670 THE COLLIERY GUARDIAN October 1, 1915. a good gas for steel-smelting purposes. Nevertheless, as much as 11,000 tons of the “ batts ” have been used in one year in the Kerpely producers. Messrs. Lumb and Company's Plant, Castleford.— This plant consists of three producers, each 8| ft. in diameter, the gas from which is applied in heating glass furnaces, good washed nuts being used. Onl$ one pro- ducer when in use when the writer visited the works, the amount of coal gasified being a little over 18 tons a day. The producer is of the water-jacketed -type pre- viously described, with rotary grate and mechanical ash remover, the grate revolving only once in about three hours. As the coal is of good quality, there was not much ash to remove, so that a very slow movement was necesasry. The following is an average analysis of the gas obtained from six tests made during January and February 1915 :— Per cent. Carbon dioxide...................... 3*4 Carbon monoxide ................... 27’5 Hydrogen .......................... 9*4* Methane............................ 3*7* Air-blast pressure below the grate. 3*5 in. Saturation of air-blast with steam. 4 degs. C. Varies a great deal. Wilson Gas Producers. Littleton Colliery Plant.—This plant consists of three gas producers, each of 650-horse power, two being in operation at once, and the third being provided as a reserve. The plant is illustrated in fig. 8. on the lines of a Livesey apparatus, in which tar instead of water is used as the cleansing medium. After this there is the usual sawdust purifier, which acts as a sort of final catch box, from which the gas passes in a perfectly clean and cool state to the gas holder, and thence to the engine. It will be noticed that this plant is operated without any cleaning fan or mechanically-driven apparatus, except the small Roots blower for the air and steam blast. As the washer is worked entirely on tar as a cleansing medium, no added water for cooling or cleaning pur- poses is ever brought into contact with the gas. The result of this is that it is subjected to a condensing operation throughout, no extra water being evaporated which requires to be subsequently condensed by water fans or further cooling surface, and, as a consequence, the tar effluent contains the minimum percentage of water; the separation of tar and water is also naturally effected in the smallest compass. The cost of erecting such a plant may be taken as £2 10s. per brake horse-power, including cooling and cleaning plant, as also the blowers and engines, steam boiler, and gas holder, but not including excavations and builder’s work. The gas is used for driving two large National gas engines which generate electric power for running all the machinery both above and below ground, except the winding engines. This is a very good example of an electrically-driven colliery plant, and the writer has to thank Mr. James (general manager) and Mr. Edge (engineer), as well as the hot gas passes through a vaporiser to cool the gas and raise the steam required for making the gas; it then passes through a water seal and through special scrubbers to remove dust, soot, etc. In this process there is no tar, as it is converted into gas in the pro- ducer, and no mechanical or other tar extractor is required. Good small non-clinkering nuts are used for gasification, the gas being used for obtaining power by a Crossley gas engine, which gives about 200-horse power. Where there are several engines, or an engine and heating w’orks to be served by gas, it is advisable to put in a feeding holder, which also acts as a governor. For 25 to 100 brake horse-power on bituminous fuel, the producer can be worked with suction from the engine only; but when larger power producers are required, a blower becomes necessary. For gasifying a non-clinker- ing coal this is a very simple and economical plant, as the gas engine runs without any unusual trouble. Kynoch “ Cambridge ” Bituminous Suction Gas Producer. One of these plants is installed at the Bolton Pure Ice and Cold Storage premises at Bolton, Lancashire, and, as the design of the producer differs from the other plants described, the writer thinks it desirable to give some particulars. (Fig. 10.) This gas producer is of the down-draught type, and is fitted with an air jacket, from which heated air is drawn into the fire zone through auxiliary air ports. These air ports are adjustable, so that the amount of air required can be regulated to suit the quality of the fuel PRODUCER Fig. 8.