Problem with flat pan bowing and flat pan conversion ?

[Hornby]

My 3' x 7' flat pan is made from one piece of stainless steel and then the sides are folded up and the corner uprights are welded together. When the pan is empty or cold with 2 inches of sap it sits flat on the level fire arch. As the pan and sap heats, the pan will lift on each end and bow so it does not sit flat on the arch. This year I used ratchet straps to hold the corners down so I was not losing heat. Ever had this problem before? I thought about welding some latches like the ones that are on my pop up camper to help hold the pan flat. Is something I can do to my pan to prevent it from bowing without securing it to the arch.

Also, has anyone ever turned a flat pan into a continuous flow pan? Is it as simple as welding partitions in the pan?

Thank you for any insight.

Joel

[Ausable]

Hornby - The ends raise up on the pan when heated? Never heard of this problem - but metals expand and contract with heat and cold as we all know. Yes - You can turn a flat pan into a continuous flow evaporator - but - with the problem you are having - I wonder? To have a continuous flow work things have to remain level. My little continuous flow is a 2'x5' steel pan with a divider going side to side to make a sap pan and a syrup pan. The sap pan is nearest the stack with a divider going lengthwise giving me two sap sections. The Syrup Pan is nearest the fuel door with two dividers giving me three syrup sections. The approx. 1" square openings are placed in the dividers so a flow can go from the first sap section to the last syrup section and out the draw off valve. Hope I helped some.

[Bucket Head]

My homemade front pan was made like that and it would raise up at one corner quite a bit. I welded tabs with a hole in it on the arch and bent some threaded rod into "J" shaped hooks (like the old battery hold downs) and put a wing nut on the bottom at the "tab" end. That way I could draw the pan down easily and remove it quickly. Just don't make it tight- everything expands when its heated and you'll need pliers to get them off! The interesting part of this is after a season of doing this, the pan set on the arch fine without the hooks. The heating and cooling cycles with it drawn down must have corrected the "warp" that was caused when bending and/or welding the pan corners. Now will your pan straighten out also? Who knows, but is worth a try. Even if it does'nt correct it, you will be able to keep heat from escaping with the hooks in place.

Steve

[SeanD]

I would think that across 7' of pan there is enough temperature gradient to cause the bowing and lifting. I think if you add dividers, you may kill two birds with one stone - you'll get a continuous flow and you'll give the pan enough structural support to withstand the pressure to bow.

Sean