GB660937A - Automatic control apparatus for driers - Google Patents

Abstract

660,937. Drying apparatus. HOWLAND, F. W. June 8, 1949, No. 15234/49. Class 34(ii) The apparatus has a work container 12 provided with cold and hot air supply passages 14, 15 having damper 22, 23 so connected for operation in unison that when one set opens the other closes, a blower 20 to cause the hot or cold air to flow through the container 12, an operating member 25 for the dampers which are biassed by a spring 27 to move toward the hot-air open position, a vertically slidable rack 30 meshing with a pinion 29 on a damper shaft and contacting a roller 33 on a lever 34 biassed by a spring 36 stronger than spring 37 and which may be latched in an inoperative position until released by a time controller, and a thermostat which maintains the temperature at a predetermined maximum prior to the actuation of the time controller. In operation the lever 34, pivoted at 35 is raised and is maintained in position by toggle links 37, 38 pivoted to the lever and casing wall. An arm 39 on a shaft 40 of a clock type timer travels round and breaks the toggles to release the lever 34, causing roller 33 to raise the rack 30 to close the hot air dampers and open the cold air dampers, a signal disc 70 on a lever 71 pivoted at 72 and linked to the lever 34 by a link 74, being raised to notify the operator. The thermostat arrangement comprises a lever 46 pivoted at 47 and having near its end a pad 45. The lever is moved by expansible metal bellows 52 connected to a temperature responsive bulb 55 in the blower outlet and moves the rack 30 to control the dampers.