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Brian Graham
05-03-2012, 12:49 PM
Interesting article on IFB in the May issue of Iron & Steel Technology. In a nutshell - it compares the thermal properties of IFB manufactured by three different methods - Cast, slinger and extrusion. Cast IFB offered the lowest thermal conductivity and reduced energy usage by up to 38%. This was for both 23 and 26 IFB's. The test were done by constructing identical test ovens.

Mark Armstrong
05-11-2012, 09:59 PM
Great article. Does anyone know off the top of their heads which companies manufacture in what manner? I would assume ( which I should'nt ) that Thermal Ceramics cast their bricks, as it appears the authors of the article are employed by them.

Hugh Jenkins
05-12-2012, 02:23 AM
Great article. Does anyone know off the top of their heads which companies manufacture in what manner? I would assume ( which I should'nt ) that Thermal Ceramics cast their bricks, as it appears the authors of the article are employed by them.

I know the Thermal 2600 are cast. It has improved the insulating properties since I last bought from them.

Mark Armstrong
05-13-2012, 10:09 PM
Thanks Hugh

Hugh Jenkins
05-13-2012, 11:56 PM
I once considered the 2500 that Thermal makes to be the best buy for glory holes. At that time they were better insulating, less expensive, and had enough of a temperature margin. With the improved 2600, that no longer stands up. I wonder if they will also improve the 2500 to catch up.

Now, the new 2600 is better insulating, cheaper because it is the standard and not a "special" variety, and has a slightly higher performance range, and a lower permanent change of size (shrinkage). The 2600 is a no brainer.

I combined some 2300 IFB with some 2600 in the same glory hole. I thought that putting the 2600 where the flame impingement occurred made sense. What I found out over several years is that both the expansion when they heat up and the shrinkage over time from repetitive heating were different. It caused some problems with the wall corners and with pushing out the face ring. It still is a great glory hole and has proven the recuperation system, but if I ever rebuild it, I won't make that mistake again.

Pete VanderLaan
05-14-2012, 05:15 AM
Hugh, Do you subscribe to the notion that insulating brick and castables should operate at 85% of their rated capacity? I used to build stuff with 2600's and using that math a 2600 was at design capacity well below the temps that I work a gloryhole at. So, I went up to 2800's which don't really insulate as well and certainly cost more. They do seem to hold up better.

Hugh Jenkins
05-14-2012, 07:42 PM
I have checked the BNZ specs. The higher the rating, the denser and stronger the bricks are, but also progressively less insulating. The linear change tests are run at 24 hour soak at 50 F degrees below max heat range.

There are also conductivity tests that report at the mean temperature, which is the temp at the center of the brick. I was told by the rep I buy from that there is no real strength or size change right up to the rated temperature. 15% is quite a lot when you think of 2600 brick. That would mean not running above 2210, or not above 1960 for 2300 brick. I run above that all of the time, usually in the 2250 +/- range.

I am almost eight years into this glory hole and other than the mixed brick mistake, I don't think that it shows any other major problems. I doubt it would disassemble and have many intact reusable bricks, but that I would expect. Fast heat ups over and over again have to take a toll with time. Some day I will see if the 2600 have survived better than the 2300, or someone else will.

Pete VanderLaan
05-15-2012, 07:17 AM
I agree that 15 percent is a lot but at the same time, I have been singularly underimpressed with the condition of 2600F brick in gloryholes. I admittedly run hot at around 2400F but I see a lot of shrinkage. I sometimes wonder what atmosphere does in that equation.

Hugh Jenkins
05-15-2012, 01:47 PM
I have looked again at the "old" charts I have for BNZ and the shrinkage for 2600 IFB has definitely changed since 2008. Things may be getting better.

I'll confirm those numbers and post them with proper units and temperature limits. Just give me a few days. I have a compressor repair that is calling me.