Moreover, the liquid which in this manner escaped from the pump discharge penetrated on the engine side of the impeller to the adjacent bearing of the impeller shaft, and, since such. liquid was under high pressure, it quickly penetrated for the full length of the bearing and rapidly cut away and otherwisei injured the bearing. o 45 Furthermore, a stuing box had to be provided which was capable of withstandingthe high pres-y sure on the liquid in the casing or' the liquid could ilow along theshaft and out of the 'casing through' the stuing box with further resultant loss in the iluid pumped and in the pressure obtainable in the pump discharge. s.

DespiteV the fact that the` pump impeller and casing have been made heretofore of abrasion resisting materials the pum'ps so constructed have not been satisfactory commercially, so far as'I am aware, for long continued operation without more or less close attention on the part of an operator.

By my present invention, however, which involves a method of pumping that I believe is new, and by pumps suitably constructed, in what Ibelieve to be a new and improved manner, I am enabled commercially to pump liquid/carrying substances'which may be of various compositions and which would have an injurious effect upon the pump parts of the prior art. Among such substances I mention ash water, sandy water, salt water and the like merely-as being illustrative of this general class of materials. \r My invention enables me to reduce substantially wear of or injury to the impeller and casing and bearing of a centrifugal pump; to maintain over long periods of use avery close running clearance between the casing and impeller; to construct a pump which is highly eiilcient initially and whose efficiency can be maintained for a longtime without close personal attention; and to vmaintain an effective liquid pressure closely approximating the theoretically calculated pressure as deduced from Athe impeller peripheral Speed. For the purpose of disclosing my invention so that those skilled vin theart may understand and be able to practice the same I have shown apparatus embodying my invention in the drawings accompanying and forming a part of this specification in Which Fig. 1 is a vertical sectional view through a horizontal centrifugal pump; Fig. 2 is a vertical longitudinal cross sectional 35 View of a vertical centrifugal pump having parts broken away; and

' Fig 3 is a chart showing the pressure head capacity curve of the impeller blades of the pump of Fig. 1.

Referring rst to the modification of my invention disclosed in Fig.' 1 the pump is mounted on a horizontal base l which Vis preferably of suilcientv length also to constitute a base for pump driving means (not shown), for example, 45 an electric, motor suitably connected to shaft 2 of the pump.. On base I restsa supporting body which, if desired, may be composed of two sections 2 and 3 slidably engaging the baseV I and provided with means for attaching the 50 to each other.I v,These sections 2 and 3 are preferably composed of cast. iron'. Section 3 has a doubly portion I bored to receive bearings for vtheshaft 2, here shown as Aconsisting of ball-bearings', the 55 outer races 5 of which engage the inner surface of the portion 4 and supports ball bearings 6 which seat in' inner races 1 on the shaft 2 and against the shoulder 8 thereon. Suitable adjusting screws 8 serve to adjust the bearings in the portion 4 and lock nuts I0 press the races 1 against the shoulder 8.

Section 2 consists of a cylindrical portion vII havinga 'flanged end I2 `adapted to be attached to a correspondingly flanged part of section 3 and is bored lengthwise to receive the shaft 2 and a bearing I6 therefor. The shaft 2 is prefer- `ing material I8 is disposed in the bore of cylinder II on the engine side of the bearing I6 and together with a gland I9 constitutes a stuffing.

box.

The cylindrical'portion II of section 2 isprefeJ erably formed integrally at the pump end,tliereof with a member2ll which constitutes the engine side plate of the impeller casing. The remainder `of the impeller casing consistsr of a central member 2| and the intake side plate 22, these two plates 20 and 22 and intermediatemember 2| being'conveniently and detachably connected together by bolts inserted in open- ended notches 23 and 24 of cooperating marginal portions of the several parts.- The intake side plate 22 has a central inlet .opening in which is positioned a member 25 preferably provided with an inwardly aring inlet opening, the member 25 being adapted for attachment ,to the side plate 22 and to an inlet pipe (not shown) in a manner similar to that just described above for the several parts of the `impeller casing.

