New pan for the upcomming season

[Cjadamec]

I've decided to try and upgrade from boiling in steam table pans to a proper evaporator pan. My oil tank arch is a customizable as I need it to be as long as my welder has wire and there is scrap steel laying around. As it sits a 2x5 pan would sit down with minimal changes and it would be easy enough to get a 2x6 pan to fit.

A brand new continuous flow pan would be nice but I'm not sure I want to spend quite that much on either the pan or shipping charges.

I've been looking at some used pans and noticed there are a handful of used 6x2 cross flow pans available and more affordable than buying new. Is it possible to use a single cross flow pan like you would use a continuous flow pan? Or would it be better with just one pan to use is as a batch pan?

Or should I deal with steam table pans for another season and build a small RO system....

[maple flats]

The cross flow pans would likely work except you would want an inlet float box and an outlet draw off. Most likely those could be made as two the same to do both operations, then just switch the float and source piping to reverse the flow in the pan. Look at the pans and decide if that could be done.

[Cjadamec]

Having never really seen or thought of a cross flow pan before how important is it to reverse the flow in the pan? What are the reasons needed to reverse the flow?

As for feeding in raw I don't use a float box at least not currently. I have a variable flow pump set up, so I match the flow of my pump to the evaporation of the boiler. In that way reversing flow would simply mean moving the outlet tube of the pump from one side of the pan to the other.

[RileySugarbush]

If you are comfortable with adjusting your inlet flow you can do without a float box. It gets easier if you are using a flat bottom pan since the evaporation rate will be more modest than if you have a flue pan. The key with a continuous flow pan is getting and keeping a gradiant from raw sap at the inlet and near finished at the outlet. To maintain that gradiant the channels keep the flow moving in a narrow path like a river and you keep the depth low so it doesn’t mix back and forth along the channels. Maybe keep it around 1.25 inches or so. Lower if you dare.

You need to reverse flow occasionally, probably each time you boil, because niter will build up near the outlet Reversing clears that up. When you reverse, you will want to pull the near syrup off the old end and put it back in at the new draw off end.

[SeanD]

I used a flat-pan cross-flow setup on a 2x6 for years. I had it split into two 3' pans. It set up a gradient easily and I used it as a continuous flow. I regulated the intake manually with a valve on a preheater pan.

Given the size of your operation, you really aren't going to need to reverse flow. By the time you might think about it, you'll be done for the day. You can just as effectively drain the pan and clean it between boils. I spent extra money to make my current pans reversible and I never use it. An overnight soak in vinegar is like magic.

The one advantage I had over your plan was I had two pans connected by valves. That was nice for just needing to drain and clean a 3' pan versus a 6' pan and it helped reestablish the gradient more quickly at the next boil. Having that valve between pans also made up for the inevitable "running deep" situations when I'd get distracted or just not fire well. I could pinch the valve to keep the wave of fresh sap from ruining the flow up front.

In all, going from batch to continuous was well worth it for this one-man operation, but reversible pans were unnecessary.

[Cjadamec]

Thank you both for the info. I feel a lot more comfortable going with a used 2x6 cross flow pan on my arch. It should be a big step up from 5 steam table pans. it also keeps everything under budget which will make the boss happy. After getting a new John Deere tractor this year I need to watch my "hobby" spending.