Furnace expansion joint with compressible graphite joint filler and manufacturing method
Expansion joints located in the upper part of the hearth walls of a reduction furnace are filled with a plate-shaped compressible graphite filler having a density of 0.1 to 0.2 g/cm 3 . A method of manufacturing such a joint filler is also provided.
1. An expansion joint located in an upper part of hearth walls of a reduction furnace, the expansion joint consisting of:
two lining blocks forming two horizontal gaps each having a height of 25 to 45 mm and a vertical seamless joint therebetween; and
a plate-shaped compressible graphite filler having a density of 0.1 to 0.2 g/cm 3 obtained by compacting expanded graphite precursor material, said filler filling said horizontal gaps.
2. The expansion joint according to claim 1 , wherein said compressible graphite filler includes a stack of up to five plates having a thickness of 0.5 to 1.5 cm.
3. The expansion joint according to claim 2 , wherein said compressible graphite filler stack is cut to a required size and glued together by suitable high-temperature glues.
4. The expansion joint according to claim 3 , wherein said high-temperature glues are phenolic resin.
5. A method of assembling an expansion joint, the method consisting of the following steps:
gluing the compressible graphite filler according to claim 1 to the respective lining blocks with suitable high-temperature glues; and
subsequently forming the expansion joint with the lining blocks.
6. The method according to claim 5 , wherein the high-temperature glues are phenolic resin.
7. A method of manufacturing a compressible graphite filler, the method consisting of the following steps:
compacting a conventional expanded graphite precursor material having a density of 2 to 7 mg/cm 3 to a desired density, by at least one of pressing in a conventional press or calandering; and
trimming to final dimensions following the compacting step to form the compressible graphite filler according to claim 1 .
8. The method of manufacturing a compressible graphite filler according to claim 7 , which further comprises implementing reinforcing carbon fibers or carbon fiber non-woven or woven mats into the conventional expanded graphite precursor material before compressing.
9. The method of manufacturing a compressible graphite filler according to claim 7 , which further comprises further treating the graphite filler with oxidation retarding agents.
10. The method of manufacturing a compressible graphite filler according to claim 8 , which further comprises further treating the graphite filler with oxidation retarding agents.
11. The method of manufacturing a compressible graphite filler according to claim 7 , which further comprises further treating the expanded graphite precursor material with polyphosphoric acid before compressing.
12. The method of manufacturing a compressible graphite filler according to claim 8 , which further comprises further treating the expanded graphite precursor material with polyphosphoric acid before compressing.