The impeller comprises-a hub portion 2'6 suitably securedfas by a key and keyway, to the shaft 2, a disc 21, main impeller blade 28 on` one side of thesdisc and auxiliary impeller blade 29 on the other side thereof and a centrally perforated disc 38 serving as a cover for the main liquid to be pumped may pass 'into contact withA the main blade 28. Thediscs'21 and 38 arev provided with ilangedperipheral portions 3| and 32 respectively having a. relatively` close running clearance with adjacent portions \of the intermediate casing'member 2| and cooperating with adjustable ' wear rings 33 and 34 carried respectively by the side plates 20 and 22. The side j plate 22 also carries an adjustable wear ring 35 casing to cooperate with a raised and ground or machined annular boss or -land ,on the outer surface of the disc 38. A

It willbe noted that the disc 21 serves to sub-Y divide the interior of the impeller casing into a chamber 36 between the disc `21 and engine side plate 28 and the main chamber 31 in which the main blade 28 is disposed. In a similar manner the disc 38 sub-divides the interior of the impeller casing into a chamber 38 between the intake side plate 22 and the disc 38 and the main chamber 31 in which the main blade 28 is. disposed. Thus the impeller casing has three sepa,-

size of the annular passage 39 between chambers 36 and 31 may be controlled by relative adjustment of the disc 21 and wear ring 33 while relative adjustment of the wear members 34 and 35,

and disc 30 control the sizes of the annular passages 48 and 40a betweenthe chamber 38 and chamber 31.

Chambers 36 and 38 communicate with each other through a piping connection 4| and also communicates through piping 42 with the bearing I6 in cylinder I I. Pipe connections 43 which opens into chamber 46 serves to supply liquid which is substantially free from injurious substances to the interior ofthe impeller casing.-` The operation of the above described device is substantially as follows:

The pump driving means is energized and rotates shaft 2 and the impeller. Liquid is admitted into the casing through pipe 43 and pumped by `the auxiliary impeller blade 29 into the chamber 36 under considerable head pressure applied thereto. The liquid so pumped passes through the passage 39 in the chamber 31 and also passes through conduit or pipe 4I into'chamber 38 where substantially the same head pressure is created and maintained as exists in chamber 36. At the same time liquid passes through pipe 42 and proceeds through the riing grooves in the bearing I6 back into the chamber 36. This travel is partly due to the higher pressure existing in the outer peller end of `the bearing I6 by the auxiliary.

blade 28.

When liquid to be pumped is admitted throughl member 25 into the casing the main impeller blade 28 pumps such liquid to the outlet opening of the casing. inasmuch as the casing outlet opening is larger in comparison to the size of the blade 28 than is the case with the outlet opening of chamber 36 and the auxiliary blades V29, and further since the blades 28 are somewhat longer than the blades 28 and, therefore, tend to create a greater head pressure on liquid in chamber 36, the result is that the liquid in chambers 3.6 and38 will be under a greater pressure than the liquid in chamber 31 and hence the liquid from these two chambers will flow into the chamber 31 against the pressure on the liquid in the latter. This flow :of

impeller blade 2s and as a' member through which liquid from chambers 36 and 38 into the chamber H1 31 effectually' prevents any liquid carrying substances injurios to the pump vparts from entering the spaces between the impeller and the casing walls 'or penetrating to the shaft bearing. Hence liquid carrying 'various materials which might be injurious to the pumps heretofore constructed can be satisfactorily handled on a commercial scale by a pump embodying Amy invention without the ordinary troubles incident to the use of the prior art pumps.

It will be understood that in the pump above described the impeller will. be hydrostaticallybalanced. If the pressure in chamber 36 exceeds ythat in chamber 38 the impeller will tend toA move away from the wear ring 33 thereby enlarging lthe opening 39 and correspondingly closing the openings `4I) and 40a. The variation in these openings will automatically vary the pressure in the two chambers and when the pressure in chamber` 38 exceeds that in chamber 36 the impeller will move in the opposite direction. It will be understood that these slight movements will be permitted by the ball bearings inthe portion 4 of section 3. In this manner the impeller will to a member 54 corresponding to cylinder il of tend automatically to find a position in which the pressure on opposite sides thereof from chambers 36 and 38 will be substantially equal and thus the impeller will be hydrostatically balared. As

the pressure of the auxiliary flushing liquid within the chambers 3B and 38 is substantially equal during operation of the pump, the tendency for the flushing liquid to ow into the main pumping chamber will be substantially equal at4 all points of communication between the main and auxiliary chambers. These points of communication are three in number, namely, the passage between the ring 33 and the portion 3l of the impeller, the passage between the ring 34 and the portion 32 of the impeller and the passage between the 'inner periphery of the disc 30 andthe pump inlet pipe 25.

