GB173930A - Improvements in internal valve gear for steam engines - Google Patents

Abstract

173,930. Marks, E. C. R., (Worthington Pump & Machinery Corporation). Nov. 2, 1920. Fluid-actuated gears.-In a fluid-actuated valve-gear for direct-acting pumps &c., the inner valve 21, Fig. 4, controlling the supply of fluid to the main cylinder 10, is moved by a plunger 22 moving in cylinders 24, 25, supply of fluid to which from the main valve-chest 18 is controlled by auxiliary valves 26, 27. Each of these has differential upper and lower surfaces which are in constant communication with the main supply passage 14 or 15 of the other end of the cylinder through a passage 45 and ports 46, 47. In the position shown, steam is supplied to both the cylinders 24, 25 through passages 31, reduced diameters 30 of the valves 26, 27 and passages 32 from the valve-chest 18. When the piston 11 reaches the left-hand end of its stroke, steam from the right-hand side of the piston passes by a port 41 and passage 40 to one edge of the seating of the main valve 21. A recess 43 in the valve connects the passage 40 with a passage 38 leading to a shoulder beneath the head of the valve 27. The ends of the valve are at the same time open to exhaust through the passages 45, 14, so that the valve rises, closing the passages 31, 32, and opening the cylinder 25 to exhaust through a passage 33 and a passage 34 leading to the main exhaust 13. The main valve 21 is now reversed and, by means of the recess 43, puts the passage 38 in communication with a passage 70 leading to the passage 15, thus opening the shoulder beneath the head 29 to exhaust. At the same time, steam is supplied from the passage 14 through the passage 45 to the ends of the valve 27, so that the valve descends.