| 摘要 |
A valve assembly for a liquid storage tank, the storage tank having a wall, the assembly comprising: a pressure relief conduit; a gas inlet valve device having a gas inlet aperture through which gas may pass into the tank; and a gas outlet valve device having a gas outlet aperture through which gas may pass out from the tank, the inlet valve device and outlet valve device being arranged to control a flow of gas into and out from the storage tank, respectively, whereby a pressure of gas in the tank may be maintained between an upper pressure value being a value in excess of a reference pressure value by a prescribed amount and a lower pressure value being a value below the reference pressure value by a prescribed amount, the gas inlet and outlet apertures being provided in gaseous communication with the pressure relief conduit, the pressure relief of conduit being arranged such that gas flowing into or out from the storage tank by means of an operation of the value assembly is caused to pass through the conduit, the tank further having a liquid inlet, the liquid inlet being switchable between a sealed condition in which liquid may not be fed into the tank through the liquid inlet and an open condition in which liquid may be fed into the tank through the liquid inlet, wherein the inlet valve device comprises a valve member arranged whereby movement of the inlet valve device between closed and open conditions, respectively, the assembly being arranged to be coupled to the tank so as to assume a first orientation in normal use with the tank in the sealed condition, in the first orientation movement of the valve member of the inlet valve device between the open and closed conditions being arranged to involve movement of the valve member in a substantially non-vertical plane.
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