By the time the pulpy mass arrives to the farthest end of the machine, it has acquired sufficient tenacity to be taken up by a larger cylinder, covered with felt or flannel, and is then passed between a series of similar cylinders, and finally delivered on to a reel; and when this reel has sixteen or eighteen quires wound upon it, it is removed, and another put in its place; the paper is now cut off the reel by a longitudinal incision through the coil, when it undergoes a similar series of operations to that we have described in making paper by hand. A full description of this machine is given in the Repertory of Arts, Vol. XIII. Second Series, to which we must refer our readers, in order that we mav find room for the description of a variety of improvements in paper making, founded upon the admirable mechanism we have briefly noticed, for which the public stand indebted partly to the skill, and wholly to the determined perseverance of the Messrs. Fourdrinier. It is indeed to be lamented that these gentlemen have never received any adequate remuneration for the benefit which they have conferred upon their country.
The first invention which we have to notice possesses a considerable degree of novelty and ingenuity; the authors and patentees of which are Messrs. Dennison and Harris, paper-makers, of Leeds. The paper-mould is, in this case, continuous, but differently arranged, forming simply the exterior or periphery of a large drum, which revolves in the pulp vat. The preceding engraving exhibits an elevation of the apparatus, shown partly in section, a is a vessel containing the pulp, considerably diluted, which is preserved at the desired level by any of the usual means, so that the pulpy liquid, when the machine is at work, shall flow over the curved side of the vessel into a revolving cylindrical mould b. In the vessel a, a vane c is made to revolve, to keep up a powerful agitation, and prevent any of the fibres from subsiding. The rotatory mould b is formed on its periphery like a sieve (which will, hereafter, be particularly described), and, as it turns round in the direction of the arrow, the pulp is received upon it; the chief part of the water instantly drains through the bars of the mould, and the paper, in a loose, spongy, wet state, is formed.
The continued motion of the mould brings this pulpy matter in contact with an endless felt d, which, by a superior attraction of cohesion, attaches to itself the pulpy fabric, and carries it forward between that felt and another felt e, where it receives pressure, first from a pair of wet rollers f f, then a greater pressure from the dry rollers g g; from thence the paper, in a comparatively dry state, is taken up by a rotatory vane h, upon which it is folded; when this vane is fully charged it is removed, and another vane substituted in its place. In this manner a sheet of any required length may be made. The cylindrical mould b revolves in a vessel of water i, which serves to wash off the fibrous matter that may adhere to it, and to receive the water which drains from the diluted pulp as it passes over. The cast-iron frame upon which the mould revolves is jointed, to facilitate that lateral shaking or trembling motion, essential in the making of paper, which is effected by a crank and rod, or by any of the other usual means, motion being communicated from the gearing which drives the rollers, etc. The roller k is called the combing roller, as it takes the paper off the mould. This roller is provided with a regulating screw, to tighten the web, or adjust the pressure against the mould.
The upper wet rollersf and the upper dry rollers g, have also regulating screws, by which they may be elevated or depressed in the long slots wherein their axes revolve, so as to increase or diminish the pressure upon the wet paper. A small roller l is employed for assisting in separating the paper as it passes from the felt on to the vane h. As the lowermost web becomes very wet by receiving the water from the paper, a small cylinder m is employed to press out the water from it as it revolves. For the perfect cleansing of the webs from the fibrous matter, small rotatory brushes are directed to be fixed so as to brush over their surfaces; and the employment of jets of water to wash over the felts is also recommended by the patentees. As the peculiar construction of the rotatory mould forms the principal feature of this invention, and the ground of patent-right, it is proper that we should describe it more particularly. In its outline it presents precisely the figure of a military drum; its periphery is formed by connecting together a series of metallic rings; the cylinder is then covered longitudinally with numerous small thin bars of copper, three-eighths of an inch wide, placed edgeways, so as to form a complete grating over the whole surface.
The copper bars have numerous small lateral projections, to keep them at a regular distance apart; these are directed to be made by passing plain slips of copper between cylindrical steel rollers, with indentations on one of them, adapted for producing an uniform series of little slabs.
Messrs. Dennison and Harris's Patent Paper-making Machine.
It has been usual to distinguish laid paper (or paper made in hand moulds) from machine paper, (or that made on the endless wire web in a machine,) by the peculiar water-mark lines. Hitherto the machine paper has been made on very fine woven wire, which gives it that smooth, woven appearance; while the laid paper is marked by distinct parallel lines, crossed by a few thicker lines about an inch apart. The usual process of working wire, in making the hand moulds that produce the last-mentioned effect, is tedious and expensive; but the paper made from them is generally preferable, and, we believe, is worth more in the market.
The object of the invention we shall next describe, is to make a paper resembling the hand paper by a machine. For this purpose. Mr. Louis Aubrey, of