US3457869A - Centrifugal pumps - Google Patents

Description

July 29, 1969 R. w. JA-NETZ CENTRIFUGAL PUMPS 5 Sheets-Sheet 1 Filed Feb. 13, 1967 INVENTOR R40 4/. A T2 July 29, 1969 R. w. JANETZ 3,457,869

CENTRIFUGAL PUMPS Filed Feb. 15, 1967 s Sheets-Sheet 2 July 29, 1969 R. w. JANETZ 3, 7,

CENTRIFUGAL PUMPS Filed Feb. 13, 1967 5 Sheets-Sheet r5 United States Patent "ice U.S. Cl. 103-104 9 Claims ABSTRACT OF THE DISCLOSURE Compact centrifugal double suction pumps having vertical split cases and vertical nozzles. Inlet passageways integrally included in dual cover plates along with bearing cavities in each of the cover plates combine to provide a high capacity compact pump.

This invention relates to centrifugal pumps and more particularly to vertical split case centrifugal double suction pumps having vertically displaced inlet and outlet ports.

The use of hydronic temperature control systems in large apartment and industrial buildings has increased the need for system pumps having larger capacities. Larger capacities can be provided by using a plurality of stages of pumps. Such a solution is costly in both money and space. A more eflicient solution is the use of double suction pumps. In addition to providing greater capacity, double suction pumps eliminate the problem of end thrust resulting from the unequal axial forces created by the single eye impeller of single suction pumps.

While double suction pumps take less space than a plurality of single stage pumps nonetheless since space is at a premium in commercial buildings an ubiquitous problem in pump design is to make pumps more compact.

A companion problem associated with pumps is that most pumps have at least one of the nozzles normal to the other nozzle. Thus, space consuming elbows are required to connect the pumps into the system.

The necessity for using space consuming elbows can be overcome by arranging to have both the inlet and the outlet pump nozzles parallel to each other and to have both nozzles protruding from the pumps case in the same direction. The most efficient type of centrifugal pump for this type of nozzle arrangement is the double suction pump. In the past, space gained by using pumps having parallel nozzles have been lost, at least in part, by the larger size of the double suction pump.

Previous attempts at providing compact double suction pumps have only raised other problems, such as maintenance problems, leakage problems and axis support problems. For example, cantilevered shafts have been used to reduce the size capacity ratio of the pumps. However, such pumps have not matched the durability, or reliability of pumps using straddle the impeller bearings; that is wherein the shafts are supported on bearings at both sides of the impeller.

When such dual bearings were used in the past, the size of the pumps increased disproportionately because the bearings were placed outside of the packing glands in order to assure accessibility of the bearings for maintenance purposes.

If the bearing were within the actual pump casing then problems of inadequately sealing the shaft ends of the pumps were encountered.

Accordingly, it is an object of this invention to provide a compact dual suction centrifugal pump which can be installed into a system without using space consuming elbow fittings.

A related object of the invention is to provide such 3,457,869. Patented July 29, 1969 pumps wherein the bearings are readily accessible for maintenance and the mechanical seals are durable and reliable.

A further object is to provide vertical nozzles for the pump.

Yet another object of the invention is to provide pumps having vertically split cases with interchangeable parts and straddle the impeller bearing arrangements.

In accordance with one preferred embodiment of the invention a vertical split case centrifugal pump is provided with bearings at both ends of the pump shaft. The bearings are enclosed within dual end plates fastened to the pump body. The end plates are provided with complete fluid intake passages to conserve space and thereby assure a more compact pump. Removable bearing housings and covers attached to the end plates make the bearings and seals readily accessible for inspection and maintenance purposes. Further, the bearings are provided with an extra wide sleeve or inner ring to facilitate the removal of the bearings.

These and other objects of this invention and the manner of obtaining them will become more apparent, and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a pictorial representation of the inventive P p;

FIG. 2 is a cross sectional side view of the pump taken along line 2-2 of FIG. 1;

FIG. 3 is a side view of the outboard cover plate taken along line 3-3 of FIG. 4;

FIG. 4 is a sectional view of the outboard cover plate taken along line 4-4 of FIG. 3;

FIG. 5 is a front view of the bearing cover plate; and

FIG. 6 is a sectional view of the bearing cover plate taken along line 6--6 of FIG. 5.

