US3598502A

US3598502A - Centrifugal pumps

Info

Publication number: US3598502A
Application number: US807061A
Authority: US
Inventors: Harold Philip Sidney Paish; Harold Lloyd Dagwell; Peter John Anley
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-03-14
Filing date: 1969-03-13
Publication date: 1971-08-10
Anticipated expiration: 1988-08-10
Also published as: GB1209827A

Abstract

A centrifugal pump for pumping liquid in which pieces of contaminating material may be present; the pump comprising a reservoir chamber, an impeller casing, a rotary impeller mounted to rotate in an annular space within the casing which is formed with at least one inlet to the eye of the impeller and is mounted at least partly within said chamber, and a volute; and the pump being characterized in that a subchamber from which said inlet opens is provided and is formed with an inflow opening which is so dimensioned that it presents a passageway which is at least as restricted to the passage of pieces of contaminating material as are each of the passageways presented by, firstly, the inlet to the eye to the impeller, secondly, the annular space in which the impeller rotates, and, thirdly, the volute and other waterways in the pump.

Description

United States Patent [72] Inventors Harold Philip Sidney Paish;

Harold Lloyd Dagwell; Peter John Anle all 01 53h Southwark Street, London, S.E.1,

England [21] Appl. Nov 807,061 [22] Filed Mar. 13, 1969 [45] Patented Aug. 10, 1971 [32] Priority Mar. 14, 1968 [33] Great Britain [31] 12485/68 [54] CEN'I'RIP'UGAL PUMPS 4 Claims, 2 Drawing Figs.

[52] US. Cl 415/98, 415/213, 415/204 [51] lnt.C1 ..1 ..F0ld 25/00, F04d 7/00 [501 Field 01 Search 103/104, 1 14; 230/133 C; 415/204, 205, 206, 170, 97, 98, 213 A, 219

[56] References Cited UNITED STATES PATENTS 3,296,973 1/1967 Paish et a1 103/104 3,279,386 10/1966 Rupp et a1. 103/114 2,430,299 11/1947 Mann 103/104 2,278,772 4/1942 Duden 103/104 2,251,807 8/1941 Ruthman 103/104 2,143,032 l/1939 Ruthman... [03/104 3,130,679 4/1964 Sence 415/213 A 3,190,226 6/1965 Judd 415/213 A FOREIGN PATENTS 1,108,531 10/1955 France 103/114 Primary Examiner-Henry F. Raduazo Attorneys-William D. Hall, Elliott l. Pollock, Fred C. Philpitt, George Vande Sande, Charles F. Steininger and Robert R. Priddy ABSTRACT: A centrifugal pump for pumping liquid in which pieces of contaminating material may be present; the pump comprising a reservoir chamber, an impeller casing, a rotary impeller mounted to rotate in an annular space within the casing which is formed with at least one inlet to the eye of the impeller and is mounted at least partly within said chamber, and

pump.

CENTRIFUGAL PUMPS BACKGROUND OF THE INVENTION This invention relates to double entry centrifugal pumps for pumping contaminated fluids, e.g. water in which dirt and stones may be present.

One example of this type of pump is sold under our Trade Mark VELOVAC and is described in the specification of our British Pat. No. 1,048,272. This prior pump comprises a reservoir chamber in the lower part of which a pump casing is arranged, and in use water is drawn from the chamber into a pair of annular inlets to the eye of the rotary impeller which feeds to the volute. Although an intake with orifices to restrain solids larger than the impeller will pass is normally provided for the inflow ends of the suction pipes or hoses for use with such pumps, it not infrequently occurs that the users omit to fit the intakes; it is also true that lengths of pipe and hose for use with the pumps are sometimes stacked in the open and are frequently dragged into position in such a manner that large solids enter the pipes and hoses. Such solids, unless previously removed, immediately enter the pump when it is started.

It should be understood that the fitting of a strainer with small orifices at the delivery end of the suction pipe or hose is not the solution as such a strainer very soon becomes choked and has to be cleaned, and it is an object of this invention to overcome the above disadvantages and to make possible long unattended periods of satisfactory operation in pumps of the kind described above.

