US1894165A - Centrifugal pump - Google Patents

Description

Jan. 10, l1933. J w. W- DRYSDALE 1,894,1`65

CENTRIFUGAL PUMP Filed March 4, 1952 Patented Jan. 10, 1933 UNITED sTA'rEs PATENTff OFFICE JOHN WEITEHEAD 'WILSON DRYSDALE, OF YOKEB, GLASGOW, SCOTLAN D, ASSIGNOB T0 DBYSDALE AND vCOJNIPAISI'Y,1'.|IIbII'I'IE`.D, OF YOKEB., GLASGOW, SCOTLAN'D i cEN'mIrUeAL PUMP Application filed March 4, 1932, Serial No. 596,870, and in Great Britain March 30, 1931;

This invention relates to centrifugal pumps of the self-priming type comprising essentially an impeller (or impellers) rotatable about a Vertical axis, an air-separating chamber, an air-exhauster preferably of the waterring type for extracting the air from said chamber, and a driving motor coupled to the impeller and to the air-exhauster.

The invention will be defined in the annexed claims. For convenience it may here be said that the invention in fact consists in a new and improved construction characterized by the provision of a passage in the form of a loop interposed between the main suction inlet and the eye of the water-impeller, vsaid passage comprising ascending and descending branches separated by an inclined partition or Weir overhanging the ascending branch and presenting an air trap.

Preferably the motor is disposed above the impeller, and the air-exhauster located between the motor and the Water-impeller, or above the motor.

Desirably the water-impeller is of the single-entry type, with the sucton eye looking upwards, thus avoiding the possibility of airlock atthe impeller eye and permitting the air to vent upwards.

In practice, the inclined partition or weir is formed at the upper edge with an overturned lip adapted to trap the ascending air. Water entering at the main sucton inlet and rising in the ascending branch of the passage overhung by the inclined partition or Weir flows over the lip and thence to the eye of the impeller.

Side vents lead from vthe air trap to the upper part of the separating chamber, air caught in the trap escaping gradually to the topv of the chamber without being interfered with by the main current of water.

With the described arrangement there is realized the maximum of air separation from the water and hence increased efliciency of the ump when handling Water which ischarged with air, whether due to air leaks in the suction pipe or entrained in the process of prim- 'i The liberation of air from the upper part of the separating Chamber is controlled by a float-operated valve housed in a valve com-V partment,

A pipe leads from the valve compartment to the sucton compartment of an air exhauster of the water ring type incorporating a runner rotating within a Vortex chamber surrounded by a Water jacket and having controlled connections whereby the water constituting the Water ring may be forced out of the Vortex Chamber and delivered to a reservoir, when it is desired to cut the air-exhauster out of action.

The runner of the air-exhauster may be provided on its under side With a set of radial vanes, ensuring that a suitable back pressure is maintained from the ring Vortex and efi'ectively preventing air leakage.

The runner is desirably formed integral with a bush which extends above the level of the water in the air-exhauster casing and thus prevents water leakasre from the exhauster whether thepump is standing or running.

In the case where the air-exhauster is situated between the motor and the water-impeller there may be provided on the driving side of the exhauster adjoining the motor coupling a plain neck bush constructed with suitable clearance and adapted to form a water seal which comes into action whenever the air exhauster is exercising sucton and thus prevents air leakage during working.

A centrifugal pump oonstructed in accordance with the invention is illustrated more or less diagrammatically in the accompanying drawing, in which Fig. 1 is a part Vertical section, part elevation, Fig. 2 a section on the line 2-2 of Fig. 1, and Figs. 3 and 4 are fragmentary horizontal Sections.

The centrifugal pump shown comprises a Water-impeller 1 rotatable about a Vertical axis, a driving motor 2 to which the waterimpeller 1 is coupled, an air-separating chamber 8, and an .air-exhauster of the waterrfng type indicated generally at 4, also cou- .pled to the motor 2, for extracting the air from the Chamber 3.

The impeller 1 is of the single-entry type with the sucton eye 5 lookingupward's.

lnterposed between the main sucton inlet 6 and the eye 5 is a passage in the form of aloop comprising ascending and descending branches 7, 8 respectively, separated by an inclined partition or weir 9 overhanging the ascendin branch 7 and formed at the upper edge wit a downturned lip 10 forming an air trap 11. Water entering at the main suction inlet 6 and rising in the ascending branch 7 flows over the lip 10 and down the descending branch 8 to the suction eye 5. Air passin up from the suction inlet 6 and travellmg along the lower side of the partition or weir 9 is cau ht in the air trap 11.

Side Vents '13 lead from the air trap 11 to the upper art of the Chamber 3, air caught in the tra 111 escaping gradually to the tag of said cliamber without being interfere With by the main current of water.

The liberation of air from the chamber 3 v is controlled by a valve 1.4 housed in a compartment and operated by'a float 15 exercising a owerful leverage; any tendency to back-lasii or undue Wear of the parts being avoided by the provision of ample trunnibon supports at 16 for the float leVer 17 the free end of which coacts with stops 18, 19.

