US3367273A - Rotary fluid pump - Google Patents

Description

Feb. 6, 1968 w. DODSON 3,367,273

ROTARY FLUID PUMP Filed Feb. 15, 1966 WALTER oooso/v /4 INVENTOI? A T7'ORNEYS United States Patent C ABSTRACT 6F THE DISCLOSURE A rotary fluid pump characterized by improved leak resistance having a housing providing an inlet and an outlet, an impeller in the housing, powered means connected to the impeller for driving the impeller to pump fluid from the inlet to the outlet and to produce relatively low and high pressure zones within the housing, the powered means communicating between the exterior and interior of the housing only at the low pressure zone and having provision for improved sealing at the point of such communication, and a baflle mounted within the housing adjacent to the inlet to minimize vortexing of fluid therein.

The present invention relates to a rotary fluid pump and more particularly to such a pump which is substantially leak proof so as to maintain the area in which it is located free of unsightly, hazardous and wasteful leakage or accumulation from the pump and to avoid exposure of the pumped fluid.

During the production of wine in a winery, fluid pumps are employed to transfer the wine between the various production, fermenting and storage tanks prior to bottling. In order to maintain proper health standards, the areas in which the wine is produced must be maintained as clean and free of waste material as possible. The conventional pumps presently in use for this purpose are not able to operate for any protracted length of time without experiencing objectionable leakage. Such leakage is undesirable in that it is wasteful, violates the health laws, and constitutes a serious safety hazard to workmen attending such production equipment. The hazard is particularly acute in the pumping of highly volatile and combustible fluids, such as alcohol in brandy plants.

The conventional pumps usually employ an impeller housing having a powered impeller drive shaft extended therefrom with a packing type seal of felt or other similar material disposed in a pump housing around an impeller shaft which requires frequent replacement. Even at best, such packing material requires continuous adjustment and attention to maintain even minimum operating standards. In order properly to operate, a minimal amount of leakage of fluid is permitted through the packing which serves to lubricate the packing material. Consequently, if the packing is adjusted to have a sufficiently tight contact with the impeller drive shaft to prevent such minimal leakage, the packing material burns, causing disintegration and collapse of the seal. For the same reason, conventional packing type seals cannot be employed where the pump may run dry for any extended period. Furthermore, seals provided with an external lubricant supply have not been employed in this environment because of the danger of fluid contamination upon failure of the seal and intermixing of the fluid with the lubricant.

The difficulty in providing an effective seal in such conventional pumps is due in a substantial degree to the arrangement of the impeller drive shaft with respect to a high pressure impeller chamber within the pump housing. In these pumps, the shaft is extended through a wall of the pump housing immediately adjacent to the high pressure impeller chamber. This necessitates the use of a seal or packing unit in the wall around the shaft to prevent leakage at a position of maximum pressure exposure.

3,367,273 Patented Feb. 6, 1968 Since the high pressure fluid is continually directed against the seal, if not properly and frequently adjusted, it soon permits excessive leakage along the shaft outwardly of the pump housing. It was recognized, therefore, in developing the improved pump of the present invention that such leakage could be better controlled if the powered impeller shaft were extended into the housing from the low pressure or suction end of the pump only. In such arrangement, the high pressure end of the housing can be completely closed except for the discharge outlet therefrom without the need for a seal in such a vulnerable location.

Accordingly, it is an object of the present invention to provide an improved rotary fluid pump which is capable of operating for extended periods without fluid leakage.

Another object is to provide such an improved rotary fluid pump which has a housing completely closed at its positions of highest internal pressure.

Another object is to provide a rotary fluid pump of the character described which extends a powered impeller drive shaft into its housing in optimum location for effective sealing.

Another object is to provide a rotary fluid pump having a housing which admits an impeller drive shaft at the low pressure or suction end of the housing.

Another object is to provide a rotary fluid pump capable of providing fluid tight integrity with a minimum of attention, adjustments and re-packing.

Another object is to provide a rotary fluid pump having a housing capable of effectively utilizing a mechanical seal about an impeller drive shaft.

Another object is to provide a rotary fluid pump having a powered impeller drive shaft extended therein which has a replaceable peripheral wear surface for engagement with the seal.

Another object is to provide a rotary fluid pump capable of utilizing an external lubricant supply for a mechanical seal thereof about a drive shaft.

Other objects and advantages of the present invention will subsequently become more clearly apparent upon reference to the following description and accompanying drawing.

In the drawing:

FIG. 1 is a side elevation of a rotary fluid pump embodying the principles of the present invention disposed in operating connection with a drive motor and mounted on a common base.

FIG. 2 is a somewhat enlarged central longitudinal section through the pump of FIG. 1.

FIG. 3 is a somewhat enlarged transverse vertical section through an impeller compartment and discharged opening of the pump taken generally on line 3-3 of FIG. 2.

Referring more particularly to the drawing, a rotary fluid pump embodying the principles of the present invention is generally indicated by the numeral 10. As best shown in FIG. 1, the pump is adapted to be mounted on a base 11 by a plurality of anchor bolts, one of which is shown at 12 extended through a flange 14 of the pump and screw threadably received within the base. An electric motor 18 is similarly mounted on the base by a plurality of anchor bolts 19 extended through corresponding support feet 20 on the motor and screw threadably received within the base. An elongated drive shaft 22 is extended from the motor and into the pump 10'.

