US2868133A - Centrifugal pumps - Google Patents

Description

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4 Sheets-Sheet 1 Filed Sept. 14, 1956 ///f/V-r@ John C/ar l (deceased) 5)/ Jane arr Chr@ Jan. 13, 1959 J. CLARK 2,868,133

CENTRIFUGAL PUMPS Filed Sept. 14, 1956 4 Sheets-Sheet 2 jpl/p7] Y] Atto rzeyS 4 Sheets-Sheet 3 Filed Septy 14, 1956 a m 0 M a ma Z 6 M f u w/p d M /ac r rib mmf arf/m r ZJ ,.2 wm Jaw Att rneys Jan. 13, 1959 J, @ARK 2,868,133

CENTRIFUGAL PUMPS Filed Sept. 145.1956 4 Sheets-Sheet 4 #VVE/V70@ John CMPK (deceased) om e ys United States Patent() CENTRIFUGAL PUMPS John Clark, deceased, late of Rutherglen, Scotland, by Jane B. Clark and Margaret S. L. Clark, Rutherglen, and Helen MacMurchy, Strathaven, Scotland, executrices, assignors to Jane Barr Clark, Rutherglen, Lanarkshire, Great Britain Application September 14, 1956, Serial No. 610,026

2 Claims. (Cl. 103-87) This invention has reference to centrifugal pumps of the kind provided with a conical impeller having spiral vanes which form therebetween ducts each preferably of substantially uniform cross sectional area throughout its length and non-rotatable spiral vanes which receive the liquid delivered thereto by the impeller for onward delivery to the discharge outlet of the pump.

The present invention has for its object to provide a pump of the kind set forth of high elllciency, reliable in operation and simple in construction.

According to the present invention in a pump of the kind set forth the impeller is fast on the shaft of an electric motor enclosed in a cylindrical casing constituting the pump body, said casing having lixed spiral ducts and communicating therewith an annular axial passage which delivers the liquid received from the impeller to the pump discharge outlet.

The invention further consists in a pump as set forth in the preceding paragraph wherein the motor and its shaft are sealed. .against contact with liquid flowing through the pump.

The pump may be provided with a flanged impeller cover secured to the cylindrical pump body, an inlet branch secured to the said cover and a non-rotatable floating sealing ring located between said cover and inlet branch and arranged to bear on an external flange of the impeller and an annular bearing face of the inlet branch, the construction being such that the ring is held to bear on the said flange and bearing face by the pressure of liquid which may leak thereto or by the minus pressure which may exist in the inlet branch.

One construction of pump in accordance with the invention will now be described, by way of example, with reference to the annexed drawings wherein:

Figure l is a sectional elevation of the improved pump;

Figure 2 is a sectional elevation of the impeller;

Figure 3 is a section on the line 3 3 of Figure 2;

Figure 4 is an elevation partly in section of the right hand end of the pump body showing a number of the fixed vanes;

Figure 5 is an end view thereof looking to the left with the pump body cut away to show the vanes; and

Figure 6 is a section on the line 8-8 of Figure l.

The improved pump as shown in the drawings is provided with a pump body in the form of a cylinder or casing 10 with external flanges 11 at its ends and provided with supporting feet 12. The cylinder is formed of an outer and an inner shell or shroud 13 and 14 respectively which form therebetween an annular axially-extending passage 15 which at its right hand end curves inwardly. The shells are maintained in spaced relationship by fixed longitudinally-extending vanes 15a and also by means of a series of integral bridge pieces 21 located at the left hand end. Said vanes 15a and bridge pieces form therebetween a series of circumferentially extending gaps 22 (see Figure 6).

Provided between the curved ends of the outer and 2,868,133 Patented Jan. 13, 1959 Nce inner shells 13 and 14 and also extending partly along the annular passage is a series of fixed spiral vanes 17 integral with axial vanes 17a said vanes forming therebetween spiral ducts 18 and axial ducts 18a.

The cylinder at the end provided with the fixed-spiral vanes is provided with an inwardly-turned flange 19 which supports a housing 20 in which is fitted a combined journal and thrust anti-friction bearing 20a.

To the other end ofthe cylinder is secured a flanged discharge member 23 which supports a housing 24 by means of annular support 23a cast integral with the discharge member 23 and forming therewith an annular passage 2311. The annular support 23a is connected to the discharge member 23 by means of a series of bridge pieces 23e forming therebetween a series of circumferentiallydisposed passages which register with the gaps 22. In said housing 24 is fitted a further combined journal and thrust anti-friction bearing 25. Journalled in the two bearings is a shaft 26 which carries the rotor 27 of an electric motor, the stator 28 of which fits snugly within the cylinder to which it is anchored. The housing 24 embodies a cover plate 29 by which the passage of water to the shaft and its motor is prevented.

The stator is located within the cylinder by means of screws which pass through holes in the outer and inner shells and through holes 15b in the vanes 15a.

Fast on the right hand end of the shaft is the impeller formed of outer and inner cone-like shrouds or shells 30 and 31 and spiral vanes 32 between the shells, the vanes forming with the shells a series of spiral ducts 33 each, in preference, of substantially uniform cross sectional area throughout its length, see particularly Figures 2 and 3. That is, each of said spiral ducts widens in a circumferential direction and diminishes in depth as it approaches the fixed vanes to maintain uniformity of cross sectional area. The outer shell 30 is formed with a throat or annular extension 34 which constitutes the inlet to the impeller, the inner ends of the ducts communicating therewith. Snugly enclosing the impeller but permitting the free rotation thereof is a flanged impeller cover 36 secured to the adjacent end of the cylinder 10 and to which in turn is secured the flanged end of an inlet branch 36a to the pump. Said branch is annularly recessed to receive an external flange 37 formed on the throat and also a sealing floating ring 38 which bears on the flange and also on an annular bearing face on the inlet branch. Said floating ring is prevented frorn rotating by means of a number of locating dowel pins 39.

