The backs of the valve, t, and the piece, q, are provided with grooves, which are designed for giving passage to the steam, the pressure of which on these surfaces partially balances that that it exerts in an opposite direction.
Automatic Regulation (Figs 5 and 6).—The upper part of the rod, e', carries a cam, f, that plays freely between two connecting rods, f¹, and the travel of which is limited by two rollers, f² and f³, situated between the rods, f, which latter are themselves suspended from a rod, F. The latter slides in a support, F², which serves likewise as a guide to the rods, q' and t², of the slide-valves, and which is fixed upon a projection cast in a piece with the frame, B, and is suspended from the short arm of a bent lever, F', whose longer arm carries a roller that runs in a vertical groove, t³, in the back of the expansion slide-valve. The lower extremity of the connecting rods, f', is connected with the sleeve of the regulator, Q, by a lever, f4, and a bent lever, Q'. This latter revolves on an axis passing through its elbow and mounted at the extremity of a projection that is cast in a piece with the support of the regulator. This bent lever is prolonged beyond the sleeve, and carries suspended from its extremity a small piston-rod that plays in a dash pot, Q³, and limits the too abrupt motions of the apparatus. The regulator is driven by a belt and through the intermedium of the bevel pinions, u.
It is easy now to understand the purpose and the modus operandi of the mechanism that permits the regulator to act upon the expansion gear. When running normally the connecting-rods, f', occupy a vertical position, and the rollers, f² and f³, are placed exactly at the two extremities of the travel of the cam, f.
When the velocity exceeds the normal, the sleeve of the regulator rises and the lever, Q', tips to the right and forces the rods, f', to oscillate in the same direction around their upper joint. After that, the lower roller, f², being situated on the line of travel of the convex part of the cam, will be carried along by the latter and cause an oscillation to the right of the bent lever, F. The piece, t', will then be pushed back in such a way as to partially close the inlet orifices of the slide-valve, t, and, as the steam will thereupon enter into less quantity, the engine will quickly resume its normal velocity. If the velocity becomes less that the normal the action will be just the opposite of that just described.
The Large Cylinder (Figs. 1 and 2).—The two eccentrics, E and E', which control the distributing gear of the small cylinder, A, actuate at the same time that of the large one, C, through two rods, e² and e³; such distribution is also effected by means of a sliding-plate valve. The two steam ports are 45 millimeters and the exhaust port 84 millimeters in diameter.
The large cylinder is 650 millimeters in diameter, and 930 in length. The stroke of the piston is 650 millimeters.
The Feed-Water Heater (Figs. 1 and 2).—The exhaust from the small cylinder enters the heater through a pipe, r, 140 millimeters in diameter. This feed-water heater consists of a large cast iron cylinder, 400 millimeters in internal diameter, and 1.15 meters in length, connected with the pipe, r, on the one hand, and with the cylinder, C, on the other, by means of two couplings, R' and R². In its interior are arranged 60 copper tubes, of 29 millimeters internal, and 31½ millimeters external diameter. These tubes are fixed at their extremities into two circular supports that are riveted to the interior of the cylinder. The exhaust from the small cylinder passes into these tubes, around which circulates steam coming directly from the boiler through the tube, r', and escapes toward the bottom, with the condensed water, through the tube, r². The heater is surrounded with a 2 mm. plate iron jacket.
A communication, r³, with a valve-cock, R³, permits of the introduction, into the large cylinder, of the steam from the heater. The exhaust steam from the large cylinder goes directly to the condenser, but there is likewise provided a pipe through which it may make its exit into the open air, in case, for example, the condenser needs repairing or there is a failure of water.
The Condenser (Figs. 1, 2, and 4).—The condenser is represented, half in section and half in external view and in elevation in Fig. 1, and in plan in Fig. 2; Fig. 4 is a transverse view of it. It consists of a large cast iron chest, D, bolted by means of its flanged base to a masonry support. This chest is cast in a piece with a pump chamber, D', in which works a piston mounted on the prolongation, d', of the piston-rod of the cylinder, C. The diameter of this piston is 210 millimeters, and its stroke is 650. The condensing jet, whose flow is regulated by the cock, d², is brought into contact with the steam by a rose, d³, which divides it into small drops.
The pump is a double acting one. Its valves are of rubber, and the passage-way allowed the water is, in each of them, in section, one-half that of the piston. The rod, d', slides in a stuffing-box, with metallic lining, which is shown in Fig. 10.