The Inefficiencies of Convection Powder Coating Ovens
The importance of powder coating oven system control can assessed by considering a medium sized gas fired convection powder coating oven. A typical system will probably have gas burner capacity totaling approximately 1500 kW. There will be very little control with this type of system, except to maintain an air temperature within the oven. The burners are either on at full output or off. No account is made of the part size or batch size. Because it can take up to an hour for a convection to come up to temperature, operators will keep the oven on for a full shift. This will include work breaks and with no regard to the work load for that shift. Such a typical system will produce a Carbon output of 1 tonne in a ten hour period.
The Department of Trade in the UK have analysed a series of standard plant and their figures show that gas fired convection ovens are generally less than 7% efficient. Even worse, industries which process light sheet-metal, the efficiency may drop to 5% or less. Where does the remaining 95% of the burner power go? It is lost in exhaust gasses, leakage from silhouettes, through the oven walls and explosion panels and in heating the conveyor or track. The oven continues to work hard even when it is completely empty.
Add in the fact that conventional ovens take about an hour to come up to operating temperature, and cannot be turned off until the end of a shift. This means that the oven will be running at full power during breaks in production and worker break times. Overall, there is very little powder coating oven system control that can be applied. This is expensive and wasteful of energy.
Powder Coating Oven System Control with Gas Pulse Technology
A Gas Catalytic Infrared Powder Coating Oven can be very carefully controlled by creating a programmed and repeatable heat profile throughout the oven which is easily customized to the parts, our powder coating oven control system reduces the total amount of heat that is output by the system. We do this by creating zones within the oven that can be individually controlled via the PLC control panel. The heat output of each individual zone is controlled to suit the parts going through the oven.
The physical control of the gas flow to the heaters is achieved using Gas Pulse technology which gives a high degree of temperature control. At Low Fire (0%) the average surface temperature of the heater is 300-350°F. (149-177°C.), while at High Fire (100%), the average temperature is 850-900°F. (454-482°C.) depending on heater orientation and position in an oven.
In practical terms, powder coating oven system control in gas catalytic infrared ovens means that gas usage can be reduced by up to 50%, hence reduced energy bills.