The present invention pertains to a gas-tight packaging for a device, especially a respirator containing a chemical which releases oxygen. A safety device is provided for checking the state of packaging. The safety device acts on a flexible partial area of an envelope which surrounds the respirator and is under vacuum, and whose status indication is made visible by a visible mark surrounding the envelope on a housing.
Instruments or devices which must be protected in the state of storage or during readiness from undesired or harmful effects originating from the surrounding atmosphere are preferably placed in a gas-tight packaging. In the field of respirators, such devices are especially devices in which a cartridge containing a chemical releasing oxygen is put into operation when needed. Since the release of oxygen is maintained essentially by the moisture present in the breathing air, these devices must be protected especially from the penetration of water vapor during the readiness period.
A respirator according to West German Patent Specification No. 909,299 is accommodated in a double housing whose inner housing part can be evacuated. A spring-loaded pin, which is led through the solid outer housing as a visible mark, is placed on a movable diaphragm part. In the evacuated state, the force pulling the pin toward the inside is compensated by the spring pressure, so that the pin end is flush with the outer housing. The spring force prevails only when the vacuum in the inner housing subsides, so that said the pin will project above the contour of the outer housing. It can thus be recognized that the packaging of the device is no longer sealed satisfactorily.
A disadvantage of the prior-art packaging is the fact that the visible marking must be positioned precisely at the suitable place on the inner housing, i.e., the diaphragm valve, in order to be recognizable in the intended place even through the outer housing. In addition, the spring force of the pressure spring must be adjusted to the maximum vacuum that can be reached in order to ensure detection of the declining vacuum, because, for example, excessive spring force (or too low a vacuum) may lead to misinterpretation, since the pin will project above the outer shell despite the fact that the vacuum meets the specifications. In addition, the external shape of the device to be packaged determines the design of the safety device. A device of a different shape requires at least adapters if the same safety device is to be retained; in any case, a modified design of the device is required.