January 23, 1914. THE COLLIERY GUARDIAN. 189 distribution of the working pressures around the circumference of the crank-shaft boxes. The Correlation of the Gas Lighting and Coke Oven Industries The main frame of the Sullivan angle-compound com- pressor is horizontal, and supports the entire machine. To one end is attached the low pressure cylinder and on the other is bolted an upright pedestal, which carries the vertical or high pressure cylinder. The crank shaft is a heavy, open-hearth steel forging, of the centre crank type. The crank pin is of a proper length to accommodate both connecting rod boxes on it, side by side. A heavy cast-iron counterweight is bolted to each crank cheek, equalling the whole weight of the recipro- cating parts of either the high or low pressure member. This crank shaft extends from one side of the machine to receive the driving pulley or motor, and in all except the smallest sizes is provided with an outboard bearing, consisting of a babbitted box, carried in a heavy pillow block upon a strong sole plate, which is bolted to the foundation. The air inlet valves are of the Corliss type, of cast iron, and are driven by steel valve stems having “ T ” heads on their inner ends. The air discharge valves are of the poppet type, internally guided on cast iron plugs, and held to their seats by light steel springs. As these valves act in a direction radial to the axis of the cylinder, they avoid losses in efficiency due to clearance space to the greatest possible degree. The intercooler, for removing the heat of compression in the air from the low-pressure cylinder, is a substantial, cylindrical cast iron shell containing an amount of cooling surface sufficient to produce thorough cooling of the compressed air. It is located immediately over the low-pressure cylinder and frame, and has flanged inlet and outlet openings, and cast iron flanged con- nections between it and the high- and low-pressure air- cylinders. It is supported on its inner end by a hollow, cast iron, flanged leg, into which any accumulation of water or oil will dram. This water or oil may be blown off through a drain cock, provided at the bottom. A pop safety valve, attached to an opening on top of the intercooler, prevents unsafe pressures in the intercooler or low-pressure cylinder. The intercooling surface consists of a nest of aluminium tubes through which the cooling water circulates, entering at one end, traversing one-half the tubes, and returning through the remainder. The ends of these tubes are expanded into two headers, the outer header being bolted against a packed joint on the outer end of the intercooler body, while the other header, inside the intercooler body, is free to move with the expansion or contraction of the tubes. Suitable baffle plates, in the interior of the body, are so arranged that the air, in flowing through it, will be compelled to pass three times across the tubes, thus insuring a thorough cooling effect. The crank shaft bearings, crank and crosshead pins and crosshead guides, of both high- and low-pressure members, are supplied with steam lubrication, the amount of oil flowing to each point being regulated by adjustable sight feed connections. The air cylinder and rolling inlet valves are oiled from a separate five-feed positive oil pump of special design, driven from the air- valve gear. Each feed may be regulated separately. An unloading valve is provided, when specially ordered, for cutting off the supply of air to the compressor, when the receiver pressure has reached the desired limit. The following shows some dimensions of these angle- compound compressors:— Cylinder Displacement ■±2> diameter. ca capacity. Cubic £ Inches. o feet free air. Ph 43 O ® *2 g £ s i High essure. o 1 Per olution. Pm g .2? > ® ® aa | s £ ft"? a g P 08 p4 & s a Pm o o PP 14 ... 8| ... 10 . .. 1’78 ... 445 ... 250 . .. 80 16 ... 9| ... 12 . .. 279 ... 628 ... 225 . .. 113 18 ... 11 ... 14 . .. 412 ... 886 ... 215 . ... 160 20 ... 12 ... 14 . ... 5'09 ... 1,094 ... 215 . ... 196 At a meeting of the Staffordshire Iron and Steel Institute at Dudley on Saturday, Mr. H. J. Coe, M Sc., read a paper on “ Phosphorus in Iron?’ The author stated that the temperature of the commencement of solidification of iron saturated with carbon was lower by the addition of phosphorus, each 1 per cent, lowering the temperature by about 27 degs. Cent. This effect reached a maximum with 6 7 per cent, phosphorus ; further additions raised the temperature of the commencement of solidification. With the addition of phosphorus a new arrest of 950 degs. Cent, appeared, the position of which was independent of the phosphorus content, although its intensity increased up to 6’7 per cent., and then decreased with further addition. The solubility of iron for carbon was diminished by the addition of phosphorus, By J. E. CHRISTOPHER, The two industries—coke manufacture and gas manufacture—have many points in common. Both show signs of genuine scientific and economic develop- ments, and both, by reason of this development, must further the same laudable object, the conservation of our fuel supplies. The following diagram (fig. 1) shows (A) the increase in the production of sulphate of ammonia from gas- works during the last 10 years. The writer ventures to suggest the dotted curve as the probable increase in output. The lighting industry has a great advantage over the coke industry in that artificial light must be produced either by electricity or gasification, and the market for “ light ” is assured. On the other hand, the 2o 900 t B /OfO (/ /b Fig. 1. A = Sulphate of ammonia (gasworks), thousands of tons ; B = total pig iron, millions of tons ; C = sulphate of ammonia (coke ovens), thousands of tons. Fig. 2. © market for the coke from coke-ovens is by no means stable, and is dependent mainly on the pig-iron industry, the fluctuations in which are shown on the same diagram. At the same time, however, there is a solid foundation for the coke industry; and its advance might reasonably be expected to follow the dotted portion of curve B. The writer has dealt with this point on the assumption that gasworks and coke works will devote their attention solely to their primary objects—i.e., gas and coke manu- facture respectively. Are we correct in this assumption, and to what extent are these systems likely to encroach on each other’s field of operation ? In the first place, the gas retorts of the present day are not suited for the manu- facture of furnace coke, and both the design and method of working them would have to be very materially altered. The present gasworks coke is much too soft to stand the severe crushing effect met with in our modern blastfurnaces. A comparison of the crushing strength of various cokes is shown in Table 1. In the *Frjm a University lecture to the Manchester and District Junior Gas Association, January 10. second place, the supply of gas from coke-ovens is largely a question of geographical position. Table 1.—Crushing Strengths of Coke. Crushing ( Strength. Lb. porsq in. Unstamped charges (coke-ovens) ....... 850") Stamped ,, „ ....... 2100 J Unstamped „ „ ....... 1,360) Stamped „ „ ....... 2,700) Unstamped „ Beehive ovens ........... 1.950 Glover-West ...... 2,060 „ G-asworks (horizontals) 960 At the present time there are 103 by-product coke plants in this country, congregated in a few selected areas, while the gas plants number 1,248, scattered in a fairly uniform manner throughout the whole country. On the accompanying map (fig. 2) the circles represent the blastfurnace districts, the areas of the circles being in proportion to the number of blastfurnaces actually in blast. Some triangular dots represent by-product coke plants in 1913. Each of the plants dealt with approximately 100,000 tons of coal per annum. Allowing 3,000 cubic feet of gas per ton as surplus from each of the cokeworks, we arrive, he said, at a figure of 300 million cubic feet of gas per annum ; and accordingly circular dots were inserted to represent gas plants dealing with this quantity of gas per annum. The map also shows that the cokeworks are situated in the more densely-populated areas, and that there ought to be a reasonable market for coke-oven gas; but in most cases gasworks were in existence long before the by-product ovens. The systems of distribution were already laid, and the natural outlet for coke-oven gas would appear to be in the sale of it in bulk to existing gasworks leaving the details of distribution to the industry most qualified for the work. Gas Industry and the Possibilities of Coke-Oven Gas. Again, we must not forget that certain coke plants are situated near to collieries and works, &c., under the same ownership, and the available gas in many cases is used to good advantage in the development of electrical power to be used for lighting, pumping, haulage, &c. Other coke plants have entered into contracts with electric power supply companies, who take the whole available power from several coke and blastfurnace plants. As yet the coke industry cannot be looked on as a serious competitor to the gas-lighting industry. The Field for Metallurgical Coke. The writer now offers a forecast of the opposition or shall we say competition ?—that the gasworks may expect from coke plants in the future. The iron trade