JPS5457234A - Temperature-controlling unit - Google Patents

Abstract

PURPOSE: To make sure the control of low temperatures by use of a temperature- controlling unit wherein ignition and main burners are controlled by comparison of two temperature set-up values with a temperature detected.

CONSTITUTION: Comparators 14, 16 are connected to an electric source 12. The comparator 14 comprises a temperature-sensitive section 4 and a variable resistance 15 for setting up temperatures. Two types of temperatures, high and low, are given to the comparator as set-up values, and the difference of the two is kept even if the set-up values are changed. If the temperature signal ranges between a high set-up value B and a low set-up value A on comparison of the temperature signal and the set-up values, an output B is delivered, an igniter 5 being actuated by means of an OFF-delay timer 17, the output B signal and a combustion-detection signal by a thermocouple 9 from the comparator 16 being sent to an AND circuit 18, an output from the AND circuit 18 being sent to an OR circuit 20 with a signal from a timer 17, and a pilot burner valve 10 opening. If the temperature signal is below the set-up value A, the signal A and the combustion-detection signal are sent to an AND circuit 19 to open a main electromagnetic valve 7. At the set-up value B or more, no output is delivered, and the whole unit stops operation

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