Air sampling pump

Claim 1

An air-sampling pump system for drawing air through a collection device, comprising: an electric motor driven air pump having an inlet and outlet, an inlet passageway, means for sealably connecting the inlet passageway in series with the collection device, a normally collapsed bellows, an outlet passageway sealably connecting the outlet of said pump with the interior of the bellows, electrical power supply and timing pulse circuit means to start, at pre-set frequency, said electric motor and pump, first switch means operable upon said bellows reaching desired expanded condition to stop said electric motor and said pumping cycle; second switch means operable (1) on collapse of said bellows to close a motor-pump control circuit and allow said electric motor to receive said timing pulse, and (2) on initial movement of said bellows to open said control circuit such that upon failure of said bellows to reach said expanded condition, said timing pulse is directed to activate an alarm circuit; valve means connected to said outlet passageway and operable to an open position to exhaust said outlet passageway and permit said bellows to collapse and to a closed position, at the start of said pump, to permit said bellows to expand; and counter means to indicate the number of times said bellows has reached said expanded condition.