Heat stains

We are using so2 in order to keep heat stains from adhering to glass. our problem is this is not always effective in preventing this problem. we have increased the flow of so2 without decreasing the incidents of stain. any suggestions?

Guest User
Thu, 07/08/2008 - 16:03

Try adjusting the heat profile (and aspirators, or hot-fans, if you have them) to try and keep the glass as flat as possible on the roll bed during the early stages of the heating cycle. The lower furnace temperature set-points should be as low as possible (maybe 10 to 15 degrees below the upper zone set-points). Generally speaking, lower furnace set-points (top and bottom) with a longer heating time produces a better quality of glass, but the production manager usually objects to a lower furnace throughput.

Guest User
Thu, 07/08/2008 - 23:29

does the location of the so2 tank have any effect on the flow of gas into the furnace? in other words can the flow be affected by being to close to the furnace? ours is located right next to it. also have you heard of any cases where the pop off valve has popped because of heat where tanks are located to close to the furnace? we located it there over the winter to keep it warm because of clogging problems in extreme cold.

Guest User
Fri, 08/08/2008 - 15:28

Providing the flow meter is registering a flow and there are no leaks, the distance should not make any difference to the quantity entering the furnace.
Have you tried the suggestion of changing the heat profile yet? Heat stains (white marking) is always linked to a poor ride in the furnace in the early stages of heating.

Guest User
Tue, 19/08/2008 - 00:24

unfortunately production manager will not permit any slow down at this time, i have been assured that we will be able to try this soon. i did discover what the problem was with my so2 output though. it appears that the tank that had been installed had been stored improperly during the winter therefore degrading the so2. thanks much for your suggestion i look forward to giving it a try very soon.

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