Toroidal tank for LPG

The present invention relates to a toroidal tank for LPG (liquefied petroleum gas) of the type used in motor vehicles, provided with a system for isolating the valve unit from the external environment. More particularly, the present invention relates to a tank (1) for LPG, comprising a hollow body (2) and an aperture (3) which puts the inside of the tank in communication with the outside, the said aperture (3) being associated with a collar (4) designed to be engaged with a valve unit (5), characterized in that the said collar (4) is associated with a containing casing (7) of the valve unit (5).