US Patent 7174769 Monitoring contents of fluid containers

Apparatus for remote inspection of fluid containers, e.g., portable tanks or fluid pipelines, includes an electronic circuit in communication between each container (or at various locations along a pipeline) and a remote central station. The electronic circuit is adapted to issue a wireless signal to the remote central station upon detection of predetermined internal conditions, such as an out-of-range pressure condition of fluid contained within the volume of the container, or upon detection of predetermined external conditions, such as the lack of presence of the container in its installed position or the presence of an obstruction to viewing of or access to the container.