Forschungszentrum Julich Gmbh

Kernforschungsanlage Julich

Rwd-datentechnik Gmbh

Kernforschungsanlage Julich Gesellschaft MIT Beschrankter Haftung

Bernd Lindenau

Johan K Fremerey

Klaus Witthauer

Johan K Fremery

Wolfgang Rubner

Gas-friction vacuum indicator with a gas-friction sensor rotating about

Magnetic bearing control system

A movement detection system for use in measuring movements of a rotating body or shaft which is magnetized along an axis which is angularly displaced from the mechanical axis of rotation thereof. The system has a plurality of inductive coils which are connected to produce signals proportional to the movements of the body or shaft while suppressing spurious noise signals.

Coil system for inductive measurement of the velocity of movement of a

For measurement of gas pressure a gas-friction vacuum meter is used in whose measuring head a rotating body is suspended in a magnetic field contact-free between electromagnetic drive coils. The rotating body is set in motion with the aid of the drive coils and maintained at a rotational speed above a preset minimum rotational speed. The speed reduction of the rotating body occurring on account of gas friction is continually or intermittently balanced with current flows from a three-phase generator to the drive coils. In the measuring head rotational speed sensors are arranged and positioned, which detect and respond to the rotational frequency of the rotating body, and further transmit output signals to an electronic analyzer unit, which determines the pressure from the timely change of the rotation frequency. In order to increase the pressure range for which the apparatus may be accurately used further, the analyzer unit receives a temperature signal, which correlates with the temperature of the gas surrounding the rotational body, in such a way, that the pressure measurement is corrected for the influence of heat transferred to the gas during operation of the rotating body.

Method of and apparatus for gas pressure measurement by the gas-friction

A rotary measuring body for a gas-friction vacuum meter has its surface formed with a macroscopic roughness which provides a gas-friction coefficient minimally affected by the microscopic roughness of the surface. As a result, the output signal and sensitivity of the vacuum meter is high and is less susceptible to change as a result of surface corrosion.

Gas friction vacuum meter and method of making measuring body

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Julich, Germany

Bernd Lindenau