GB292022A - Improvements in or relating to triple expansion steam engines - Google Patents

Abstract

292,022. Norberg, E. Nov. 25, 1927. Compound &c. engines; engines with reciprocating cylinders; tandem-cylinder engines. - A triple expansion engine is provided with high, intermediate-and-low pressure pistons 30, 33, 27, 35 connected in pairs by rods to reciprocate in opposite directions and drive a three-throw crankshaft 5. The pistons 30, 33 reciprocate in cylinders 31, 40 secured to the opposite sides of a central partition 1. The pistons 27, 35 reciprocate in the cylinder 3 and have cylindrical extensions working over piston heads on the cylinders 31, 40. The piston 30 is connected by rods 29 to the piston 27 which operates the central crank 6. The piston 33 is connected by a rod 34 to the piston 35 which bv a rod 37, crosshead 38, guided, return rods 24, and connecting- rods 21, operate cranks 7 oppositely disposed to crank 6. Main steam is supplied to the inner ends of the cylinders 31, 40 by an eccentric-, operated, spring-pressed oscillating valve 13 arranged in the partition 1, Fig. 6. The pistons 30, 33 have spring-opened, lift valves 53; the pistons 27, 35 have two rings of opposed, circumferentially-arranged, spring-opened lift valves 46, 48. The ends of the cylinders 31, 40, 3 respectively have transfer ports 41, 51, and the pistons 27, 35 have ports 52, Fig. 8, which register with the ports 51, Fig. 3. The lift valves are closed by spring-mounted tappets. In operation, the valves 53 being closed by the tappets 55, steam enters the cylinders 31, 40 and forces the pistons outwards. At the end of the outward stroke, steam passes through slots 41 into the extensions on the pistons 27, 35. The springs open the valves 53. The steam presses the pistons 27, 35 outwards and returns the pistons 30, 33 in their cylinders. When the ports 51, 52 register, steam passes to the ends of the cylinder 3, cushions the pistons 27, 35, the valves 46 open, the return stroke of the pistons 27, 35 begins, and also a new stroke of the pistons 30, 33. As the pistons 27, 35 move inwards after the ports 51 are closed, the valves 48 open and the cylinder ends exhaust through the valves, the body of the cylinders 3, and the main exhaust 5.