In the FIG. 1 pictorial representation of a preferred embodiment of the invention, the pump 11 is shown mounted on a base plate 12. Also mounted on the base is a motor, not shown, which acts as a prime mover.

The pump shaft 13 is coupled to the shaft of the motor (not shown) with any well known flexible coupling.

The pump assembly 11 as shown is a vertical split case pump comprising a solid volute body 14 terminating in two vertically disposed nozzles 16, 17. While the nozzles 16, 17 are shown vertically disposed, it should be understood that within the scope of this invention they could also be horizontally disposed. The advantageous feature is that both nozzles, inlet and outlet protrude from the same side of the pump so that elbows are not necessary for connecting the pump into the fluid system.

The nozzles are equipped with means for coupling the pump into the system. As shown in FIG. 1 the nozzles 16, 17 each terminate in flanges 18, 19 respectively.

End covers or volute cover plates 21, 22 are provided at each end of the solid volute body 14. The end covers are fastened to the body by means such as volute cover plate screws, peripherally placed around the end cover, such as cap screw 23, for example.

Means, such as bearing covers 24, 26 assure that the bearings are accessible for inspection purposes. The covers are held in place with screws, such as bearing cover cap screw 27.

Means, such as bearing housings 28, 29 actually contain the bearings. The bearing housings are held in place with screws, such as cap screw 31. The removal of the bearing housing uncovers the seal and the internal intake system making them readily accessible for maintenance purposes just as the removal of the bearing cover makes the bearing available for repair maintenance or replace merit without the necessity of disassembling either the pump or the piping connected to the pump.

The pump body 14 rests on feet, such as foot 32, which is mounted on base 12 and firmly coupled thereto with threaded fasteners such as cap screw 33. The feet are cast integral to volute body 14.

FIG. 2 is a cross sectional view of the pump taken along vertical planes including line 22. FIG. 2 best shows the double suction, straddle the impeller bearing construction of the pump and the intake passageways which are complete and form an integral part of the volute covers.

More specifically, means, such as inlet passageways 34, 36 are provided in covers 21, 22 respectively. The use of passageways within the volute covers contributes to the compactness of the pump. The cross sectional of FIG. 2 view shows port or nozzle 16 as the intake nozzle or inlet which connects directly to the inlet passageways 34, 36 of the end covers 21, 22, respectively.

The end cover 21 is designated the inboard cover since it is on the motor side. Similarly, the cover 22 is designated the outboard cover.

Since the pump is substantially symmetrical the inboard and the outboard covers are very similar. Therefore, only the outboard cover is shown in FIGS. 3 and 4. The same designation symbols and numbers are used wherever possible on all of the figures to enhance the explanation of the invention.

FIG. 3 shows the outboard end cover 22 as viewed from the line 33 of FIG. 4. It can be seen in FIGURES l, 2, 3 and 4 that the cover has a flange 37 with holes, such as hole 38 peripherally disposed to accommodate the volute cover cap screws.

Inlet passageway inner walls 39, 41 (FIGS. 2, 3 and 4) in volute cover 22 form continuous projections extending from the bifurcating ridges 42 of the central volute fluid channel to form one side of th inlet passageways 34, 36 of the cover respectively. The inner walls 39, 41 circumscribe circular openings matching the eyes 43, 44 of the impeller. The other side of the inlet passageways 34, 36 are defined by outer walls 46, 47, respectively. The spiral-like configuration of the passageway in the cover is best seen in the cross section of FIG. 3.

Means are provided in each of the inlet passageways for inhibiting prerotation. More specifically, rib 48, best seen in FIGS. 3 and 4 projects into passageway 36 to establish a turbulence therein and thereby prevent the formation of prerotation of the fluid being pumped.

