Safety device for a tank intended to contain a pressurized gas

A safety device for a tank configured to contain a pressurized gas, comprising:

• a ventilation channel configured to establish fluid communication between an internal volume defined by the tank and an outside of the tank;
• a safety piston movable between a closure position in which the safety piston closes the ventilation channel, and a safety position in which the safety piston does not close the ventilation channel;
• a first safety member which is deformable and configured to hold the safety piston in the closure position against an elastic return force returning the safety piston in the safety position;
• deformation means for deforming the first safety member, wherein the deformation means are movable between a resting position and a deformation of the first safety member position, and
• at least a second safety member configured, in a resting position, to hold the deformation means in the resting position against an elastic force returning the deformation means in the deformation of the first safety member position when the second safety member is subjected to a temperature below a predetermined temperature and, in a working position, to release the elastic force returning the deformation means in the deformation of the first safety member position when the second safety member is subjected to an other temperature higher than the predetermined temperature,
• wherein the second safety member is formed by a safety cable made of a material having a mechanical resistance to fire of between 10 seconds and 1 hour,
• wherein the safety piston comprises a housing configured to house at least part of the deformation means when the safety piston is in the safety position and the deformation means are in the deformation of the first safety member position.