Roofing kettle control apparatus

摘要

Roofing kettle apparatus for heating asphalt includes a wheeled chassis mounting a vat and a heating system for heating the vat. The heating system includes a solenoid operated valve for controlling the flow of fuel gas from a fuel gas source to each of a pair of burner nozzles and a igniter assembly having an outlet adjacent the outlet of a first combustion chamber. An igniter generates a spark to ignite gas discharging from the igniter assembly outlet. A flame sensor adjacent to the first combustion chamber outlet end senses the burning of fuel gas. The igniter assembly has a second outlet adjacent the second combustion chamber outlet end. The ignition of fuel gas discharging from the igniter assembly ignites the gas discharging through the combustion chamber outlets. The burners extend into the combustion chambers. Electric controls include circuitry in the igniter and a temperature controller to energize and deenergize the valve and generate a spark a number of times with a time delay between each energization and deenergization to purge gas in the combustion chambers in the event the flame sensor does not sense a flame after the respective energization and to control the range of temperatures to which the material in the vat is heated.