Model of Beam Pumping Engine

Model of Beam Pumping Engine, single acting and condensing

This is a working model of an engine resembling the present Cornish pumping engine, and in its arrangement and details is somewhat similar to the ‘Old Bess’ engine (see inv. 1861-45); but it is of later date, as both piston and pump-rod ends are guided by Watt's parallel motion. The condenser, which is very small, is arranged in a tank, and by its side is the air-pump, which is driven by a prolongation of the plug rod. The valve gear is of the latch type driven by tappets from the plug rod. The parallel motion for the plug rod is derived from the parallel point by an additional pantograph. The pump is in a large wooden tank, and has its bucket weighted with lead to represent the heavy spear rods of a mining pump.