Enclosing the end of the shaft between the lrear of the impeller and the adjacent bearing housing is a flanged sealing ring housing 40 bolted to the internal flange 19 of the cylinder casing. This sealing housing forms an annular chamber 41 surrounding the motor shaft and in which is located a sleeve 42 secured to the housing 40 against rotation relative thereto by means of a pin 43, but urged axially away from the housing 40 by a spring 44. A sealing ring 45, preferably of a synthetic rubber such as neoprene is mounted around the sleeve 42 and an annular groove 45a to accommodate the rings 45 is provided in the housing 40. A further sleeve 46 is secured for rotation with a clamping ring 47 clamped to the motor shaft, and is spring-urged axially away from the clamping ring 47 by means of a spring 48 and thus bears intimately against the rear face of the sleeve 42 urged in the contrary direction by the spring 44.

A sealing ring 49, preferably also of a synthetic rubber such as neoprene, is mounted around the motor shaft and is located in an annular recess in the rear face of sleeve 46.

The sealing ring housing is provided with a radial passage 40a which communicates with a drainolf duct 40b leading from the recess to the exterior.

The discharge member 23 at the discharge end of the pump is provided with a passage 45 through which pass the leads to the motor.

When the impeller is driven by the motor it draws water through the inlet branch 36a and forces it throughl its rotating spiral ducts 33 to the inlet ends of the nonrotatable ducts 1S which register therewith. The latter serve to straighten out the ow of liquid which then passes between the vanes 17a and then between the vanes 15a in the annular duct in the casing to `the annular discharge passage 23b and then to the discharge outlet of the coupling member.

Packing glands are not required to prevent the passage of Vliquid to the motor. In pumps as heretofore constructed such packing glands are necessary. This results in substantial friction if the packing is maintained tight and if not so maintained there is leakage of air therethrough and self-priming is lost. In either case there is loss of eliciency.

In the pump of th'e present `invention no levelling up of pump and motor is necessary, the motor is self-cooled by the liquid being pumped. Output relative to bulk is considerably greater than has heretofore been the case and the pump is continuously self-priming after initial priming.

Should there by any back pressure by leakage between the impeller and its cover, such pressure holds the floating ring 38 in yengagement with the flange 37 of the impeller and bearing face of the inlet branch 36a. Should there be minus pressure in the inlet side of the pump such pressure can pass between the ange of the impeller and its seat to draw the ring into bearing contact with its ange and said bearing face.

Any leakage past the sealing ring housing is conducted to the passage 40a in the end of the cylindrical casing and is then drained ot.

What is claimed is:

ll. A centrifugal pump comprising a cylindrical casing constituting the pump body and having an annular axial passage, a wall lat each end of said casing, one said end wall leaving exposed said passage and having a central aperture, and the other end wall having a series of circumferentially-disposed passages communicating with said passage, an electric motor housed within said casing and between said end walls, the shaft of said motor being disposed along the longitudinal axis of said casing and projecting through said end wall aperture, a combined journal and thrust anti-friction bearing carried internally by each said end wall and journalling said shaft, means rendering fluid-tight the motor housing where penetrated by said shaft, a conical impeller tixedly mounted on the end of said shaft projecting from the motor housing to communicate with said casing passage, spiral vanes on said impeller, said vanes forming therebetween ducts each of substantially uniform cross-sectional area throughout its length, spiral vanes in said casing passage at the impeller adjacent end thereof and forming therebetween xed spiral ducts at the delivery end of said impeller, an annular extension on said impeller co-axial therewith and projecting therefrom in the direction away from said casing, an external peripheral annular flange on said extension, a cover mounted over 'said impeller and having a central aperture penetrated by said extension which projects therethrough, said cover having in its casing-remote face and surrounding said central aperture an yannular recess of greater radial length than said extension flange, an external peripheral iiange on said cover, means securing said cover flange to said casing radially outwardly of said casing passage, an inlet branch secured to said impeller cover in abutting relation with said casing-remote face of said cover, the abutting face where confronting said annular recess providing a bearing surface which is recessed to accommodate said extension tiange, a sealing ring floatingly accommodated in said annular recess, and means preventing rotation -of said sealing ring, whereby said sealing ring is held to bear on 'said extension flange and said bearing surface where 4surrounding the latter both by the pressure of liquid which may leak Vthereto and by the minus pressure which may exist in said inlet branch.

2. A centrifugal pump as claimed lin claim l, said means rendering fluid-tight the motor housing where penetrated by said shaft 'comprising an internal flange on said casing, said apertured end wall being secured to said flange and being recessed inwardly of its aperture to provide an annular chamber surrounding the motor shaft, a sleeve surrounding said shaft and located in said annular chamber, means securing said sleeve against rotation relative to said apertured end wall, means resiliently urging said sleeve away from said apertured end wall, a sealing ring mounted about said sleeve, the annular wall surface defining said annular chamber having an annular groove accommodating said sealing ring, a second sleeve surrounding the motor shaft inwardly of said flrst mentioned sleeve, means clamping said second sleeve to the motor shaft for rotation with the latter, means resiliently urging said second sleeve to bear intimately against the adjacent face of said first-mentioned sleeve, said adjacent face having an annular recess at its minimum diameter, and an annular sealing ring mounted about the motor shaft and located in said latter aunular recess.

References Cited in the tile of this patent UNITED STATES PATENTS 1,427,974 Sessions Sept. 5, 1922 2,066,505 Wolfe Ian. 5, 1937 2,406,947 Harlamoff Sept. 3, 1946

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