Sand-Screen
The ordinary sand-screen in the foundry is similar to the one used for coal and for the sand used by builders, etc. The regular sizes used for brickwork and plastering is 3- or 4-mesh, for fine sand 5-mesh, for gravel 2-mesh. These frames measure 6 feet high, 26 1/2 inches in width. The sizes most used are 1/4-inch openings for taking out the dust; 3/8-inch for chestnut coal; 1/2 to 5/8-inch for nut; 5/8 to 3/4-inch for stove; 7/8, 1, and 1 1/4-inch for cleaning soft coal. These screens are made with a heavy hard-wood frame, and of extra heavy crimped wire. The frame is securely fastened together with bolts, and the wires are firmly stapled to the frame, and finished at the top and bottom with sheet iron. The revolving screen consists of a grating of wire cloth secured to a framework of iron, forming a cylindrical riddle or sieve, into which the sand is thrown at one end. A slight incline causes what is too large to run through the meshes to pass out at the other end as the cylinder rotates horizontally on its axis.