A system for preheating batch materials in a glass melting furnace includes a preheater having an outlet through which fluid is exhausted and an inlet that receives fluids exhausted from the furnace and recirculated from the preheater outlet. In one embodiment, a cyclonic separator has an inlet in communication with the preheater outlet and an outlet in fluid communication with a fan. A controller controls the speed of the fan responsive to a drop in pressure between the separator inlet and outlet and a temperature at the separator outlet. In other embodiments, controllers control valves that (i) control the amount of fluids exhausted from the preheater that are delivered to a flue and recirculated to the preheater or (ii) control the amount of fluids diverted to charger for the furnace, in response to temperatures in a duct coupled to the preheater inlet.

A system for preheating batch materials includes a preheater, a charger, a first temperature sensor, a second temperature sensor, a valve, and a charger temperature controller. A first recirculation duct provides exhaust fluids from the charger to a second recirculation duct coupled to an inlet of the preheater. The first temperature sensor is configured to generate a first temperature signal indicative of a first temperature of fluids within the second recirculation duct and the second temperature sensor is configured to generate a second temperature signal indicative of a second temperature of the fluids within the second recirculation duct upstream of where the first temperature is obtained. The valve is configured to control an amount of fluid in the second recirculation duct that is diverted to the charger and the charger temperature controller is configured to control the valve responsive to the first and second temperatures.

A system for preheating batch materials includes a preheater, a charger, a first temperature sensor, a second temperature sensor, a valve, and a charger temperature controller. A first recirculation duct provides exhaust fluids from the charger to a second recirculation duct coupled to an inlet of the preheater. The first temperature sensor is configured to generate a first temperature signal indicative of a first temperature of fluids within the second recirculation duct and the second temperature sensor is configured to generate a second temperature signal indicative of a second temperature of the fluids within the second recirculation duct upstream of where the first temperature is obtained. The valve is configured to control an amount of fluid in the second recirculation duct that is diverted to the charger and the charger temperature controller is configured to control the valve responsive to the first and second temperatures.

A system for preheating batch materials in a glass melting furnace includes: a preheater configured to receive unheated batch materials and to deliver heated batch materials, the preheater including an outlet configured to exhaust fluid from the preheater and an inlet configured to receive exhaust fluid from the glass melting furnace and exhaust fluid recirculated from the outlet of the preheater; a fan configured to provide ambient air to a furnace flue; a valve configured to control an amount of the ambient air to the furnace flue; a temperature sensor configured to sense temperature of exhaust gases in the furnace flue; and a temperature controller configured to control the valve and the fan responsive to the temperature sensed by the temperature sensor.

A system for preheating batch materials in a glass melting furnace includes a preheater having an outlet through which fluid is exhausted and an inlet that receives fluids exhausted from the furnace and recirculated from the preheater outlet. In one embodiment, a cyclonic separator has an inlet in communication with the preheater outlet and an outlet in fluid communication with a fan. A controller controls the speed of the fan responsive to a drop in pressure between the separator inlet and outlet and a temperature at the separator outlet. In other embodiments, controllers control valves that (i) control the amount of fluids exhausted from the preheater that are delivered to a flue and recirculated to the preheater or (ii) control the amount of fluids diverted to charger for the furnace, in response to temperatures in a duct coupled to the preheater inlet.

A system for preheating batch materials in a glass melting furnace includes a preheater having an outlet through which fluid is exhausted and an inlet that receives fluids exhausted from the furnace and recirculated from the preheater outlet. In one embodiment, a cyclonic separator has an inlet in communication with the preheater outlet and an outlet in fluid communication with a fan. A controller controls the speed of the fan responsive to a drop in pressure between the separator inlet and outlet and a temperature at the separator outlet. In other embodiments, controllers control valves that (i) control the amount of fluids exhausted from the preheater that are delivered to a flue and recirculated to the preheater or (ii) control the amount of fluids diverted to charger for the furnace, in response to temperatures in a duct coupled to the preheater inlet.

A method of forming high strength glass fibers in a refractory-lined glass melter, products made there from and batch compositions suited for use in the method are disclosed. The glass composition for use in the method of the present invention is up to about 64-75 weight percent SiO.sub.2, 16-24 weight percent Al.sub.2O.sub.3, 8-12 weight percent MgO and 0.25-3 weight percent R.sub.2O, where R.sub.2O equals the sum of Li.sub.2O and Na.sub.2O, has a fiberizing temperature less than about 2650 F., and a T of at least 80 F. By using oxide-based refractory-lined furnaces the cost of production of glass fibers is substantially reduced in comparison with the cost of fibers produced using a platinum-lined melting furnace. High strength composite articles including the high strength glass fibers are also disclosed.

A system for preheating batch materials in a glass melting furnace includes a preheater having an outlet through which fluid is exhausted and an inlet that receives fluids exhausted from the furnace and recirculated from the preheater outlet. In one embodiment, a cyclonic separator has an inlet in communication with the preheater outlet and an outlet in fluid communication with a fan. A controller controls the speed of the fan responsive to a drop in pressure between the separator inlet and outlet and a temperature at the separator outlet. In other embodiments, controllers control valves that (i) control the amount of fluids exhausted from the preheater that are delivered to a flue and recirculated to the preheater or (ii) control the amount of fluids diverted to charger for the furnace, in response to temperatures in a duct coupled to the preheater inlet.

Provided is a method for producing a glass material whereby a glass material less likely to undergo solarization can be obtained. A method for producing a glass material includes the steps of: preparing a glass; and subjecting the glass to heat treatment for six or more hours at a temperature of not lower than (Tg?70?) C and not higher than (Tg+40?) C where a glass transition point of the glass is represented as Tg (? C.).

A method of forming high strength glass fibers in a refractory-lined glass melter, products made there from and batch compositions suited for use in the method are disclosed. The glass composition for use in the method of the present invention is up to about 64-75 weight percent SiO.sub.2, 16-24 weight percent Al.sub.2O.sub.3, 8-12 weight percent MgO and 0.25-3 weight percent R.sub.2O, where R.sub.2O equals the sum of Li.sub.2O and Na.sub.2O, has a fiberizing temperature less than about 2650 F., and a T of at least 80 F. By using oxide-based refractory-lined furnaces the cost of production of glass fibers is substantially reduced in comparison with the cost of fibers produced using a platinum-lined melting furnace. High strength composite articles including the high strength glass fibers are also disclosed.