| 摘要 |
1,129,059. Burner control and ignition. DANFOSS A/S. 24 Feb., 1967 [3 March, 1966], No. 8874/67. Heading F4T. In a burner ignition and control system for use with either gaseous or liquid fuel, an element 6 having a negative temperature coefficient of electrical resistance, e.g. silicon carbide granules bonded by silicon oxy-nitride, is used as an incandescent igniter and flame sensor. When a switch 9 is closed current passes through relay coil 13 to element 6 and through heater 19 to the element. The element on obtaining incandescence will have reduced its resistance such that the relay operates breaking contacts 16 and 21 but completing the circuit through the coil 22 associated with fuel valve 3. Fuel to nozzle 4 is then ignited and the element 6 remains energized through a variable resistance 18. A heater in series with a fuel supply motor 1 and coil 22 will open contact 10 of a safety trip 11 if either of the components 1 and 22 is overloaded. If the flame fails or the fuel fails to ignite the element 6 will cool causing its resistance to increase such that the current through the relay will no longer be able to retain contacts 16 and 21 open. Thus they will close and the ignition sequence will be repeated. A heater 19 of the safety trip 19 will cause contact 10 to open after a predetermined number of ignition attempts. |
