Vacuum pump

Details Vacuum pump Vacuum pump

2000-12-21

2002-08-27

Denion, Thomas (Department: 3748)

Rotary expansible chamber devices

With plural working fluid inlet or outlet passages

C418S191000, C418S206200, C418S206400

Reexamination Certificate

active

06439865

ABSTRACT:

FIELD OF THE INVENTION
the invention relates to a pump for simultaneously generating pressure and negative pressure.
BACKGROUND OF THE INVENTION
Such pumps are advantageous if an industrial process requires compressed air and negative pressure at the same time, since the pump only needs one drive. Aside from the suction port, such a pump requires a separate charging port that is connected to the atmosphere in order to ensure the volume flow for the compressed air. Accordingly, the pump chamber has to have several cells that are separated from each other. In the state of the art, this has only been achieved with vane type pumps which are known, for example, from the GB-A-818 691. Vane type pumps, however, are prone to wear and tear, and can only be operated without lubricants when special materials are used.
SUMMARY OF THE INVENTION
The present invention provides a pump for simultaneously generating compressed air and negative pressure, that is virtually free of wear and tear and that can be made without the use of special materials. In the pump according to the invention, there is a pair of rotors in the pump chamber that has at least three blades and that rotates in opposite directions around parallel spaced axes and these rotors intermesh free of contact so that, together with the peripheral wall of the pump chamber, they define cells that are separate from each other. The cells needed for simultaneously generating compressed air and vacuum can be separated from each other by means of the rotors. Since the rotors interact free of contact with each other and with the peripheral wall of the pump chamber, no wear occurs in the area of the pump chamber. The sealing gap between the rotors can be kept very small by optimizing their geometry; in practical embodiments, the gap is just fractions of a millimeter, so that good pressure and vacuum values are ensured. These values even improve with increasing service life since the deposits that form over time reduce the size of the sealing gaps.
A pump with a pair of rotors each having three blades and rotating in opposite directions around parallel axes is known from the DE-A-2 422 857. That pump is not equipped, however, with a charging port and is therefore not suited for producing compressed air and negative pressure at the same time.
The pump according to the invention is particularly well suited for use in the paper-processing industry, especially for applications that do not require a separate supply or adjustment of compressed air and vacuum. Compressed air is needed, for example, to blow air onto a stack of paper from the side to help separate the sheets. The generation of pulsating compressed air by the pump according to the invention proves to be very practical here since the paper edges can be separated more easily by means of the pulsating compressed air that is generated. Negative pressure is required in such applications to pick up the top sheet of paper.
In the preferred embodiment of the pump, the rotors, together with the pump chamber, define a suction cell that is connected to the suction port and whose volume increases during the rotation of the rotors and they also define a pressure cell whose volume decreases when the rotors rotate and that is connected to the pressure port. This pressure cell is comprised of two charging cells that are initially separated from each other during the rotation of the rotors, whereby these charging cells each have an associated charging port and that, during the further rotation of the rotors, are united with each other to define the pressure cell. Before being united, the charging cells are moved essentially isobarically and isochorically in the pump chamber, that is to say, the air present in the charging cells essentially does not undergo any change in pressure or volume during the shift of the charging cells.


REFERENCES:
patent: 2764407 (1956-09-01), Alix
patent: 2967054 (1961-01-01), Glucksman
patent: 3199771 (1965-08-01), Becker
patent: 3628893 (1971-12-01), Carpigiani
patent: 3764238 (1973-10-01), Carpigiani
patent: 4008019 (1977-02-01), Carling
patent: 4480970 (1984-11-01), Smith
patent: 4859158 (1989-08-01), Weinbrecht
patent: 5071328 (1991-12-01), Schlictig
patent: 142 587 (1902-03-01), None
patent: 564 152 (1932-10-01), None
patent: 1 133 500 (1962-07-01), None
patent: 1915269 (1970-08-01), None
patent: 1 915 269 (1970-10-01), None
patent: 1 628 347 (1971-06-01), None
patent: 20 27 272 (1971-12-01), None
patent: 24 22 857 (1975-11-01), None
patent: 33 21 992 (1984-03-01), None
patent: 41 18 843 (1993-02-01), None
patent: 195 03 716 (1996-03-01), None
patent: 0 290 662 (1988-11-01), None
patent: 0 370 117 (1990-05-01), None
patent: 0 426 078 (1991-05-01), None
patent: 0 458 134 (1991-11-01), None
patent: 0 475 535 (1992-03-01), None
patent: 0 578 853 (1994-01-01), None
patent: 0 680 562 (1997-04-01), None
patent: 622873 (1949-05-01), None
patent: 818 691 (1959-08-01), None
patent: 1 350 636 (1974-04-01), None
patent: 2233042 (1991-01-01), None
Gunter Leuschner: “Kleines Pumpenhandbuch fur Chemie und Technik,” 1967, VERLAG CHEMIE GMBH, WEINHEIM/BERGSTR. XP002113407, Seite 226, Letzter Absatz-Seite 227, Letzter Absatz; Abbildung 4.13.2.
“Pulsationsfreie Drehkolbenpumpen”, p. 104, Jun. 2, 1998, Industriepumpen & Kompressoren.
De Vries, English-German Technical and Engineering Dictionary, p. 730, 1954, First Edition.

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