Means such as volute gaskets 51, 52 are provided for preventing leakage of the pumped fluid past the volute covers 21, 22, respectively. It should be noted that the gaskets are perfectly placed for sealing. That is, the sealing process is aided by the flush fit of shoulder 53 for example, against the inner shoulder 54 of the body. Also, there is no shaft, for example, extending through the gasket sealed section of the pump as is the case in the horizontal split case pumps.

Inner diameter 56 forms an opening in the volute cover 22 for example, for receiving bearing housing 28.

A notch 57 is provided in the flange 37 to enable the end cover to be properly aligned. This notch emphasizes the fact that with the inventive pump it is not necessary to marry the split portions of the case to one another, instead the design enables the interchangeable use of common parts.

Means are provided for adequately bearing the shaft in the inventive pump. More specifically, the pump utilizes a straddle ball bearing construction, that is best seen in FIG. 2. Therein is shown a bearing housing at each end of the shaft 13. The outboard housing 28 contains the bearing designed to take thrust. The inboard bearing housing 29 contains the bearing designed to take radial forces. Both bearings are similar in constructiv parts. Therefore, only the outboard bearing parts will be described herein. The bearing assembly comprises (see FIG. 2)

a locking collar 58 held in place on the shaft 13 by any well known means such as set screw 59. The locking collar holds the inner bearing ring or sleeve 61 in place. Note that the inner sleeve 61 of the bearing raceway is relatively wide. This facilitates easy removal of the bearing assembly if such removal is required.

To remove the bearing the four bearing cover cap screws 27 are first removed. This allows the bearing cover 26 to be removed. The bearing is then accessible for inspection. Set screw 59 is then loosened and the four bearing housing cap screws are removed. The bearing assembly comprising raceway 61 and ball bearings 62 can then he slipped off the shaft with the bearing housing.

The bearing cover is shown in detail in FIGS. 5 and 6. Incidentally, the bearing covers on the inboard and outboard sides of the pump are substantially identical hence only the outboard side bearing cover is described in detail.

FIG. 5 shows the cover 26 as viewed from the outboard side of the pump. It has a basically circular shape with four corner ears having holes 67, 68, 69, 71 to allow the bearing cover cap screws to pass therethrough into threaded holes, such as hole 27A, in the bearing housing. A tapped hole is provided to receive a grease fitting, such as fitting 73 shown in FIG. 2. An opening 74 is left in the center of the body of the cover. On the outboard side this opening receives a bearing cover plug 76 as best shown in FIG. 2. On the inboard side the opening is left unplugged and the pump shaft fits through opening 74.

The cover 26 is designed to slip fit into the bearing housing 28 with outer shoulder 77 of cover 26 contiguous to surface 56 when the cover cap screws are tightened to hold surface 78 juxtaposed with surface 79 of the hearing housing. The inner surface 81 of cover 26 presses against the outer face of the bearing raceway to help lock the cover 26 in place. The inside of the cover 26 is normally filled with grease injected through the grease fitting 73.

As explained above, the removal of the cover allows inspection of the bearings and is a first step in the removal of the bearing housing, bearings and seals. It should be noted that the bearing housing depicted in the drawings (FIG. 2) includes a water slinger 82.

A mechanical seal assembly 83, 84 is used at both ends of the shafts to insure a reliable seal. The assembly comprises a ring of packing material which is pressed by spring 86 into a cavity designed to receive the ring. The spring is pressed between collar 87 which is threaded onto shaft 13 and is held in place by set screw 88. It is readily apparent that the removal of the bearing housing enables the removal of the seal making the volute lnterior accessible.

A gasket 89 is pressed between the bearing housing and the volute cover to prevent any fluid leakage at this point. The gaskets used in the pump embodied in the figures form complete closed figures and thus are relatively simple in construction and operation.

The impeller 90 is attached to the shaft by any well known means, such as key 91. In addition to the key, an impeller nut such as the threaded collar 87 may be used to assure a stable impeller operation. The collar 87a on the other side of the impeller need not be threaded.

