and then the safety-valve will shut again, by the predominance of its weight, over the pressure of the interior steam. ... top of the boiler; a perpendicular stem passes through the centre of the valve, and is retained in sockets, which guide the valve into its proper seat, as it rises and falls. ... As the steam in the boiler cools, when the fire is extinguished, the air must be admitted into the boiler, or else a vacuumanbsp;...
|Title||:||A Treatise on the Steam Engine Historical, Practical, and Descriptive. By John Farey ... Illustrated by Numerous Engravings and Diagrams|