Patent GB-190107841-A (GB)
Title: Improvements in and relating to Telescopic Steam Engines.
Inventor: WHITFIELD MARCY LELLAND
Filed: 1901-04-16
Granted: 1901-09-07
Abstract: 7841. Whitfield, M. L., and Schneider, W. April 16. Central-valve engines; cycles or systems of working; valves and valve gear.- Relates to " telescopic " engines in which a high-pressure cylinder, open at its outer end, reciprocates on a fixed piston or abutment, and carries a piston reciprocating in the low-pressure cylinder, which is stationary, the high-pressure cylinder driving the crank shaft by a connecting-rod. The improvements comprise the general arrangement and construction of various modifications, and means for adapting the engines to various grades of economic working. Fig. 2 shows a vertical section of one of the improved forms of engine. The engine framing 3 is mounted on the base 2, forming a crank chamber, and supports the low-pressure cylinder a in which works the high-pressure cylinder b. This cylinder reciprocates on a fixed piston or abutment head 9 supported by a bifurcated abutment c, the legs of which are hollow and communicate at the lower end with the live steam supply pipe. Attached to extensions from the cylinder b and working in guides in the framing 3 is a crosshead 6, by which the crank shaft s is driven through the connecting-rod 7. Disposed axially in the two cylinders and secured to the abutment head is a valve chamber d, in which works a piston slide valve e, f, g, actuated, in the example shown, through a rocking lever 19 from a variable-throw eccentric and shaft governor q. The low-pressure cylinder is furnished with a final exhaust rocking valve in a casing 23 worked by an eccentric k. Several forms of slide valve are described affording different amounts of receiver or clearance space between the valve heads e, g, which valves may be used interchangeably for the purpose of varying the operation of the engine. The valve shown is constructed so that at starting, or when, during running, additional load is suddenly thrown on the engine, the greater travel that the valve has at those times results in live steam being admitted both to the high-pressure and lowpressure cylinders, so that the engine acts temporarily as a high-pressure double-acting engine. The concentric arrangement of the valve-chest and cylinders also results in the heating of the internal parts of the engine. A modification is shown in which the admission of steam is regulated by a governor-controlled throttle valve. ; and another modification,. suited for marine propulsion and furnished with double-eccentric expansion and reversing link-motion, is also shown. Fig. 11 shows another marine engine with the condenser formed in the main frame in which the central slide valve is worked by a variable-expansion and reversing radial gear: In this gear the valve is operated by a floating lever 65 suspended by a pivoted radius bar 72 and linked both to the connecting-rod 7 and to an arm 62 on the shaft of the air-pump lever which is actuated by the engine crosshead. The control of the engine is effected by adjusting the pivot 77 of the radius bar 72 about the centre 70 by hand-wheel and screw mechanism. A two-cylinder horizontal arrangement of the engine, which is furnished with this valve gear and is suitable for motor cars, is also shown.