Method of forming thin sheet glass by float process

In a method of forming a relatively thin sheet of glass in a glass forming chamber which includes a molten metal bath constituted of a bottom structure, two opposite side walls, a molten glass inlet structure at one end and a sheet glass outlet structure at the other end and a roof structure defining an interior space above said molten metal bath, the method having the steps of feeding molten glass onto the surface of the molten metal in said bath, causing the molten glass to spread on the surface of said molten metal bath to form a layer of the molten glass, stretching the molten glass layer in a direction substantially parallel to said side walls so as to reduce the thickness of said layer and advance said layer towards said outlet structure, and cooling the thinned molten glass layer;

• the improvement comprising the steps of:
• providing a sluice-forming wall in said interior space at a distance downstream from said inlet structure so as to extend widthways of said molten metal bath and leave a vertically narrow gap between a lower end of said sluice-forming wall and the surface of the molten metal in said bath thereby producing a pool of the molten glass on the molten metal in a region between said inlet structure and said sluice-forming wall, a front side of said sluice-forming wall facing said pool being formed with a slant surface contiguous to said lower end of said wall such that the surface of the molten glass in said pool intersects said slant surface and that the vertical distance of said slant surface from the surface of the molten metal decreases as the horizontal distance of said slant surface from said inlet structure increases, the rear side of said sluice-forming wall being formed with a vertical surface contiguous to said lower end of said wall;
• and
• forming said layer of the molten glass by causing the molten glass to flow out of said pool through said vertically narrow gap.