373 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[Decembeb, 



for loading. Fourthly, a self-acting compressor, preventing the 

 gun fnun recoiling home upon the breecliing, consequently no 

 breeching can be carried away, therefore the dangers attending 

 such a misfortune are obviated. Fiftlily, the gun much better 

 secured uithin-hoard through the nature of the machinery, as 

 when the gun being lashed by the usual tackle, no violent motion 

 of the ship can act upon the guns to disarrange them. Sixthly, 

 the inventinn is well adapted for a bow or stern-gun, being 

 ca])able of transporting from one port to another, possessing the 

 same advantages in firing as the pivot-gun, although less and con- 

 siderably lighter; and. Seventhly, the invention allowing of being 

 fixed on deck as a pivot-gun of any calibre, not covering so large 

 a space on deck as the slide, and weighing less, and will be less 

 expensive. 



VENTILATION OF MINES. 



RoBKBT Gordon, of Heaton Norris, Lancaster, engineer, for 

 improrfyiieiits in the ventilation of mints." — Granted April -t; Enrol- 

 led September 29, 1849. 



{With Enyravings, Plate XXII.) 



The invention relates to improvements in the ventilation of 

 mines, and consists of certain apparatus, as shown in the engrav- 

 ings, by which a larger and more uniform amount of atmospheric 

 air is passed through the workings of a mine than by the arrange- 

 ments at present in practice. 



Fig. 1, is a vertical section of the shafts of a mine, along with 

 the exhausting apparatus ; and fig. 2, is a plan of the same, a, is 

 the down-cast shaft through which the pure air descends; b, is the 

 iip-cast shaft, which is closed at the top with an air-tight door, 

 below which a culvert or air-course c, is carried under-ground, and 

 connected to the air-courses d, which terminates at the ash-pits e, ! 

 to supply the steam-boiler or other furnace fire_/J with air. The 

 ash-pits e, being closed at the front by a door i, so that the whole 1 

 of the air required to support combustion must ascend the up-cast i 

 shaft h. When steam-boiler furnaces are employed, as in figs. 1 

 and 2, from the air-course </, there is a connecting culvert or flueAr, 

 passing into the base of the chimney h, which may be opened when 

 the steam is "up," and the furnaces yj do not require attention. 

 ]{y this arrangement, the power of the chimney A, is not checked 

 liy dampers when the steam gets too high, but it is checked and 

 modified by the admission of air through the culvert /r, all of which 

 is drawn from the up-cast shaft b; and if at any time the air taken 

 from the up-cast shaft in this arrangement should contain "choke- 

 damp" or carbonic acid in such proportion as to endanger the com- 

 bustion in the furnaces_/J the door j, of the ash-pit can be opened . 

 and pure air admitted at pleasure. 



Fig. 3, is a sectional elevation of a shaft divided by a partition 

 or air-tight "bratice" into two compartments, one part being used 

 as the up-cast shaft 6, and the other as the down-cast shaft a. The 

 h compartment is connected with the air-culvert c, which leads to 

 the air-course rf, and the ash-pits e, of the furnaces f, as in the 

 former figs. 1 and 2. 



