Combined electrostatic and gas filtration system

摘要

The filter system, for the separation of particles and fire-generated gases from air in road tunnels or spaces, consists of an electrostatic filter, through which the air passes, followed by a gas filter, through which air passes only when a fire occurs. Preferably, the gas filter is pivot-mounted in a holder and held by a connection which can be released to allow the gas filter to pivot into the air stream. The connection preferably comprises a solder, which melts at a predetermined temperature to release the connection, or a retaining magnet, which releases the connection on interruption of the magnetic flux preferably by a fire alarm.