US2518597A

US2518597A - Pumping apparatus

Info

Publication number: US2518597A
Application number: US600437A
Authority: US
Inventors: William C Brooks
Original assignee: Niagara Alkali Co
Current assignee: Niagara Alkali Co
Priority date: 1945-06-20
Filing date: 1945-06-20
Publication date: 1950-08-15
Anticipated expiration: 1967-08-15

Description

Aug 15, 195o w. C. BROQKS 2,518,597

PUMPING APPARATUS Filed June 20, 1945 ,m @gf L20 44\ 79g 7g; i5 f 1 J n;

VA 24M 1 25 3'/ l ENTOR MMQW@ BY A ATTORNEYS Patented Aug. 15, 1950 UNITED S'I`'-I.`lE1S PATENT OFFICE PUMPING APPARATUS vWilliam C. Brooks, Niagara Falls, N. Y., assigner to NiagaraAlkali Company, Niagara Falls, N. Y.

Application June 20, 1945, Serial No. '600,437

2 Claims. l

This invention relates to pumping devices or appara-tus for use in connect-ion with the .pumping of liquids, and more particularly liquefied gases and corrosive liquids, such for example as liquid chlorine, anhydrous hypochloric acid, liquid sulfur dioxide, hydrogen ysulfate and other' liquids.

One of the objects of this invention is to provide a pumping device of this kind in which the rotor of the motor which operates the pump operates in a gas phase only and not in contact with the liquid being pumped. Another object of this invention is to provide a pump of this kind .which is so constructed that the usual stuiling boxes can .be eliminated. Other objects and advantages of this invention will appear from the following description and claims.

Pumping devices have heretofore .been provided for use in connection with liquids of this type in which the rotary part oi the motor operates in the liquid which is being pumped, which, hoW- ever, has proven unsatisfactory because of the additional power required to operate the rotary part of the motor in a liquid medium and because of the possibility that the parts oi the motor may be damaged by the liquid. In my improved pump, l have provided an upright chamber with the upper portion thereof sealed so as to form an `air-tight pneumatic domein which the rotary part oi the 'motor may operate in air or in a gas phase, the lower portion of the chamber through which the liquid being pumped owsand in which the pump is located being in Acommunication with the upper portion, 4so that the liquid being pumped may enter the upper portion. The rise of liquid into the upper porticnof the chamber is resisted by the air or gas cushion 4confined in the upper portion.

Any suitable means may be provided for producing such contruction, and in the particular embodiment of the invention shown in the accompanying drawing, which .is -a Vvertical central sectional elevation voi a pumping apparatus embodying this invention, I ,have provided an upright chamber including a substantially tubular or cylindrical upper portion 5, which is tightly sealed to prevent escape of air or other gas from the interior .oi the chamber. The chamber also includes a lower portion il in 'which the pump is located and .into which liquid is admitted by means .of an inlet v`pipe l and discharged through an outlet or discharge pipe B. The lower por-tien 5 of the chamber is .also for-med to provide a. pump housing 9 of any suitable type tn which a rotor 9a is arranged. The middle or inlet portion of the rotor receives liquid from an upright passage I8 for the liquid to be pumped. The upper and lower portions oi the housing may be secured together in any suitable manner and suitable packing means l2 are provided to prevent escape of gas or liquid through the joint between the two portions of the housing.

li desired, a plate or partition I4 may be interposed between the upper and lower portions of the housing, but this plate or partition is not intended to form a vseal to separate the two portions of the housing from each other, the plate in the construction shown being provided .fith a central hole or aperture l5 therein through which liquid and gas may pass from one portion of the housing to the other, and preferably :1 driving :shaft l5 secured to the pump inipeller Ba also lpasses :through this hole. This pla'e may be a part of the pump housing and se .es to prevent excessive su-rging or splashing o2 the liquid in the upper portion of t? e housing.

