Method for making glass

• US 4,325,724 A
• Filed: 10/06/1977
• Issued: 04/20/1982
• Est. Priority Date: 11/25/1974
• Status: Expired due to Term

• Current Assignee: Cooper Industries, Inc. (Eaton Corporation PLC.)
• Original Assignee: Owens-Corning Fiberglas Corporation
• Inventors: Froberg, Magnus L.
• Primary Examiner(s): Kellogg, Arthur D.
• Application Number:
  US05/841,860
• Time in Patent Office: 1,657 Days
• Field of Search: 65/134, 65/135, 65/136, 65/121, 65/178, 65/179, 65/180, 106/52, 106/DIG. 8
• US Class Current: 65/474
• CPC Class Codes: C03B 5/173 Apparatus for changing the composition of the molten glass in glass furnaces, e.g. for colouring the molten glass chemical aspects C03C
• CPC Class Codes: C03B 5/1875 of the screw or pump-action type
• CPC Class Codes: C03C 13/00 Fibre or filament compositions manufacture of fibres or filaments C03B37/00
• CPC Class Codes: C03C 3/089 containing boron
• CPC Class Codes: C03C 3/091 containing aluminium
• CPC Class Codes: C03C 3/115 containing boron
• CPC Class Codes: C03C 3/118 containing aluminium

Abstract

An improved method of preparing a molten glass composition is presented. The constituents of the molten glass composition are classified into two or more melting groups according to mutual melting properties or characteristics such as volatility, corrosiveness or fusion point. Of the constituent groups one is selected and prepared as a molten base glass composition into which the remaining groups are sequentially introduced and homogenized into the base glass forming a molten glass composition of desired forming characteristics.

Claims

1. A process for forming a borosilicate glass fiber of a predetermined chemical composition containing 5-15% B₂ O₃ comprising:

(a) separating the batch ingredients for said predetermined fiber composition into ingredients for forming a host glass and for forming a B₂ O₃ -containing additive glass, said host glass having a higher liquidus than said additive glass and said additive glass being more corrosive than said host glass;

(b) melting said ingredients for forming said host glass in a horizontally disposed, continuous flow, main-melter;

(c) flowing said molten host glass from said main melter to a location where said fibers are formed;

(d) separately melting said additive glass and combining, with forceful mechanical mixing, said molten additive glass with a larger portion of said molten host glass prior to said fiber forming location to form a fiberizable borosilicate glass, and

(e) forming said borosilicate fiber at said fiber forming location from said fiberizable glass, at least a major proportion of the B₂ O₃ content of said fiber being supplied by said additive glass, said melter exhibiting longer life and the volatilization losses of B₂ O₃ being substantially less than that obtained when melting the ingredients of said additive and host glass together in said melter.

2. The process of claim 1 wherein substantially all the B₂ O₃ of said fiber is supplied by said additive glass.

3. The process of claim 2 wherein said fiber includes fluorine, substantially all of which is supplied by said additive glass.

4. The process of claim 1 wherein the composition of said host glass is such that its viscosity and/or liquidus temperature are unsuitable for practicable forming and said additive glass is added in an amount so that the combined glass is suitable for practicable forming.

5. The process of claim 1 wherein said ingredients for forming said host glass are pelletized and preheated to a temperature below which they will agglomerate prior to melting in said melter.

6. The process of claim 1 wherein about 11% by weight of the ingredients of said fiber are supplied as said additive glass.

7. The process of claim 1 wherein about 8% by weight of the ingredients of said fiber are supplied as said additive glass.