US3088415A - Submersible pump - Google Patents

Description

May 7, 1963 J. T. CULLETON SUBMERSIBLE PUMP 2 Sheets-Sheet 1 Filed June 15, 1960 m M m m JOH/V 7'. CULL T [V ATTORNEY y 1963 J. 'r. CULLETON 3,088,415

SUBMERSIBLE PUMP 2 Sheets-Sheet Filed June 15, 1960 INVENTOR. t/oH/v r. GZLLHZ BY ATTORNEY 3,088,415 Patented May 7, 1963 3,088,415 SUBMERSEBLE PUMP John T. Cuileton, Hayward, Calif assignor to Pacific Pumping Qompany, Oakland, Calif, a corporation of California Fiied June 15, 1961 Ser. No. 36,226 1 Claim. (Ci. 103-193) This invention relates to improvements in centrifugal pumps and, more particularly, it relates to an improved sealing system for preventing the passage of material from the pump chamber along the pump-shaft and into the interior of the pump.

With centrifugal pumps a serious problem arose in sealing the pump-shaft where it entered the pump chamber. Without proper sealing, the material being pumped, which often included suspended solid abrasive particles as well as all types of liquid, would migrate along the shaft into the inner section of the pump, where it would enter the pump-bearings and cause rapid wear and deterioration of vital components. Although a small flow of liquid is sometimes tolerable, in many instances it is necessary to stop it completely, in order to prevent corrosion and electrical short-circuits. This requirement greatly increases the sealing problem.

For relatively small, compact pumps the problem became even more critical, since less space was available for shaft-packings and there was less distance for the liquid and particles to travel before damaging results occurred. Also, the use of increased pressures in the pump chamber increased the sealing problem, since more pressure also was placed on the shaft-seal and packing.

In the early prior art, a lantern-ring or gland was used in an attempt to prevent the migration of particles from the pump-chamber. The ring or gland was fitted around the pump-shaft and supplied with liquid from another source, under a pressure which exceeded the pumpchamber pressure, so that the liquid flowed into the pump-chamber. This kept the pumped liquid and any particles from migrating along the impeller-shaft and served to lubricate the shaft at this point. However, the lantern-gland, in its many forms, always required an external source of fluid under pressure. Also, the rings, being subject to wear, often became loose and misaligned with the impeller-shaft, causing an unequal flow or channeling of the liquid at some points around the ring.

Another unsuccessful attempt to solve the problem 'did not use the lantern-type gland but sought to stop the leakage by putting severe pressure on the packings. This proved to be unsatisfactory, due to the increased frictional load and the wear on the shaft, which eventually reduced the effectiveness of the seal.

Another sealing method found in the prior art employed around the pump shaft a sealing means which was acted upon by a body of fluid under pressure that forced the sealing means against the shaft. This method required an external source of pressure considerably greater than the pumppressure, to act on the body of flui-d adjacent the sealing means, and conduit means to transmit this pressure to the pump. Its bulky arrangement of components proved to be impractical for all but the larger, permanent-type pumping installations, and thus provided no sealing solution for small, compact, portable-type pumps as, for example, the semisubmersible pumps used to pump out liquid and debris from construction sites.

It is therefore an important object of the present invention to provide a new and highly efiective answer to the pump-sealing problem, which eliminates the need for an external source of liquid under pressure and also the need for extremely close-tolerance packings.

Another object of the invention is to provide a centrifugal pump which utilizes its own fluid-discharge pressure to purge the clearance around the impeller-shaft and prevent the migration of liquid and particles from the pump-chamber along the shaft.

Another object is to provide a portable pump with a self-energized shaft-purging and sealing system which utilizes the pressure of the fluid being pumped at the impeller-discharge, to provide a sealing function.

Still another object is to provide a compact, portable pump with the driving-motor located in close proximity to the pump-impeller chamber and protected by selfpressurizing sealing means which reduces all leakage from the pump-chamber.

Another object is to provide a compact pump having a self-pressurized body of sealing-fluid acting on a sealing means around the shaft and reduced pressure in the pump-chamber adjacent the sealing means.

Other objects and advantages of the invention will appear from the following description of a preferred embodiment thereof, presented in accordance with the statute.

In the drawings:

FIG. 1 is a view in perspective of a pump embodying the principles of the present invention.

FIG. 2 is a view in elevation and in section of the pump shown in FIG. 1 and taken along the plane 22 of FIG. 1.

