Fill-up control valve device

A fill-up control valve device comprising:

• a casing attached to a fuel tank and having a ventilation passage communicating between an inside and an outside of the fuel tank, the casing including an inner wall and an outer wall both extending downward from the casing and a gap arranged between the inner and outer walls;
• a float valve unit movably accommodated in a float guiding portion including the inner wall extending downward from the casing, the float valve unit being movable in a vertical direction in accordance with fuel liquid level in the casing and being brought into contact with an open end of the ventilation passage to operatively open and/or close the ventilation passage;
• wherein, when the fuel liquid level in the fuel tank is raised to reach a first predetermined level, the fuel liquid level in the casing is raised to a second predetermined level which is higher than the first predetermined level, so that the float valve unit is moved up to close the ventilation passage;
• wherein the casing has a ventilating aperture formed at a position higher than the second predetermined level, the ventilating aperture communicating between the inside of the fuel tank and the float guiding portion;
• wherein the casing has a vessel portion with a closed end bottom, in which the float valve unit is arranged;
• wherein the vessel portion further comprises:
• a side wall portion being arranged in the gap between the inner and outer walls extending from the casing, the side wall portion forming a liquid-fuel pooling space being configured to pool the liquid fuel and the float valve unit being arranged in the liquid-fuel pooling space;
• an inlet port formed at a portion higher than the closed end bottom and for introducing a part of the liquid fuel into an inside of the liquid-fuel pooling space of the vessel portion when the fuel liquid level reaches a third predetermined level higher than the second predetermined level;
• and
• a fuel drain through-hole formed at the vessel portion at a portion lower than the inlet port and for discharging the liquid fuel introduced into the inside of the vessel portion from the inlet port, and a cross sectional area of the fuel drain through-hole is smaller than an opening area of the inlet port.