Rotary kinetic fluid motors or pumps – With lubricating – sealing – packing or bearing means having... – For shaft sealing – packing – lubricating or bearing means
Reexamination Certificate
2001-11-27
2003-09-02
Look, Edward K. (Department: 3745)
Rotary kinetic fluid motors or pumps
With lubricating, sealing, packing or bearing means having...
For shaft sealing, packing, lubricating or bearing means
C415S231000, C415S121200, C415S169100
Reexamination Certificate
active
06612805
ABSTRACT:
FIELD OF THE INVENTION
The invention concerns generally a machine and more particularly a hydrodynamic machine involving a flow of a fluid medium, for example a pump, an agitator or the like. The invention further concerns a wheel such as an impeller or propeller, preferably for use in a hydrodynamic machine.
BACKGROUND OF THE INVENTION
A typical configuration of a machine such as a hydrodynamic machine such as a pump or agitator comprises a stationary housing with a motor-driven shaft supported in the housing and a wheel on the shaft for moving a fluid medium. The shaft engages through an opening in the housing, and the wheel which is arranged at the free end of the shaft is disposed outside the housing. The hub of the wheel engages into the opening in the housing, forming an annular gap between the inside wall of the opening and the outside wall of the hub. A seal seals off the shaft and/or the hub and the housing relative to the medium and a spiral arrangement is arranged in the region of the hub in fixed relationship therewith to produce a flow of medium which is directed out of the annular gap to prevent particles from being deposited therein.
In this respect, consideration may be given to EP 0 252 037 B1 disclosing a sealing arrangement for an agitator or a pump, which, as indicated above, has in the region of the annular gap between the hub of the wheel and the opening in the housing a spiral arrangement which opposes particle deposit in the gap by virtue of producing a fluid flow which is directed out of same. In that structure the spiral arrangement is of such a configuration that a spiral surface structure is formed in the inside wall of the opening in the housing and the outside wall of the wheel of the hub. The annular gap is in the form of a cylindrical gap between those mutually oppositely disposed concentric walls which in effect are provided respectively with male and female screwthread configurations. When the hub is rotated in the opening in the housing, an outwardly directed flow is generated in the annular gap, and is intended to transport particles outwardly thereof. In addition, provided at the upper edge of the opening in the housing is a cutting device insofar as cutting edges are provided at the annular edge of the opening in the housing and on the wheel hub. When the hub rotates, the cutting edges co-operate with each other and are intended to make the particles as small as possible.
It will be appreciated that this design configuration is relatively complicated and expensive in regard to its structure as it involves machining a plurality of mutually co-operating, especially machined surfaces on each of the co-operating components. Disturbances can occur in operation thereof, particularly if there are relatively large amounts of large-size particles, for on the one hand the operation of reducing the size of the particles means that the amount of material which can involve sedimentation in the annular gap is increased, while on the other hand blockages can occur in the region of the cutting arrangement itself, particularly once a certain amount of wear of the cutting edges has occurred.
Attention may also be directed to U.S. Pat. No 6,053,500 A disclosing a further sealing arrangement for a shaft of a pump impeller. That arrangement has a housing with an opening therein, into which the hub of the impeller engages. Provided in the region of the inside wall of the opening is a screw pitch which is formed in fixed relationship with the housing and operable to counteract particle deposition there. When the hub rotates in the opening in the housing, the result is a flow therein, with which particles are to a certain extent entrained outwardly thereof.
Reference may also be made to EP 0 542 530 B1 disclosing a seal for a shaft, in which the sealing member itself has a spiral structure and thereby, upon rotation of the shaft, a flow which is directed outwardly in the region of the seal is generated. That is intended to oppose deposit of particles to a certain extent.
EP 0 879 977 A2 also involves a further sealing arrangement for a shaft, in which a sealing member comprising polymer material has sealing lips with taper angles of different gradients, which co-operate with the peripheral sealing surface on the shaft. The shaft in that region has grooves extending in a helical configuration, with a groove depth of less than 15 &mgr;m, in order to transport lubricant back into the sealing region in order to lubricate the sealing edges during rotation of the shaft.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a hydrodynamic machine of such a design configuration in the sealing and shaft-supporting area thereof as to counteract deposit of particles in the region of the shaft seal at the medium side in a structurally simple manner with a high level of operational reliability.
A further object of the present invention is to provide a hydrodynamic machine such as a pump or agitator adapted to resist fibrous constituents possibly contained in the medium becoming wrapped around the wheel hub.
Still another object of the invention is to provide a hydrodynamic machine which while being of a simple structure more effectively produces a flow of fluid medium operable to remove particles and other contaminating matter in the fluid medium from the region of a wheel such as an impeller or propeller of the machine.
Yet a further object of the invention is to provide a wheel such as a propeller or impeller for a hydrodynamic machine, which is capable of resisting particle deposit in its bearings and at least in part reducing the likelihood of elongate contaminating material in the fluid medium becoming wrapped around the wheel hub.
In accordance with the principles of the present invention in the machine aspect the foregoing and other objects are attained by a machine such as a hydrodynamic machine, for example a pump, agitator or the like, comprising a stationary housing with a motor-driven shaft which is supported in the housing and which has a preferably non-rotatably connected wheel for moving a fluid medium, more particularly for example an impeller, propeller or the like. The shaft extends coaxially through a pot-shaped opening in the housing and the wheel which is arranged at the free end of the shaft is disposed outside the housing. The hub of the wheel on the shaft engages into the pot-shaped opening in the housing, forming an annular gap between the inside wall of the opening in the housing and the outside wall of the hub. The machine further includes a seal for sealing off the shaft and/or the hub and the housing in relation to the fluid medium, while a spiral arrangement is disposed in the region of the hub non-rotatably with respect thereto to produce a flow of medium which in the annular gap is directed out of same, to prevent particle deposit. The outside diameter and/or the cross-section of the annular gap between the inside wall of the opening in the housing and the outside wall of the wheel hub is or are of a configuration which increases towards the wheel.
Further in accordance with the principles of the invention, in the wheel aspect thereof, the foregoing and other objects are attained by a wheel in the form of an impeller or propeller, preferably for use in a hydrodynamic machine such as a pump or agitator, comprising propeller blades or impeller vanes and a wheel hub, preferably for engagement into a pot-shaped opening in a housing such as a sealing housing of the hydrodynamic machine. The wheel hub is connected in one piece to the propeller blades or impeller vanes and has a spiral arrangement on its outside wall.
In a modified form of that wheel the spiral arrangement extends at the outside of the wheel hub from a position on the wheel hub which is remote from the propeller blades or impeller vanes, preferably from the end of the hub remote from the propeller blades or impeller vanes, to the underside of the propeller blades or impeller vanes.
As will be seen from the description hereinafter of preferred embodiments of the in
EMU Unterwasserpumpen GmbH
Look Edward K.
McAleenan J. M.
Schweitzer Cornman Gross & Bondell LLP
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