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BLOWING MACHINES,

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in the Russian church. The priest who adminis- board preventing its return. The weight on the zers baptism, is enjoined to blow thrice on the upper board now presses the air with a uniform child's face, making the sign of the cross and blast through the pipe. During this time the pronouncing the words, exi ab eo Satan. lower board descends, which fills the lower cavity

BLOWING, in gardening, the action of flowers, with air from the atmosphere. This again rises, whereby they open and display their leaves. and gives its contents to the upper cavity, and The regular blowing season is in the spring; thence through the nose-pipe. Hence we see though some plants have other extraordinary that irregular puffing blast, which belongs to the times and manners of blowing, as the Glaston- single bellows, is here confined to the lower oury thorn. Some flowers also, as the tulip, board only, which supplies air to the upper close every evening, and blow again in the cavity, while the upper board is constantly presmorning. Annual plants blow sooner or later, sing uniformly upon the air in it. But this does as their seeds are put into the ground; whence not completely obviate the irregularity of the the curious in gardening sow some every month blast. So long as the lower board is not in in summer, and have a constant succession of action, the pressure of the upper board being flowers. The blowing of roses may be retarded uniform, the blast is the same. Every time, by shearing of the buds as they expand. however, the bottom board rises to force the air

Blowing of Fire-Arms, is when the vent into the upper cavity, an extra pressure is given or touch-hole is run or gullied, and becomes to the air in the upper cavity, and a temporary wide, so that the powder will fame out. puff is produced. In the application of bellows

BLOWING OF Glass, one of the methods of to the smith's forge, the continued blast was of forming various kinds of works in the glass ma- less importance than in the blast-furnaces applicd nufacture. It is performed by dipping the point to the smelting or refining of ores. The single of an iron blowing-pipe into melted glass, and bellows are at present alinost exclusively emblowing through it with the mouth, according to ployed by anchor-smiths and cutlers, while the the circumstances of the glass to be blown. See blacksmith and most others use double bellows, Glass.

which are doubtless better. BLOWING OF Tin, denotes the melting of its ore, In France and on the Continent, where belfter being first burnt, to destroy its mundic. lows have been wholly formed of wood, instead

BlowinG MACHINES, in the arts and manu- of the flexible sides of leather, they consist of factures, are improved bellows or instruments for two boxes, each open on one side, and the one producing the strongest continued current of air, being just capable of containing the other. The for a given purpose, or for facilitating the com- outer box being placed with the mouth upwards, bustion of fuel, and the production of heat. the other is made to descend into it, with the

For the common bellows which bears the mouth downwards; the latter being capable of greatest resemblance

to lungs, BEL- moving up and down, while the other remained Lows. It was a very early contrivance for fixed. In the bottom of the fixed box is a valve artificial blowing. The blast, however, in this like the common bellows, and a pipe on the machine, is not continuous, but in puffs; or at same level, to let out the blast. The change of intervals of time required for the air to enter capacity, by the motion of this box, causes the through the valve; the blowing interval being blast, and with less waste of power than that ocas the areas of the apertures to the filling in- casioned by the bending of the leather in the terval. This was for some time attempted to be common bellows. remedied by employing two bellows which blew A machine of this kind appears in our plate alternately, the blowing of one taking place BLOWING Machines, figs. 1,2,3. A BCPE F, while the other was filling. To this succeeded fig. 1, is a wooden box, which has its top and the invention of what are called double bellows, two sides fat or straight, and the end, B A E, which was a valuable acquisition in the art of formed into an arched or cylindrical surface, of blowing. We have only to take a third board which the line FP at the other end is the axis. exactly of the shape of the two belonging to the This box is open below, and receives within it single bellows, and connect it with the lower the shallow box K HGM, &c. fig. 2, which exboard by a piece of leather similar to that of actly fills it. The line FP of the one coincides the single bellows, making two cavities exactly with FP of the other, and along these lines is a sirnilar, and separated by the lower board of the set of hinges, on which the upper box turns as single bellows, which now becomes the middle it rises and sinks; the lower box is made fast to board of the double. The third board we shall a frame sunk in the ground. A pipe or tube, now call the lower board. This latter has a QQ, proceeds from the end of it and terminates valve in it exactly similar to the first, which still at the furnace, where it ends in a small pipe retains its place in the new construction. The called a tuyere. This lower box is open above, middle board is now fixed in a horizontal po- and has in its bottom two large valves, VV, sition, the pipe being placed to the fire to be opening inwards. The conducting pipe is also blown. The lower board is held down by a weight, sometimes furnished with a valve opening outwhich keeps the lower cavity constantly full of wards, to prevent burning coals from being air, and the top board has a weight laid upon it sucked into the bellows when the upper box is which presses all the air out of the upper cavity drawn up. The joint along P F is made tight through the pipe. The requisite action by which by thin leather nailed along it. The sides and the blowing is performed, is, first, to lift up the ends of the fixed box are made to fit the sides lower board. This forces the air from the lower and curved end of the upper box, so that this into the upper cavity, the valve in the middle last can be raised and lowered round the joint

