Emergency emptying for tankers

The lorry (1) has two inner spacers (7a, 7b) extending from an aperture in a tank wall (4) into a tank interior, where the inner spacers are partly extended in the tank interior in different directions. Ends (8a, 8b) of the inner spacers are locked in a tank opening portion in a non-operable state and linked with external conduits for transferring the spacers from the non-operable state to an use state, where the conduits are utilized for emptying tank liquid i.e. petrol (3) and/or for ventilating the tank interior. An independent claim is also included for a method for discharging tanks on a vehicle side tank lorry.