The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 04, 1987
Filed:
Dec. 13, 1985
Kurt Leichnitz, Gross Gronau, DE;
Dragerwerk AG, , DE;
Abstract
Gas filters protect the user of respirator equipment against the inspiration of harmful gases. The protection decreases with the use of the filter. To alert the user in time to the imminent exhaustion of the filter material, the respirator is equipped with an indicator that makes the remaining time of use visible through optical characteristics such as color change. The indicator provides for the inclusion of an indicator granulate loosely filled between two discs and permeable to the respiration gas, which changes its color as it detects a gas to be filtered out. The indicator is located in a container open to the gas flow which is covered by an inlet screen and it extends to a given immersion depth into the filter material. The immersion depth guarantees that the respiration gas flows uniformly through the indicator with each inspiration.