US2994275A - Self-priming centrifugal pump - Google Patents

Description

7 Sheets-Sheet 1 INVENTOR ATTORNEY V. STEPNICA SELF-PRIMING CENTRIFUGAL PUMP 1 1 LLI Aug. 1, 1961 Filed May 23, 1957 Aug. 1, 1961 v. STEPNICA SELF-PRIMING CENTRIFUGAL PUMP 7 Sheets-Sheet 2 Filed May 23, 1957 A T TOR/VE Y Aug. 1, 1961 v. STEPNICA 2,994,275

SELF-PRIMING CENTRIFUGAL PUMP Filed May 23, 1957 7 Sheets-Sheet 3 )Z'IIIIIIII ATTORNEY Aug. 9 v. STEPNICA 2,994,275

SELF-PRIMING CENTRIFUGAL PUMP Filed May 25, 1957 7 Sheets-Sheet 4 INVENTOR A TTOR/VEY Aug. 1, 1961 Filed May 23, 1957 V. STEPNICA SELF-PRIMING CENTRIFUGAL PUMP 7 Sheets-Sheet 5 Fig.5. f

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A T TORNE Y Aug. 1, 1961 v. STEPNICA 2,994,275

SELF-.PRIMING CENTRIFUGAL PUMP Filed May 23, 1957 7 Sheets-Sheet 6 k I Fig .6.

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Aug. l, 1961 v. STEPNICA 2,994,275

SELF-PRIMING CENTRIFUGAL PUMP Filed May 23, 1957 7 Sheets-Sheet 7 Fig.7.

J lA/I/ENTOR ATTORNE Y United States Patent 2,994,275 SELF-PRIMIN G CENTRIFUGAL PUMP Vladimir Stepnica, Gateshead, England, assignor to Sigmund Pumps Limited, Gateshead, England, a British company Filed May 23, 1957, Ser. No. 661,140 Claims priority, application Great Britain June 8, 1956 4 Claims. (Cl. 103113) The present invention relates to a self-priming centrifugal pump for liquids and of the kind having a dividing member in a discharge space or chamber adjacent the impeller chamber providing flow passages in said chamber such that liquid delivered by the impeller through one of said flow passages may recirculate towards the impeller through the other flow passage during a priming phase in the operation of the pump, liquid flow being unidirectional in said flow passages to the outlet from the pump during normal operation of the pump.

It is an object of the present invention to provide a pump of this kind specially suitable for use in locations of limited area e.g. on board ship.

In accordance with the present invention a self-priming,

centrifugal pump of the kind indicated is provided comprising a horizontal impeller chamber or housing and an impeller mounted for rotation about a vertical axis in the impeller chamber, a suction chamber communicating with the impeller chamber or housing, a discharge chamber having a lower end at or near the plane of and extending around a part of the circumferential length of said impeller chamber including the cut-Water end thereof and an upper end with an outlet above the plane of said impeller chamber and a dividing member extending from one closing end wall of the discharge chamber adjacent the cutwater end of the impeller chamber part way around the impeller chamber and extending upwards in the discharge chamber and terminating with its upper edge above the plane of the impeller chamber and below the outlet from the discharge chamber.

One embodiment of the invention is illustrated by Way of example in the accompanying drawing in which FIG. 1 is a perspective view showing one form of complete pump.

FIG. 2 is a view in sectional side elevation of a complete pump taken on the line II-II of FIG. 3.

FIG. 3 is a view in sectional plan taken on the line III-III of FIG. 2, and

FIG. 4 is a sectional side elevation of a part of the pump of FIGS. 1 and 2 taken on the line IV--IV of FIGS. 2 and 3.

FIG. 5 is a view generally similar to FIG. 2 but showing an alternative driving arrangement for the pump, and

FIGS. 6 and 7 are views generally similar to FIGS. 2 and 3 but showing parts of the pump specially liable to Wear as being detachable and replaceable as a unit.

Referring to FIGS. 1 to 4 of the drawings the improved pump shown comprises a casing having an approximately circular bed-plate 1 surmounted by a suction chamber 2 in communication with a source of the liquid to be pumped, through a vertically disposed intake conduit 3 (FIG. 4) leading downwards :from a suction inlet 4 above the suction chamber.

