| 摘要 |
A float valve is mounted within the ullage of a liquid storage tank and is fitted to a lower end of a vapour vent line. The float valve includes a generally tubular vent body 11 having an opening arrangement 12 which allows vapour to escape from the tank into the vent line, and a float assembly 14 which undergoes damped upward movement in response to the liquid level within the tank exceeding a threshold level. The float assembly comprises a sleeve 15 and a float arrangement 17 separated from each other by an adjustable distance. This permits the volume of liquid required in the tank to make the float assembly move upward to be changed. The float valve may include a relief valve 30 or a plug (41, Fig. 7) with a bleed orifice to permit vapour to flow from the tank to the vent line in the event that the pressure within the tank exceeds a predetermined value. |