The pump shown in Fig. 2 is like the pump in Fig. l in many respects which concern the general construction of the impeller and casing but differs therefrom in respects incident to the changing of the horizontal pump of Fig. 1.

. f The shaft driving means l(not shown) iscarried on a plate 50 supported inv any suitabler manner, for example, on the walls of a sump containing liquid to be pumped. The shaft 5I extends downwardly through the plate 50 and is attached to the impeller at the lower end. A, shaft housing and non-abrasive fluid reservoir 52 depends from the plate 50 carries la bearing 53 intermediate the ends of theshaft and is secured Fig. 1 in which cylinder 54- and a bearing 55 are disposed, this bearing 55 being constructed of suitable material such as those previously d e' scribed and preferably suitably riiied but with a pipe 56 corresponding .to pipe 42 of Fig. 1 leading into the bearing 55 intermediate its ends; A pipe 51 serves to bring liquid substantially free of pump injuring substances into the housing 52 and a pipe 58 serves to withdrawliquid from the lower portion of casing 52 and conduct it into the impeller housing through a communicating' pipe .7, corresponding to pipe 43 of Fig. 1.

At the intake side of the impeller casing an inlet pipe 59 is provided at the-inlet end of which an annular conduit 60 is disposed provided with a plurality of nozzle openings 6I through which conduit and openings fluid under pressure may be discharged to dislodge any pieces of solids which might clog the pipe 59 and toinsure the presence of the proper amount of diluting liquid for satisfactory pumping of the solids. A steadying support 62 is associated with the pipe 59.

In` Fig. 3 I have shown achart which illustrates the characteristic curves :of the pump just described. The head pressure capacity curve of the distance between the point X and Y indicates the excess of' head pressure on liquid pumped by the blades 29 over that pumped by the blades 28. This chart shows why the liquid in chambers 36 and 38 will Iiow into chamber 3T.

Having thus described my invention so that those skilled in 'the art may be enabled to practice the same what Idesire to secure by Letters Patent is defined in what is claimed, it being understood that many changes may be made in the described method and apparatus without departing from the spirit and scope of the invention.

What is claimed is:

l. In combination in a centrifugal pump of the class described, a pump casing, ashaft bearing having an end opening into said casing, a liquid reservoir disposed at the opposite end of said bearing, said oppositel end of said bearing opening into said reservoir., a shaft supported by said bearing, an impeller disposed in said casing and mounted on said shaft yfor rotation therewith, said impeller having side discs adapted to divide said housing into a central main chamber and auxiliary side chambers and having main impeller blades disposed in the mainchamber and auxiliary impeller blades disposed in the auxiliary side chamber on the side of the housing into which said shaft bearing opens, a fiuid conducting passage extending from said reservoir to said auxiliary chamber into which said bearing opens at a iliary chamber at a point adjacent the periphery of said auxiliary. impeller to'said bearing at a point between the ends of. the bearing, a fluid conducting conduit extending from saidlast mentioned` auxiliary chamber to the auxiliary chamber on the opposite side of said main chamber, and means for conducting non-abrasive fluid from a source of supply to said reservoir.

2. In combination in a. centrifugal pump of the 4class described, a pump casing, a shaft bearing .having an end opening into said casing, a shaft mentioned auxiliary chamber at a point adjacent the periphery of said auxiliary impeller to said bearing, a .uid conducting conduit extending from said last mentioned auxiliary chamber adjacent the periphery of 'said auxiliary impeller to the .auxiliary chamber on the opposite side of said main chamber, and means for conducting non-abrasive uid from a source of supply to said auxiliary chamber into whichsaidfbearing opens.

. FRANK B.. AILEN.

'point adjacent the bearing, a fluid conducting L conduit extending from said lastmentioned aux-

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