The suction inlet 4 is provided with a non-return or check valve 5.

As shown in FIG. 1 the casing may be provided with two suction inlets 4 one on each side for selective use, the aperture in the casing at which no inlet 4 is in use being covered by a suitable closure plate 4'.

A horizontal impeller chamber or housing 6 of volute form is formed between the'upper surface of a horizontal wall 7 constituting the upper boundary of the suction chamber or housing 2 and a second horizontal wall '8 (FIG. 2) spaced above the wall 7. The first horizontal wall 7 is provided with a suction aperture 9 delivering at the centre of the impeller chamber 6 and the second horizontal Wall 8 embodies a stufling box 10 for the lower end of a vertical spindle 11 carrying a horizontally arranged vaned centrifugal impeller 12 of known form for rotation in the impeller chamber 6.

Bearings 13a for the spindle 11 are provided in a hearing housing 13 carried by the pump casing (see FIG. 1) and a coupling element 14 is provided at the upper end of the spindle 11 for convenient connection of an electric driving motor or other appropriate pump-driving means located above the top of the casing.

A discharge chamber or housing 15 for receiving liquid delivered by the impeller 12 from the impeller chamber 6 is defined by a part 16 of the first mentioned horizontal wall 7 at the delivery side of the impeller chamber 6 (FIG. 2) and vertical upstanding walls 17, 18 merging into one another at their upper ends as shown in FIG. 2, the wall 17 being an outer wall of the casing extending upwards from the lower horizontal wall 7 and containing an aperture 19 at its upper end and well above the impeller chamber 6 for the discharge from the pump, and the wall 18 being an inner wall extending upwards from the upper horizontal wall 8 (FIG. 2).

The discharge chamber is of a general arcuate form in plan the outer wall 17 in plan conforming for the main part approximately to a continuation of the external volute wall of the impeller chamber 6 and the inner wall 18 being concentric with and conforming approximately with a projection of the outer periphery of the impeller 12, its position being indicated by dotted lines at 18 in FIG. 3.

The discharge chamber 15 is closed at one circumferential end by an end wall 20 merging into the outer and inner vertical Walls 17 and 18, the wall 20 being located beyond but close to the cut-water end 21 of the outlet side of the impeller chamber 6. The closing end wall 20 also forms a part of the boundary wall of the above described inlet conduit 3.

Within the discharge chamber 15 is provided a dividing member 22 in the form of an arcuate vertical wall extending from a junction 20;: (FIG. 3) with the end wall 20' of the discharge chamber 15 adjacent the cut-water end 21 of the outlet side of the impeller chamber 6 for a distance approaching a semi-circle around the said impeller chamber 6, said dividing member terminating in a vertical free end 23 (FIG. 3).

The arcuate dividing member 22 is located approximately mid-way between the two vertical walls 17 and 18 of the discharge chamber 15 and it extends upwards from the top wall 16 of the suction space 2 i.e. from the plane of the lower side of the impeller chamber 6, with its upper edge approximately mid-way between the general plane of the impeller chamber 6 and the outlet 19 at the upper end of the discharge chamber 15.

Bracing webs 25 and 26 are provided between the walls 17 and 18 and the dividing member 22, these webs extending from the free end 23 of the member 22 around the impeller chamber 6 and being of limited length so that flow apertures 27 and 28 (FIG. 3) are formed bounded by the ends of the webs 25, 26, the closing end wall 20' of the chamber and parts of the dividing member 22 and the walls 17 and 18 of the discharge chamber.

The webs 25 and 26 are co-planar and upwardly inclined in the outward direction as seen in FIG. 2 in order to provide an increase in radial cross section of the passage beneath the webs 25 and 26 such as to render said passage an approximate smooth continuation of the volute of the impeller chamber 6.

Thus two separate flow passages 29 and 30 for liquid are formed in the lower end of the discharge chamber 15 one on each side of the dividing member 22.

The flow through the pump is illustrated by arrows in the drawings, arrows in chain or dot-dash lines representing air or gas, arrows in dotted lines representing air or gas and liquid mixture, and arrows in full lines representing liquid.