SUMMARY OF THE INVENTION In accordance with the present invention there is provided a double-entry centrifugal pump comprising a principal or reservoir chamber, a pump casing, a rotary impeller mounted to rotate in an annular space within the casing which is formed with at least one inlet to the eye of the impeller and is mounted at least partly within said chamber, and a volute, characterized in that a subchamber from which said inlet opens is provided and is formed with an inflow opening which is so dimensioned that it presents a passageway which is at least as restricted as each of the passageways presented by, firstly, the inlet to the eye to the impeller, secondly, the annular space in which the impeller rotates, and, thirdly, the volute and other waterways in the pump.

Suitably, the impeller comprises blades which are of parallel form, as opposed to the outwardly tapered blades which are usually employed in pumps of this kind.

It will be appreciated that any stones or relatively large pieces of contaminating material which might block the inlet to the impeller eye or a subsequent part of the liquid delivery system or which might damage the rotary impeller, will be arrested at the aforementioned inflow opening which is preferably of annular form.

It is a further feature of the present invention that one or more easily removable plugs are provided at the base of the chamber to allow the oversize solids arrested by the inflow opening to be removed.

Other objects and features of the invention will appear from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing a centrifugal suction pump;and,

FIG. 2 is a partly sectional elevation in the direction of arrow II of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, the centrifugal pump functions as a suction pump to deliver water and is provided with a continuously running auxiliary vacuum pump P for priming and for removal of air during operation of the centrifugal pump.

The pump, according to the present invention, comprises principal chamber 10 in the lower part of which a pump casin; 11 is arranged. The pump casing encloses a rotary impeller 12 mounted near the end of a shaft 13 which extends through an opening in chamber wall 14 and through a central inlet 15 in casing part 16. Casing I1 is provided with spaced walls a which extend radially with respect to the axis of rotation of the impeller, and which are disposed closely adjacent the opposing edges of impeller blades 17 to define an annular space a-a surrounding the axis of rotation of the impeller, in which space the blades 17 rotate. The impeller with blades 17 are of parallel form, i.e. are of constant dimension (measured in the direction of the axis of the impeller) along their radial lengths. A spring-loaded seal 18 is provided around the shaft I3 where it passes through the chamber wall 14. The shaft is driven, by means of a suitable motor (not shown) at 19. The pump casing is also provided with spaced walls b which define, between themselves and the walls 0 of the principal chamber, a pair of subchambers 23 disposed respectively on opposite sides of the impeller, and a pair of fluid inlets 27 from the principal chamber 10 into the subchambers 23. The pump casing is provided, in addition, with further spaced walls d which define a pair of

fluid inlets

15, 20 from the subchambers 23 to the annular space a-a at the eye of the impeller. The

inlets

15, 20 to the eye of the impeller are arranged in part 2l of the pump casing, and a boss 22 on the end of the impeller shaft extends through opening 20. Thus an annular inlet is provided at each side of the impeller 12, these inlets opening from subchambers 23 in the interior of the principal chamber 10 which is, of course, water filled after priming and during the operation of the pump.

A volute 24 surrounds the annular space a-a in the pump casing. The outlet from volute 24 extends tangentially upwardly from around the pump impeller to open into a reflux box or nonretum valve (not shown) for delivery of water which is drawn into the pump through an inlet opening indicated at 26 in FIG. 2.

In operation, after priming of the pump, water is drawn in through inlet opening 26 to enter the principal chamber I0 and thence through substantially annular openings 27 into subchambers 23; each of the openings 27 is interrupted by three bolt-socket parts 28 of minimum size. The water is then drawn in through the

inlets

15 and 20 and forced by the centrifugal action of the impeller 12 into the volute 24 and out through a reflux box.

