HORN has a drainage system which addresses the problem of zircon cords.
The equipment enables the draining of small glass quantities from the forehearths in order to minimize contaminants such as zircon cords (known as cat scratches), stones or other substances.
The system basically consists of a specially shaped channel block with a deepened part and centered drilling and a metal orifice plate of high temperature resistance, which is braced underneath the forehearth. An electrical heating element is positioned below the orifice and leads, when heated, to glassflow. The advantage of this VARI-DRAIN system is that it works without counter electrode in the glassmelt.
The drainable glass quantity ranges between 0,2 - 2,0 tpd depending on glass viscosity and colour. The precise and constant amount of glassflow during operation is controlled via temperature at the draining point by a PID control loop.
Additional cooling air distribution completes the system for halting the glass flow if necessary.
The HORN Vari-Drain system significantly improves the glass quality and therefore the profitability of a production plant.