The Locomotive Of Today

~2 The Engine : Metallic Packing. which are increased freedom for the rod, saving in wear of glancis, and reduction of labour in packing, whilst extra first cost is its only drawback. At F, a pattern called the “United Kingdom Metallic Packing ” is shown in section. The stuffing box is bored out, and a ring of brass inserted, having a flat face to bear on the bottom of the hole, and a curved face on which the next por- tion of the packing bears. At the outer end of the stuffing box, a cover, instead of a giand, is required, bored out and having a curved face similar to that on the neck ring. These two curves each form portions ot two concentric spheres, so that the rod with its packing’ on it has free movement in any direction without difficulty. The packing itself consists of two cases of brass bearing at the outer ends of each one, on the curved surfaces before mentioned, and being hollowed out to receive each three or more white metal rings, and a seating for the ends of a flat Steel helical spring-, which, being- com- pressed when the joint is first made, presses the two inner brass seatings outwards, and forces the white metal rings down to the rod by means of angular faces provided. When the joint leaks it can be repacked by taking off the cover, and inserting another ring of white metal. The front joint is made steam-tight against the stuffing box with a ring of sheet asbestos or a piece of round soft copper wire. At G-, the “ United States Metallic Packing” is drawn in section. It consists of a cover fastened to the front of the stuffing box, somewhat similar in shape to the previous example, with a ring of brass inside bearing against a spher- ical surface upon it. This ring has a flat side, on which bears a cast iron ring containing a conical cavity on its inside, into this white metal rings are inserted. These are cut into several pieces or sections, and a, solid bra.ss ring" is forcød a,g"ainst them by a spring, which at its other end rests against the base of the stuffing box to press them into the cone, close them on the rod, and form a steam-tight joint ; the steam also assists the spring in pressing the rings into the cone. By means of the ball joint just mentioned, and the flat surface on the opposite end of the first brass ring, the rod has freedom to move in case it should by any means get out of line. A third form of metallic packing is shown at H, and is known as the “Jerome.” It has a similar stuffing box and cover to the previous examples, with a neck ring to act as a bearing surface for a spring, which, pressing on a collar, forces several white metal rings into a recessed bush, fitting closely to the piston rod at its outer end. The action of the spring here is precisely similar to those already explained.