Compound Engine

Steam engine with two cylinders. One receives steam from the boiler and exhausts it at a pre ure higher than the atmosphere; this is the high pre ure cylinder. This exhaust from the first cylinder enters the second cylinder, whose area is three to four times that of the first, and after working in it is exhausted into the condenser. This is the low pre ure cylinder. The advantages of this form IMG:content-0947.jpg:[graphic][merged small] of engine over the single cylinder condensing engine are that: first, the steam can be used at high expansions and with high initial boiler pre ure, and yet follow the crank through a large angle from the dead-points; this follows from the greater volume of the second cylinder into which the steam from the first expands. Second, that the range of temperature (from initial boiler to final condenser temperatures) occurs in two IMG:content-0948.png:[blocks in formation] IMG:content-0949.jpg:[graphic] Rocroi 1643, the Bavarians at Freiburg and Nordlingen 1644-5; took Dunkirk 1646; won another victory at Lens 1648; was imprisoned 1650-51; raised the third war of the Fronde; served Conde, Louis I. Spain against France 1653-59; changed sides again, and succeeded Turenne in command 1675.