Gestra Gmbh

Gestra Aktiengesellschaft

Kerstin Borchers

Holger Schroter

Joachim-Christian Politt

Jan-Hermann Muller

Herbert Laupichler

Gunter Schmitz

Heinrich Hansemann

In cases of application where the critical temperature occurs or could occur, safe monitoring of the level of the liquid was not possible heretofore because the physical properties of the liquid and of the gaseous medium present above the latter in the container no longer differ at this temperature. The method includes the temperature in the container in the monitoring of the level of the liquid. Below a lower comparative temperature value (Tu), the output signal of the evaluator unit is determined by the measuring signal of the level sensor. The measuring signal of the level sensor is disregarded above this value (Tu). The evaluator unit supplies an output signal that is on the safe side with respect to the level of the liquid. The comparative temperature (Tu) is below the critical temperature to an extent such that the inaccuracies in the measurement of the level sensor and the temperature sensor have no interfering effect.

Method of monitoring the level of a liquid in a container

A probe for monitoring a medium within a container, which includes a mounting housing for mounting the probe on a container, a neck part attached at one end to the mounting housing, and at the other end to a radially cantilevered head housing. The head housing extends on only one side of the neck part. A sensor is attached to the mounting housing. An electrical conductor is attached to the sensor and extends through the neck part and into the head housing where it is connected to an electronic circuit, which is mounted inside the head housing. The head housing is made so that its dimensions in the radial direction of the neck part are greater than the dimensions of the neck part. The cantilevered mounting of the head housing allows heat from the container to dissipate into the atmosphere without contacting a significant portion of the head housing. The configuration of the head housing also allows easy access to the electronic circuit, even if two probes are placed in close proximity to each other.

Probe with unilaterally cantilevered head housing

In the presence of a defect in the insulation cover of known probes, liquid medium can leak from the container into the interior space of the housing of the probe, and from there into the surrounding environment, and endanger or even injure persons present there. The probe housing has an interior space with two chambers. The first chamber, which is close to the container, is capable of withstanding the pressure prevailing in the container. A passage opening present between the first chamber and the second chamber for the sensor electrode, or for its electrical conductor, is closed by a movable closing part or a stationary closing element. In the event of leakage through the insulation cover, the pressure would be transmitted from the container into the first chamber, but could not propagate from there into the second chamber and on from there. In this way, in the event of a defect, medium that is discharged under the operating pressure prevailing in the container, is prevented from flowing through the probe housing and into the environment, where it would become a hazard to persons present there.

Probe for monitoring liquid with protection against leakage

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Bremen, Germany

Kerstin Borchers