Respiratory analyzer calibration apparatus with controlled respiratory gas exchange simulation

Claim 1

Apparatus for simulating the respiratory cycle of a biological subject which comprises: a piston chamber; a piston slidably movable within said piston chamber; power means for moving said piston within said piston chamber in a reciprocal forward and backward cycle of movement, each complete cycle of movement of said piston corresponding to an inhalation phase and an exhalation phase of a single respiratory cycle; a first container means adapted to contain calibration gas; a first conduit means; a first valve means for introducing, via said first conduit means, a known volume of said calibration gas to said piston chamber from said first container means during said inhalation phase of each of said cycle of piston movement; a second conduit means; a second valve means for introducing, via said second conduit means, a known volume of air to said piston chamber for admixture with said calibration gas, in said piston chamber during said inhalation phase of each said cycle of piston movement, both said calibration gas and air introduced into said piston chamber during said inhalation phase, simulating inhalation and a given metabolic rate; a third valve means for expelling said admixed air and calibration gases from said piston chamber during said exhalation phase of said cycle of piston movement, said expelling of said gases simulating exhalation and a predetermined metabolic rate; and a third conduit means for communicating said expelled gases, resulting from a series of complete cycles of movement of said piston, into a respiratory analysis system for calibration and adjustment of said respiratory analysis system with reference to the known compositions and volumes of gas expelled from said piston chamber.