Supplementary gas distribution circuit - for use in cold weather with main distribution circuit of vaporised liquefied petroleum gas from open air storage vessels

摘要

Plant for the distribution in the gas phase of liquefied petroleum gas (L.P.G.) e.g. butane comprising in known manner an L.P.G. storage vessel and a main distribution circuit connecting the gas space of this vessel to the point of use, consisting of a feed pipe provided with a main expansion valve calibrated for a pre-determined pressure, together with a sec. distribution circuit designed to supply a feed of L.P.G. in the gas phase to the point of use at a sufficient pressure when the environmental conditions round the storage vessel no longer permit gas phase withdrawal normally ensured by the main distribution circuit, the sec. circuit then comprising (a) a vaporiser connected on one side to the storage vessel via a feed valve and on the other side to the point of use via a sec. expander calibrated for a pre-determined pressure below that of the main expansion valve; (b) a pump group consisting of a hydraulic pump between the storage vessel and the L.P.G. feed valve, driven by a pneumatic motor connected to the terminals of the sec. expander and (c) regulation and safety devices for control of the operation of the pump group and vaporiser as a function of the gas demand and the pressure required at the point of use, irrespective of the temp. of storage. Where outdoor storage is used and temps. may fall to or below 0 degrees C, a constant supply of gas can be ensured.