—Longitudinal Section taken THROUGH A 650-B.H.P. EXTENSION OF A Wilson Producer-Gas Plant. The producers are of the simplest type, having no fire- bars or grate, and are of the usual circular shape, the steel shell being lined with firebrick, with a water lute extending entirely round the base for withdrawing the ashes. The charging hopper at the top is provided with the usual machined, self-sealed, gas-tight, cover, with four ball poke holes. There is also a chimney for the escape of smoke when the fires are lit, and for the escape of the surplus gas which issues for a short period after stopping the engine, and which burns away as it escapes. A Roots blower with engine combined supplies the air blast, and the exhaust steam from the engine is mixed with the air in a proportion regulated by a tap accord- ing to a thermometer. The air and steam blast are passed into the producer through a specially designed circular central tuyere, as shown in fig. 8. The area of the top of the central tuyere bears a relative propor- tion to the size of the charging bell at the top, which regulates the distribution of the fuel so as to put the small and the larger pieces in a proper admixture for making the best gas with the least labour. When the supply of gas exceeds the requirements of the engines, there is an automatic discharge for the surplus air, thus keeping the pressure constant and ensuring that fuel is not gasified to waste. It is claimed for this design of tuyere that it has the advantage over a grate that the ashes and clinkers in their descent pass down in front of the louvred horizontal parts in a circle, so that none of the scoriae coming down can ever enter them to obstruct the air exits to the fuel. When the air admission is through a grate, even if steeply inclined, much obstruction to the air inlet arises through pieces becoming wedged in the spaces between the bars, and thereby holding up finer ashes behind. And if the grate areas are made large to minimise this trouble, then the first cost and upkeep are increased. On the outlet of each producer is a stop valve of a special water-luted pattern, which is found to be very superior to any form of slide or “ mushroom ” valve. Sticking or burning difficulties are rendered non-existent, and cleaning is reduced to a minimum. Not the least advantage of this luted type is that it is absolutely gas- tight when closed, with an efficient seal of water—a point of vital importance at times in all gas plants. The gas on passing this simple form of stop valve enters vertical tubes, in which most of the mechanically carried dust comes down, and as these chambers are luted in water at the bottom, clearance of mud at any time is facilitated without the plant being stopped. Next comes the main condenser, of annular construc- tion, in which the gas deposits most of its thin tar and is atmospherically cooled to a temperature little above the surrounding air. There are tar outflows at the base of each column, luted with the usual seal pots, and the tar and condensed water pass to a separator which takes the form of a brick tank in the ground fitted with baffles. The gas is then passed through a spray washer Fig. 9.—Dowson-Mason Bituminous Gas Plant. REFERENCES central blast GRATE. FIELD TUBE VAPORIZER. SEAL PLATE. WOOD GRIDS. COKE. WOOD WOOL. BLOWER. BVEPASS VALVE. BLOW-OFF COCK. GOVERNOR. BALANCE WEIGHT ■ the Horsehay Company, who erected the plant, for kindly giving all facilities for obtaining the information. Dowson-Mason Plant. The following is a description of this plant, as erected at Messrs. Smith and Faires’ Works, Leicester, by Messrs. Dowson and Mason, of Alma Works, Levens- hulme, Manchester, and illustrated in fig. 9, which shows the general arrangement of the plant. The special feature of this plant is that it is double-acting, that is, air is drawn in through the top and through the bottom of the fuel column. The producer is open at the top, and coal is put in there, but there is no escape of smoke, as air is drawn inwards by an exhaust fan. The upper part of the fire burns downwards, the hydrocarbons are distilled off, and the coke which remains sinks down- wards into the lower part of the producer, where it meets an upward current of steam and air, and is converted into ordinary producer gas. The mixture of gases leaves the producer through an outlet situated about half-way between the top and the bottom. The producer, which is 4| ft. in diameter, has a water bottom, so that clinker and ash can be drawn out while the plant is working, and almost any kind of coal can be used which does not contain more than 30 to 35 per cent, of volatile matter. After leaving the producer, and load condition The body of the producer is rectangular, being the same width for all sizes, the length only being increased. It consists of a cast iron base and a steel plate riveted shell, lined with firebrick. A special crusher grate is fitted when required, with rotary firebars, which break up any clinker formed. There is a water-luted bottom to the producer, which allows of the plant being seen while the ashes are being removed. The operation of the producer is as follows : The fuel in the upper part of the fuel bed is partly burned, giving off its volatile constituents; the extra air drawn in through the ports creates an intensely hot zone in the fire, and as the gas containing the volatile matter from the partly burnt fuel is drawn through this hot zone by the suction of the engine, the tar is split up and converted into a useful fixed gas. There is no tar in the gas at the outlet from the generator, and no compli- cated rotary tar extractors or other mechanical devices are necessary. The fuel is fed from the top. No hopper valve is necessary. The condition of the fire can be kept under constant observation. These producers have been in use for some years in Australia and New Zealand, upwards of 50,000-horse power having been installed in plants varying from 50 to 500-horse power. They burn bituminous coal, lignite,