As a result of continuous R&D on the mechanism of rat holing, Lubisol Ltd. has developed a new method for hot repair of silica crowns.
It was based on the principle, that rat holing can be avoided by a hermetic sealing of the silica crown, preventing the movement and passing of hot flue gases and the condensation of fluxing materials in the loose joints.
Lubisol Si-Seal is applied as a protection hermetic sealing layer and is very suitable for hot application in the form of plastic balls to fill up the Rat-holes during a hot repair or the expansion joints of a silica crown after heat-up.
The new method offered by Lubisol proved to be a big success.
The hot repair is carried out by patching and covering of the rat-hole with Lubisol Si-Seal kit and with thin silica plates.
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Lubisol Si-Seal is a hermetic sealing kit, having unique properties. It develops a strong and durable adhesive bond with silica bricks up to 1620 °C, having a coefficient of expansion - very close to the one of the crown bricks.
Lubisol Si-Seal is showing a very high resistance towards alkaline corrosion.
The special thin silica plates used in the new hot repair technology are usually 230 x 114 x 30 mm in size. The two materials – Si-Seal and silica plates are bonded together forming a monolithic composite structure. The thickness of the crown in any corroded area can be increased.
Highly successful hot repair results have been observed on many container glass, float glass, TV glass, boro-silicate and sodium silicate furnace crowns, with no visible signs of new corrosion over the rat holes 6 years after the repair.
Lubisol is offering all materials needed for the repair, together with the know-how and a detailed application technology, adaptable for each individual case.
The method is universal and very suitable for the repair of silica crowns with any kind of rat hole problems melting soda-lime glass, but it proved to be especially helpful for protecting or repairing silica crowns of air-fuel or oxy-fuel furnaces melting boro-silicate, lead, opal or sodium-silicate glasses.
The new hot repair techniques, offered by Lubisol, are simple and reliable, giving in all cases durable and long lasting solutions at moderate additional expenses.
Successful results have been reported after the application on more than 100 glass furnaces and the new method is now spreading rapidly all over the world.
