Pumps – Successive stages
Patent
1996-01-29
1999-03-09
Freay, Charles G.
Pumps
Successive stages
418 2, 418 13, 184 616, F04B 300
Patent
active
058791388
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention pertains to a rotary vane vacuum pump with a high vacuum stage, with a fore-vacuum stage, with a substantially cylindrical rotor which has bearing and anchor segments, a bearing segment being situated between two anchor segments and the anchor segments having vane slots, and with a roughly pot-shaped housing which contains the pump chambers and whose base is designed as a bearing piece with a passage for the rotor drive.
High vacuum pumps require that the individual parts which effect the pumping of the gas be manufactured with the utmost precision. If, for example, in the case of a rotary vane vacuum pump, the slots between the vanes and the related vane slots in the rotor, the slots in the area of the anchor systems, or in the case of a two-stage rotary vane pump--the slots in the sealing area between the high vacuum stage and the fore-vacuum stage are too large, then flows occur which oppose the intended direction of flow (backstreaming) and which significantly impair the pumping characteristics, pumping speed, compression, ultimate pressure characteristic etc.
From FIG. 3 of DE-A-2354039 a two stage rotary vane vacuum pump of the aforementioned kind is known. Besides the bearing segment being situated between two anchor segments, the rotor has on one of its two face sides, (on the side of the fore-vacuum stage) a further bearing segment. Both vane slots must therefore be milled from the direction of the other face side--(the high vacuum side)--into the rotor. This has the disadvantage that a milling disc having a relatively large radius, greater than the sum of the lengths of the two vanes and the length of the bearing segment in the middle, must be employed. Moreover, after milling of the vane slots and for the purpose of manufacturing an operational rotor, a filling piece must be inserted again at the level of the middle bearing segment, so that a leak-tight mutual separation between the two stages of the vacuum pump is ensured. The manufacture of a rotor of this kind is involved. Milling of the vane slots is only possible with limited tolerances owing to the necessity of having to employ a milling disc of a relatively large diameter.
SUMMARY OF THE INVENTION
It is the task of the present invention to create a two-stage rotary vane vacuum pump of the aforementioned kind which can be produced in a simpler way and with greater precision.
This task is solved by the present invention according to the characteristic features of the patent claims. Because it is no longer necessary to provide a second bearing segment on one of the two face sides of the rotor, each vane slot may be milled into the rotor cylinder from its respective face side. The manufacture of a slot segment which must be filled again after it has been produced is no longer required. Milling discs having significantly smaller radii may be employed, and thus significantly smaller tolerances for the slot dimensions can be attained. Thus not only are the pumping properties improved; also assembly of the vane is simpler, since both slots are each accessible from their respective face side.
BRIEF DESCRIPTION OF THE DRAWINGS
Further advantages and details of the present invention shall be explained by referring to drawing FIGS. 1 to 5.
Drawing FIG. 1 shows a longitudinal section through a design example for a rotary vane pump according to the present invention.
Drawing FIG. 2 shows a rotor according to the present invention.
Drawing FIG. 3 shows the high vacuum face side of the rotor with projections.
Drawing FIG. 4 shows the fore-vacuum face side of the rotor with projections.
Drawing FIG. 5 shows a longitudinal section through a further design example for a pump according to the present invention.
Drawing FIG. 6 shows a further design example for a rotor according to the present invention.
The presented pump 1 comprises chiefly the subassemblies housing 2, rotor 3 and drive motor 4.
DESCRIPTION OF THE INVENTION
Housing 2 substantially has the shape of a pot with an outer wall 5, with the lid 6
REFERENCES:
patent: 2877946 (1959-03-01), Garrison et al.
patent: 2902210 (1959-09-01), Power
patent: 5178522 (1993-01-01), Abelen et al.
patent: 5372489 (1994-12-01), Matsuda et al.
Arndt Lutz
Muller Peter
Balzers Und Leybold Deutschland Holding AG
Freay Charles G.
LandOfFree
Two-stage rotary vane vacuum pump does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Two-stage rotary vane vacuum pump, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Two-stage rotary vane vacuum pump will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1314185