GB190418264A - Improvements in and relating to Steam Engines - Google Patents

Abstract

18,264. McKinney, W. S. Aug. 23. Cylinders; valve chests and casings; valves and valve gear; valves, reversing. - The admission piston valves 6, 7, Fig. 3, are fluid-actuated and control the communication between the ends of the cylinders and the inlet chamber 5, Fig. 1. Each valve stem 14 has a piston 17 which slides in a chamber 15, the inner end of which communicates with the main cylinder through the passage 26. The outer end communicates with the interior of a spirally-perforated tube which registers with holes in the main cylinder. When the piston passes one of the holes in the cylinder, depending upon the position of the tube, steam enters the tube and acts on the valve piston and cuts off steam to the main cylinder. The tubes 21, 22, Fig. 6, one for each inlet valve, may be simultaneously turned by a hand-wheel with a screw gearing with teeth on their surfaces, to vary the expansion. When the piston finishes the stroke; the cushioned steam enters the passage 26 and opens the inlet valve. In automobile engines, the tubes may be rotated by a more rapidly operating mechanism than that shown. The exhaust chamber 27 is situated opposite the steam chamber and communicates with the cylinder through ports 28, 29. The valves 31, 32 have a common stem 33 and pistons 34, 35 fitting chambers 36, 36<1> which communicate with the ends of the cylinder. As the main piston finishes the stroke, the cushioned steam acts on the back of the small piston and places the valve in the position for the return stroke. The tubes 21, 22 need not rotate but may reciprocate, in which case they may be of other than circular section. In Figs. 7 and 8 are shown modifications of the above arrangement. In Fig. 7 is shown a governor which, through a rack and pinion, turns the screw controlling the tubes 21, 22. In Fig. 8, the passages leading from the exhaust small piston chambers are shown communicating first with a reversing-valve 45 provided with crosspassages. The valve is turned to reverse the engine, and, as soon as the engine is reversed, it is returned to its normal position.