US2933045A - Centrifugal pumps - Google Patents

Description

A ril 19,1960 M. D. ISSERLIS 2,933,045

CENTRIFUGAL PUMPS Filed Jan. 27, 1954 .11 l'nfilli 26 i 24 Hi us I N VE N TOR Mom/s a fssz/ms BYKMQM 1! TTORNE I United res This invention pertains to rotary pumps and particularly to centrifugal pumps suitable for pumping liquids containing solid materials by pressure or gravity feed and by suction.

A typical centrifugal pump comprises a housing having fluid inlet and outlet conduits connected thereto and an impeller rotatably mounted therein for directing the passage of fluid into and out of the housing. Ordinarily, the rotor or impeller is carried by a drive shaft which is driven by a motor. The drive shaft extends through the pump housing which is closed by a packing box designed to prevent liquid from leaking out of the housing and air from entering the housing. However, such packing boxes are generally not completely effective, particularly after a period of time during which wear takes place and the operation of the pump is adversely affected. When a packing or stufiing box loses its sealing efficiency, fluid leaks out of the pump and air leaks in. The presence of air in the pump prevents the proper feeding of liquid into the pump and the pump becomes inoperative. This condition is known as air-binding.

Accordingly, an important object of this invention is to provide a rotary pump of new and improved form.

Another object of this invention is to provide an improved centrifugal pump having an impeller drive shaft sealed in fluid and adapted for operation without becoming air-bound.

A further object of this invention is to provide an improved vertical centrifugal pump capable of receiving and pumping fluid containing solid materials in large or small volume as desired and without becoming air-bound.

Still another object of the invention is to provide an improved centrifugal pump adapted to operate without a packing box.

In general, the principles and objects of this invention are accomplished by the provision of a vertical centrifugal pump having a housing and a rotary impeller provided therein. A cylindrical fluid feed chamber is connected to one wall of the housing which has an axial fluid feed opening which also provides passage for the impeller drive shaft. The drive shaft is journalled outside of the fluid feed chamber and is driven by a motor. To prevent the pump from becoming air-bound and to promote the feeding of fluid into the pump housing, the fluid inlet chamber is provided with one or more double-curved cup-like bafiies which direct the flow of fluid smoothly through the axial opening into the pump housing. According to one aspect of the invention the fluid is fed tangentially into the fluid feed chamber into the cup-like baifles. According to another aspect of the invention, the pump receives the fluid by axial suction feed and the fluid chamber and the curved baffles serve as an overflow control mechanism.

The invention is described in greater detail by reference to the drawing wherein:

Fig. l is a sectional elevational view of a vertical centrifugal pump embodying the principles of the invention;

Fig. 2 is a sectional elevational view along the line 2-2 in Fig. 1; and

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2,933,045 Patented Apr. 19, 1960 ice Fig. 3 is a sectional elevational view of a modification of the pump shown in Figures 1 and 2.

Similar elements are designated by similar reference numerals throughout the drawing.

Referring to Figures 1 and 2, a vertical centrifugal pump according to the invention includes a housing 10 of steel or the like horizontally disposed and having a pair of planar, parallel side walls 12 and 14 and a circumferential wall 16 which are bolted together or otherwise retained in liquid-tight engagement. The housing has a conventional outlet conduit 17. One wall of the housing, for example 14, has a circular, axial opening 18. A rotary impeller 20 of steel or the like having a plurality of vanes or blades 21 is rotatably mounted within the housing and has a drive shaft 22 connected thereto in any suitable fashion. The drive shaft or impeller shaft extends through the axial opening 18 in the wall 14 and is journalled in two or more conventional bearing boxes 24 at a suitable distance from the pump housing. The shaft 22 is connected to a motor 26 which may be of any suitable type. The bearing boxes 24 and motor 26 are supported on any suitable support member.

