GB1020931A - Automatic electric control system for a combined printing and ammonia gas developing machine for sensitive papers - Google Patents

Abstract

1,020,931. Automatic temperature control. S. MITA. Feb. 5,1963 [Feb. 5, 1962], No. 4753/63. Heading G3R. A combined printing and ammonia gas developing machine for sensitive papers, which is of conventional construction and operation, Fig. 2 (not shown), is provided with the automatic control system of Fig. 1 which includes two thermostats 11, 16 to ensure that the ammonia liquid supply pump is not started until the ammonia gas chamber has reached a desired temperature, that the energization of a pilot lamp 28 indicates the attainment of a further higher desired temperature at which developing may be commenced, and that after the developing operation has been terminated the motors 9,10 driving the machine conveyer belts and cooling and exhaust fans continue to run for a predetermined period. Operation of the machine is commenced by actuation of the "ON" button 4 which closes the contacts A1, A2, A3 of a relay 2 to energize the motors 9, 10. Simultaneous energization occurs of a light 30 inside the glass printing cylinder and of a space heater 22 and an ammonia liquid evaporating heater 29 inside the ammonia gas chamber, the heater 22 being controlled by the contacts C1 of a relay 17. When the temperature in the gas chamber is high enough to evaporate liquid ammonia the thermostat 11 closes to energize a relay 6 and so start a motor 8 driving the ammonia liquid supply pump. When the temperature in the chamber has risen to a further desired value, the thermostat 16 opens to de-energize the relay 17 and thus the heater 22, closure of contacts C2 of relay 17 energizing a relay 23 to light the pilot lamp 28 indicating that the temperature suitable for developing has been reached. Thereafter this temperature is maintained by operation of the thermostat 16 to switch the heater 22 on and off, the relay 23 being self-holding to keep the lamp 28 continuously alight. When the developing operation is finished the "OFF" button 5 of relay 2 is actuated to de-energize members 8, 17, 22, 23, 28, 39, 30, the motors 9, 10 continuing to run until thermostat 11 opens to de-energize the relay 6. Hunting of the contacts of relays 6, 17 is prevented by time delay circuits comprising members 12,13,14 and 19, 20, 21. A further such circuit comprising members 25, 26, 27 prevents energization of the relay 23 (through the contacts C2) when the "ON" button 4 is actuated. A switch 15 is parallel with the thermostat 11 enables the motors 9, 10 to be operated independently of the relay 2 and other circuit members.