Buss governor

Buss governor fitted with automatic expansion regulator

This governor regulates the speed by cutting off the steam at an earlier point in the stroke when the speed rises above the normal amount, so giving a higher grade of expansion as the power required from the engine diminishes. It is arranged for fitting to a simple engine with the ordinary slide valve, and so converts it into one with an automatic expansion gear. The upper part consists of a Buss governor similar to inv. 1888-186, but below this, instead of a throttle valve, is a cylindrical gridiron valve. Yhis valve is in the main steam pipe, as near the cylinder as possible, and is slightly oscillated by a trip gear rocked by the eccentric rod of the ordinary slide valve. The gear consists of a horizontal rocking shaft carrying two catches, which engage with a stop on the expansion valve spindle, but when free the valve is returned by springs to the closed position. The catches project upward as curved horns, while a nearly horizontal arm from the governor spindle obstructs the swing of these horns, and so releases the catches at a period of their swing dependent upon the position of the governor balls. A dash-pot is provided to steady the tripping arm.