Plaque for measuring the dose of reactive gases

摘要

Plaques for rapid retrospective recognition of an overdose of noxious gases are of great importance for industrial protection in the chemical industry. These plaques carry an indicator which undergoes a color change on exposure to the gas. Visual assessment of the indicator is considerably facilitated by subdivision of the indicator surface into a plurality of measuring fields with graded sensitivity by means of different covering membranes. Rapid allocation to a given range of dose is possible by separate or combined visual observation of the individual fields of the indicator.