The PERMANENT DRAIN system is used on various glass furnaces such as tableware, flacons, specialty display glass and fiberglass to prevent defects like zircon cords and cat scratches. Glass is drained from the bottom of the furnace, forehearth or working end, making precise, slow and stable flow control essential. Excessive drainage creates a funneling effect, pulling hotter upper glass instead of the cooler and more viscous bottom layers. The PERMANENT DRAIN provides a fully controllable
system capable of very low flow rates.
The system includes an electrically heated platinum flow bushing with water cooling controlled via transformer and thyristor, a flow adjusting plunger, a specially designed AZS channel block, a PLC control enclosure and a cooling water station. A high temperature alloy nozzle forms the outlet, monitored by a thermocouple to maintain stable temperature and flow. Operation can be continuous or intermittent with typical daily drain rates of 500 to 1300 kg per line and power use between 1.0 and 2.5 kW. The system can also be installed later or retrofitted on existing furnaces by drilling from the outside. system capable of very low flow rates.
