A very ha.ndy form of cylinder pulper is seen in Fig. 502. The pulping parts consist of an iron cylin der a, 24 in. by 15 in., covered with punched copper, and a pair of iron chops set to the breast of the cylinder. Below the cylinder, is a, sieve b, provided with circular motion, for separating the clean pulped beans or parch ment from the pulp and imperfectly pulped cherry. The parchment is carried by a spout to the cistern ; the unpulped cherry is returned to the hopper c, and again passed through. Worked by six coolies, it will pulp 30-40 bush. cherry an hour ; by power, 50-60 bush.
Fig. 503 represents a, " gearless " pulper. It has two pulping cylinders, two pairs of chops, hopper and feed-boxes of galvanized iron, a large sieve with circular motion, and a set of elevator buckets. It easily pulps 100 bush. cherry an hour, and can be made to do 150-160 bush.; for effective speed, it requires a 16 ft. water-wheel, or a 3 h.-p. engine. The cherry is dropped into the central hopper a, whence it passes laterally into the two side hoppers b ; from these, it drops on to the sides of the cylinders, and the pulping is effected at the chops under c. The pulp is floated away. The beans, together with some pulp and unpulped cherry, fall into a sieve d, through which the beans pass nearly clean, and are carried by spouts e to the cisterns. The pulp and unpulped cherry are delivered into a well f, whence they are re turned, by the elevator g, to a, to be 'again passed through with fresh cherry.
The use of chops is now often superseded by a breast,. This arrangement is shown in Fig. 504. The breast a is pushed hy hand against the barrel b, and adjusted by the nut c and the screws d, which bear on the ends e of the breast by means of wooden wedges f ; it is thus kept tightly in its place, as close as possible to the barrel without being in actual con tact. The part g of the hopper h forms a water-box, to prevent stones from en tering the machine. The cherry descends from the loft, through a trap-door, into the perpendicular spout reaching nearly to the bottom of the water-box. A con tinual influx of water carries the cherries gradually over the lip of the box into the hopper ; the supply thus depends upon the rate at which the water is fed. When purchasing pulpers, care should he taken to obtain clear directions for setting them up, such as are issued by the makers, Walker Bros., Lime Street Square ; and J. Gordon and Co., 8, New Broad Street.
There are three points which need attention in all pulpers—(1) regular feeding ; (2) exact adjustment of the pulping parts; (3) suitable sieves. The first condition is best ensured by the arrangement shown iu Fig. 504 ; the second will depend iu a great measure,upon keeping the parts quite clean, and watching their wear ; tlae third consists in providing a circular mesh of such a size as to stop the smallest cherry, while admitting the largest parchment bean. It is common to have kileVUI3 WILLI Mt/ till11/11eL pun. Ming ILL the back, where the coffee comes down with force, the larger at the front, where it merely passes for ward. This latter part should permit the largest beans to pass. In some seasons, there will be but little sacchaaine matter between the pulp and the parchment, so that they will adhere so strongly as to render pulping a difficulty. Instead of reducing the grade of the pulper, it is much better to leave it at the full size for ripe cherry, and to pass the coffee through several times, the pulp gradually becoming separated without damage to the bean.
The pulpers above described comprise those most commonly in use ; a fow others demand pees ing notice. The " bevel-gear " pulper is made with three pulping cylinders, or with two cylinders and a crusher. The office of the latter is to squeeze the cherries with sufficient force to effect the separation of the beans and the pulp of the larger chenies, while rendering the smaller ones more easily acted on hy the pulper ; it consists of o, cylinder covered with overlapping steel plates, and does not get rid of the pulp, but sends every thing forward into a sieve, whence all, except the proportion of pulped beans, is passed to the pulpers. It works well, but is somewhat complicated. The " double pulper and crueller " has two pulping cylinders and a fluted crushing roller, which latter is sometimes replaced by a third pulp ing cylinder. The " spur-gear " cheaper than the gearless, or the bevel-gear, and will pulp 90-120 bush. an hour. " Butler's" consisted of two cylinders covered with grooved metal, revolving inversely ; it worked well with uniform coffee.