FIG. 3 is a plan view in section taken along the line 3-3 of FIG. 2.

FIG. 4 is a view in elevation and in full section of the pump shown in FIG. 1, and taken along line 44 of FIGS. 1 and 3.

FIG. 5 is a plan view in section taken along line 55 of FIG. 4, showing the back side of the impeller.

FIG. 6 is a fragmentary view in section of a typical sealing member used in the present invention.

The pump 10 shown in FIG. 1 embodies the principles of the present invention and is of the submersible type arranged in the upright position, so that it can be lowered into any flooded area to pump out the water and debris that has collected therein. As described in the specification, an important feature of the invention is a selfcontained shaft-sealing system which utilizes a self-pressurized sealing reservoir of oil (FIGS. 2 and 4) 12. Moreover, this improved system provides the basis for other improved structural features which are embodied in the pump ill. It will be obvious, however, that the smartsealing features of my invention could be applied to any centrifugal pump, whether oriented in an upright or horizontal position, or Whether of large or small size.

Referring now specifically to the drawings, FIG. 1 shows a full view of the pump 10 which has an upright housing 15 having an inlet 1.6 at the lower end and a discharge-outlet 17 at the upper end, which can be coupled in some suitable manner to a fixed or flexible conduit 18. Within the housing 15 is mounted a driving motor 19 (FIGS. 2 and 4) having a shaft 20 which is connected to an impeller-shaft 14. An impeller 21 is attached to the shaft 14 and is rotatable within a pump-chamber 22, which is formed at the lower end of the housing 15. Some convenient form of filter-screen 23 may be attached to the lower end of the housing to prevent large pieces of debris from entering the pump.

Extending upward from the lower end of the housing 15 which contains the circular pump-chamber 22 are two enclosed discharge passages 24 and 25 which bulge out with a substantially semi-circular cross-section and extend upwardly along opposite sides of the housing 15.

One passage 24 connects directly with the outlet 17 located at one side of the housing 15, and the passage 25 on the opposite side of the housing 15 is connected to the outlet 17 by means of a similarly shaped passage 26 across the top of the housing 15.

The housing 15 may be formed conveniently in four principal sections, 30, 31, 32, and 33, which preferably are cast and machined where necessary, so that they may be assembled easily according to well-established production methods.

As shown in FIGS. 2 and 4, the first or upper housing section 30 houses the driving motor 19, which can be any suitable type of electric motor having an adaptable work cycle for pumping use, such as a single-phase or threephase alternating-current motor. In FIG. 4, the upper housing section 30 is shown with a cable-inlet fitting 34 through which a motor cable 35 extends. Powersupply wires 36 for the cable 35 are attached to motorwires 37 within the fitting 34, which is sealed to keep out moisture and attached by a bolt 38 to the upper housing 30. An integral eye-member 39 extends across the top of the upper housing 30 so that the pump can be raised and lowered by a rope or cable 40.

Inside the upper housing section 30 is an integral bearing-mount 41 to which is fixed an upper ball-bearing 42 for the motor 19. The second housing section 31 is shaped to match the cross-section of the first or upper housing section 30, and attaches thereto near the lower end of the motor 19. An integral circular flange 43 on the upper surface of the second housing section 31 is adapted to fit inside the first or upper section 30 and provide therewith an enclosure for an O-ring seal 44 between the two sections 30 and 31. In the center of the second section 31 is a second bearing-mount 45 having an opening 46 in which is placed a lower ball-bearing 47 for the :motor 19. In cross-section as seen in FIGS. 2 and 4, the second housing-section 31 has an annular wall portion 48 connected to an upper conical surface 49 on which is formed the bearing-mount 45 containing the bearing 47 through which passes the impeller-shaft 14.

The third housing-section 32 is shaped in cross-section to mate with the second housing-section 31 and has an annular wall 50 which abuts against the rim of the annular wall 48 on the second housing-section 31. An annular ridge 51 of reduced height and shorter radius lies inside the annular wall 50 and between them lies an annular channel or circular-slot 52. At the center of the third section 32 is provided a circular opening 53 through which passes the impeller-shaft 14. With the shaft 14 in place, the joining together of the second and third housing- sections 31 and 32 forms the annular fluid pressure-chamber 12, which will hold oil under pressure during operation.

