Rotary kinetic fluid motors or pumps – Smooth runner surface for working fluid frictional contact
Patent
1980-11-05
1983-08-02
Coe, Philip R.
Rotary kinetic fluid motors or pumps
Smooth runner surface for working fluid frictional contact
415149A, 415203, F01D 136, F04B 1700
Patent
active
043963480
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to viscosity pumps, which comprise a rotor and stator ring, the rotor having a surface co-operating with an inner surface of the stator and being capable of rotation with respect to the stator ring, one of the surfaces having a channel for pressurising fluid between an inlet and an outlet.
BACKGROUND ART
In one known application such a pump comprises a thrust collar on a driving shaft, whose external cylindrical surface moves in close co-operation with an internal cylindrical surface of a surrounding stator ring in which the channel is formed. Viscous drag enables the rotor to pull the fluid from the channel and to pressurise it.
The collar may be a collar provided as a shaft to co-operate with thrust pads to carry shaft thrust loads. Since such pads require forced lubrication, a viscosity pump may be eminently suitable for providing that lubrication, and indeed may also provide auxiliary lubrication for the motor driving the shaft.
Difficulties with viscosity pumps are that there can be an unacceptable amount of wear between co-operating surfaces of the stator and rotor other than at the channel with consequent leakage and also that priming of the pump at starting is not easy, and wear may occur before the pump has been fully primed.
It is an object of the present invention to overcome these disadvantages.
DISCLOSURE OF INVENTION
According to the invention, a viscosity pump is characterised in that the channel has a substantially constant cross-sectional area, and is of such a shape that its width changed smoothly from being comparatively wide in the area of the inlet to being comparatively narrow in a region displaced from the inlet.
The collar conveniently constitutes a part of a thrust bearing for the driving shaft so that the pump may provide lubricant to the bearing surfaces as well as to auxiliary equipment, and also possibly to an oil cooler.
There will thus be maximum viscous forces adjacent the inlet where the channel is wide and shallow, while at a position displaced from the inlet the channel is narrower and deeper, so that it will be possible at that position to have comparatively wide lands on the stator ring on either side of the channel. This may then provide a substantial area for carrying bearing loads through the medium of a hydro-dynamic lubricant film between the co-operating surfaces.
Conveniently the depth of the channel at its deepest point may be between 1.5 and 3 times the depth at its most shallow point.
Preferably there is an area of the stator surface between the inlet and the outlet which does not have any part of the channel formed in it so that the whole of that area is available for taking bearing loads.
An inlet and/or an outlet passage may lead into the channel tangentially and may be of converging shape as it approaches the channel to act as a diffuser so that there is little turbulence where the oil enters and leaves the channel.
Where a converging passage merges tangentially into the cylindrical co-operating surface of the stator ring, a sharp edge may be formed to act as a scraper for removing oil which has been pressurised in the channel and is about to leave by way of the outlet.
The stator ring may be capable of taking up either of two positions in relation to supply and discharge lines so that the functions of the inlet and outlet apertures can be changed over if the sense of rotation of the rotor changes. Thus the pump ring could be symmetrical about a plane containing the axis of rotation.
In accordance with the invention, a thrust bearing may comprise a thrust collar on a shaft, and thrust bearing surfaces against which the collar bears during shaft rotation, so that the thrust collar may act a rotor of a pump for providing pressurised lubricant for the bearing surfaces.
BRIEF DESCRIPTION OF DRAWINGS
The invention may be carried into practice in various ways, and one embodiment will now be described by way of example, with reference to the accompanying drawings, in which
FIG. 1 is an end view of a viscosity pump
REFERENCES:
patent: 3497273 (1970-02-01), Muijderman et al.
patent: 3617148 (1971-11-01), Endress
patent: 3794447 (1974-02-01), Bullough
AEPLC
Coe Philip R.
Pitko Joseph M.
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