The first means in the earliest times of steam engineering, for opening and shutting the passages in the pipes of steam engines were cocks and these were all worked by hand and required close attention. A boy named Humphry Potter being in charge of one of the cocks of Newcomen’s pumping-engines, and desiring time for play, it is said, managed to fasten the lever-handles of the spigots by means of rods and string to the walking beam of the engine, so that each recurrent motion of the beam effected the change required. This was the first automatic valve-motion.
Fig. 150.
Fig. 151.
Fig. 152.
VALVES.
The valve is any device or appliance used to control the flow of a liquid, vapor or gas, through a pipe, outlet, or inlet in any form of vessel. In this sense the definition includes air, gas, steam, and water cocks of any kind.