Rotary kinetic fluid motors or pumps – Smooth runner surface for working fluid frictional contact
Patent
1995-10-30
1997-09-02
Look, Edward K.
Rotary kinetic fluid motors or pumps
Smooth runner surface for working fluid frictional contact
415229, 4174234, F04D 2966
Patent
active
056624565
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a friction vacuum pump, with a housing, a rotor and a rotor bearing which is supported in the housing via a sleeve-like support.
Gaede pumps (cylindrical rotor with a pumping slot and a barrier slot between inlet and outlet rotating in a housing), Holweck pumps (cylindrical rotor with spiral grooves on the stator or on the rotor rotating in a housing), Stegbahn pumps (rotating and fixed annular discs with spiral grooves) and turbomolecular pumps which are equipped with rotating and guiding blades, belong to the class of friction pumps. It is known to equip friction pumps with differently designed pumping sections.
The pumping characteristics of a friction pump depend chiefly on the distance between the active pumping surfaces which move relative to each other. The smaller the slot, the better in particular the compression of that friction pump will be. However, there are limits as to the minimum dimensions of the slot, since small oscillations of the rotor must be permitted. This applies particularly when passing through the range of resonance frequencies as the rotor runs up to its operating speed.
It is the task of the present invention to design, for a friction pump of the aforementioned kind, the support for the rotor bearing in the housing in such a way, that in spite of a support which permits oscillations of the rotating system, optimally small distances can be selected between the active pumping surfaces.
SUMMARY OF THE INVENTION
According to the present invention this task is solved by a sleeve-like support which supports the rotor bearing and which is in turn supported in the housing via several, preferably three, substantially axially extending rods. In a rotor which is suspended in this manner in a housing, oscillations which the rotor is still capable of, are constrained specifically in the radial direction. Motional components of the rotor in the axial direction are practically zero even in the case of relatively short rods. Radially extending slots between the active pumping surfaces can thus be made optimally small. Only in axially oriented slots the radial oscillations of the rotor will have to be taken into account.
To attenuate and reduce the radial oscillation amplitudes of the rotor it is expedient to provide an attenuation arrangement. This arrangement preferably consists of an O-ring which is located between the sleeve-like support and a housing section. This defines the maximum oscillation amplitude of the rotor. The slots extending in the axial direction must be selected in such a manner, that these will permit the slight maximally possible oscillations which may still occur.
BRIEF DESCRIPTION OF THE DRAWINGS
Further advantages and details of the present invention shall be explained on the basis of the design examples of the drawing figures.
Drawing FIG. 1 shows a longitudinal section through a friction vacuum pump designed as a turbomolecular pump having a rotor suspension designed according to the present invention.
Drawing FIG. 2 shows a cross section through the design example according to drawing FIG. 1.
Drawing FIGS. 3 and 4 show further design examples for friction vacuum pumps having a rotor suspension according to the present invention.
DESCRIPTION OF THE INVENTION
In the design examples, the different friction vacuum pumps are each generally marked as 1, their housing as 2 and the upper cylindrically designed housing section as 3. The cylindrical housing section 3 centers the stator 4 which comprises numerous stator rings 5, 6 and 7. The rotor 8 is supported by the bearings 9. In the design examples which are presented, the bearings 9 are designed as rolling bearings. Also magnetic bearings or sliding bearings may be used at these points. The drive motor is marked as 11. During operation of the pump, a vacuum chamber which is to be evacuated is connected to inlet flange 12. Due to the rotation of rotor 8, the gases are pumped to the outlet 13, to which a backing pump is connected.
The design example according
REFERENCES:
patent: 1677464 (1928-07-01), Taylor
patent: 3416723 (1968-12-01), Schmitz et al.
patent: 3969039 (1976-07-01), Shoulders
patent: 4456433 (1984-06-01), Henning et al.
patent: 4541772 (1985-09-01), Becker
Journal of Vacuum Science & Technology, No. 4, July 1988, Woodbury pps.2518-2521, "Developement of a new Type of Oil-Free Turbo vacuum pump", Mare et al.
Leybold Aktiengesellschaft
Look Edward K.
Sgantzos Mark
LandOfFree
Friction vacuum pump with bearing support does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Friction vacuum pump with bearing support, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Friction vacuum pump with bearing support will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-302766