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FP without sensible friction; and yet without blast is rendered nearly continuous, but certainly suffering much air to escape ; but as this would not so equable as is desirable in most cases. An not be sufficiently air tight, by reason of the improvement upon this construction has been shrinking and warping of the wood, a farther introduced at the Patent Iron Cable Manufactory contrivance is had recourse to. A slender lath of Messrs. Brunton and Co. Commercial Road; of wood divided into several joints, and covered where, instead of the flexible pipe K H T, a pipe on the outer edge by soft leather, is laid along is standing up a little above the surface of the wathe upper edges of the sides and ends of the ter under each cylinder; through which the air lower box. This lath is so broad that, when its is made to pass by the compression caused by inner edge is even with the inside of the box, the descent of each cylinder; the air also passing its outer edge projects about an inch. It is kept into a general reservoir or wind chest, is kept in this position by a number of steel wires, constantly under a given pressure and led to any which are driven into the bottom of the box and required point. The lever to which the cylinstand up touching the sides. By these means ders are suspended, is attached immediately to the laths are pressed close to the sides, and curved the beam of a small steam engine applied wholly end of the movable box, and the spring wires to this purpose, and thus the utmost uniformity yield to all their inequalities. A bar of wood, of action is secured. Each of these is, in fact, a RS, is fixed to the upper board, by which it is species of hydraulic bellows. The extensive use either raised by machinery, to sink again by its of coal in smelting iron, first rendered it necessary own weight (having an additional load laid on in this country to construct durable machines, it), or it is forced down by a crank or wiper of capable of affording a powerful and constant the machinery, and afterwards raised by the blast. The first cylinders of magnitude used as same. The operation here is precisely the same blowing machines were erected by Mr. John as in the common household bellows. When Smeaton, in 1760, at the Carron Iron Works. the board is lifted up, the air enters by the valves The pumps were wrought alternately by a water V V, fig. 3, and is afterwards expelled at the wheel, having four cranks upon its axis, each of pipe Q Q. These machines, used in the larger which moved the piston of a cylinder, which had metallurgic operations of mining countries, and a stroke of four feet six inches ; the diameter of throughout the continent, are sometimes of very each cylinder being also four feet six inches. great size, and are made capable of expelling Where a fall of water could not be obtained, ninety cubic feet of air at one stroke, repeated steam engines were employed to work the pumps. eight times in a minute.

A water regulator has been introduced of late English blowing machines have been chiefly years, connected with a double acting blowing improved by means of a piston and cylinder, the cylinder, wrought by a steam engine. latter commonly of iron, but sometimes com- A machine of this kind, of large dimensions, is posed of wood on the plan of coopers' work. represented in fig. 5. It is wrought by a steam The piston is surrounded with a broad strap of engine of thirty-five horse power, with a steam thick soft leather, and stuffed similarly to that of cylinder of thirty-three inches diameter, acting the steam engine. The cylinder is furnished with a seven feet stroke. On the opposite end with one or more large valves in the side or of the beam from the steam cylinder is jointed bottom, by which the air enters when the piston the rod D, which is turned exceedingly true, so is drawn upwards, and is expelled of course as to move through the stuffing box without when it goes down: this action driving it along a allowing any air to escape, and without any unlarge pipe which terminates in a small orifice necessary friction. A quantity of hemp is placed connected with the furnace, and sometimes with round the rod in the box a a, which forms part a wind cellar or reservoir of air, which supplies of the lid of the cylinder, and is held tight by the forges, &c. by means of a cock. The pistou in iron nuts b, b. The piston is fitted to the lower these cases is raised by water or other works ; end of the rod D, and is packed with leather so and sometimes two or more are working at a as to fill exactly the internal diameter of the cytime to ensure a uniform blast.

linder A A. To this cylinder are fixed four The blowing machine of Chastillion consists necks, B, F, G, H; two of which, B, F, contain of two cylinders, A, B, fig. 4, loaded with weights, the suction valves, by which the air enters the which are suspended from the two extremities of cylinder, while the other two contain the forcing a lever, or beam, moving about a central fulcrum valves, through which the air is expelled at E. From the top of each there is a large flexible every elevation and depression of the piston into pipe, which are both united in H, whence a pipe the chambers I, K, and through the pipes L, M, HT leads to the tuyere.

There are valves at G into the regulating receiver OP, which is of the and H opening upwards, into the flexible pipes; form of a parallelopipedon, or an inverted box and other valves, L, M, adjoining to them, in the without the lid, and is immersed in a cistern RS, top of each cylinder, opening inwards, but kept filled with water. Let us suppose that the piston shut by a slight spring. Motion is given to the is at the bottom of the cylinder A A, and begins lever by a machine, which may of course have to be raised by the engine. The air above the water, wind, or steam, for its impelling agent. piston will obviously be condensed, and forcing The operation of this engine is evident: when the open the hanging valves in the neck G, will rush cylinder A is descending, the water entering at through them into the pipe L, and thence into its bottom compresses the air, and forces it along the receiver OP. While the piston thus rises the pipe FHKT. In the mean time the cylin- and condenses the air above it, there is a vacuum der B is rising, the air finding an entrance through below the piston, and the external air rushes the vaive M: having reached the top, it begins to through the valves in the neck F, and fills the descend, and the other to ascend, and thus the space below the piston. When the piston descene's

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