Evaporator Pan Flatness/Depression

[kstevens]

Bought a homemade barrel evaporator last winter with a small 18 x 32" divided flow pan. I never really had enough sap to treat it as a continuous flow pan, and would just pull the pan at the end of the day and finish on propane. The barrel itself has remained nice and flat, but I noticed this fall that the pan itself has a gradual depression of about 1/8 - 3/16" in the center. The edges are all still planar and the pan sits flat on the welded support surface. Should I be concerned about it at all? I can see how having the edges flat is important, but maybe this isn't a big deal. Don't see how it could be fixed without major surgery.

[NhShaun]

Depending how the dividers are laid out it could cause some disturbance in the flow. I have something similar in the middle section of my front flat pan, about 3/8" dip spread over 8 inches or so. I have had to run my level a bit higher since that incident when the pans warped. Otherwise it concentrates the same in that dip as the end of my pan where the draw off and thermometer are located. Certainly makes it a little tricky to draw off accurately as it goes down and then back up in temp once i crack the valve.

[buckeye gold]

Just run your sap a little deeper and you'll be fine. I had an old divided flat pan like that and it made a lot of syrup. I used to run it about 1 1/4 -1 1/2 and after the warp 1 3/4 + and it done fine.

[kstevens]

Thanks, very helpful. Any tricks on how to monitor sap level without a fancy sight glass?

[berkshires]

Thanks, very helpful. Any tricks on how to monitor sap level without a fancy sight glass?

I set a stainless bolt on its head where the sap flows in, and there's no boil. I can see how much of the bolt is sticking out. And if it ever gets to below where the threads start (3/4") I know it's too low.

Hey, you asked for low-tech. :)

GO

[TheNamelessPoet]

I set a stainless bolt on its head where the sap flows in, and there's no boil. I can see how much of the bolt is sticking out. And if it ever gets to below where the threads start (3/4" I know it's too low).

Hey, you asked for low-tech. :)

GOI use my strainer I use to scoop out foam with I know if I stick it in, and it goes below a certain spot on the edge, i am under 3/4 inch also. Hey you use what you have :-)!

[DrTimPerkins]

Thanks, very helpful. Any tricks on how to monitor sap level without a fancy sight glass?

If sap runs over the sides of the pan it is too full. If it turns into black smoke while you're boiling the level is too low. Keep it somewhere between those two. :D

If you have a small warp, just run it a little deeper (as Buckeye Gold mentioned).

You should be able to keep relatively good track of depth in the floatbox or drawoff depending upon how they are configured. As long as the foam isn't too bad you might be able to eyeball it, but putting a metal ruler (no backing) in the box can help too.

[kstevens]

Love the stainless bolt!! Will give that one a try for sure.

And thanks Dr. Tim, such a Vermont answer...:)

[randolphvt]

If sap runs over the sides of the pan it is too full. If it turns into black smoke while you're boiling the level is too low. Keep it somewhere between those two. :D



LOL. Good one! :)

[johnpjackson]

Thanks, very helpful. Any tricks on how to monitor sap level without a fancy sight glass?

I got myself a fancy sight glass and it was very reasonably priced. I love it! I installed it between my draw off valve and its port into the pan. Here's the link to it: https://www.amazon.com/dp/B0713Y48J5