The Locomotive Of Today

The Boiler: Regulators. 35 forming a joint with the wrapper plate; whilst the “wagon top” arrangement, common in America, has the last plate of the barrel sloped upwards to meet the wrapper plate to which it is attached, and which carries the dorne. Here, the dorne is usually placed upon the barrel often at the front end when the barrel is made in two lengths, or, at or near the centre of the midclle plate when the barrel is composed of three. The latter practice of having the dorne nearer the centre would appear to have the advantage of being above the water at its most uniform level, as in starting, the water will wash towards the back and necessarily rise higher. Engines with the dorne near the chimney end, especially if tank engines, will be liable to prime-when starting in back gear for this reason. The regulator, by means of which the steam is controllecl and allowed to leave the boiler for the steam chest, is usually placed in the dorne with the inlet at the upper part so that the steam shall be taken as far from the surface of the water from which it is generated, as possible. When no dorne is provided the steam is collected in a pipe some 5-in. or 6-in. in diameter, fixed in a horizontal position along the top of the inside of the barrel, and running its entire length ; this is perforatecl at its upper side to allow the steam to enter there. The design of regulator shown at A, Fig. 7, is called the Ramsbottom, from the name of its originator, it is fixecl in the dorne and is of the double beat type; the valve, which is cast in brass, having two seats, the upper one being slightly larger in diameter than the lower, and made with a boss to which the rod for lifting is connected ; it has four radial wings to allow the steam to pass to the lower seating. To open this regulator the valve is raised, thus opening the upper part, then steam also has access through the inside of the valve to the lower seat, allowing a large opening to steam for a slight lift of valve. The movement of the handle in the cab is trans- mitteel to the valve by means of an eccentric. This is a very ■easy regulator to work, and it is much liked by drivers. The form shown in section and elevation at B, is also fixed vertically in the dorne in a similar manner to the last ’example, but is of the sliding type, the top head of cast iron having two ports which are coverecl by a valve of brass having 'One similar port through it, also a smaller port covered by •another slide of cast iron, these two valves are connected ■through a prolongation at their lower end by means of a pin passing also through the fork end of a connecting rod; in the larger valve the hole is slotted, but in the smaller one it is round. The rod from the foot-plate fits at this end into a ■Socket cast on the pipe, and has a crank to which the other