Sampling means for exhaled air

Claim 1

A sampling means for diverting the end tidal portion of air exhaled by a patient and conveyed through an exhalation air line, and sampling means comprising: a diverter valve having an inlet arranged for connection to such line, an exhaust port, an outlet diverter port and means including a valve member normally in position closing said diverter port and movable to a position opening said diverter port and closing said exhaust port; valve-operating means including an electromagnet means connected to said valve member and effective when energized to move said member to said position opening said diverted port; means including temperature-sensitive electrical resistor means disposed in said inlet and means for electrically heating said resistor means to a temperature above that of such exhaled air and said resistor means disposed to be cooled to a lower temperature by exhaled air incident to passage of exhaled air into said inlet whereby to produce an electric signal incident to being so cooled; and signal translating means connected to said resistor means for reception of signals therefrom and including an adjustable time delay means for adjustably delaying translation of received signals, said signal translating means connected to said electromagnet means for energizing the latter for operating said valve to cause said valve member to open said diverter port and close the exhaust port at a selected time during passage of exhaled air into said inlet, whereby to divert through said diverter port only the end tidal portion of the exhaled air.