During a starting or priming stage of operation of the pump a mixture of air or gas and liquid represented by the arrow marked A in FIG. 4 enters at the inlet 4 leading to the suction chamber 2, passes from the suction chamber 2 to the impeller chamber 6 as indicated by the arrow marked A in FIG. 2, and a mixture of air or gas and liquid is delivered by the pump impeller 6 directly to the lower end of the discharge space below the inner web 25 (FIG. 3) and this mixture being of relatively low density, tends to pass upwards in the discharge chamber 15 by way of the aperture 27 at the end of the inner web 25 and into the space above the web 25 represented by the passage 29 forming part of the lower end of the discharge chamber 15 and which is at the side of the dividing member 22 nearest to the impeller chamber 6, and as indicated by the arrow A in FIG. 2.

The air-or-gas liquid mixture emerging from the upper end of passage 29 as indicated by the arrows A in FIGS. 2 and 3, separates out in the upper part of the discharge chamber 15. The separated air or gas is delivered at the outlet 19 from the discharge chamber as indicated by the arrows A in FIGS. 2 and 3, and the separated liquid, wholly or partly according to the stage reached in the priming operation flows over the upper edge 24 (FIG. 2) of the dividing member 22 functioning after the manner of a weir, and down through the fiow passage 30 forming part of the lower end of the discharge chamber 15 on the outer side of the dividing member 22 as indicated by the arrows A in FIGS. 2 and 3, and through the aperture 28 at the end of the outer web 26 (FIG. 3) whence it is deflected by the dividing member 22 in conjunction with the closing end wall 20 in a direction counter to that of delivery of the pump impeller and as indicated by the arrow A in FIGS. 2 and 3, until it passes around the vertical free end 23 of the dividing member 22 as indicated by the arrow A in FIG. 3 and gains access to and mingles with the air or gas and liquid in the impeller chamber 6 of the pump to increase the proportion of liquid therein.

The improved arrangement makes for very rapid achievement of the primed condition.

As priming proceeds the densities of the contents of the inner and outer passages 29 and 30 on the two sides of the In both the above described constructions a detachable cover plate 37 is provided in the base of the casing to give access to the interior of the pump casing for inspection, and the impeller chamber casing is split in a plane containing the axis of the bearing i.e. on the line x x in FIGS. 3 and 7 to permit removal of the motor spindle 11 or and the impeller thereon from the impeller chamber 6.

Under some conditions of service such for example as those encountered on board ship it is found that the dividing members 22 and the webs 25 and 26 are liable to wear at a faster rate than other parts of the casing structure of the pump.

In FIGS. 6 and 7 there is illustrated a construction of the improved pump in which the parts particularly susceptable to rapid wear are constructed as a readily replaceable unit.

In FIGS. 6 and 7 a replaceable unit is shown in the form of a unitary casting comprising the part of the lower wall 7 of the impeller chamber 6 at the side of the dividing line x x adjacent the discharge chamber 15 and including the part 16 of said wall, the cut-Water member 21, and dividing member 22, the webs 25, 26 and fixing parts 38 below the wall 8, this unit being indicated by close cross hatching in FIGS. 6 and 7.

The inner edge of the wall 7 defines, together with the edge of the removable outer part 41 of the casing the suction aperture leading to the impeller chamber 6 and a split and apertured half sleeve 42 extends downwards from said inner edge of the wall 7 and terminates in a half ring 38 the ends of which mate with the lower part of the removable outer part 41 of the casing.

The outer edge of part 16 of the wall 7 is grooved for the reception of a rubber sealing stop 39 of 0 section for engagement with a flange on the outer wall of the dividing member 22 in the discharge chamber 15 approach I a condition of balance, until substantially liquid only is being sucked at the inlet 4 to the pump as indicated by the arrow B in FIG. 4 and delivered from the suction space 2 to the impeller chamber 6 as indicated by the arrow B in FIG. 2.