Any sediment contained in the water near the surface is prevented from gaining access to the compartment 20 by the provislon of a cylindrical strainer 21 which houses the working parts of the float mechanism, thus eflectively avoiding damage to the float mechanism and ensuring freedom from leakae caused by solid material lodging between t e air valve 14 and its seat.

F A' pipe'22 leads from the outlet side of the valve compartment 20 to the suction compartment 23 of the air-exhauster 4, which may be of known construction and which in the form illustrated includes a Vaned runner 24 operating in an eccentric or Vortex 'chamber 25. rIhe chamber 25 communicates by way ofl a suctiony port 231 Figs. 3 and 4) with the compartment 23 an by way of a discharge port 232 with a discharge compartment (not shown) a'djacent to the com artment 23. As is understood, lthe Vortex c amber 25 contains water which is caused by the rotation' o'f the runner 24 to adhere to the lsides of the chamber 25`and thus to leave the axis of rotation of the runner 24. There are thus left in the intervane s aces of the runner 24 cavities which expan and contract alternately, the suction port v231 being open to the ex anding cavities and the discharge port 232` eing open to the contracting cavities.

The Vortex chamber 25 is Water-jacketed by a cooling-water pocket`26 (Figs. 3 and 4) and by a sealing-water reservoir 27 for the air exhaster. Cooling water is circulated through the pocket 26 by way of connections 261, 262 connected, respectively, 'to the centrifugal, pump suction and to the centrifugal ,pump discharge by way' of pipes, not shown.

,The discharge compartment of the air-exhauster is connected to the water reservoir 27 by wa of a port 28 through which water entraine by the air discharged by the exhauster is drained back to the reservoir 27.-

29 denotes a make-up water supply duct conn'ecting the reservoir 27 to the under side of the runner 24. Fitted to the Water j acket is a switch-cock shown only in F igs. 3 and 4 including a plug 30 rotatable in a cock-body 31. The plug 30 is prvided with ports 32, 33 adapted to co-operate with ports 34, 35, respectively in the plug-body 31. The plug port 32 is continuously connected to a pas- Sage 36'comn1unicating with the interior of jexhau'ster out of action atmospheric air being admitted by way of t e orts 33, `to the. vsuction compartment 23 W ereby to break the vacuum therein. When lthe plug 30 is in the position shown in F ig. 4, all the ports are masked. so that the exhauster isV permitted to function normally.

The runner 24 is unitary with a bush 37 extending above the level of the water in the exhauster casin and surrounding withJ clearance a bearing bush 38 embracing the intermediate portion 40 of the shaft 39-41, the arrangement being such that there is afforded between the bushes 37, 38 a water seal which comes into action whenever the exhauster is exercisin'g suction and thus prevents air leakage during operation.

v Having thus describedmy invention, what I claim as new and desire to secure by Letters Patent is 1. A centrifugal pump of the self-prim- `ing type comprising a water-impeller arranged to rotate about a Vertical axis, an airseparating Chamber, an air-exhauster for extracting the air from said chambr' and mounted above the said water-impeller, and a driving motor mounted above and coupled to the water-impeller and to'the exhauster a passagein the form of a loop interposed between the main suction inlet and the eye of the water-impeller, said passage comprlsing ascending and i'descending bfanches, an inclined partition separating the two branches and forming at its top a weir which overhangs the ascending branch.

2. A centrifugal pump of the self-primin type comprising a water-impeller'arrang to rotate about a Vertical axis, an air-separating chamber, an air-exhauster for extracting the air 'from said chamber and mounted above the said water-impeller, and a driving motor mounted above and coupled to the water-impeller and to the exhauster, a passage in the form of a loop interposed between the main suction inlet and the eye of the waterimpeller, said passage comprising ascending and descending branohes, an inclined partition separating the two branches 'and forming at its top a weir which overhangs the asoending branch, the weir being provided with an overturned lip adapted to trap the ascending air.

8. A centrifugal pump of the self-priming type comprising a water-impeller arranged to rotate about a Vertical axis, an air-separating Chamber, an air-exhauster for extracting the air from said Chamber and mounted above the said water impeller, and a driving motor mounted above and ooupled to the water-impeller and to the exhauster, a passage in the form of a loop interposed between the main suction inlet and the eye of the waterimpeller, said passage comprising ascending and descending branches, an inclined partition separating the two branches and forming at its top a weir which overhangs the ascending branch, the weir being provided with an overturned lip adapted to trap the ascending air, side vents leading from the hollow below the overturned lip to the top of the air-separating Chamber.

4. A centrifugal pump of the self-priming type comprising a water-impeller arranged to rotate about a Vertical axis, an air-separating Chamber, an air-exhauster for extracting the air from said Chamber, a driving motor ooupled to the water-impeller and to the exhauster, and a passage in the form of a loop interposed between the main suction inlet and the eye of the water-impeller, said pas- Sage comprising ascending and descending branches, and an inclined partition separating said branches and forming at its top a weir which overhangs the asoending branch and 'afords an air trap and connections bet-Ween said air trap and said separating Chamber.V I hereby sign my name to this specification.

JOHN WHITEHEAD WILSON DRYSDLE.

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