Filter with memory, communication and pressure sensor

A method of determining the integrity of individual filtering elements within a multi-filter housing, comprising:

• a. placing a plurality of filtering elements in parallel, each having an input side and an output side, and a corresponding plurality of pressure sensors, inside said multi-filter housing, each of said plurality of sensors being associated with said output side of a respective one of said plurality of filter elements and located in close proximity to said respective one of said plurality of filter elements so as to be able to determine the diffusion rate for said associated individual filtering element;
• b. introducing a gas at a predetermined pressure into said multi-filter housing at the input side of each filtering element;
• c. measuring with each said sensor a pressure at the output side of each filtering element with which each respective sensor is associated while each of said filtering elements is within said multi-filter housing;
• d. determining whether each said measured pressure is within a predetermined range;
• and e. identifying any individual filter elements with measured pressures outside said predetermined range.