According to the present invention, the width, i.e. axial dimension w, of the annular openings 27 (or of the larger opening if they are unequal) is arranged slightly smaller than the smaller radial width x of the impeller inlets l5 and 20, the axial width y of the annular space in which the blades 1' rotate, the minimum dimension of the cross section of L volute 24 and all other waterways within the pump. As a result of such dimensioning of these various openings, any oversize solids such as stones or even metallic objects such as bolts or studs, which inadvertently reach the centrifugal pump, will be arrested by the restricted openings 27 and will collect in sump 29 of the chamber 10.

Referring to FIG. 2, two readily removable plugs 30 are provided in the sump 29. Each plug comprises a pair of plates 31 which are drawn together by a butterfly nut 32 on a stem 33 to sandwich a rubber sealing ring 34 and so jam the plug securely at the mouth of opening 35 into the chamber sump 29. These plugs can be withdrawn to allow the sump to be cleared of oversize solids.

A further general advantage of the construction described is that plate 36 which forms a sidewall of the chamber is readily removable for inspection and servicing of the pump interior and even withdrawal of the rotor 12 and part of the pump casing without removal of the suction pipe or hose.

We claim:

1. A double-entry centrifugal impeller pump for contaminated fluids, comprising a principal chamber having a pump casing at least partially disposed therein, an impeller having radially extending blades provided with axially oppossaid pump casing having spaced first walls extending radially with respect to the axis of rotation of said impeller and,

disposed closely adjacent the opposing edges of the impeller blades to define an annular space surrounding the axis of rotation of said impeller in which space the blades of said impeller rotate, a volute surrounding said annular space in said pump casing, said pump casing having spaced second walls defining between themselves and the walls of the principal chamber a pair of subchambers disposed respectively on opposite sides of the eye of the impeller and a pair of first fluid inlets from said principal chamber into said subchambers, said pump casing having spaced third walls defining a pair of second fluid inlets from said subchambers to said annular space at the eye of said impeller, whereby fluid flows, during operation of said pump, from said principal chamber through said first fluid inlets to said subchambers and thence via said second fluid inlets to the eye of said impeller and to said annular space whence it is impelled to said volute; the spacings of said first walls, of said second walls, and of said third walls being such that the axial spacing between said second walls and the walls of the principal chamber at said firstfluid inlets is no greater than the minimum dimension of each one of said second fluid inlets in a direction transverse to the direction of fluid flow through said second inlets; is no greater than the minimum axial dimension of said annular space; and is no greater than the minimum cross-sectional dimension of said volute.

2. A pump as claimed in claim 1, wherein said impeller blades are of parallel form.

3. A pump as claimed in claim 1 in which at least one removable plug is provided in the walls of said principal chamber to permit removal of oversize solids.

4. A pump as claimed in claim 1 in which a readily removable plate is provided in a sidewall of said principal chamber to facilitate inspection and servicing of the pump interior.

Claims

1. A double-entry centrifugal impeller pump for contaminated fluids, comprising a principal chamber having a pump casing at least partially disposed therein, an impeller having radially extending blades provided with axially opposing edges and mounted for rotation within said pump casing, said pump casing having spaced first walls extending radially with respect to the axis of rotation of said impeller and disposed closely adjacent the opposing edges of the impeller blades to define an annular space surrounding the axis of rotation of said impeller in which space the blades of said impeller rotate, a volute surrounding said annular space in said pump casing, said pump casing having spaced second walls defining between themselves and the walls of the principal chamber a pair of subchambers disposed respectively on opposite sides of the eye of the impeller and a pair of first fluid inlets from said principal chamber into said subchambers, said pump casing having spaced third walls defining a pair of second fluid inlets from said subchambers to said annular space at the eye of said impeller, whereby fluid flows, during operation of said pump, from said principal chamber through said first fluid inlets to said subchambers and thence via said second fluid inlets to the eye of said impeller and to said annular space whence it is impelled to said volute, the spacings of said first walls, of said second walls, and of said third walls being such that the axial spacing between said second walls and the walls of the principal chamber at said first fluid inlets is no greater than the minimum dimension of each one of said second fluid inlets in a direction transverse to the direction of fluid flow through said second inlets; is no greater than the minimum axial dimension of said annular space; and is no greater than the minimum cross-sectional dimension of said volute.