Gas extraction from closed containers

Abstract

Apparatus and an associated method of operation are disclosed for removal of gaseous contaminants, particularly oxygen, from closed containers. The apparatus is economical, simple to install and operate, of convenient size, and highly effective. A gas extractor communicates with a container for a gas-sensitive product. A high gas concentration in the container causes operation of the extractor until the gas concentration is reduced to a desired low level, when the extractor operation stops. Separate sensors and controllers responsive to concentrations can be present, or the extractor can be self-actuated by use as a power source of a battery which operates on gas generated by operation of the extractor. The system preferably is used for oxygen extraction from containers holding oxygen-sensitive contents. The preferred extractor includes an electrochemical cell which has a ion-permeable membrane disposed between two electrodes. Reduction of the oxygen occurs at the cathode of the cell and oxidation of an oxygen-containing species occurs at the anode of the cell, thus having the effect of removing the oxygen from the container. Use of a metal-air battery to power the cell allows the generated oxygen to be used within the system such that the extraction unit can be entirely enclosed and self-contained, as well having its operation self-initiated and self-limiting. Gases other than oxygen, particularly hydrogen and the halogen gases, can also be extracted from containers, and self-limiting systems other than for oxygen are included, using battery types appropriate to the gas being extracted.