385. Hall, J. Jan. 7. Moulding concrete pipes.-Relates to the manufacture of concrete pipes, for drainage purposes, or lining wells, with steel wire embedded in the interior. The concrete used is formed of crushed stone, brick, burnt earth, burnt clay, waste pottery, furnace clinker, cinder, or slag, mixed with cement or lime and water. The mould used is mounted on a rotating plate and built in sections, which are forced out against spring pressure by centrifugal force to allow the water in the concrete to run off. When the pipe is nearly finished, the plate is stopped and the concrete is thus further compressed by the springs. The core is moved up gradually into the body of the mould as the tube is built. Fig. 1 shows a sectional view of the core n and the frame carrying the rotating plate a. This frame consists of T-irons c held by rings d and a spiral strip e. At the bottom of these irons is mounted a belt pulley f. The core is raised by means of fluid under pressure flowing into the cylinder p through the tube r, which is attached to the piston q. This tube is made of flattened section, and fits into a similarly-shaped eye p<1> to prevent rotation of the core n. On the plate a, and fastened to it by bolts z', is the structure shown in sectional elevation in Fig. 4 and in plan in Fig. 5. The pieces t are held together by rings 4, which contain springs 5. Between these pieces are placed T-irons w, as shown in Fig. 7, so that the openings between the sections t are covered when these pieces are separated by centrifugal force. Slots in the bottom flanges of the pieces t permit of this radial movement. When the moulding of the concrete is completed, the core is taken out, and the mould and pipe are taken away, a new mould being provided for the next pipe. The sections of the mould may be bolted together, and the core may be raised by a rod connected to a separate hydraulic cylinder.