The Exhalation Valve Tester　EXV-01 is designed to test according to JIS T 8151 the airtightness of exhaust valves used on particulate respirators. First, the tester draws air though an exhalation valve at a flow rate of 1 L/min and checks the degree of depressurization inside the valve caused by the exhaust valve closing airtight. Then,  the tester measures the time required for the internal pressure to reach atmospheric pressure.

The basic configuration consists of a pump to produce a depressurized state, a flowmeter for controlling the suction flow rate, a U-tube manometer for displaying pressure changes, 3 optical fiber sensors to detect the liquid levels in the manometer, and a timer to detect the time required for the liquid level to move between the optical fiber sensors.