Patent ID: 8069875

Claim:
A ventilation member comprising: a first gas permeable membrane, a second gas permeable membrane, and an absorbing layer allowing a gas passing through an opening of a housing or a tank to permeate therethrough, with the ventilation member being fixed to the opening; a support body, having a first hole and a second hole that are independent from each other and penetrate through the support body, for supporting the first gas permeable membrane, the second gas permeable membrane, and the absorbing layer; and a first one-way valve, wherein: the first gas permeable membrane and the second gas permeable membrane are disposed in such a manner that the gas permeates through the gas permeable membranes independently of each other; the first gas permeable membrane and the first one-way valve are placed in the first hole in such manner that the first one-way valve covers the first gas permeable membrane; the second gas permeable membrane and the absorbing layer are placed in the second hole in such a manner that the gas permeates through the second gas permeable membrane and the absorbing layer successively; the gas flow direction of the first one-way valve is a direction in which the gas passes from the interior to the exterior of the housing or the tank when the ventilation member is fixed to the opening; the gas passes from the exterior to the interior through the second hole when the interior is under a negative pressure condition relative to the exterior; part of the gas passes from the interior to the exterior without permeating the absorbing layer when the interior is under a pressurized condition relative to the exterior; the first and the second gas permeable membranes comprise a porous material of fluororesin; and the absorbing layer contains a water absorbent.