Within the pressure-chamber 12 and around the shaft 14 is installed the shaft-seal 13 which seats at its upper end in a counterbored seat 54 in the opening 46 of the third housing-section 31 and at its lower end in a similar counterbored seat 55 in the opening 53 of the housingsection 32.

The seal 13 is of the well-known double-end spring-bellows type, a standard form of which is shown in FIG. 6. In the form of seal shown, end-gaskets 56 are held in position within their respective seats 54 and 55 by gasket end-plates 57, and abutting the seats 57 are rotating washers 58 which are held inside a retaining-cap 59 having a flange 60. Adjacent both of the end rotatingwashers 58 is a bellows member 61 having turned-out end portions which are held to the washers 58 by drivingbands 62, each said band being retained inside one of the retaining caps 59. A coil-spring member 63 fits around both retaining-caps 59 and presses outwardly against the flanges of the two retaining caps 59 and forces them against the gasket end-plates 57 to hold the sealing unit in position around the shaft 14.

The third housing-section 32 is substantially fiat on its bottom side, but on its upper side, which forms the lower inside surface of the fluid-reservoir 12, it has an annular ring or channel 65 formed between the annular ridge 51 and a raised annular center-portion 67, the inner portion of which also includes the seal-seat 55.

Mounted within the annular channel 65 is a doughnutshaped pressure-diaphragm 68. The diaphragm 68 is substantially U-shaped in cross-section so that it conforms substantially to the shape of the channel 65, and it has inner and outer annular beaded edges 69 and 70 which serve as a means to hold the diaphragm in a fixed, predetermined position within the channel 65. It may be formed from some suitable deformable but preferably resilient oil-resistant material, such as neoprene.

To retain the diaphragm 68 in its proper position, the outer annular beaded edge 69 fits within the annular slot 52 between the abutting annular walls 48 and 50 of the second and third housing- sections 31 and 32. The inner annular beaded edge 70 is similarly retained by means of an annular clamp-ring 71 which has an annular groove 72 with an overhanging lip 73 to grip the bead 70. The clamp-ring 71 is retained on the central raised centerportion 67 of the third housing-section 32 by a bolt 74- Spaced at intervals near the outer edge of the third housing-section 32 are pressure-tap orifices 75 which provide through-passages from the pump-chamber 22 near peripheral outlets 76 of the impeller 21 to the underside of the diaphragm 68 in the annular-channel 65.

Along one side of the third housing-section 32 as shown in FIG. 4 is a removable filler-plug 77 which provides a means to supply the lubricating fluid to the fluid-pressure reservoir 12. An internal check-valve 78 is supplied in this passage to assure no loss in pressure when the chamber 12 is being filled. On the opposite side of the third housing-section 32 is located a vent-plug 79 which allows for the escape of air during the filling of the chamber 12. Once the chamber 12 is properly filled with oil, the plugs 77 and 79 are put in place and remain there at all times during operation of the pump.

As seen in FIG. 4, the first, second, and third housingsections 30, 31, and 32 are held together by bolts 80. The lowermost or fourth housing-section 33 is attached by means of bolts 81 to the bottom of the third housingsection 32 and forms the pump-chamber 22 with the inlet-eye 16. The impeller 21 is attached to the impellershaft 14 by means of a bolt 82 and is spaced from the lower surface of the third housing-section 32 by a retaining-ring 83. The inlet-side of the impeller 21 may incorporate any well-known blade design, such as the mixedflow type as commonly used in centrifugal pumps. However, on the rear or upper face 84 of the impeller 21 in the present invention is provided a series of small pumping-blades 85 of relatively narrow width, which are spaced at intervals around the center of the impeller 21 and arranged in the conventional manner to perform some pumping action. As the impeller rotates, the narrow blades 85 produce a pressure which is much less than the pressure created by the discharge from the main impellerblades 86 and this reduced pressure is created in the area around the impeller-shaft 14. This reduced pressure, when used in conjunction with the seal-pressurizing means of reservoir 12, produces a sealing-system which stops completely the flow of any fluid or suspended particles from the pump-chamber 22 into the pump interior.

