RUNNING AGRIMOTORS ON PRODUCER-GAS.
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Interesting Details of the Operation of the Parker Appliance and an Analysis of its Running Costs.
trO countries where the use of trac tors with internal-combustion engines is severely handicapped, owing to the difficulty of obtaining supplies of petroleum fuels, the development of the producer-gas apparatus, which burns common wood charcoal, is of great importance. This is particularly the case in arid zones, where large tracts of land which are now mere deserts, owing to this fuel problem, could be converted into fertile areas by the use of modern farming appliances.
Certain engineers during the past few years have been devoting their energies to the production and perfection of these gas plants, but have been handicapped in their attempts to place the appliance on a practical footing chiefly because they have hitherto been unable to reduce the apparatus to suitable dimensions for use with ordinary tractors.
The Parker Producer-Gas Plant Co., 170, Piccadilly, London, W.1, has, however, now succeeded in attaining this object and has manufactured a gasproducer of this type which can be adapted for use with most tractors or lorries now On the market.
We were recently afforded an opportunity of inspecting one of these plants which, in this case, was fitted to a Fordson tractor, at the company's experimental field at Argyle Road, Creenford.
In order to make the description of the apparatus clearer to our readers, it is first necessary to explain the method by which the gas is produced. It is obtained by passing a mixture of atmospheric air and steam through red-hot charcoal, which last, while burning in the air, Produces carbon dioxide. This gas (CO) passes through the lot fuel and, owing to its combining with more carbon, forms carbon monoxide.
The steam is also drawn through the charcoal and is thus reduced to hydrogen and oxygen. The former, in passing through the fuel, mixes with the carbon monoxide, whilst the latter becomes, in the same way as the atmospheric air. carbon dioxide and then carbon monoxide. The last-named and the hydrogen, after being mixed with more air which makes the combination more explosive, ate then ready for detona thin and are drawn through the carburetter and into the combustion chambers of the engine.
The method of operating the plant is very simple. -A few sticks of wood are first lighted inside the generator or furnace. This fire is then drawn up by a hand-operated fan which is provided for the purpose. Small quantities of charcoal are then thrown into the generator, via the hopper, until the fire is well alight. The hopper can then be filled with fuel and its lid shut down and secured.
Then, when the air supply has been adjusted and gas starts to escape from the control valve, the engine may be started. The water feed should then be regulated. These operations take about 15 mins. but time may be saved by starting ;he motor on petrol and switching over to the producer-gas when a sufficient quantity of the latter has been generated.
The complete apparatus is mounted
on a special steel frame which can easily be seen in the accompanying illustra tion. The generator and hopper arc built in one and are fitted a the near side of the tractor. The hopper, a gastight cylinder with a tapered base and on the side of which is fitted the water tank, feeds the charcoal through a wide aperture into the generating furnace, which is located immediately below. The furnace with which the ash box and grate are incorporated has a special heat-resisting lining. A pre-heater, which can also be seen in the photograph, is fitted at the side of the furnace. Thie device is simply arranged so that the hot gas passes through it on, its way from the generator, thus heating the air which is being drawn into the furnace and vaporizing the drops of water corning from the tank.
The water tank is fitted with an easily adjustable visible drip-feed. The fan, which is of a simple standard pattern, is mounted above the pre, heater and is, as we have stated before, intended solely for starting purposes, as the engine suction draws a sufficient current of air through the furnace to keep the fuel ablaze.
From the generator the gas passes to the cleaner through the medium of a large-diameter flexible metal pipe. The cleaner is a welded box containing a specially arranged series of plates or baffles. These prevent the passage of any particles of dust which may be suspended in the gas and at the same time they are so placed that very little resistMice is offered to the mixture as it passes on its way, through another pipe, to the filtering box. The pipes allow plenty of cooling surface and thus considerably reduce the temperature of the gas. The filter is mounted on the off side of the tractor and is situated near
the engine intake. The mixture is first passed through a scrubbing-wad of horsehair and is then bubbled through water before passing through the carburetter and into the combustion chambers. The filter and the cleaner should be emptied at the end of each day's work.
A throttle is provided in the induction pipe between the filter and the carburetter. This can be set by means of a thumb-screw and, once the engine is running satisfactorily, it should be lift fully opened, as the supply of gas can then be controlled by the usual accelerator. The amount of air in the mixture is regulated by a special valve operated by a wire control.
It is stated that he best results may be obtained from this apparatus by running the engine at a uniform speed. Acceleration should be effected gently, so as not to empty the generator of gas while the fire is low from slow running.
The hopper on this particular model of the plant, type J, holds from 70 lb. to 90 lb. of charcoal, according to the
density of the fuel used. This is claimed to be sufficient for from three to four hours' running. 'The consumption of fuel is rated.at 1 lb. per b.h.p.-hour and the running costs of the plant per b.h.m-hour, as given by the Parker Producer-Gas Plant Co.' are .21 of a penny with charcoal at £2 per ton. .32 of a penny with fuel at £3 per ton and .42 of a penny at £4 per ton. This gives 6.30 pence, 9.60 pence end 12.00 pence respectively for 30 b.h.p.-hotirs. It is further stated that 12 hours' running at full load will therefore cost 6s. 3411. on charcoal at 1.2 per ton Os. 6d. at 13 per ton and 12e. 7d. at liper ton. Besides the economy in operation this gas has much to recommend its use in place of paraffin, the nearest rival as a cheap fuel. The latter is inclined to mix with the oil in the engine and thus reduce the viscosity, which, sooner or later, results in worn bearings and injury to other working parts. It is also claimed that a great reduction in carbon deposit is effected by its use.
The price of a completely equipped Fordson tractor, fitted with a special cylinder head to increase compression, this being one of the essential points of the system, is 1275. The apparatus Separately costs 1100.
We had hoped to witness a demon
stration of a Fordsou tractor fitted with this apparatus, but owing to ignition trouble the engine was unable to run at low speeds, so very little ploughing was done, but the few furrows that were made appeared to be quite satisfactory. Recently a Peterboro' tractor, manufactured by Peter Brotherhood, Ltd., of Peterborough, and fitted with this gas plant, gave an excellent demonstration of the capabilities of the apparatus at the company's experimental ground. A large gathering of Government officials from home and abroad and others interested in the development of the agricultural application of the producer was present.