In the mixing of white lead and other paints, there are many difficulties to encounter, one of the greatest -being In feeding the millstones regularly and constantly,,so that an even and smooth paint may be obtained. The process consists in first mixing the dry white lead with oil and then grinding this mixture into a smooth white mass. The invention we are about to describe relates to the conveying of the white lead from the mixers to the millstones, and so arranging them that there is always a continuous and regular supply given to the stones. It is as ingenious as simple and affords a better lead than has yet been made in America, being almost as stiff as the British and possessing a smoothness of tint that we iliave rarely seen equaled. Our large engraving gives a perspective view of the mixing and grinding room, which we will now describe. A is an iron pan having in it a series of mixers, a', rotating, which are turned by an engine in the story below. B is another mixing pan, having mixers, b'; and C, another with mixers, c'; each of these pans is provided with doors and shutters in their lower part indicated by (i, b, c. D are the millstones and d the shoot from it, by which the ground lead is discharged. E is the the bevelgearing turning the millstones; and F, the shaft that receives the power from the engine. Let us suppose that the mixing tub, A, is full and thoroughly mixed, while the charge in B is being prepared; the- shutter, , is drawn up and a continuous stream of lead falls on the endless belt, G, being by it conveyed over the roller, L, seen in Fig. 3, when the scraper cuts it off, and lets it fall onto the endless band, H, which again conveys it into the mixer, C, from which it is taken by the endless belt, I, to D', seen in Fig. 2, where the scraper, i, takes it off, thus allowing an even and regular stream to fall into the millstones. Theao endless belts are moved independently of the rest of the machinery by the belt, 0, pulley, K, belt, J, which drives the pulley, L, the band, p, driving the pulley, g, and with it the endless belt, H. P is the shoot from the mixer B. The advantages gained 'oy this arrangement are obvious: first by having the two mixers, A and B, in alternate action, the mixer, C, is always kept full of thoroughly mixed material, and supplies the millstones at an even rate ; secondly, conveying the lead on the endless belts will only allow a given and definite quantity to be carried along, which must be regulated by the gates, a, b, or c, in accordance with the capability of the millstones, so that the process can never be hastened and an inferior quality turned out; and thirdly, there is great economy, as with 100 lbs. of lead, three quarters of a gallon of linseed oil are found sufficient to effect a thorough grinding, and no labor is required from the time the materials are put in the tubs to cask-ing it up finished, thus adding to its value as a labor-saving apparatus. This invention was patented the 3rd of November, 1857, and any information may be obtained by applying to the patentee, W. H. Dolson, 188 Avenue C, New York.
This article was originally published with the title "Dolson's Feed for Paint Mills"