Hidden sensor e.g. for monitoring flange of pipe, door frame, transported container, disturbance analysis or reaction monitoring

摘要

The warning device responds to a change in an environmental parameter. The unit has a capsule in which a long-life energy source (12), e.g. lithium battery, is in contact with a detonator (17). Located in line with the battery is a spring-loaded (15) firing pin (16) retained by a mechanical plate (19). The plate is held back against a spring (15) by a blocking pin (20). The blocking pin is held by an insert (23) of material that responds to a specific agent e.g. water, oil to break down. The agent is admitted through a hole (25), and when breakdown occurs the blocking pin is released allowing the plate to move with the firing pin moving to trigger the detonator.