Furnace system

A furnace system, comprising:

• a preheater for preheating materials to be supplied to a melting tank, the preheater including a fluid inlet and a fluid outlet;
• a duct system in fluid communication with the preheater, and including
• a preheater outlet duct to transmit exhaust fluids from the fluid outlet of the preheater,
• a preheater intake duct to transmit a mixture of combustion air and recirculated exhaust fluids from the fluid outlet of the preheater to the fluid inlet of the preheater,
• a preheater recirculation duct to transmit a portion of the exhaust fluids from the preheater outlet duct to the preheater intake duct, and
• a preheater exhaust duct to transmit another portion of the exhaust fluids from the preheater outlet duct out of the duct system;
• a recirculation valve to control an amount of flow of exhaust fluids from the preheater outlet duct into the preheater intake duct to control a temperature of the mixture of combustion air and recirculated exhaust fluids into the preheater;
• a temperature sensor to generate a temperature signal indicative of a fluid temperature between the fluid inlet of the preheater and a junction of the preheater recirculation duct and the preheater intake duct;
• a regenerative furnace including
• a melting tank having a fluid port, and
• a regenerator having a lower port, an upper port in fluid communication with the fluid port of the melting tank, and an intermediate port disposed between the lower and upper ports;
• a pressure sensor configured to generate a pressure differential signal indicative of a difference in pressure across the intermediate port of the regenerator;
• a fan configured to control an amount of fluid flow from the fluid outlet of the preheater responsive to the pressure differential signal;
• and
• a controller in communication with the temperature sensor and the recirculation valve to receive temperature input signals from the temperature sensor indicative of temperature of the mixture of combustion air and recirculated exhaust fluids in the preheater intake duct, to process the temperature input signals, and to transmit valve position output signals to the recirculation valve to adjust an opening amount of the recirculation valve to control the temperature of the mixture of combustion air and recirculated exhaust fluids in the preheater intake duct, and wherein the controller is also in communication with the pressure sensor and the fan to receive and process the pressure differential signal from the pressure sensor to produce fan speed output signals to the fan.

A furnace system, comprising:

• a preheater for preheating materials to be supplied to a melting tank, the preheater including a fluid inlet and a fluid outlet;
• a duct system in fluid communication with the preheater, and including
• a preheater outlet duct to transmit exhaust fluids from the fluid outlet of the preheater,
• a preheater intake duct to transmit a mixture of combustion air and recirculated exhaust fluids from the fluid outlet of the preheater to the fluid inlet of the preheater,
• a preheater recirculation duct to transmit a portion of the exhaust fluids from the preheater outlet duct to the preheater intake duct, and
• a preheater exhaust duct to transmit another portion of the exhaust fluids from the preheater outlet duct out of the duct system;
• a recirculation valve to control an amount of flow of exhaust fluids from the preheater outlet duct into the preheater intake duct to control a temperature of the mixture of combustion air and recirculated exhaust fluids into the preheater;
• a temperature sensor to generate a temperature signal indicative of a fluid temperature between the fluid inlet of the preheater and a junction of the preheater recirculation duct and the preheater intake duct;
• a fan to draw the exhaust fluids from the preheater outlet duct into the preheater recirculation duct and the preheater exhaust duct;
• a controller in communication with the temperature sensor and the recirculation valve to receive temperature input signals from the temperature sensor indicative of temperature of the mixture of combustion air and recirculated exhaust fluids in the preheater intake duct, to process the temperature input signals, and to transmit valve position output signals to the recirculation valve to adjust an opening amount of the recirculation valve to control the temperature of the mixture of combustion air and recirculated exhaust fluids in the preheater intake duct, and wherein the controller transmits fan speed output signals to the fan to control a speed of the fan to control the amount of fluid flow through the preheater recirculation duct;
• and
• a regenerative furnace including furnace regenerator pressure sensors,
• wherein the controller receives and processes pressure input signals from the furnace regenerator pressure sensors to produce the fan speed output signals.

A furnace system, comprising:

• a regenerative furnace including a melting tank and at least one regenerator configured to operate in forward and reverse modes and having an intermediate port for diverting a portion of combustion air;
• a preheater for preheating materials supplied to the melting tank, the preheater including a fluid inlet and a fluid outlet;
• a duct system in fluid communication with the preheater and the at least one regenerator, and configured to transmit a mixture of combustion air diverted from the intermediate port of the at least one regenerator and recirculated exhaust fluids from the fluid outlet of the preheater to the fluid inlet of the preheater;
• a recirculation valve configured to control a flow of the recirculated exhaust fluids from the fluid outlet of the preheater into the duct system;
• a temperature sensor configured to sense a temperature of the mixture;
• and
• a controller in communication with the temperature sensor and the recirculation valve and configured to adjust the recirculation valve responsive to the temperature sensor to control the temperature of the mixture delivered to the preheater.