Australia Shows the Way with Town Gas Fuel
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How a Successful Compressor Plant was Erected from Information Gleaned from Continental
Literature
AS a result of the restricted supply of petrol, the State Electricity Corn'mission of Victoria, Australia, decided to convert a number of its vehicles to run on compressed town gas. It was, however, a case of starting from gero, because, apart from the gas itself, there were no facilities of aey kind to assist the promoters of the scheme.
For instance, it was quite impossible to obtain storage cylinders capable of withstanding a pressure of 3,000 lb. per • sq. in., and so the working pressure had to be lowered to 1,800 lb. per sq. in. Moreover, they had to be specially manufactured.
An even bigger proposition was, of course, the building and equipping of a compressor station, of which no very precise details were available. However, all difficulties were eventually overcome, with the result that up to
• February of this year 30 vehicles had been successfully converted.
In*connection with the provision of a compressor station, those responsible were guided mainly by descriptive matter dealing with 'Continental star tioris, more particularly that at Lille, in France.
The gas compressor is of the four. stage, single-acting type, operating at a speed of 360 r:p.m. and having a capacity of 100 cubic ft. per minute at 3,000 lb. per sq. in. With a common stroke of 6 ins., the cylinder diameters are :—First stage, 12/ ins.: second stage, 6/ ins.;,third stage, 31 ins.; and fourth stage, 14 ins.; de respective pressures, when in full operation, being: 44, 100, 720, and 3,000 lb. per sq. in.
The 32 cylinders, each of 562 cubic A20
ft. capacity, to which the gas is led after compression, were used by the 13ritish Navy in submarines during the 1914-1918 war. Of course, had it been possible to make, or obtain cylinders designed for the purpose, the number would have been reduced to four, of larger capacity, to the elimination of many connections.
A 100 h.p. three-phase, 400-volt motor is employed to drive the compressor, the motor room being effectively sealed off from the compressor. room, even to the extent of providing a packed gland in the partition wall.
Au interesting feature of the installation lies, in the use of an hydraulic pump, which delivers water to the bottom Of the storage cylinders to restore gas pressure at times when storage pressure falls too low, such as happens When the supply of gas to the main compressor is restricted.
The gas cylinders on the vehicle are replenished through the medium of what is called a serving pillar, connection, between the pillar and the vehicle cylinder being by means of a flexible, high-pressure " grease-gun " hose, which is fitted with a small valve at the vehicle connection end. When the connection is made, this valve opens, as does the non-return valve on the gas cylinder.
In practice, six vehicles have been replenished in 24 minutes, which compares favourably with the time taken to take liquid fuel on board.
Engine-performance curves show that, by comparison with the maximum power .output obtained on commercial petrol, gas fuel gives 97 per cent, power at 20 m.p.h., dropping to 80,2 per cent. at 50 m.p.h.
Since the inception of the plant in April, ,1942, over 2,000,000 cubic ft. of gas have been compressed and delivered. The petrol equivalent of the total gas issued to January, 1943, calculated on the basis that 250 cubic ft. is equal to one gallon, is 8,291 gallons. The bensole extraction, which is at the rate of a quarter gallon per 1,000 cubic ft., has amounted to 518 gallons.
One man controls the whole of the plant, including the servicing of vehicles and the keeping of the records.
We are indebted to the Journal of the Institution of Engineers, Australia, for the foregoing interesting data.