Gas generator

“ The equipment for this work consists of a single gas generator, rated at 150 h.p., and a three-cylinder, vertical gas engine of the same capacity. The producer is a Loomis-Pettibone, down-draft, made by the Power and Mining Machinery Company, of Cudahy, Wis., and is known as its “Type C” plant. The gas generator consists of a 285 cylindrical shell, 6 ft. in diameter, carefully lined with fire-brick, and having an internal diameter of approximately 4 ft. Near the bottom of the generator there is a fire-brick grate, on which the fuel bed rests. ”

“ Are not the starting up, the operation and the keeping in repair of a gas generator actually more complicated and more delicate than the same elements of a steam engine? Does not the poor gas manufactured in a gas generator present, from a hygienic point of view, danger sufficiently great to proscribe the use of such apparatus in many circumstances? ”

“ Witz, a comparison of the two systems in pressure, steam or gas, let us state in a few words in what the latter consists, the steam engine and the boiler that supplies it being so well known that no description is necessary.
The Dowson gas generator does not differ essentially from the numerous generators devised during recent years for the manufacture of gaseous combustibles, the use of which is so often convenient. The motor that it supplies is the most powerful single cylinder one that has hitherto been constructed. ”

“ Water-gas, very rich in hydrogen, and made by a very similar process, is therefore not suitable for internal combustion engines.
There are many types of producers, but they fall under two main heads, i.e. the pressure and the suction.
The pressure producer contains the following essential parts:—
The generator, a vertical furnace fed from the top through an air-tight trap, and shut off below from the outside atmosphere by having its foot immersed in water. Any fuel or ashes which fall through the bars into the water can be abstracted without spoiling the draught. ”

“ This mixes with the volatile hydrocarbons the coal-gas given off when fresh coal is introduced into the generator and the mixture passes at once to the chamber above the melting tank. The air necessary for the burning of these generator gases is first heated by passing through a number of chambers in the lower part of the furnace. It is mixed with the gases to be burned just before they reach the fire-clay bridge separating the gas generator from the melting tank. ”

“ There are no pressure or water gauges to attend to, because no more gas is ever produced than is absolutely wanted. A steam boiler may require to be stoked once every quarter of an hour, whilst a poor gas generator only requires charging about once every six hours, according to demand for power. The Simplex motor itself requires very little attention, and all bearing surfaces are made as large as possible to avoid the risk of heating. ”

“ In passing into the incandescent fuel that fills the generator, the steam is decomposed, and there forms carbonic oxide, while hydrogen is liberated. The mixture of these two gases with the hydrocarburets furnished by the fuel constitutes water gas. This gas on making its exit from the generator through the pipe, M', passes through the chambers, B, and abandons therein the greater part of its heat, and enters the pipe, R, whence it passes through Q into the purifiers, and then into the gasometer. ”

“ The gas generator requires the use of English anthracite, while a steam boiler is heated with any kind of coal. The prices of unity of weight are therefore very different. Moreover, the gas motor necessitates an immense amount of water for the washing of the gas and the cooling of the cylinder, through circulation in the jacket. It is well to keep this fact in view. On another hand, the lubrification of the cylinders requires a profusion of oil whose flashing point must be at a very high temperature, else it would burn at every explosion and fill the cylinder with coom. ”

“ The super-heater comprises a hollow ring-shaped cast-iron piece arranged in the chamber of the generator, in which the gases are developed, and is thus heated to a high temperature. The mixture of air and steam circulates in this super-heater before traveling to the ash-pit.
The feeder of the Winterthur gas-generator (Fig. 122) is composed of a receptacle having the shape of a tank or basin containing water and located below a closed cylindrical box. In this box a piston moves, which is provided at its lower end with a needle-valve. ”

“ Of course, at times gas is liable to be generated more rapidly than it can be consumed. What happens? The apparatus is not provided with facilities to receive the surplus gas. Being unable to escape upwards through the generator tube, it collects at the bottom, and as the pressure increases it gradually forces the water away from the carbide, so that generation ceases, and is not resumed until the surplus gas has been absorbed, when the water once more is able to come into contact with the carbide. ”

“ The amount thus taken up depends chiefly upon the temperature and the amount of gases coming from the generator, so that the greater the amount drawn into the engine, the more energetic will the vaporization be, and the richer the gas will become. It will be understood that when a generator is working at its maximum production, the interior temperature is highest and most favorable to the decomposition of the largest amount of steam. ”

“ The generator works best while hot. The gas cock on the generator should now be opened and the mixture allowed to flow into the gas chamber until it spurts out of the gas cock, which must then be closed. By this action all the air in the gas chamber is expelled, leaving it free to generate pure gas at once. This is a sure method of exhausting the air in the gas chamber. The acid then attacks the zinc, causing it to decompose the water and free the hydrogen contained in the acid. ”

“ Wilson gas-producer.—The generator is broader than it is high, and it is possible to use in it all sorts of cheap coal and coke. A window is provided, so that the attendant can see if the fuel is sticking and not settling down properly. The air is blown into the centre of the hearth by a steam injector at a low pressure of about two inches of water or less. Stoking is effected by turning spiral grate bars which rid the fire of clinkers and ashes. The air is heated by waste gases from the motor, a process which gives a slight gain in economy. ”

