Pulsation suppressing air flow system for an air sampling instrument

A pulsation suppressing air flow system for an air sampling instrument instrument requiring continuous air flow therethrough comprising:

• a housing having a sealed volume with an entrance air inflow port and an exit airflow port;
• an air pump having a non-uniform pumping characteristic occupying a portion of the volume of the housing in a sealed manner, the unoccupied portion of the volume constituting a surge chamber, and having an air inlet spaced from the entrance air inflow port and having an outlet connected to the exit airflow port, the pump having a non-uniform pumping characteristic that reduces pressure to a first pressure in the surge chamber below a second pressure outside of the inlet, with a two sided flow restrictor in the inlet that establishes a vacuum that pulls a continuous airflow into the surge chamber through the air inflow port with the first pressure on one side of the restrictor and the second pressure on the opposite side of the restrictor;
• an air sampling instrument associated with a flowmeter connected to the air inflow port of the sealed housing;
• and
• a particle filter associated with the exit airflow port of the housing trapping particles generated by the pump within the housing;
• whereby the non-uniform pumping characteristic of the pump is throttled by the restrictor acting with the surge chamber to produce uniform, continuous air flow through the air sampling instrument.

A method of generating a continuous air flow from an air pump comprising;

• supporting a continuously operating air pump of the type having repetitive surges in an air stream inside of a sealed housing wherein the pump occupies a portion of the housing in a manner causing a lower pressure inside of the housing than ambient pressure outside of the housing;
• providing an air intake to the housing spaced a distance from the air pump wherein the distance spans a portion of an unoccupied space of the housing forming a surge chamber, wherein the air pump receives air from the air stream in a manner where surges are diluted across the distance to the air intake via the surge chamber;
• and
• providing a filtered air exhaust from the housing in piped airflow communication with the pump;
• wherein surges of the air pump being taken into the housing are suppressed by the surge chamber.