Patent ID: 8047393

Claim:
Tank filler neck comprises an outer wall ( 1 ) and a concentric and cylindric inner wall ( 2 ) and, in its interior, forms a space ( 19 ) which is closed in relation to the environment during operation and is opened for refueling, wherein a single combined valve which acts as a negative and positive pressure relief valve is provided for equalizing the pressure when the space ( 19 ) is closed, the single combined negative and positive pressure relief valve ( 20 ) is arranged in an annular space ( 18 ) formed between the outer wall ( 1 ) and the inner wall ( 2 ) and the single combined valve surrounds the entire inner wall, which single combined valve ( 20 ) is firstly connected to the space ( 19 ) and secondly to the atmosphere and opens in the one or other direction in order to reduce a pressure differential between the space ( 19 ) and the atmosphere.