Container leakage detecting appts. - measures time taken for specified pressure change after creating reduced pressure by releasing pressurised fluid

摘要

A thermodynamic process is used to detect leakage of a container. Cooling is produced as a fluid under pressure enters a container to create a reduced pressure in the space between container and sealed envelope. The time for increase of pressure is measured. A sealed container (1) is in communication with an exterior envelope (2) whose external boundary (3) is perforated and blanked by a flexible membrane (4) carrying an electrical contact (5). A spring (6) pressed against the contact which operates in conjunction with an adjustable contact (8) to close a signalling circuit. Cooling produced by releasing air under pressure creates a reduced pressure region to move the membrane against spring action to close the electrical circuit within a time period. This period is increased when leakage is present.