Liquid delivered from the impeller chamber 6 now flows unidirectionally to both the passages 29 and 30 on the two sides of the dividing member 22 as indicated by the arrows B in FIGS. 2 and 3 and flows upwards in both said passages and away to the outlet 19 from the discharge chamber 15 as indicated by the arrows B in FIGS. 2 and 3.

FIG. 5 illustrates an alternative arrangement of the driving motor for the pump permitting a reduction in over: all height with only a small increase in the transverse dimensions as compared with the construction of FIGS. 1 to 4.

In this case the upper wall 8 of the impeller chamber 6 includes a central detachable part 31 formed integral with an upward peripheral extension 32 the upper end of which forms a platform for a driving motor 33 located for at least the major part below the upper end of the pump casing as shown. r

The central detachable part 31 is also shaped to form the sleeve 34 of a stulfing box for the spindle 35 of the motor 33, said spindle 35 projecting into the impeller space 6 and having the pump impeller 36 afiixed thereto.

discharge chamber 15 to provide an airtight joint between the suction chamber 2 and the discharge chamber 15.

The lower half ring 42 on its exterior makes sealing engagement with the edge of a part of the aperture in the bottom wall of the casing receiving the detachable inspection cover plate 37.

To replace a worn unit, the cover plate 37 is removed and this is followed by detachment of the outer part 41 of the casing making abutting engagement with the inner end of wall 7 and the lower half ring 39.

The worn unit can now be drawn downwards and swung outwards through the now open side of the suction chamber 2.

The new unit can next be inserted in position by introduction through the suction chamber, the dividing member 22 and the webs 25 and 26 being thrust upwards into the discharge space 15 until the sealing strip 39 engages the internal flange 40.

Application of the part 41 of the casing and thereafter the cover plate 3 7 into position fixes the new unit in posiend of said casing; an inlet port in the upper part of said casing; a discharge outlet in the upper part of said casing; an impeller rotatable about a vertical axis in said impeller housing; a suction chamber in the pump casing below said horizontal impeller housing; means establishing fluid communication between said inlet port and the under side of said impeller housing; a substantially vertical inner wall within said casing, a substantially vertical closing end wall within said casing and a substantially vertical outer casing wall, an upwardly directed discharge housing being defined by said irmer wall, said closing end wall and said outer wall, said discharge housing being above the level of said impeller housing and communicating at its lower end with the impeller housing and extending around a part only of the circumference of said impellerhousing,

' the closing end wall of said discharge housing being adjacent the cut-water end of said impeller housing; and a substantially vertical dividing member within said discharge housing extending from said vertical closing end wall part way around the circumferential length of said discharge housing and extending upwards from the bottom of said casing to a point below the level of said discharge outlet whereby liquid is caused to rise, during priming, between said dividing member and said inner wall, poured over said dividing member and back into said impeller chamber until priming is complete.

2. A self-priming pump as claimed in claim 1 wherein the dividing member is in the form of a vertical wall with transverse Webs extending across the spaces between opposite sides of the said vertical wall and inner and outer Walls of the discharge housing and from approximately the plane of the upper side of the impeller housing and defining with said vertical wall and said inner and outer walls flow passages between the impeller housing and the upper part of the discharge housing.

3. A self-priming pump as claimed in claim 1 wherein the webs are above the level of the impeller housing and inclined upwards from the horizontal in the outward direction away from the impeller housing.

6 4. A self-priming pump as claimed in claim 1, wherein the dividing member and the transverse webs and a part of the bottom wall of the discharge housing are constructed as a unit, the unit being detachably mounted within the pump casing.

References Cited in the file of this patent UNITED STATES PATENTS 1,474,708 Drysdale Nov. 20, 1923 1,894,165 Drysdale Jan. 10, 1933 1,916,212 Jacobsen Feb. 6, 1934 2,244,397 La Bour June 3, 1941 2,257,507 Mann Sept. 30, 1941 2,292,529 La Bour Aug. 11, 1942 2,297,001 La Bour Sept. 29, 1942 2,451,030 Jones Oct. 12, 1948 2,461,925 Rupp Feb. 15, 1949 2,490,575 Bartolucci Dec. 6, 1949 FOREIGN PATENTS 33,041 France Ian. 24, 1928

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