The pump 10 provides a housing 25 which includes a generally circular high pressure discharge or outlet end 26. The pump housing further includes an elongated, some what smaller diameter, suction or inlet end 28 providing an annular flange 29 secured to the discharge end 26 by a plurality of cap screws 30 extended through the flange 3 in screw threading engagement with screw threaded bores 31 in the discharge end of the housing.

The discharge end 26 of the pump housing provides a completely unobstructed end wall 32 and an integral substantially circular side wall 34 having an inner annular surface 35 circumscribing and enclosing an impeller compartment 37. The side Wall further includes an integral, radially outwardly extended outlet conduit circumscribing a discharge passage 42 communicated with the impeller compartment 37 The outlet conduit includes an outer end 43 which is connectable with any suitable fluid directing conduit, not shown.

The inlet end 28 of the pump housing 25 provides a side wall 46 having an annular inner surface 47. The inlet end further includes an end wall 48 which combines with the side wall to enclose and circumscribe a fluid suction chamber 50 communicated with the impeller compartment 37 of the discharge end 26 0f the housing. An annular boss or protuberance 52 is axially outwardly extended from the end wall 48 in concentric relation with the side wall 46. An annular recess 54 is formed in the boss and is closed by an annular end plate 55 removably mounted on the boss by a plurality of cap screws 57. An elongated fluid inlet tube is radially extended through the side wall 46 and provides an inner end 62 inwardly spaced from the side wall and an opposite outer end 64 extended from the wall for connection to a fluid supply conduit, not shown. An elongated flat substantially rectangular baflle plate 66 is secured to the inner surface 47 of the side wall 46 closely adjacent to the inner end 62 of the fluid inlet tube 60.

A motor drive shaft 22 is extended into the pump housing 25 in concentric relation to the side walls 46 and 34 of the housing. The drive shaft provides a reduced diameter screw threaded end portion 70 extended into the impeller compartment 37 of the discharge end 26 of the housing. The screw threaded end of the drive shaft affords a shoulder 72 and has an elongated longitudinally extended key way 73. An impeller hub 75 is slidably mounted on the screw threaded end of the drive shaft and is constrained thereon for rotation with the drive shaft by an elongated key 76 disposed in the key Way 73. The hub is axially constrained in such position by a lock nut 77 screw threadably received on the end of the drive shaft tightly to clamp the hub against the shoulder 72.

As best shown in FIGS. 2 and 3, a pair of arcuate centrifugal type impeller blades or vanes 80 are mounted in diametrically opposed relation on the hub 75 for rotary movement within the impeller compartment 37 by a plurality of cap screws 82. The blades include outer ends 84 which are individually disposed in closely spaced relation to the inner annular surface 35 of the side wall 34. A pair of helical fluid supply blades are mounted on the hub 75 for rotation with the drive shaft 70 within the suction chamber 50. The supply blades are secured to the hub as by Welding or the like or may be formed integrally therewith, as desired.

An elongated tubular sleeve 92 is disposed about the drive shaft 70 and provides an inner end 94 which has a notch 95. The notch receives a protuberance or integral dog 96 on the impeller hub 75 to provide a driving connection there-between for rotation of the sleeve with the drive shaft. A pair of mechanical seals 100 are disposed within the annular recess 54 of the boss 52. Each of the seals includes an annular sealing ring 102 which is held in sliding, sealing engagement against the outer periphery of the sleeve 92 by an annular coiled spring 104. The seals are disposed in axially spaced relation to form therebetwee an annular lubricant compartment 106 within the recess. A radially extended lubricant supply passage 108 is formed in the boss 52 and is provided with a suitable fitting 110 for directing lubricant into the compartment 106.

4 OPERATION The operation of the described embodiment of the subject invention is believed to be clearly apparent and is briefly summarized at this point. Prior to operation, the lubricant compartment 106 is filled with a suitable grease or other lubricating material under pressure through the fitting 110. Such lubricating material completely encircles the periphery of the sleeve 92 about the motor drive shaft 70 which, in combination with the springs 104, tends to urge the seal rings 102 into sealing engagement with the periphery of the sleeve. With this sealing arrangement, it is readily apparent that the pump 10 can be operated dry without any adverse effect upon the seals 100.

When the inlet tube 60 is connected to a source of fluid, the motor 18 is energized to cause rotation of the pump impellers 80 and 90, in a counterclockwise direction, as viewed in FIG. 3. Such rotation of the impellers produces a low pressure or suction Within the suction chamber 50 to draw such fluid inwardly of the pump housing through the inlet tube 60. Ordinarily, the entrance of such fluid into the housing would tend to swirl and create an undesirable vortex within the suction chamber before being drawn axially through the helical supply blades 90 into the discharge end 26 of the housing. Such swirling effect is prevented by the baflle plate 66 which effectively breaks up and precludes the formation of a vortex. This maintains the suction chamber at a sufhciently low pressure to preclude cavitation and any adverse effect upon the seals 100.