A hollow cylindrical fluid reservoir or chamber 28 of steel or the like is welded or otherwise fastened in liquidtight engagement to the wall 14 of the housing 10 at the periphery thereof. According to the invention, one or more fluid flow control baflies 30 are positioned within the fluid chamber 28. The baffles are generally cupshaped and are, in effect, portions of spherical surfaces. Each baffle includes a side edge 50, a top edge 52, and a bottom edge 54. The side edge 50 of each baflie is secured to the inner wall of the chamber 28 and the bottom edge 54 is secured to the horizontal wall 14. Each batfle curves outwardly as it progresses from the top edge to the bottom edge to provide a convex outer surface 56 and a concave inner surface 58. Each baffle also curves radially inwardly from the inner wall of the chamber 28 toward the central opening 18 in the wall 14. This can be seen in Fig. 2 by the curve defined by the bottom edge of each baffle at its line of attachment to the horizontal wall 14. The bafiles may thus be defined as being doublycurved since they extend from the inner wall of the chamber 28 in a smooth, gradual curve inwardly and downwardly toward the central opening 18. The inner end of each baffle is curved around and surrounds a portion of the central opening so that fluid which strikes the balfles is directed in a swirl into the central opening but at the periphery thereof. The baffles are spaced apart in the chamber 28 with the convex surface of each facing the concave surface of the one behind it and the concave surface of each facing the convex surface of the one in front of it. This construction and arrangement of the baffles insures that, as the fluid enters the housing 10, air escapes through the opening 18 and air-binding virtually cannot occur.

One or more fluid inlet pipes 32 are connected to the chamber 28 and are disposed, preferably with their axes substantially tangential to the periphery of the chamber. The pipes 32 may also be tilted downwardly if desired depending on the point of entry into the chamber 28. The pipes 32 are thus adapted to feed fluid into the baflles 30 whereby the desired swirling action is promoted.

One of the particular advantages of the pump shown in Figures 1 and 2 is that the axial fluid feed opening 18 may be larger or smaller than such an opening in a pump which is not equipped with the baffles 30. This is made possible because of the positive force applied to the fluid by the swirling action induced by the bafiies and because of the fact that the bafliles direct the fluid into the housing by way of the periphery of the axial opening. Thus air may escape from the center of the opening in the vicinity of the drive shaft 22 and air-binding is prevented.

A- modification'ofthe pump shown in Figure 1 is shown in Figure 3 and comprises a vertical centrifugal pump which is particularly suitable for providing controlled overflow and feedback or the material being pumped. The pump includes all of the elements shown in the pump of Figures-1 and-2'and-includesin addition a'central suction inlet opening 34 in'the-wall -12 to which a conduit or pipe 36 is'connected: The pipe'36;'- int-urn, is connected to areservoir 38 which contains the-liquid or material to be pumped. Ii -addition, an overflow/pipe 40 leadsfrom the chamber-28 to the liquid reservoir.

In operation of this embodiment of-the invention, fluid is drawn from the reservoir 38 into thehousing-l!) where it is pumped by the impeller into the outlet pipe -17i As this-pumping operation proceeds, someof the-fluidescapes from theaxial, opening 18- in the wall 14. However,-the escaping fluid strikes the bafiies 30'and some of the fluid tends'tobe returned throughthe opening into the housing whereby the housingtends to-remain'filljed with-fluid being pumped. However, if the fluid-continues to escape, its'rise in the chamber is controlled and reduced in turbulence by the baffles 30. As-thefluid reaches the level of the overflow pipe, it flows back into the reservoir 38: I

The vertical centrifugal pumps describedahove have the advantage that extremely close tolerances are not required for any of the component parts; Thus; ifthe impeller bladesshould become worn dueto abrasion, the motor 26 and'drive shaft-22*rnay-be loweredior-raised to properly position the impellerwithirrthe housingwlll. Furthermore; if holes should be worn in any of the walls of-the-housing, they-may be 'filled by welding: or by any other convenient -means;

A centrifugal pump including an impellerhousing, a

horizontal wall comprising a portion of said housing and having-"a central opening through which fluid -material may pass, an impeller horizontally disposed within said housing and having a vertical drive shaft extending through said central opening in said horizontal wall of said housing, a hollow cylindrical reservoir having a peripheral wall extending-vertically from the periphery of said housing, and a plurality of baflies spaced apart and secured withiusaid reservoirto .saidperipheral wall thereof, said baflles curving inwardly from vsaid peripheral wall to said central opening insaidhorizontal wall, said bafiles having concave and convex surfaces and disposed with the concave surface of one facing the convex surface of the one ahead of it, and an inlet pipe secured to said peripheral wall of said reservoir and aimed at the concave surface of one of said bafiles whereby fluid flowing into said reservoir is directed into said central opening in the wall of'said housing.

References Cited :in the file of this patent UNITED STATESPATENTS Great Britain Feb. '12, 1937

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