Patent ID: 7976700

Claim:
A water separation unit for separating water from liquid fuel, which includes the water as impurities, the unit comprising: a water separation portion, wherein: the water separation portion includes a component separation wall, a liquid chamber, and a gas chamber; the component separation wall divides the water separation portion between the liquid chamber and the gas chamber; the liquid fuel is led to the liquid chamber; the component separation wall includes a separation membrane, which the water selectively permeates to be separated from the liquid fuel in the liquid chamber; the water, which passes through the component separation wall, is temporarily stored in the gas chamber; and the liquid chamber is located above the gas chamber in a vertical direction of the water separation portion; a negative pressure inlet that opens on a sidewall of the gas chamber; a negative pressure generator connected to the negative pressure inlet for generating negative pressure in the gas chamber; and a water draining means for selectively draining the water temporarily stored in the gas chamber, at a bottom portion of the gas chamber.