Suction Gas Plants in New Zealand.
At present, when the attention of those who are desirous of effecting economy in the production of power is being turned to suction gas plants, it may be as well to give a few well-authenticated results in the way of fuel consumption by this class of power producer in New Zealand. The conditions existing here are so different to those obtaining in Great Britain that the published results of trials there can have very little more than academic interest for us, seeing that the fuel used in each case is so different. In the Old Country they have an almost ideal fuel, consisting of practically pure carbon, in the shape of anthracite. Here anthracite is still unavailable and the most economical fuel is gasworks' coke, much of which is of a very poor quality. All the same, however, even under the serious handicap imposed by these unfavourable fuel conditions, the gas plant has achieved almost marvellous results in the production of power when compared with the steam engine or gas engines driven by town gas. The first suction gas plant said to have been set up in the colony was a Campbell of 25 b.h.p., which was installed in the works of the Wanganui Enterprise Cordage Co., at Aramoho. The gas plant was imported from Home, but the engine, which was purchased second-hand by the company, was adapted to the gas by being fitted with magneto ignition and larger valves. Nothing was done
to increase the compression. There was no machinery for the engine to drive, but it was run on the brake for long periods, several engineers taking an active interest in the novelty with a view to testing its power and consumption. The plant was found to be quite reliable, and the consumption of coke for getting up the fire in the morning and running throughout the day was ascertained to be slightly less than i|-lbs. per b.h.p. per day. The money cost of such a plant doing a full day's work was estimated at 2/6 per hour. The next Campbell plant to be installed afforded an excellent opportunity to compare the relative
cost of the suction gas system and its rival, the steam engine. A leading firm of flaxmillers Messrs. Lind & O'Connor, of Shannon, had two mills running close together. In one was alO b.h.p. steam engine, and in the other they installed a 40-b.h.p. Campbell gas engine and plant. Both the coal for the steam engine and the coke for the gas plant had to be railed from Wellington, so the contestants started quite fairly. The cost of fuel and attendance for the steam engine amounted to £1 12s. per day. The fuel consumed by the gas plant averaged about 4oolbs. per day, and the cost of attendance was estimated at 2/6. As a ton of coke lasted nearly six days of nine hours at £1 135., the cost of the gas plant was barely 8/6, showing a saving over the steam plant of £1 3s. 6d. per day, it was enough to make the latter blush. 1 -1A valuable comparison of the cost of running a gas engine with town gas and suction gas was made wi^h another installation at the Southern Cross Biscuit Co.'s flour mill, at Wanganui. It will enable millers, at any rate, to accurately comprehend the work done if we give a list of the machinery driven. This consists of — 5 sets of double rolls. 2 rotary scalpers. 1 double-ended centrifugal. 2 purifiers. 2 separating sieves. 6 centrifuga-ls. 2 wheat-cleaning machines. 1 pair of stones. 16 sets of elevators. 1 sack hoist, and- a considerable length of shafting. The output amoiints^o about four sacks per hour without the stone's. The engine and plant are of 35 b.h.p. and they have some reserve of power above what is required for the work. Town gas was also laid oh to the engine shed with a view to being used if there was any necessity to enrich the suction gas to push the engine to higher power, and this fact, it is stated, has been used by unprincipled people as the basis for their statements that the plant had been a failure. Nothing, however, could have given greater satisfaction than this plant. For a day or two, as an experiment, the engine was run entirely on town gas, and at 5/- per 1000 ft., the cost of running amounted to over 3/- per hour ; if working on suction gas the outlay for nine hours is very little more. Taking into account the whole amount of coke required to start the fire in the morning, and to keep the plant at full work during nine hours the consumption averages 4olbs. per hour, or "a total cost of 3/6 per day. This, it should also be noted covers the total consumption. Some reports of trials ignore the amounts of fuel jused to get the generators into condition to give out full power. The fuel consumed is computed only from the starting of the engine. On the same basis it has been ascertained that the 35 h.p. grinding its four sacks per hour, only requires 32lbs. of coke, or a money cost of about id. per sack. These facts require no hammering into sensible heads. Economy in the working of power gas plants is now established and the large Campbell engines are splendid specimens of Pritish engineering work in this respect.
Permanent link to this item
Suction Gas Plants in New Zealand., Progress, Volume I, Issue 9, 2 July 1906
Suction Gas Plants in New Zealand. Progress, Volume I, Issue 9, 2 July 1906
Using This Item
See our copyright guide for information on how you may use this title.