GB452792A - Improvements in or relating to valve gear for fluid-pressure engines - Google Patents

Abstract

452,792. Engine valve-gear. WORTHINGTON-SIMPSON, Ltd., Lowfield Works, Newark-on-Trent. - (Worthington Pump & Machinery Corporation; Harrison, New Jersey, U.S.A.) Feb. 28, 1935, No. 6407. [Class 122 (ii)] A fluid-actuated valve 7 comprises a central portion with enlarged differential heads 8, 9, and has negative exhaust laps and positive pressure laps so that the valve in passing its central position exhausts from one cylinder port before opening another to fluid-pressure to prevent stalling. Starting-ports are provided to start the valve reversal. Fluid is passed from one end of the cylinder to the other through the valve to bring the piston to rest. Larger ports permit fluid to pass to the cylinder after the piston has started its reverse movement. The valve is provided with cushioning means, and auxiliary distributing-sliding rings may be carried thereby. Steam is supplied from inlet 15 to branches 16, 16<1>. In the position shown in Fig. 12, steam passes from branch 16<1>, through sleeve ports 18<1>, valve ports 231, sleeve ports 191 to the cylinder 1 and moves the piston to the left. Steam also passes through port 251 to the cylinder end. Steam exhausts from the left-hand side of the piston through port 21, valve recess 26 to the outlet 13, Fig. 7. As the valve is moved to the left, trapped steam in space B<1> cushions the valve. The valve is held to the left by the differential steam and exhaust pressures in the inner diameter of the valve. When the piston covers port 21 cushioning-steam is trapped in the cylinder end. An auxiliary exhaust takes place through passages 31, 32. When the piston passes port 28, steam passes to space A, and from there to the left of the piston to effect cushioning. The steam valve starts its movement to the right under differential pressure, and steam is also supplied to space B<1> from space A<1> through the holes 381 and the clearance between the ring 12 and the valve, Fig. 4. The cut-out portion 26 provides negative exhaust lap, so that steam will be exhausted from one cylinder port before the other is open to steam. When the valve in its motion passes port 8, main steam enters the chamber A and completes the valve movement, first opening ports 18, 431 and next closing ports 18<1>, 43. The main piston in its motion to the right, receives increasing quantities of steam through ports 35, 31, 40, and finally through port 21.