Patent ID: 8122753

Claim:
A portable metered flow apparatus for accurately providing calibration gas from a calibration gas source to a gas monitoring instrument in order to permit calibration/bump testing of the instrument, the apparatus comprising: A. a regulator having two opposing ends, a hollow passageway that extends axially through the regulator between the two opposing ends, the first end of the regulator including a regulator inlet and the opposing end of the regulator including a regulator outlet, and a means for regulating pressure located in the hollow passageway between the regulator inlet and the regulator outlet, the regulator inlet allowing for connection of the regulator to the calibration gas source and passage of the calibration gas into the regulator, B. a gas delivery device comprising a hollow case having a case inlet and a case outlet and having disposed within said case: 1) a solenoid valve having an entrance for calibration gas and an exit for calibration gas, the entrance for calibration gas allowing for connection of the solenoid valve to the regulator outlet and the exit for calibration gas allowing for connection of the solenoid valve to the gas monitoring instrument, the solenoid valve allowing for the passage of calibration gas through the solenoid valve when the valve is opened; 2) an electronic timing circuit connected to the solenoid valve, the electronic timing circuit controlling the time interval during which the solenoid valve is opened and closed, wherein the electronic timing circuit has a timing interval which varies from about one millisecond to about eight minutes, 3) means for providing power to the solenoid valve and the electronic timing circuit, 4) a power switch for activating the electronic timing circuit; 5) means for activating the release of calibration gas; and 6) means for varying the time for gas flow comprising a potentiometer and a means to adjust the potentiometer, the potentiometer being disposed inside of the case and the means to adjust the potentiometer either being disposed inside of the case or an integral part thereof.