The Mechanical Handling and Storing of Material

240 THE MECHANICAL HANDLING OF MATERIAL as to offer surfaces of different areas to the water pressure at both sides. The smaller area of the ram is exposed to the sea water pressure (due to the immersion of the ship), and the larger area to the secondary cone flow between G and H. As soon as the flow of the ejector water from the jets f, g, and h is sufficiently Fig. 340. Stone’s Hydraulic Ash Expeller Shut Oft. powerful to create suction, and thereby reduce the pressure at the secondary cone opening, which is in communication with the larger area of the ram, the sea water pressure on' the smaller area of the ram becomes sufficiently powerful to move the ram and open the way for the ashes; these remain, however, stationary in the hopper until the small auxiliary jets of swilling water are started, which happens as soon as the ram has completed its full stroke and has reached the extreme backward position. In this position the large end of the ram exposes a port to the water on the small area, whic i opens a valve by a piston to which the large ram acts as a valve, and then passes on and flushes the hopper, releasing the ashes. Fig. 341. Stone’s Hydraulic Ash Expeller when Working. Should the quantity of ashes with the incoming flush from the hopper be too gieat, and therefore reduce the speed of the ejector flow and simultaneously allow pressure to form on the larger area of the ram, and so overcome again the sea pressure at the smaller area, the ram moves forward again sufficiently to cut off the flushing water, and reopens immediately the correct speed is re-established.