Figs. 4., and 5, rejjresent a sectional elevation and plan of another 

 arrangement of the improvements, in which the culvert c, leading 

 from the up-cast shaft b, is connected with the chimney A, and at 

 the ash-pits e, by the air-courses d. This powerful cliimney is 

 placed in any convenient position, near the up-cast shaft, and pro- 

 vided with four furnaces y;/,/;/'; the ash-pit e, being closed by 

 doors a, as in the former arrangement, so that the supply of air 

 re(piired to support combustion is taken from the up-cast shaft 6, 

 through the culvert c, and the course or current of the air is indi- 

 cated by the small arrows at fig. 4; the smoke, gases, and heated 

 air from four furnaces returning to the chimney A, by the main 

 flues (/, figs. 4, and 5. By this arrangement not only the air and 

 gases heated by the furnaces ascend the chimney h, but a large 

 quantity of air from the up-cast shaft is drawn up direct without 

 going through the furnaces, by the intensely heated gases passing 

 off from the fires, making the exhaustion of the up-cast shaft more 

 complete and efficacious. The result from measurement of the 

 quantity of air passing through a large coal-mine ventilated by an 

 ordinary under-ground furnace, as compared with one arrangement 

 of the improved system, is as follows: — The sectional area of the 

 up-cast shaft of the coal-mine in question is 55 square feet. The 

 fire being 200 fathoms from the surface, the average amount of air 

 found to pass through the workings was rather less than 18,000 

 cubic feet per minute. In one of the arrangements, a chimney 

 75 yards high, and connected with the furnaces of four steam 

 boilers, gives an exhausting power equivalent to a column of 1 inch 



of H ater, and as a column of water an inch high equals a pressure 

 of •031(i of a pound, or 5-198 pounds on the superficial foot, which 

 pressure will cause the air to pass through the said diinuiey at a 

 velocity of 32ii miles per hour, or 2,H()0 feet per minute; then 

 2,S0O feet multii)lied by 34'33, the sectional area of the cliimney, 

 gives 98,183 cubic feet of air per minute for ventilation in place of 

 18,000, or more than five times the quantity obtained by the ordi- 

 nary system. Not only is the ventilation materially increased by 

 the improved arrangements, but the ease with which they can be 

 carried out render them much more valuable and efficient. The 

 ventilating fires being at the surface and the stoker at all times 

 under the cognisance of the bank-manager, preclude the proba- 

 bility of neglect. Should the mine be ventilated with one or more 

 boiler fires, as shown in the drawing, figs. 1, and 2, a valve is 

 placed in each of the air-courses d, with a spindle attached to 

 regulate it, as shown at /, fig. 1, which may be closed to prevent 

 the atmospheric air from returning should it be desirable to stop 

 one or more fires for repairs. 



It is further proposed to close up the top of the down-cast shaft 

 a, figs. 5, and 6, at any convenient opportunity when the miners 

 are absent from the pit, and at the same time keep up the venti- 

 lating fires until the workings ai'e exhausted, equivalent to a 

 column of 1 inch of water or more. This would extract the light 

 explosive gas from the charged receptacles more effectually than 

 any means at present employed, as the pressure of the atmospheric 

 air being diminished in the mine the highly-charged cavities would 

 discharge part of their contents, and when pure atmospheric air 

 was allowed to rush into the workings, the explosive gas in the 

 recesses would become adulterated and its dangerous power de- 

 stroyed. The position in which the chimney and furnace are 

 placed as regards the up-cast shaft may be varied to suit the 

 locality and character of the mine, and it is obvious that a similar 

 effect may be produced by building the chimney within the up- 

 cast shaft, leaving an opening or annular Rpace between it and the 

 native rock, to allow the water to descend without cooling or im- 

 peding the ascending ventilating current, which is ))roduced by an 

 ordinary furnace at or near the bottom of the up-cast shaft. 



RAILWAY AXLES AND WHEELS. 



William Kilner, of Sheffield, engraver, for '■'•certain improve- 

 nicnt.f in mainifacturing railway and other axles and wheels; and in 

 machinery to be emjilnyed in such mattafacture." — Granted April 24; 

 Enndled October 24, 1849. [Reported in the Mechanics Maga- 

 zine.'] 



1. The inside surface of the tyre, after being bent into a circle, 

 is raised to a welding heat, by placing it into a hollow fire or 

 closed hearth, after which it is laid on a block, and the spokes, 

 previously heated at one end, are successively welded to it. The 

 nave is composed of two half-naves formed of bar-iron coiled into 

 rings, with the internal hollow of less diameter at one end than the 

 other; and the inner ends of the spokes are arranged on the face 

 (with the smallest bore) of one of the half-naves, and the corre- 

 sponding face of the other half-nave laid on them. Care is taken 

 to leave a space between each pair of spokes, and to piinch holes 

 in them, in order that the inside surfaces of the half-naves may be 

 welded together at these points. The nave and spokes are heated 

 to the welding point by being placed above the fuel in a furnace, 

 the top of which is made moveable for tlie purpose of admitting 

 the wheel, after which they are welded together by swages, and 

 the small ends of the half-naves welded over the ends of the 

 spokes. Or, two chains, united by a right and left hand screw- 

 coujiling, and passing through the centre of the wheel, are 

 attached to the opposite sides. The wheel is placed in a project- 

 ing hearth above the fuel, and when heated to the proper degree 

 of temperature, the chain is tightened and the wheel formed. 

 Instead of welding the spokes to the tyre after the latter has 

 been bent into a circle, they may be welded to a straight bar of 

 iron, which is then bent to the required shape around the ends of 

 moveable blocks arranged to form part of a circle, with interven- 

 ing spaces to receive the spokes. 



2. To give the necessary rotundity to the tyre, a bed-plate is 

 employed which has a central vertical shaft, on which the wheel 

 is placed, and is free to revolve thereon. Around the rim are two 

 pairs of equidistant rollers, supported on spindles in the ends of 

 four levers, the other extremities of which encircle two screw-rods, 

 whereby they can be made to approach or recede from the tyre, 

 while above and beneath it are two other rollers, capable of being 

 brought closer together. The rollers are driven by toothed gear- 



