GB602058A - Improvements in and relating to valve gears for direct-acting reciprocating steam engines - Google Patents

Abstract

602,058. Steam-engine valves. WERKSPOOR, N. V. Oct. 25, 1945, No. 38139. Convention date, Dec. 31, 1941. [Class 122 (ii)] In a valve gear for a direct-acting reciprocating steam engine comprising a main slide valve 2 actuated by steam and an auxiliary slide valve 3 actuated by the piston, the auxiliary valve being accommodated in an individual valve chest and adapted by its reciprocation to control the admission of steam to the main slide valve, the auxiliary slide valve is reciprocated by the main valve in a direction at right angles to that wherein it is moved by the piston in such a manner as to close the exhaust of the main slide valve prior to the latter reaching the end of its stroke. Reciprocation of the main valve 2 and its associated pin 14 imparts motion to an arm 15 to rotate the valve 3. When the piston has completed its stroke in one direction, the valves are in the position shown. Steam flows from inlet chamber 5 into duct 9, passage 11 and duct 7 to move the piston in the other direction, steam being exhausted through duct 8 and recess 13 into the exhaust chamber 6. The piston moves the valve 3 to the right until passages 17 and 19 are placed in communication by the recess 21 with the exhaust chamber 6, and passages 18 and 20 are connected with the inlet chamber 5, whereby valve 2 is moved. During this movement the pin 14 and arm 15 rotate valve 3 to cut-off recess 21 from passage 17 and thereby close the exhaust at the end of valve 2. The steam not exhausted is then compressed so as to cushion the valve. The movement of the main valve 2 reverses the inlet and exhaust to the piston which then moves back again and the cycle is repeated through the other set of passages.