To summarize the operation of the present invention: the reservoir 12 of the pump 10 is first filled with a lubricating fluid such as oil through the orifice provided by removal of the filler-plug 77. Any air in the reservoir 12 is allowed to escape during the filling process (FIG. 4), through the vent-plug 79, so that only incompressible oil will be in the reservoir 12 when the pump is ready to operate. The pump may then be lowered into an area containing the liquid material to be pumped. The liquid is drawn by the impeller 21 through the filter-screen 23 and the eye 16 of the impeller 21 into the pumpchamber 22, thence up the discharge passages 24 and 25 and out through the outlet 17. In the pump-chamber 22, at the periphery of the impeller 21, the discharge pressure of the pump is at its maximum and as the pressure increases here it forces liquid through the peripheral orifices 75 up into the annular channel 65 and against the doughnut-shaped diaphragm 68. Thus the diaphragm 68 transmits the impeller-discharge pressure to the fluid sealing reservoir 12, and the lubricating fluid within the reservoir 12 presses against the gasket end-plates 57 of the sealing member and around the gaskets 56 to seal the impeller-shaft 14. While the sealing member 13 alone would prevent a large amount of leakage from the pumpchamber 22, along the shaft 14, over a period of time, there would be passage of liquid or particles past the gasket 56 unless there were a suflicient force from within the reservoir 12 to resist this flow. The present invention supplies this force constantly at a pressure which assures that no liquid will pass from the pump-chamber into the internal section of the pump.

At the same time as the impeller-discharge pressure is being utilized to provide pressure for the fluid-reservoir 12, the short blades 82 on the rear-face 81 of the impeller 21 are causing a slightly reduced pressure from that produced by the impeller-discharge. Therefore, not only has the impeller-shaft 14 been sealed by the action of the fluid-reservoir 12 on the sealing means, but by creating a lowered pressure in the pump-chamber 22 near the shaft 14, the tendency to force liquid and particles out of the pump-chamber 22 and up along the shaft 14 has been further reduced.

The combination of these two sealing means described above; namely, (1) the self-pressurized lubricant reservoir 12 acting on the sealing member 13 and (2) the back pressure-reducing vanes 86, combine to provide perfect sealing over very long periods of time. It would be possible, of course, to employ only self-pressurized reservoir means, but by use of the pressure-reducing vanes the very maximum of effectiveness is assured.

My invention is particularly useful where compact pumps are required and where pumps are installed to remain for long periods with severe duty cycles. With the major source of bearing-wear and deterioration thus eliminated by a foolproof, self-pressurizing sealing-system, a much longer running-life can be expected. And this increased performance has been accomplished by elimination of the extra pressurizing equipment heretofore required for sealing purposes.

To those skilled in the art to which this invention relates, many changes in construction and widely differing embodiments and applications of the invention will sug- 6 gest themselves without departing from the spirit and scope of the invention. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.

I claim:

A self-sealing centrifugal pump, comprising in combination: a pump housing having a pumping chamber therein; an impeller mounted on a shaft within said pumping chamber and adapted to rotate in said impellerchamber, said housing having an inlet, a fluid reservoir within said housing, located substantially adjacent said impeller-chamber and separated therefrom by a rigid wall member through which passes said impeller-shaft and filled with a substantially incompressible fluid, a sealing member mounted around said shaft within said fluid reservoir and seated within and engaging said rigid wall-member, said sealing member being responsive to fluid pressure in said reservoir to increase the sealing pressure around said shaft where it enters said rigid wall member from said impeller-chamber on an increase of pressure in said fluid seal reservoir, an annular flexible diaphragm means encircling said shaft and having inner and outer securing means to hold said diaphragm in a fixed position with its lower surface adjacent said rigid wall-member and with its upper surface forming an inside-wall of said fluid reservoir, orifice means in said rigid Wall member intermediate the inner and outer flexible diaphragm securing means to communicate pressure from the discharge of said impeller in said impellenchamber through said orifice means to said lower surface of said flexible diaphragm to thereby exert pressure on said fluid in said reservoir whereby sealing pressure on said sealing mem her is increased, said impeller having pumping-vanes on one face facing the inlet to the impeller-chamber in said housing and being positioned to rotate in said impellerchamber and having a back-face adjacent said rigid wallmember, and vanes smaller than said pumping-vanes on said back-face of said impeller, radially inwardly of said orifice means to create a low pressure chamber adjacent the impeller shaft.

References Cited in the file of this patent UNITED STATES PATENTS 2,002,907 Sessions May 28, 1935 FOREIGN PATENTS 381,508 Great Britain Oct. 6, 1932 736,187 Germany June 9, 1943

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