The upper or tubular portion 5 of the chamber is provided with a head i3 which is suitably secured to the upper end of the tubular or cylindrical member 5 to form a tight joint therewith and this head is preferably provided with a bearing for the upper end 'of the shaft IE. This bearing may be of any suitable construction, and as shown, is formed in a substantially cylindrical bore or recess in the axial portion of the head, and includes a bushing I9 which may be made of graphite or other suitable material not attacked by the gas which may be contained in the upper part of the chamber. This be; preferably self-lubricating. The axial reces or bore in the head i8 in the particular cons-truction shown extends into an integral .tubular part or hollow lug Eil extending upwardly from the head I8 and the upper end of which is tightly closed by any suitable means, such as a cap 2l. As `a result of this construction, it will :be noted that the upper end of the cylinder 5 is tightly sealed, without requiring any stuing box, and consequently, air or vapor from the liquid being pumped, or a mixture oi both, will sures, depending lupon the pressure of `the ,d in the lower part oi the chamber. he tu a l. part of the chamber is made of suihcient height so that regardless of the pressure of the liquid in the lower part of the chamber, there will a rays be a considerable vspace nlled with air other gas in the upper l:part of the chamber, and for .this Pur- DOSE V.the clear space inthe tubular .part

part is located within the chamber and operates v in the air or other gas trapped therein. Any

suitable or desired type of motor maybe employed for this purpose, and in the construction ,l

shown by way of example, I have provided anl induction motor with a stator thereof arranged on the outside of the tubular chamber part 5 and with the rotor thereofY arranged withinthe chamber. For this purpose, the upper portion 24 of the wall of the tubular part 5 of the chamber is made of greatly reduced thickness and-a stator core 25 is arranged about the relatively thin part 2d of the housing, preferably in such sion of which may be adjusted by means of a threaded plug i6 arranged within the tubular part 29 of the head I8. If desired, a ball may be interposed between the upper end of the shaft and the stem or plunger lill. By adjusting the lower screw 36, the shaft may be adjusted to correctly position the rotor within the pump housing 9 and by adjusting the threaded screw plugll, the pressure which the spring 45 exerts on the upper end of the shaft may be varied as desired. Any other means for mounting the shaft I5 in the pump chamber or housing may be provided.

In the operation of the apparatus thus far described, assuming that the inlet duct l is connected with a source of liquid to be pumped and .the discharge'passage 8 with a suitable delivery a manner that the core itself forms a reinon a rotor 2l which may be of any suitable or v,

usual construction, and which is secured to the upper part of the shaft i6. The thin walled portion 2d of the tubular part 5 of the upright chamber or housing must, of course, be made of a non-magnetic material. Since the construction and operation of induction motors is well understood, no further description is deemed necessary. The stator core and its winding may, if desired, be enclosed in a head or enclosure 28 in the form of a cap resting on the head i8 of the housing and having a depending part surrounding the stator, and the lower portion of the cap may be closed by means of a ring or annulardisk Sil welded to or otherwise secured to the tubular housing part 5. Cooling fins or vanes Si may be provided on the outer surface of f the stator enclosing cap 23 to dissipate heat developed in the stator. This cap protects the stator against damage, but may be omitted, if desired.

The shaft It may be journalled at its lower end i in an upright aperture formed in the base portion 33 of the lower portion of the pump chamber and a bearing bushing 34 of a material, which is not attacked by the liquid which is being pumped, is provided. The lower part of the aperture in the base may be providedV with internal screw threads 35 and 'an adjusting screw 35 having a stem 3l extending into the bearing bushing may form the lower thrust bearing for the shaft, a ball 38 being interposed` between the stern 3l .and the lower end of the shaft l5. The aperture in the base extends through the same and the lower end thereof may be suitably sealed in any desired manner. In the construction illustrated, the base is mounted 'on a plate l0 having an annular upwardly extending projection 4| formed to enter into a corresponding recess in the base and to cooperate with a packing ring 42 arranged in the recess. Endwise movement of the shaft may be opposed at the upper end of the shaft by means of a suitable plunger or pin iid, the lower end of which extends into the bearing bushing i9 and which may be pressed downwardly against the upper end of the shaft by means of a coil spring 45, the teil,-

