Sensor unit for checking of monitoring areas of double-walled containers or double-walled pipelines, or double-walled vessels

A system for checking of monitoring areas (6) of double-walled containers (1) or double-walled pipes (7) or double-walled vessels, having at least

• one double-walled container (1) and/or at least one double-walled pipe (7) and/or at least one double-walled vessel, at least one vacuum source which produces a vacuum pressure in the monitoring area or areas (6),
• an apparatus for checking of monitoring areas (9) of double-walled containers (1) or double-walled pipelines (7) or double-walled vessels by means of at least one pressure sensor (10) for measurement of the monitoring area internal pressure and by means of a media sensor (13) for detection of a medium in the monitoring internal area (6), wherein the apparatus determines a material constant K of the medium in the monitoring internal area (6) with the aid of the media sensor (13), as well as
• at least one alarm apparatus, wherein
• the apparatus for checking of monitoring areas (9) is connected via a connection means to the monitoring area or areas (6) of the double-walled container (1), double-walled pipe (7), or double-walled vessel,
• the apparatus for checking of monitoring areas (9) is furthermore connected to at least one signal processing unit such that the latter can receive and process the signals produced by its pressure sensor (10) and by the media sensor (13), in which case
• the signal processing unit is designed such that it compares the signals with predetermined values, in particular the pressure signal value with a pressure nominal value and the material constant signal value of the media sensor (13) with a material constant nominal value, and uses this to produce new control data and control commands, in particular for the vacuum source and the alarm apparatus,
• in that the signal processing unit
• in the situation in which the pressure signal from the pressure sensor (10) is higher than the pressure nominal value and the material constant measured by the media sensor (13) corresponds to a material constant nominal value which is equal to that material constant value of the medium (17) in the container, pipe or vessel,
• produces a control command for the alarm apparatus, which initiates the alarm “PRODUCT LEAK”, as well as a control command for operating external apparatuses, and/or
• in the situation in which the pressure signal from the pressure sensor (10) is higher than the pressure nominal value and the material constant measured by the media sensor (13) corresponds to a material constant nominal value which is equal to that material constant value of an aqueous mixture,
• produces a control command for the alarm apparatus, which initiates the alarm “EXTERNAL LEAK, LIQUID”, and/or
• in the situation in which the pressure signal from the pressure sensor (10) is higher than the pressure nominal value and the material constant measured by the media sensor (13) corresponds to a material constant nominal value which is not equal either to that material constant value of the medium (17) in the container, pipe or vessel, or to that of an aqueous mixture,
• produces a control command for the alarm apparatus which initiates the alarm “AIR LEAK”, and
• the vacuum source and the alarm apparatus are each designed such that they can carry out the control commands intended for them from the signal processing unit.