An apparatus for monitoring an apparatus for the inductive heating of a metal material including a detection device and an evaluation device. In order to automate the loading of the inductive heating apparatus with bulk material or metal material, according to the invention the detection device is an optical sensor for detecting distance and the evaluation device is designed to determine, on the basis of the distance detected by the detection device, the fill level of the inductive heating apparatus and to output a corresponding signal, the signal being suitable for further use in a control process for the feeding of metal material to the inductive heating apparatus. The invention also relates to a method for automatically loading an apparatus for the inductive heating of a metal material and to a control system for an apparatus for the inductive heating of a metal material.

A refill system includes a tempering furnace, a refill furnace which stores the molten potassium nitrate obtained by melting powdered potassium nitrate, a supply unit which supplies the molten potassium nitrate to the tempering furnace, a tempering furnace side load measuring unit which measures a load amount of the molten potassium nitrate in the tempering furnace, a refill furnace side load measuring unit which measures a load amount of the molten potassium nitrate in the refill furnace, and a central control unit which checks the load amount of the molten potassium nitrate in the tempering furnace and the refill furnace in real time, and controls the supply unit to stop supplying the molten potassium nitrate to the tempering furnace when the load amount of the molten potassium nitrate in the tempering furnace is greater than or equal to a predetermined load amount.

An electric furnace equipment including: a body part having an inner space capable of processing a raw material; an electrode part installed to be inserted into the inner space of the body part; an input part installed in the body part to be capable of inputting the raw material to the inner space of the body part; and a photographing part installed in the body part to be capable of photographing the area around the electrode part in the inner space of the body part; and an input control part which detects a spacing distance (D.sub.m) between the electrode part and a raw material stack formed by the raw material stacked around the electrode part by using a photograph image acquired by the photographing part and controls an input of the raw material input to the body part from the input part according to the detected spacing distance (D.sub.m).