Since the pump operates on the dual suction principle to provide the required capacity per unit weight, the im' peller has two eyes. The impeller blades 92 are shown enclosed by shrouds 93. The volute is provided with a plug 94 for removal if a test gauge is desired and various drain plugs such as plug 96.

Thus, in construction the pump ports are not married; instead the volute covers, for example, are interchangeable as are the other separate parts of the pump. Once assembled the pump is easily maintained because of the removable bearing housings and bearing covers. These parts of the pump can be removed while the pump remains connected to the piping of the system. Hence, notwithstanding the pump compactness it is easily serviced.

The vertically disposed suction and pressure nozzles enable the pumps to be connected to the system without the use of elbow fittings. Thus, a minimum of space is required for connecting the pump into a system.

In operation, the fluid such as heated water, is drawn into inlet port 16. Bifurcating ridge 42 separates the fluid into inboard and outboard inlet channels 34, 36, respectively. From the channels the fluid is sucked into the impeller eyes 43, 44 and carried by the impeller into the pressure volute and finally into the outlet port 17 where it is under pressure.

While the above principles of the invention have been described in connection with a specific embodiment it is to be clearly understood that this description is made only by way of example and not as a limitation on the scope of the invention.

What is claimed is:

1. A dual suction centrifugal pump for handling liquids, the assembled pump being adapted as a unit for attachment to or removal from a pair of fixed conduits, said conduits providing the intake and discharge passages to and from the pump, said pump being constructed of a heavy metal assembly of parts, said pump assembly comprising: a vertically split casing including a unitary volute body terminating in two nozzles generally parallel and extending in the same direction from the unitary volute body, one forming an intake nozzle for connection with the fixed intake conduit, the other forming the dis charge nozzle for connection with the fixed discharge conduit and an inboard cover means and an outboard cover means abutting opposite ends of the unitary volute body, each of said cover means having an intake channel communicating with the intake nozzle in the volute body, a dual intake impeller in said unitary volute body communicating with the intake channel in the inboard and outboard cover means, said inboard cover means and said outboard cover means being of sufficient size whereby on the removal of either of said cover means, said impeller may be removed as a unit or inspected without the separation of the pump from the fixed conduits, bearing means in each cover means removable as a unit from said cover means without disturbing the connection between the volute body and the respective cover means whereby each of said bearing means may 'be inspected or replaced.

2. The centrifugal pump of claim 1 wherein fluid bifurcating ridge means are located in said inlet nozzle for separating said supply fluid to flow into the inlet channels of both inboard and outboard cover, said inlet channel formed to cooperate with said bifurcating ridge.

3. The centrifugal pump of claim 2 wherein said bearing means comprise bearing housing means, means for removably connecting said housing means to said volute case cover means.

4. The centrifugal pump of claim 3 wherein said hearing housing means comprises bearing raceway means, bearing cover means for removably connecting said bearing cover to said bearing housing means whereby when said bearing cover means are available for inspection.

5. The centrifugal pump of claim 4 wherein said bearing raceway means have wide inner rings to facilitate removal of said bearing housing.

6. The centrifugal pump of claim 5 wherein said gasket means are fitted between said bearing housing and said volute case means and wherein mechanical seal means cooperate with the pump shaft where said shaft extends into said housing to prevent fluid leakage.

7. The centrifugal pump of claim 6 wherein said nozzles are both vertically disposed.

8. The centrifugal pump of claim 7 wherein said volute case cover means and unitary volute body are interchangeable.

9. The centrifugal pump of claim 1 wherein means are provided in said inlet channels for preventing prerotation.

References Cited UNITED STATES PATENTS 827,750 8/1906 Rateau 103104 1,269,063 6/ 1918 De Laval. 1,673,151 6/1928 Lindemann. 2,329,373 9/ 1943 Hornschuch. 3,160,107 12/1964 Ross 103104 FOREIGN PATENTS 43 8,635 1912 France.

23,696 1908 Great Britain. 186,243 9/ 1922 Great Britain. 186,243 9/ 1922 Great Britain.

45 HENRY F. RADUAZO, Primary Examiner U.S. Cl. X.R. 103-111

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