GB191229199A - Improvements in Steam Valves for Steam-driven Direct-acting Pumps. - Google Patents

Abstract

29,199. Weir, G. & J., and Peterm÷ller, J. Dec. 19. Combined fluid - actuated and mechanical valve-gears; beat or lift valves; expansion valves. - Double-beat admission and exhaust valves a, b, which are nearly balanced, are arranged on a common spindle e and control the top of the cylinder through a port w. Similar valves c, d are arranged on a second spindle f, and control the bottom of the cylinder through port x. The seats g are slightly larger than the seats h. The spindles e, f are provided with extensions k, n, p, q which work in cylinders m, o, r, s. The cylinder m is in constant communication with the inlet passage u, the cylinder s is in constant communication with the outlet passage v, and the cylinders r, o communicate through pipes y, z with a chamber 5 which is alternately put into communication with the steam and exhaust by means of a pilot valve 4. When one valve on one of the spindles e, f is opened the other is closed, and vice versa. The differential pressure on each steam valve tends to open it and close the exhaust. When the pressures in the opposite cylinders are equal, the steam-valves are opened, and when the greater pressure exists in the top cylinders, the steam-valves are closed. The valve 4 is provided with a single-beat valve 6 controlling the admission of steam to the chamber 5, and a double-beat valve 7 with unequal seats controlling the exhaust connexion. Piston extensions 11, 13, 14 are provided in the valves 6, 7 to necessitate a small movement before the valves are fully opened or closed. The valve 4 is moved during the first part of its stroke mechanically and during the second part by fluid pressure, and is held in either of its two end positions by fluid pressure. The chambers r, o, upon the reciprocation of the valve 4, are alternately put into communication with the steam and exhaust, and cause the spindles e, f to reciprocate simultaneously in opposite directions. In a modification, an expansion valve which controls the supply of steam to the passage u is secured to the pilot valve spindle, upon which are collars which actuate the pilot valve with lost motion. The valves a, b, c, d are reversed in position and also the steam and exhaust chambers and ports.