With continued rotation of the drive shaft 70, the helical fluid supply blades 90 force the fluid within the suction chamber 50 axially into the impeller compartment 37. The fluid is then picked up by the inner ends of the impeller blades 80 for centrifugal discharge radially outwardly through the discharge passage 42 of the outlet conduit 41 During such pumping action of the impeller blades 80, a small amount of fluid is permitted to bypass each of the blades between their outer ends 84 which maintains the blades in self-centering relation within the compartment 37. Consequently, a bearing and seal structure is not required in the end wall 32 of the housing to support the end of the drive shaft 70.

The sleeve 92 on the drive shaft 70 is concurrently rotated therewith through the meshing relation between the protuberance 96 on the impeller hub 75 and the notch in the sleeve. As previously described, the periphery of the sleeve provides a wear surface for the seal rings which sleeve can be easily and quickly replaced when such wear occurs without replacing the motor drive shaft. It is readily apparent that the sleeve be provided with a notch 95 at each end so that the sleeve can be merely reversed to present a new wear surface for the seals 100. It is noted that the seals are continually lubricated by lubrication in the annular compartment 106 which enables the pump to operate dry without any adverse effect upon the seals.

In view of the foregoing, it is readily apparent that the structure of the present invention provides an improved rotary fluid pump for pumping fluids such as wine, alcohol and the like, without contaminating such fluid and with virtually no leakage of the fluid from the pump. The structure, by its novel drive arrangement, is able to utilize a mechanical seal which has an external lubricant supply so as not to be adversely affected by running the pump dry. A low pressure area is maintained Within the pump housing adjacent to the seals which minimizes the internal pressure tending to force fluid through the seals. Furthermore, the pump impellers are entirely supported on the motor drive shaft and do not require the usual support bearings and seals in the high pressure end of the housing as in conventional pump structures.

Although the invention has been herein shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom Within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus.

Having described my invention, what I claim as new an-d desire to secure by Letters Patent is:

1. A rotary fluid pump comprising a housing having a high pressure outlet end and an opposite relatively low pressure inlet end, impeller means disposed Within said housing, a drive shaft mounting said impeller means for rotation within the housing and extended through said low :pressure inlet end of the housing, an elongated tubular sleeve releasably mounted on said shaft for rotation therewith providing a readily replaceable peripheral Wear surface, a seal disposed in the inlet end of the housing in circu-mscribing relation to the shaft and engaged with the peripheral wear surface of the sleeve, the outlet end of the housing providing an uninterrupted end wall to preclude leakage having a circular impeller compartment providing a discharge orifice, the inlet end of the housing having a suction chamber communicating with the impeller compartment and having fluid supply means connected to said suction chamber, the impeller means including a centrifugal impeller disposed for rotation within the impeller compartment on the drive shaft and an axial flow impeller on the drive shaft disposed closely adjacent to the centrifugal impeller within the suction chamber for impelling fluid from the suction chamber axially into the centrifugal impeller, and a baflle plate secured to the housing at the inlet end within the suction chamber disposed to minimize the development of a fluid vortex Within the suction chamber.

2. The rotary fluid pump of claim 1 in which said h-ousing includes an internal annular recess at said inlet end; and said seal comprises a pair of annular seal rings mounted in axially spaced relation within said recess in the housing and having resiliently flexible inner peripheral portions circumscribing said sleeve on the drive shaft in sliding sealing relation, said seal rings providing therebetween an annular lubricant passage; and means mounted on the housing to supply lubricant to said passage.

3. A rotary fluid pump comprising a housing having an outlet end and an opposite inlet end, impeller means disposed within said housing, a drive shaft mounting said impeller means for rotation Within the housing and extended through said inlet end of the housing, a seal disposed in the inlet end of the housing in circumscribing relation to the shaft, the outlet end of the housing providing an uninterrupted end Wall to preclude leakage therefrom having a circular impeller compartment providing a discharge orifice, the inlet end of the housing having a substantally cylindrical suction chamber communicating with the impeller compartment and adapted to have fluid supply means connected to said suction chamber, the impeller means including a centrifugal impeller disposed for rotation Within the impeller compartment on the drive shaft and an axial flow impeller on the drive shaft disposed within the suction chamber for impelling fluid from the suction chamber axially into the centrifugal impeller, and a baffle plate mounted within the suction chamber and extended substantially radially therein to minimize the development of a fluid vortex within said suction chamber.

References Cited UNITED STATES PATENTS 809,653 1/1906 Ward 230-127 971,850 10/1910 Krogh 103-103 1,931,724 10/1933 Fageol et al. 103-103 2,013,078 9/1935 Slocum 103-88 2,348,246 5/1944 Dixon 103-103 2,385,730 9/1945 Read 103-103 2,853,018 9/1958 Stark 103-103 3,079,865 3/1963 Lipe et al. 103-103 3,196,799 7/1965 Loss 103-109 FOREIGN PATENTS 1,249,642 11/ 1960 France.

HENRY F. RADUAZO, Primary Examiner.

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