Show TRAVELING TRAV ELING BELT SCREEN in previous issues of the minin mining review brief mention has been made of callows traveling belt screen invented ani patented by J al callow of salt lake and manufactured and sold by the utah mining machinery and supply company also of salt lake this machine an illustration of which can be seen in the advertisement of the utah mining machinery and supply company in this number is described in the companas comp anys bulletin no as follows the fundamental principle of this machine is a traveling band or belt of screen cloth over which the ore and its carrying water is spread by means of distributing 1 aprons or feed soles this band or belt of screen cloth passes over head and tall tail rollers and the belt is caused to travel continuously in a horizontal direction at a speed varying from 15 to 30 feet per minute according to the nature and quantity of the material to be screened these feed soles or aprons play a most important part in the operation of the machine and its successful and proper operation depends ina in a great measure upon this feature and its proper construction and adjustment it is with this that a preliminary sorting or sizing is done for as the particles which are of all sorts and sizes fall from the lip the coarsest and largest pieces having the greatest trajectory strike the screen at a point far ahead of the smaller ones and they are there deposited leaving a space behind free and the pores of the cloth in the rear being therefore still uncovered and open permit the free passage of the fines and water simultaneously with this action the cloth is being moved forward and the deposit of oversize is continuously and un intermittently removed from the separating or screening zone and thus the machine continues to perform its function so long as it is kept moving and is supplied with feed after leaving the screening zone the deposit of oversize is carried forward and passes under a shaking spray of clear water where any remaining traces of slime or of fine adhering particles are washed and pass through with the water from the spray into the undersize hopper beneath continuing on the oversize still clinging to the screen cloth passes in front of a small impinging spray which is conveniently situated somewhere about the mid diameter of the front roller and the oversize is there washed off the screen cloth into the oversize hopper below it will be seen from the illustration that the machine is in two parts each half being the duplicate of the other the two belts are independent of one another but operate from a common driving mechanism the speed of the two belts can be varied by means of the cone pulleys and the driving shafts are arranged so that either side can be thrown in or out by suitable friction clutches adjusted to each driving roller this is a very convenient arrangement permitting of one side of the machine being shut down for changing or the repair of screen cloth all the feed being turned on the running side pro tem it only being necessary to speed up the belt sufficiently to carry the increased load the rollers revolve on overhung shafts so that there are no outboard out board bearings to prevent the quick renewal of worn out cloths claths the new ones being clippe on after being made endless over the ends of the rollers these screen belts have rubber edges fastened to the screen cloth and on each side of the belt are sprocket chains to which the edges of the cloth are attached through the medium of the flexible edge piece at frequent intervals in the chain are special attachment links provided with knobs or buttons and on the flexible edges are correspondingly spaced holes by means of which the screen is buttoned on to the chain the holes in the rubber edges are reinforced and strengthened by knob eyelets which prevent the button holes from tearing out if subjected to any undue strains at any time the rollers have sprocket teeth which correspond with and drive the chain these chains are to control any tendency of the cloth to work sideways on the rollers and to keep them running true also to drive the screen belts and to relieve them of any of the work of operating the front roller to remove an old cloth it is only necessary to unbutton it from the knobs on the chain and withdraw it over the ends of the rollers this can be done in a few minutes and the whole operation of the taking off the old and putting on a new belt can be accomplished in twenty minutes the shafts which carry the rollers are carried in long hubs or bosses attached to each side of a central casting or girder to this casting are also attached the undersize hoppers this casting is hollow and forms besides a support for the moving and all other parts of the machine a central gutter or launder into which the combined undersize from each half of the machine discharges |