 |
||||||||||||||||||||||||||||||||||||||||||
 |
||||||||||||||||||||||||||||||||||||||||||
|
|
||||||||||||||||||||||||||||||||||||||||||
|
|
||||||||||||||||||||||||||||||||||||||||||
|
Furnace Rebuild
975 pound day tank rebuild web chronicles
Questions and Answers Why don't you cast the arch? I believe it's easier to build a brick arch. I've done a couple of cast arches and the most notable difference during construction is shear weight. We often build these in confined spaces where overhead and side clearance is an issue. Lifting 300 pound arch parts is essentially crazy and nearly impossible without mechanical assistance. A brick arch takes about 1 hour to assemble, which I believe is less time than what it would take to mix castable and clean out a mold. I have never removed an arch (that I built) that didn't appear perfectly reusable. The materials for a brick arch are about $200 more than a cast arch. Another problem with castings is setting time. My favorite low cement castables take at least 48 hours to be demoldable - safer at 72 hours. This factor alone prevents us from casting arches. How come such a big burner? We install a larger than necessary burner in this furnace, the Eclipse Thermjet TJ150, which has a 1.5 million BTU/hr capacity. I've measured gas flow in this unit and at high fire we were pulling closer to 800,000 BTU/hr. It idles (holds 2,100°F) around 175,000 at this point. The large size gives us a very quiet idle flame. You could probably get better efficiency with a smaller burner, but it would be considerably louder. Aren't you supposed to cast around the AZS liner? Casting around the AZS is a problem if you simply build a box around the AZS and cast into it. When the AZS expands the casting cracks, Unless you've installed something to create an expansion joint to con troll the cracking, you always run the risk of the casting cracking along a joint in the AZS. It also requires an additional day or 2 and a mold. |
|||||||||||||||||||||||||||||||||||||||||
|
|
||||||||||||||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||||||||||||||||
