Tragbares Messgeraet zur Bestimmung des Gehaltes verschiedener Gase im Wetterstrom unter Tage

1,097,641. Determining composition of a gas, electrically. R. HœBNER. Jan. 6, 1965 [Jan. 21, 1964], No. 514/65. Heading G1N. A portable instrument, to determine the amount of a particular gas e.g. methane in underground air current, has a built in electrical battery supply, a moving coil meter to indicate the state of charge of the battery Figs. 2, 3 and 4 (not shown) and a known type voltage stabilizing circuitry Figs. 3 and 4 (not shown), to stabilize the voltage supplied to a bridge circuit in which is connected a detector (not described) sensitive to a particular gas. The state of charge meter scale is calibrated to indicate that a further 50, 100, 200, or 300 readings can be taken. The instrument may include an electric motor driven pump to supply gas to the detector which motor may be controlled by a transistorized timing circuit Fig. 4 (not shown).