DEVICES TO INDICATE RESIDUAL CONCENTRATIONS OF ETHYLENE OXIDE IN STERILIZED MATERIALS

摘要

DEVICES TO INDICATE RESIDUAL CONCENTRATIONSOF ETHYLENE OXIDE IN STERILIZED MATERIALSABSTRACT OF THE DISCLOSUREA device for providing a visual indication cor-related with the concentration of ethylene oxide remainingin a system, including gaseous residues remaining inarticles which have been treated with ethylene oxide as abiocidal gas. The indicator device itself is in the formof a multi-layered tab in which a film or coating of aliquid crystal composition has been deposited on a dark-colored or opaque supporting carrier substrate, and coveredwith a transparent gas-permeable sheet or film. A changein a visual display (appearance or disappearance of color)is the "variable" observed and the perception which impartsuseful information. The device is duo-functional. A firstcolor change indicates that an article has been treated witha biologically effective quantity of biocidal gas. Then,after the article has been gas-sterilized, a second colorchange occurs, signalling when the residual concentration ofgas in the treated article has dropped to a predeterminedsafe level.