System and method for controlling temperature in a forehearth
Systems and methods are provided for controlling temperature in a glass forehearth. In one implementation, a system includes at least one burner disposed in said forehearth, a manifold coupled to said burner, a combustion fuel supply coupled to said burner, a combustion air blower for delivering ambient air under pressure to said manifold, and a controller coupled to said burner for controlling operation of said burner. The system may include a temperature sensor operatively coupled downstream of the blower for providing to the controller a temperature signal indicative of temperature of air delivered to the manifold by the blower. The controller may be responsive to the temperature signal for controlling operation of the burner as a function of current temperature of air fed to the manifold. Operation of the burner may also be controlled as a function of an average air temperature over a preceding time duration.
1. A system for controlling temperature in a glass forehearth that includes at least one burner associated with said forehearth for heating glass in said forehearth, said system also including a manifold coupled to said burner, a combustion fuel supply coupled to said burner, a combustion air blower for delivering ambient air under pressure to said manifold, and a controller coupled to said burner for controlling operation of said burner, said system including:
a temperature sensor operatively coupled downstream of said blower and upstream of said manifold for providing to said controller a temperature signal indicative of temperature of combustion air being delivered to said manifold by said blower,
said controller being responsive to said temperature signal for controlling operation of said burner as a function of current temperature of combustion air fed to said manifold.
2. The system set forth in claim 1 wherein said controller is responsive to said temperature signal for controlling operation of said burner as a function of an average air temperature over a preceding time duration.
3. The system set forth in claim 2 wherein said average air temperature is a moving average air temperature.
4. The system set forth in claim 3 wherein said moving average air temperature is over a preceding time duration of at least two days.
5. The system set forth in claim 3 wherein said moving average air temperature is over a preceding time duration of between 5 and 15 days.
6. The system set forth in claim 3 wherein the current temperature is divided by said moving average air temperature to provide a temperature compensation factor.
7. The system set forth in claim 1 wherein said burner includes a valve or a variable speed blower operable to control the flow of a combustible mixture through the burner and wherein said controller is coupled to said valve or said blower to control operation of the valve and the flow rate through the burner.
8. The system set forth in claim 7 which also includes a pressure sensor coupled to said manifold and said controller to provide a signal to said controller indicative of the pressure within said manifold, and said controller is responsive to the signal from said pressure sensor to vary said valve position or blower speed as a function of the manifold pressure to provide a constant mass flow rate through said burner.
9. The system set forth in claim 1 wherein the controller is operable to maintain a constant mass flow rate through said burner.
10. The system set forth in claim 9 which also includes a cooling air supply provided to the forehearth and wherein said controller is coupled to said cooling air supply to control the flow rate of cooling air provided to said forehearth to permit control of a temperature within said forehearth while said flow rate through said burner is maintained constant.
11. The system set forth in claim 10 wherein said controller is operable to vary said cooling air flow rate over a first range of forehearth operating conditions and wherein said flow rate through said burner is increased during a second range of forehearth operating conditions.