Syringe apparatus for calibrating carbon monoxide lung diffusion capacity analyser

摘要

A calibration apparatus (1) for checking the accuracy of DLco testing machines includes a pair of syringes (10, 11) mounted side by side in a frame (12) and joined by a valve controlled gas passageway (13) to a coupling (76) adapted to mate with the testing machine. The first syringe receives gas from the testing machine and the second syringe has a chamber from which gas of a known concentration is returned to the testing machine. The chamber of the second syringe is flow connected by a valve (85) to a source of test gas. The gas passageway is constructed in such a manner to reduce dead air space and to allow purging with test gas to eliminate contamination with ambient air or gas of previous tests. <IMAGE>