Patent GB-186636-A (GB)
Title: Improvements in or relating to gas distributing systems
IPC: F15B1/00
Filed: 1921-03-24
Abstract: 186,636. Mitchell, E. A. March 24, 1921. Gas distribution, varying pressure locally in.- Relates to gas-distributing systems wherein combustible gas is supplied under high pressure to a pipe line leading from the generating-station to a distributing-station at a considerable distance therefrom, where it arrives at a reduced pressure. At the distributing-station means are provided whereby part of the gas received at low pressure may be raised in pressure by the remainder of the low pressure gas, or part thereof, and transmitted through a second pipe line to a second distributing-station. The lowpressure gas utilized as motive fluid for compressing the remaining low-pressure gas may, after such use, be distributed, at a further reduced pressure, to gas users in the district supplied from the first distributing-station. The compressing-apparatus at the distributing-station may comprise two cylinders a, b. Figs. 1 and 2, of different sizes, each provided with valvecontrolled inlet and outlet passages g, h and e, f respectively. The piston d of the smaller cylinder a is operated from the piston c of the larger cylinder b. The low-pressure gas inlets g, e of the two cylinders are connected to the pipe line l coming from the generating-station, or to a gas reservoir into which the pipe line delivers. The gas outlet from the smaller cylinder a is connected by a pipe t to a compressed-gas reservoir from which a second pipe line leads to a second distributing-station. The gas outlet from the larger cylinder b is connected by a pipe o to a low-pressure gas distributing reservoir into which the gas from the cylinder passes on the return stroke of its piston, this return stroke being effected when gas from the pipe line leading from the generating-station is admitted to the smaller cylinder a. Gas from the low-pressure reservoir may be distributed, at a lower pressure than that delivered from the pipe line leading from the generating-station, to gas users in the district served by the first distributing-station. In order that the pistons of the two cylinders may work automatically, there may be associated with the piston of the larger cylinder cam, lever, or other means for operating or controlling at the required times the gas inlet valves of the two cylinders and also the gas outlet valve of the larger cylinder; or the inlet and outlet valves of the larger cylinder only may be interconnected and positively operated, the inlet and outlet valves of the smaller cylinder being automatic non-return valves. In a modified form of compressing-apparatus, as shown in Figs. 4 and 5, the piston c of the larger cylinder has a tubular extension working through the bottom of the cylinder, the smaller cylinder being constituted by the annular space between this extension and the wall of the larger cylinder. According to the Provisional Specification, the smaller cylinder is longer than the larger cylinder, and its piston is driven from that of the larger cylinder through means for causing it to travel through a greater distance than the latter.