Abstract: An apparatus for checking of monitoring areas (9) of double-walled containers (1), 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), characterized in that the apparatus determines a material constant K of the medium in the monitoring internal area (6), with the aid of the media sensor (13).

Abstract: A leak detection device for double-wall pipeline or container systems has a leak detector with a vacuum pump, a pressure-dependent switch for the vacuum pump, and an alarm device. The leak detector monitors simultaneously several containers. A collecting main is connected to the vacuum pump and by vacuum lines to the containers. Each container has a vacuum connector connected to a control space of the container. The control spaces are parallel connected to the leak detector. Each vacuum line has a first liquid lock arranged at the vacuum connector so as to block liquid that has leaked into the vacuum lines from a leaky container from penetrating into the control spaces of the leak-free containers. A second liquid lock is arranged in the collecting main to prevent liquid from entering the vacuum pump. A measuring line taps the collecting main and is connected to the leak detector.