E. C. Creitz of the NBS Gas Chemistry Laboratory installing two of the leak-detecting cells sealed in the channel around the edge of the enclosure. For each enclosure, four cells were involved. Two of these were sealed within the enclosure and two were located in the channel along with the enclosure edge. By plugging the leak detecting meter into the leads of the four cells, a small current energized the cells. The circuit of these cells was so arranged so that the instrument compared the resistance of the four cells, the two measuring cells with the two outside reference cells. The comparison indicated whether any change had occured in the composition of the gas within the enclosure. If a change had occured, the cells were not in balance and the meter indicated a leak.
National Institute of Standards and Technology
National Institute of Standards and Technology