Abb Research Ltd.

Asea Brown Boveri Inc.

Other

Walter Ruegg

Daniel A Matter

Thomas Kleiner

Thomas Christen

John Anthony Byatt

Hubert Brandle

Lothar Schultheis

Ernst Witschi

Anghony Byatt

The subject matter of the present invention is the optimization of a capacitive liquid level sensor which is suitable, in particular, for determining the location of a boundary layer,between water,and oil,in a separator tank. The known sensor principle is based on measuring the environmentally dependent capacitance between neighboring electrodes,of a rod-shaped probe,. According to the invention, the probe,is designed such that large ionic double-layer capacitors occur on the electrodes,in the more conductive medium,, and small capacitors occur between electrodes,in the insulating medium,. For this purpose, the electrode height h is selected to be large, the ratio of the electrode height h to the electrode spacing a is preferably selected to be in the range of 1<h/a<6 and, in particular, the measuring frequency f is selected to be in the dielectric cut-off frequencies of the media,. As a result, it is possible to achieve a large jump in capacitance for a digital liquid level display and/or a largely continuous increasing capacitance for an analog liquid level display. Furthermore, the influence of more conductive and/or insulating dirt films,on the capacitance signal is eliminated by suitable measuring frequencies and/or by radially offsetting the electrodes

Capacitive level detector with optimized electrode geometry

The subject matter of the present invention is a method and a device for capacitive liquid level measurement which are particularly suitable for determining liquid level between adhesive media 10, 11 of different conductivity. The known sensor principle is based on the fact that the environmentally dependent capacitance is measured between neighboring electrodes 13, 4; 4, 5; 5, 6 of a rod-shaped probe 1. According to the invention, the probe 1 has electrodes 4, 5, 6, 13 with covers 7 of different thicknesses d.sub.i. The effective thickness d.sub.s /.epsilon..sub.s of an insulating pollutant film 14 can then be determined by capacitance measurements between at least two pairs of electrodes 4, 5, 6, 13. The influence of a conductive pollutant film 14 on the capacitance signal can be eliminated by selection of at least one suitable measuring frequency. Furthermore, by optimizing the electrode height h, a large capacitance jump is achieved for a digital liquid level display, and/or a largely continuous increase in capacitance is achieved for an analog liquid level display. The sensor is preferably used to determine the location of an interface 12 between water 10 and oil 11 in a separator tank.

Capacitive liquid level sensor with integrated pollutant film detection

In a method and a device for measuring the concentration of particles present in a gas, in which a gas stream is guided past a UV light source, the particles are ionized and filtered out and the resulting ionic current is measured, the gas flow required is produced by thermal convection using an internal or external heat source. A suitable internal heat source in this context is, for example, the UV lamp (2) itself, which heats the gas via a radiation absorber (5). The elimination of a mechanical pump reduces the space requirement, power consumption and susceptibility to faults of the measuring arrangement.

Method and device for measuring the concentration of particles in a gas

A connector (2) for an optical cable (1) having at least one glass fiber (4.1, 4.2) is characterized in that the plug contact is electrical and the signal transmission is optical. For this purpose, an electrical plug contact (5.1, 5.2) is provided for the at least one glass fiber (4.1, 4.2), as well as a first converter for converting an electrical signal into an optical signal and/or a second converter for converting an optical signal into an electrical signal. The at least one glass fiber (4.1, 4.2) of the optical cable (1) is connected directly to the the first and second converters, respectively. The first and second converters, respectively, are e.g. embodied by light-emitting diodes and photodiodes, respectively.

Connector for an optical cable

The torque and/or power of a drive system in dynamic operation is ascertained by generating first signals which are at least proportional to the speed of the drive system, automatically differentiating the first signals to obtain second signals which are at least proportional to acceleration of the system, and automatically multiplying the first and second signals to generate third signals whose magnitude is at least proportional to the power and/or torque of the drive system.

Growing community of inventors

Endingen, Switzerland

Walter Ruegg