The operation is as follows :—The grid is let down, and a quantity of cotton is placed upon it. It is then Mind, and the cotton is thus brought into contact with the spikes of the re volving cylinder, which dash it against the fixed spikes on the internal face of the casing, loosen ing its matted fibres, and freeing it from sand, dust, and other foreign matters, which fall through the grid into the oavity below, or are drawn away by the operation of the exhaust-fan, and dis charged through a tube into the air. After the cotton has been subjected to the action of the machine for a few seconds, the grid is let down, and the cotton is thrown out. The process is then repeated with fresh material. This is the simplest form of the willow as it exists in use.
The willow, however, has lately undergone great improvements. It is sometimes made with an automatic motion, to let down the grid when the cotton has been in the machine for the proper length of time, which can be varied according to requirement. At other times it is made con tinuous, as seen in the figures, by placing a feed cloth a in front, and a lattice creeper e at the back, to carry away the cleansed cotton, which is then ready for delivery to the scutcher.
The second machine mentioned above, the Crighton opener, which is now in extensive use, is a modification of the cone willow. As will be seen from the accompanying illustrations, Figs. 527 and 528, in the interior of the framework, is fitted a conical grid, having its apex downwards, and resting on a cross-rail at a short distance from the bottom. On the top of the frame, stands a tripod, which forms a bearing foi a vertical shaft, carrying driving pulleys, and descending through the centre of the gria to e, foot-step in the cross-rail. Mounted on this shaft, are a number of discs b, smallest at the bottom and increasing in size as they approach the top. Fixed on these, are series of thin steel blades, for beating the cotton. At the top of the grid, is an orifice conducting to the dust cages. The space c, between the casing and the grid, forms a cavity for the reception of any foreign matter contained in the cotton. The machine is fed by means of the tube a, vvhich Ina) s 2 be introduced on any side away from the attachment. The latter includes the dust-cages, fan f, lattice-creeper d, and, below the dust-cages, a pair of small delivery-rollers, and an exhaust-fan.
The cages are hollow cylindrical wire frames, with the wires set sufficiently close to prevent the entrance of the fibres of cotton, but wide enough to permit the dust to be drawn away by the current. Only the portion of the cage opposite the orifice is left open, the remainder being closed by an internal casing, which follows the contour of the cylinder.
The details of the process are :—The cotton is fed into the tube a, emerging into the lower portion of the conical grid, where it comes into con tact with the beaters b, which strike it against the bars of the grid. This action loosens the mass of fibre, and permits any seed that may be in the lint, as well as sand, dust, &c., to fall through the grid into the dust-cavity c, and thence to the bottom 0. The cotton remains subject to the action of the beaters, until it is opened sufficiently to admit of its being drawn up ward, and carried away by the suction of the fan f, through the orifice. Fol lowing the direction of the arrow towards the dust-cage, it is taken on by the rollers, and passed to the lattice creeper d, which discharges it upon the floor, or into a receptacle provided.
This machiue has also been improved by the addition of an automatic feed or lattie,e apron, and a lap machine. By some, its action is regarded as being gentler, and less injurious to the cotton, than that of the willow, through its possessing no stationary teeth to intercept the progress of tlfe fibre ; also by its peculiar structure, which canses it to retain the cotton until thoroughly opened, but not longer, thus avoiding excessive beating.
The " Porcupine " is another opener, whose chief difference from the willow as illustrated above lies in the possession of two cylinders for opening purposes, laid parallel to each other, the first of which has twelve rows of teeth, and the second four. It is fed and discharged by lattice-creepers, and exhausted by the usual appliances.
Lord's combined opener, scutcher, and lap'machine, is a remarkable illustration of the manner in which several processes may be concentrated in what is practically one machine. The inventors largely avail themselves of the pneumatic principle seen in each of the previously described openers, and use a current of air to bring the cotton from any moderate distance.