| 摘要 |
<p>A valve chamber which communicates through flue openings with bottom flues has therein a pair of dosing frames, each mounted on a pivot and movable thereby between a closed position against the openings and an open position withdrawn from the openings. Each pivot is attached to one end of an elongated eccentric member to the other end of which is attached a spring which urges the respective dosing frame to the closed or open position thereof. One or two pull rods are attached to the eccentrics to sequentially move the closed dosing frame away from the openings to the open position thereof, and to then move the open dosing frame to the openings to the closed position thereof.</p> |
