Owens-corning Fiberglas Corporation

Avinash J Desai

Gerhard Kreikebaum

Eugene C Varrasso

Glen F Day

A bushing balance controller senses the temperature of each section of a multiple section glass fiber forming bushing by thermocouples or resistance (voltage drop) measuring techniques and injects electrical energy to all but one of the individual bushing sections and adjusts the supply of electrical energy to the entire bushing assembly thereby controlling the temperature of each individual section of the bushing. When thermocouples sensors are utilized, standard thermocouple driven temperature controllers may be utilized to provide a signal to a plurality of power packs, a primary power pack providing electrical energy to the entire bushing and smaller power packs controlling the injection of electrical energy to all but one of the bushing segments. A similar power pack and bushing control scheme accompanies the use of resistance (voltage drop) measurement techniques. Here, however, the control signal is generated by an error signal representative of the present, sensed temperature versue the set point temperature. In order to eliminate the interference between the voltage drop sensing and the injected current, an interleaving technique is utilized to sense voltage drop and inject electrical energy during alternate cycles of the applied power.

Bushing balance controller and method of using same

The bushing balance controller is an electronic device which measures the voltage drop across each segment of a multiple segment glass fiber forming bushing and measures the current flow in the bushing. The device uses these measurements to produce error signals proportional to the difference in the set point temperature and the instantaneous temperature of each segment of the bushing. The device diverts current from each segment of the bushing whose error signal is greater than the average of the error signals for all segments of the bushing. The device also sums all error signals and passes this signal to a bushing controller which adds current to the bushing when the sum of the error signals falls below a preset value.

Bushing balance controller and method for using same

The bushing temperature measurement device is a microprocessor based sensor which determines the temperature across a multi-segment electrical resistance heated glass fiber producing bushing. The temperature change is determined by calculating the change in resistance of each segment of the bushing by sensing the voltage drop across that segment and dividing by the current flowing in that segment. All measurements of voltage and current are taken simultaneously and averaged over several cycles. The microprocessor, through appropriate output circuitry, alerts other process controls to eliminate any change in temperature.

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Reynoldsburg, OH, United States of America

Avinash J Desai