An electrically operated device comprising a waterproof housing enclosing at least one dry galvanic battery cell and including gas discharge means in the housing in communication with the atmosphere exterior to the device for discharging evolved hydrogen gas from the battery cell such that the concentration...http://www.google.es/patents/US4237526?utm_source=gb-gplus-sharePatente US4237526 - Battery operated device having a waterproof housing and gas discharge vent
Battery operated device having a waterproof housing and gas discharge vent
