# US 5,707,213 A · Molecular vacuum pump with a gas-cooled rotor

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- Number: US 5,707,213 A
- Document ID: US5707213A
- Status: Granted
- Kind: A
- Application number: 08/596,018
- Filed: 1996-02-06
- Granted: 1998-01-13
- Earliest claimed: 1995-03-10
- Assignees: Balzers-Pfeiffer GmbH
- Inventors: Armin Conrad
- Web page: https://patentgrep.com/patent/US5707213A

## CPC

- F04D 19/04: specially adapted to the production of a high vacuum, e.g. molecular pumps
- F04D 19/044: {Holweck-type pumps}
- F04D 29/5846: {cooling by injection}
- F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02)

## Abstract

A method of cooling rotor elements of a molecular vacuum pump having stator and rotor elements, a suction flange defining a gas inlet, and a gas outlet spaced from the suction flange, the method including providing additional gas inlet between the suction flange and the gas outlet and admitting through the additional gas inlet a cooling gas having a thermal conductivity larger than that of the compressible gas.

## Claims

### Claim 1

A method of cooling a molecular vacuum pump for compressing gases and having stator means, rotor means, a suction flange defining a gas inlet, and a gas outlet spaced from the suction flange, said method comprising the steps of:
providing an additional gas inlet between the suction flange and the gas outlet; and
admitting through the additional gas inlet a cooling gas for cooling the rotor means and having a thermal conductivity larger than a thermal conductivity of a compressible gas.

### Claim 2 (depends on 1)

A method as set forth in claim 1, wherein said cooling gas admitting step comprises the step of admitting a cooling gas characterized by an inner friction which is smaller than an inner friction of the compressible gas.

### Claim 3 (depends on 1)

A method as set forth in claim 1, wherein said cooling gas admitting step comprises the step of admitting a cooling gas having a molecular weight smaller than a molecular weight of the compressible gas.

### Claim 4 (depends on 1)

A method as set forth in claim 1, further comprising the step of admitting a flashing gas through the additional gas inlet.

### Claim 5 (depends on 1)

A method as set forth in claim 1, wherein the additional gas inlet providing step comprises providing the additional gas inlet at one of the high vacuum side of the pump.

### Claim 6 (depends on 1)

A method as set forth in claim 1, wherein the additional gas inlet providing step comprises providing the additional gas inlet between the high vacuum side of the pump and a for vacuum side of the pump.