Device and method for preventing the formation of an unhealthy and/or explosive atmosphere in the vicinity of a liquid tank

The device has a pumping circuit (7) that it is totally sealed except at the level of an external opening of its evacuation pipe (15). The pumping circuit is equipped with an over-pressure valve (25) that is mounted directly downstream of a liquid-ring tank (21), where the gas passing through the valve in discharge mode is re-aspirated by a vacuum pump (16) mounted on the circuit. An independent claim is also included for a process for implementing the use of a tank device.