Furnace glass level control is, like many other furnace process controls, a delicate and important task of a process control system. There are several methods of measuring glass level like glass contact probes, probes you detect the ionized air layer just above the glass bath, probes using isotopes and vision systems. All faces the same problems; they need to be very precise and they will have to operate, over a very long time, in very harsh environments.
Also special strategies are required in case of a batch charger failures in which unfortunately the glass level could have dropped potentially. To get the furnace back to its normal glass level it would be necessary to increase the batch charge speed and charge tonnage. However, the glass level control needs to take the melting capacity of the furnace into account and should not try to fill up the furnace with batch as quickly as possible which will, eventually result in unwanted glass quality problems.
Taking all these constrains and consideration into account it becomes obvious that glass level control can be a complex issue and in most cases cannot be achieved by a “standard” controller. Foxboro Programmable Automation Controller (PAC) is perfectly capable of running these complex strategies in a redundant environment, it is easy, on the fly adaptable as soon as a change of strategy is required and it can be seamlessly integrated into the furnace control system.
Click to read about excess of air control.