“ The gas generator, A, is of the common Swedish type, as used for charcoal. The tube, k, conducts the gases into the refining pot, a. This pot has a lining of refinery slag, which is melted, as the apparatus revolves, to get it to adhere to the sides. The revolution of the pot, a, on its axis, d, is effected by the action of the beveled wheels, b and b', and the pulley, c, which takes from an iron chain the power given off by a turbine. ”

“ The opening of the test-cock should be so regulated as to reduce the outlet pressure of the gas sufficiently to prevent the flame from going out. During the production of the draft, as well as during the ordinary running of the plant, the filling of the apparatus with fuel should be done with care to prevent explosions of gas due to the entrance of air. Particular care should be taken never to open at the same time the lid of the charging-box and the device, be it a cock, valve, or damper, which controls the connection of the charging-box with the generator. ”

“ In introducing the oil it is not injected, but is simply allowed to flow in by gravity, at a point about half way up the column of fuel, the taps for its admission being placed at intervals around the circumference of the generator, and oil at first begins to flow down the inside wall of the generator, but being vaporized by the heat, the vapor is borne up by the rush of steam and water gas, and is cracked to a permanent gas in the upper layer of fuel. ”

“ It is advisable to continue the operation of the fan until several explosions have taken place in the cylinder and the engine has acquired a certain speed so as to be able to draw in the normal amount of gas.
Naturally the gas-outlet tube near the admission-cock should be closed after starting the engine, as well as the opening in the outlet flue of the generator. When the motor is running properly, the amount of water fed to the vaporizer and overflowing to the ash-pit is properly adjusted. The generator is then filled up to the level indicated by the manufacturer. ”

“ Gasoline gas for house lighting is manufactured in a small generator by evaporating gasoline into gas and mixing it with air, about 5 per cent gas and 95 per cent air. We are all familiar with the little brass gasoline torch heater that tinners and plumbers use to heat their soldering irons. ”

“ If a few holes should happen to find themselves in your material, the consequence would not be very serious, inasmuch as the balloon carries its flame, its hot-air generator, along with it; but when you come to have one charge of gas, the gas not renewable, you are obliged to be particular, not merely as to holes, but even loosely packed fibres. ”

“ Alcohol is used first to heat the generator because it will not smoke the iron. The gasoline, when lighted, should burn with a blue flame.
The tank should be one which has been tested to stand a high gas pressure, as the gasoline in the tank may become heated and vaporize. The gas so formed must not escape into the room, where it might be ignited by a spark. If not allowed to escape, it exerts considerable pressure inside the tank. If the pressure becomes too great, it will break the tank, escape and ignite from the flame in the iron. ”

“ A selection may rather be made on mechanical grounds. The generator must be well able to produce gas as rapidly as it will ever be required during the longest or coldest evening; it must be so large that several more brackets or burners can be added to the service after the installation is complete. It must be so strong that it will bear careless handling and the frequent rough manipulation of its parts. ”

“ It has been mentioned that the gas pressure is released or shut off before it is possible to fill the water compartment, and this same idea is carried further in making the generator inoperative and free from gas pressure before opening the residue drain of the carbide filling opening on top of the hopper. Some machines are made so that they automatically cease to generate should there be a sudden and abnormal withdrawal of gas such as would be caused by a bad leak. ”

“ A final, practical advantage which speaks in favor of a generator and motor plant as compared with a steam-engine, is the small amount of water required. Apart from the water used for cooling the engine, which may be used over and over again if cooled, any water, whether it forms scale or deposits, may be employed for cooling and washing the gas in the scrubber. ”

“ Gas-Bags and Generators.—It has already been remarked that there are two alternative methods of obtaining gas under pressure for limelight purposes, viz. gas-bags and generators (the latter for oxygen alone: there is no good hydrogen generator that I know of) . In both these cases the oxygen is generated by heating a mixture of chlorate of potash and manganese black oxide. In the case of gas-bags the gas is prepared beforehand and passed through suitable purifiers into a rubber gas-bag. With a generator the oxygen is evolved during the exhibition itself ”

“ The manual tending to be done is limited to the regular filling up of the generator with fuel and to the removal of ashes and clinkers. The charging is effected at regular intervals, which, according to the various types of anthracite-generators, vary from one to six hours. Charging the apparatus at short intervals entails unnecessary labor, while charging at too long intervals will often interfere with the uniform production of the gas. ”

“ And lastly, will it pay to use luminous combustion as a first power for generating dynamic caloric for use as a second power, as is now practiced?
At the University of Pennsylvania, in Philadelphia, gas is consumed in an Otto gas engine, which drives a Gramme generator; and the lecture room is lighted with electricity, and I am informed that the light is both better and cheaper than when they used the gas in the ordinary gas burners. Hence we may expect to see gas consumed to advantage for producing electric lights. ”

“ This form of generator will never blow acid like the floating generator.
The requirements of a hydrogen generator for lead burning are that it should be safe, economical 16and automatic in its action. It must be so constructed that it will generate gas enough to keep the supply constant, and deliver it at sufficient pressure to keep the flame steady. It must also be provided with a combination fire trap and scrubbing cup. This will prevent the explosion of the generator by firing the gas in the hose. This trap must be partly filled with a solution of blue vitriol to act as a precipitation cup. ”

“ My invention is designed to obviate all difficulty in this respect, as the burner is set or made to let out at the tip the minimum quantity of gas that will produce a good flame, and, as the gasoline remains longer in the generator and becomes weaker in its illuminating qualities, the outer tube or shell may be turned so as to let out more gas and increase the flame without liability to smoke. ”