Faignot apparatus.—The air is drawn in by a revolving pump and forced into a vessel, divided into several compartments, one above the other, separated by porous partitions and containing gasoline; several taps or valves cause the compartments to be alternately opened or closed, so that the mixture can always be drawn off rich in hydrocarbon vapour. This apparatus appeared in 1885 at the Antwerp Exhibition, and supplied a Bénier motor with carburetted air. It is suitable for lighting villages, country houses, etc., in fact, any places where coal gas is not laid on. The apparatus has been imitated by Polack of Hamburg and others.
Lenoir carburetted air motor.—Carburators for producing fuel for motive power have been carefully studied during the last ten years by reason of the rapidly extended use of gas motors. One of the most ingenious is due to M. Lenoir, constructed for a special motor designed by himself and constructed by Messrs. Rouart frères. This carburator consists of a horizontal cylinder rotated by a pinion wheel, and performing five or six revolutions a minute. Vertical perforated partitions divide the cylinder internally into several compartments, and the interior wall of the cylinder has attached to it a number of small buckets which draw up the spirit like a water-wheel, and pour it out again when they reach the summit of their path. The air and vapour are thus thoroughly mixed, and pass from thence into the cylinder. Motors supplied by such carburators have been used for agricultural operations, and also for driving small pleasure vessels, the cost of maintenance per horse-power hour being about 2½d.
Schrab carburator.—The idea of this apparatus is quite original. The jacket for cooling the motive cylinder is filled not with water but with the hydrocarbon to be vaporized. From thence it passes at a temperature of about 180° F. into a carburator containing several compartments, and through which pass part of the products of combustion; these gases passing through the already boiling liquid hydrocarbon become saturated with its vapour, but require admixture with air before they are capable of being exploded. The inventor states that the waste gases only take up 1/16th part of that which pure air would in passing through the hot liquid fuel, and thus explains the extraordinary economy of fuel which is obtained by these motors, only 1/16th of a litre of gasoline being necessary to produce one horse-power hour. This is a very remarkable result, and if it is correct places this combined plant in the foremost rank of carburetted air engines.
Meyer carburator.—This apparatus has the advantage of allowing heavier and cheaper oils to be used, at the same time completely volatilizing them. The heavy hydrocarbons are allowed to fall drop by drop into a steel chamber about eight centimetres diameter and four centimetres in height, heated by a flame. The vapour is produced at a high pressure, and escapes through a fine nozzle at high speed drawing the necessary air with it. Entering a reservoir this explosive mixture is prevented from returning by a check-valve. The apparatus is so arranged, that when the pressure in the reservoir has reached a certain point, the flame heating the vaporizer is turned down and prevents further explosive mixture being formed. The apparatus is therefore self-regulating, the supply of carburetted air being always proportional to the demand.
Delamare carburator.—M. Delamare-Deboutteville has devised a very compact carburator for use with his Simplex motor. Gasoline is contained in an upper vessel, from which it flows in a fine stream from a tap on to a horse-hair brush, and is there met by a similar stream of warm water coming from the water jacket of the cylinder. The heat obtained from this source tends to vaporize the hydrocarbon, and the two liquids fall together into a closed vessel. The gasoline rids itself of its impurities and floats on the surface of the water, which is withdrawn from underneath it by a siphon. The hydrocarbon vapour produced during the fall, and afterwards by the heat of the substratum of water, passes by a check-valve to the motor. It is found that the cleansing effect of the water renders the cylinder much less liable to become fouled by tarry products.
Lothhammer carburator.—Experience has shown that vapour of petroleum when mixed with air soon separates out; the vaporizer must therefore be placed as close to the engine as possible. In this motor it has been the aim of the inventor to obtain an exceedingly perfect mixture of the explosive gases. In order to do this the air enters the vaporizer near its base, and passes through it in a number of exceedingly fine streams of bubbles. The petroleum spirit is at the same time heated by a flame, and the result is a very close mixture of the gases. The inventor claims that he thereby obtains much more complete combustion.
Tenting motor.—M. Tenting has arranged his gas engine, which we have already described on page 57, for use also as an oil engine. The carburator is composed of three superposed vessels, through each of which the oil flows in turn. The upper vessel acts as a reservoir and will hold a day’s consumption of oil, and the lower one is traversed by the exhaust pipe, which supplies the heat necessary to obtain the change of state of the oil from liquid to gas. Although this carburator is rather crude it gives a very fair practical result.
Durand carburetted air engine (Fig. 27).—M. Durand has set himself to produce a motor which should work equally well with gas or petroleum, and which should require a minimum of attention at the same time, keeping in view such points as regularity of speed, rigidity, economy of space, and above all low price. This ideal he has, however, failed to reach, although his engine has many good points. He fails chiefly because the mechanism is too complicated. The motor works with an Otto cycle, and the ignition is by an electric spark generated by a small magneto machine. The regulation of the speed is obtained by throttling the admission, and the air is drawn through a tube heated by the waste gases; this arrangement allows a slight economy to be effected. The carburator is automatic, consisting of a closed cylinder placed vertically over the motor cylinder. Within it is placed the oil fuel, and also a spongy mass of cork which soaks up the heavier impurities found in the oil, and thereby allows cheaper oils to be used. Air is drawn through the spongy mass, becoming carburetted in the process; these gases are mixed with a further quantity of pure air in a distributing chamber before entering the cylinder.
Fig. 27.—Durand Carburetted Air Motor.