Flags are used to control the tin flows at the sides of the tin bath. Uncontrolled tin flows in the tin bath can lead to undesired optical distortions in the glass. Such flows may be caused by a glass ribbon not running smoothly. To enable the flags to achieve their full performance potential, it is vital to install them in pairs, symmetrically positioned opposite each other.
Flags consist of a support made of stainless heat-resistant steel, a specially designed side sealing, a manual positioning unit and a graphite working element. The working element can be adjusted to various specific tin bath depths and installation locations.
Irrespective of the type and location, both flags serve the same purpose, i. e. controlling the tin flows in the tin bath and thus increasing production quality.
The working element of the full depth flag consists of a thin graphite rectangle which is fixed on a stainless steel holder. These flags are placed near the shoulder of the tin bath, where the bottom graphite barrier is installed, and serve to close the gap between the bottom graphite barrier and the side wall. For a HORN® standard tin bath the required length of the graphite element is 400 mm. This length can be adapted to the requirements of a particular tin bath.
Submerged flags are used near the front of the tin bath. The graphite working element of these flags is designed in such a way that it can be placed underneath the glass ribbon without touching it.
The length of the working element depends on the selected location. Shorter working elements are used in the forming section, where the glass ribbon is wider. Longer working elements are used in the sections where the glass ribbon has reached its final width.
The standard lengths of the working elements of the HORN® submerged flags are 1000 mm, 750 mm and 500 mm. These lengths can be customised to the specific requirements of a tin bath.