pipe for the liquid and assuming the motor is started in operation by connecting the terminals of the st ator winding with a suitable supply of alternating current, it will be obvious that liquid will be pumped by the impeller from the passage Il) to the discharge passage S. The hole I5 in the partition I4 is in communication with the liquid passage lil through the housing B of the pump, and consequently, liquid can pass into the lower part of the tubular portion 5 of the housing and will rise in the housing until the pressure of the entrapped'gas in the upper part of the housing equals the pressure in the lower part of the housing, whereupon this gas will prevent further entrance of liquid into the upper part of the housing. The rotor 2'! of the motor will, consequently, operate in a gaseous medium where its resistance to rotation isI much less than when located 4in a liquid medium, thus greatly increasing the efficiency of the pumping apparatus. Furthermore, the rotor will be unaffected by any corrosive action of the liquid. The partition Ill serves to prevent splashing or surging of the liquid while being pumped in the lower part of the housing from being transmitted into the upper part thereof. By providing a pneumatic dome in the upper part of the housing, the need for stuffing boxes is entirely eliminated, and these stuffing boxes have heretofore been a source of continuous trouble with pumps of this type because of the fact that the packing and lubricant used in the stufng boxes was readily attacked by liquids being pumped, thus producing leaks, which are dangerous and very objectionable when liquids such, for example, as liquid chlorine are being handled. When the pump is started in operation, the upper part of the housing will, of course, contain air and this air will be entrapped and compressed in the upper part of the housing, but some of the liquid which is being pumped may beY vaporized and such vapor will, consequently, become mixed with the air in the upper part of the housing.

It is necessary to make sure that the temperature of the liquid does not rise to a point at which the liquid becomes excessively corrosive or easily vaporized, .and for this purpose, I preferably provide the pumping apparatus with heat responsive means which may be connected in such a way as to interrupt the operation of the pump when parts thereof become excessively heated, or to actuate 'a warning signal.

This maybe accomplished in any suitable or desired manner, for example, as illustrated diagrammatically on the drawing in which 5i? and 5I represent thermo-responsive members located in any suitable or desired position on the pumping apparatus. For example, the member Eil is located so as to be responsive to changes in temperature of the pump housing 9, and the member, 5l being responsive to temperatures of the stator of the induction motor. These devices are so constructed that current flowing through the same will be interrupted when the temperature in either thermostatic device becomes execssive. These two devices are preferably connected in series through a conductor 52 leading from a suitable supply of current, a conductor 53 connecting the two thermo--responsive members and

conductors

54 and 55 leading to a relay 56 which normally holds a switch member 58 in circuit closing position against the action of a spring 59. This switch is in a conductor 60 leading to one of the terminals of the stator winding, the other terminal being connected by a conductor 6I to a suitable source of alternating current. Another conductor 62 leads from this source of current to a terminal with which the switch member 58 contacts when the motor is in operation. Consequently, if either of the two thermo-responsive members becomes excessively heated, the circuit including these members will be broken, thus causing the magnet 56 to frelease the switch member 58 to open the circuit to the motor. Any other connections for accomplishing this result may be used.

I claim as my invention:

1. A pumping device for use with corrosive and/or poisonous liquids, which includes an upright cylindrical chamber made of non-magnetic material having a head for the upper end thereof forming a gas-tight seal therewith, said cylinder and head forming a pneumatic dome, a centrifugal pump housing secured in air-tight relation to the wall of the lower portion of said cylindrical chamber and having inlet and discharge passages for the liquid and having a central opening forming a connection between said pump housing and said chamber, an impeller in said housing, a shaft on which said impeller is secured and which extends through said central opening of said pump housing without closing said opening, a bearing for said shaft arranged on said head of said cylindrical chamber and located within the air space in said chamber and another bearing for the lower end of said shaft, said other bearing being located in a bore in said housing, said shaft terminating in said bore and the outer end of said bore being tightly sealed, an induction motor having a statorfarranged on the exterior of the upper portion of said cylindrical chamber and having a rotor. arranged within said upper portion of said chamber and secured to said shaft, said cylindrical chamber being of such height as to provide clear space below said rotor which is at leastpequal in height to the space from the lower end of said rotor to said head, said cylindrical chamber forming a pneumatic dome in which said rotor operates above the level of the liquid in said cylinder.

2. A pumping device according to claim 1, in which the upper end portion of the wall of said cylindrical chamber extending about said rotor and to thev upper end of said wall is of materially smaller lcross section than other portions of said cylindrical chamber and in which said stator includesa core which may be slid over said upper end portion of said cylindrical chamber and which fits tightly about said portion of smaller cross section to reinforce the same against pressure within said cylindrical chamber.

" WILLIAM C. BROOKS.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS