General description – PDF

For casting machines with automatic metal level regulation, the number one reason for flow stoppage is loss of control of the metal level during filling of the moulds. The inductive sensors that are generally used have a measuring range of 40 to 50 mm. The mould is therefore filled without measuring the level of metal, with the plugs in fixed positions. If, for some reason, the filling time of the different moulds varies too much, the cast will be interrupted for safety reasons. This occurs when the interval of time between the first and last moulds reaching their desired levels is too great.

The solution for resolving the mould filling issue is to measure the level as soon as the metal arrives in the bottom block. This requires use of a sensor with a larger measuring range.


The device has a head with a measuring range of 40 mm (GLS-U40). It is fixed onto a lifting jack with a travel of 160 mm. The total measuring range is therefore the sum of the two values. The GLS output signal (respectively 4-20 mA) is calculated based on the 200 mm distance. The U15 model has a smaller head diameter and its inductive measurement is 20 mm.

Movement of the head

The measuring head is always positioned at 25 mm (U40) of the aluminum surface. A dead band of +/- 8mm (U40) limits the inadvertent movements of the cylinder. Of course, even if the cylinder does not move, the measurement will always show the actual distance value with the metal. As soon as the level of aluminum exceeds this range, the head of the GLS will automatically follow the variations of height of the metal in the shells. The cylinder will reposition the head if the metal has approached 1mm (U40) or 0.5mm (U15) after 20s.

The range where the lifting jack does not move is always taken into consideration when calculating the exact value of the movement to be made. The output signal is continuously calculated with the sum of the signal measured and the distance given by the encoder, and its value is always exact, irrespective of the direction of movement.

Technical specifications