GB856942A - Improvements in apparatus for controlling the operation of mechanical stokers - Google Patents

Abstract

856,942. Controlling mechanical stokers. DANKS & CO. (OLDBURY) Ltd., E. Sept. 30, 1958 [Oct. 1, 1957], No. 30660/57. Addition to 745,661. Class 51 (1). In a furnace having a travelling grate and a firedoor regulating the depth of fuel on the grate, any two of the controls for adjusting the firedoor, the speed of the grate and the air supply are linked by a lever, and adjustment of the third control alters the velocity ratio of the lever so that the speed of the grate or the air supply is adjusted to keep the fuel/air ratio constant. A lever 63 on the firedoor control shaft 57 is connected by the inner wire 61 of a flexible cable to one end of a control rod 87 sliding horizontally in guides mounted on the casing of the grate speed regulator. The control rod 87 is biased by a spring 93 towards its free end, and its middle part 87C. An operating rod 40 for the forced draught damper, sliding vertically in guides on the regulator casing, is downwardly biased by a spring 110, and carries a pin 108 passing through a flat-sided part of rod 40 and engaging slots 133 in the arms of a clevis at the end of a lever 109 pivoted to the mid-part 87C of the control rod. A wear-resistant liner carried by the other arm of the lever 109 engages a cam 35 secured to the shaft of the control hand wheel of the grate speed regulator. Adjustment of the firedoor moves the control rod 87 through cable 61 and the effective velocity ratio of the lever 109 linking the grate speed control to the damper is altered by the movement of the pin 108 relative to the slots 133 in the forked end of the lever. Since the slots 133 are inclined to pass below the pivot of the lever 109, the damper control rod 40 is moved vertically by horizontal movement of the pivot of lever 109, so that the damper is adjusted by movement of the firedoor, independently of the grate speed control, while adjustment of the grate speed control automatically adjusts the damper setting through cam 35 and lever 109. Manually adjustable air supply or firedoor controls may be linked by a lever to the stoker speed control, the velocity ratio of the linkage being varied by a manually operable firedoor or air supply control, or the movement of the firedoor may control the air supply through a lever linkage, manual adjustment of the stoker speed altering the velocity ratio of the linkage.