Need some last minute design help on my barrel evaporator

[82cabby]

Hi gang!

I am almost done with my barrel evaporator and I need some input. Eventually I am going to have a custom pan sitting on top, but for this season, I have to stick with the ol' cafeteria warming pans.
So, the question is what level to put them at.

Option 1: It just so happens that they fit almost perfectly side by side in the opening. That would put the whole pan down into the heat.

http://img.photobucket.com/albums/v282/dkutina/Maple%20Evaporator/P1030491.jpg

Option 2: I could build an adapter plate that would cap the opening and allow the bottom inch or so of the pans to be exposed to the heat.

http://img.photobucket.com/albums/v282/dkutina/Maple%20Evaporator/P1030493.jpg


Obviously option 2 is more work and more materials, and I will only be using it one season. But I don't want to ruin a bunch of sap. Any and all advice would be very welcome!

Thanks,
Dave

[ericjeeper]

I am no expert.But I would prefer option 2. To keep the sides of the pan from scorching.

[82cabby]

Yeah, that's kind of what I'm thinking. This is my first evaporator so I don't really know.

This is not a problem I have on the stove!

[RileySugarbush]

for one season, drop them in and fill them half deep with sap. More exposed surface and a faster evaporation rate, at the expense of some scorching late in the batch. the syrup will filter up fine!

[HHM-07]

yes your pans should be exposed to the fire

[82cabby]

I know they should be exposed to the fire the question is how much of the pan. I can either drop them in up to their rims or cut holes in the plate that is shown so that about an inch of the pans drops in. In option 2 only about 1 inch of the pan would be exposed to the fire.

[Haynes Forest Products]

Option 2 raw sap not as much as a problem as when your getting to the syrup stage. Im of the opinion you cant filter out burnt. I burned some syrup once and it was like you added liquid smoke to it.

[Mac_Muz]

I wouldn't drop them in any deeper than you can to expect sap to be depthwise at any time. otherwise you will scorch the pan above the sap line on the inside.

A boat on fire only burns to the water line..

[mark bolton]

Years ago I tried boiling sap with the pans on top of flat steel over the fire- it did not work. I then cut holes in the flat steel and sunk the pans down 1"- it worked great. Could evaporate 18L sap/hr using 3, 18" dia. pans and had no scorching or burning.

[RileySugarbush]

I had 7 years of steam table pans dropped in with hot sides. Never tasted burnt, even though the sides scorched. You will be unhappy if only the bottom is exposed. Very slow going.

[Dennis H.]

I tried to make a plate for the top of my barrel evap so I could place a steam pan down in only and inch or so. I didn't have much luck. 1st I couldn't get the hole to match the pan and also if you have different makes of pans they wont be the same shape most likely. The biggest problem was with all the heat the steel plate top wanted to go into the shape of pringle chip. Not much I could do to prevent that, just different amounts of heat at different spots on the steel plate.

If you think about it a little on a flat pan only fire hits the bottom of the pan not the sides. BUT nothing beats more square inches of suface area to speed up evaporation rate, so using the sides of the steam pans would give you a small increase in evap rate. if you can keep the lquid level above the fire level or as high as possible it should, I think, help in keeping the pans form scrotching.

By the way, nice start to good looking barrel evap. If you can brick and mortar it, it will increase the evap rate. last year my evap was just dry stacked bricks and heat leaked out every crack and seam. This year I mortared the brick in and the evap rate is awsome and it looks like the barrel will last a lot longer also.

[KenWP]

I only sunk my sink evaporator into the fire 3 inches or till the hold downs touched metal. I made a template with thin plywood and filed it down until it slipped onto the sink just right. Then I traced out the hole on the metal and cut it out and filed it down until the sink slips in and out just right. Not a fast way to do it but it works and makes a nice neat job. For a sink if a person could get the template that they are shipped with it would speed things up a bit.

[seclark]

Dennis, an angle iron frame welded to the plate I think would help stop the pringle affect.

[82cabby]

I decided to make an 'adapter' plate that will allow the bottom inch or two of the pans to dip into the fire. If it is too slow, its easy enough to pull it off and drop em right in. I re-enforced it with small angle iron and bar stock to help keep it flat. It's not pretty but it only has to last this season.

Dennis- I modeled mine after yours from your great post. I have the brick ready to go, it's just not in the stove in the pictures. When you mortared yours in, did you have to use any special mortar? I am hesitating on permanately installing the brick, since that will pretty much mean I won't be able to move it.

I'll post a few pictures later.

[Dennis H.]

It is mortar that is meant for fire brick. I got it at a local dealer that sells brick, concrete block. You should be able to get it from anyplace that sells the firebrick.

The stuff I got was premixed in a 5 or 10lb bucket. I can't remember which I got. They also make mortar that comes dry and you mix.
If I understand correctly the premixed mortar cures by water evap'ing out of it. The mortar that you have to mix cures by chemical reaction. What that all means is that if the premixed gets really wet it will get soft and may degrade, while the kind that cures thru chemical can get wet and not have a problem.

I haven't had a problem with the premixed mortar but that may be a benifit for you, if you ever need to remove the brick just wet the brick and mortar down and it may soften enough to make removing easier.

Sorry for the lengthy post.

[SeanD]

Dennis,

What kind of temps do you get out of your preheater? What's that flex hose coming in the window, outside air for the evap?

Sean

[Dennis H.]

Temps on the preheater, Not that much. The temp of the sap in the bucket is mid 30's-40, well lets just say it takes the chill out of it. It was a last minute add on. ad to get the sap from the bucket into the pan and I had some tubing from an old refrig ice maker so gave it a try.

The 3" dryer vent is my forced air inlet. I have an electric leaf blower outside. It is amazing how much quiter it is with it outside. You can see the speedcontrol on the wall beside the window. Sorry I went back and looked at the pic I posted and I trimmed that part off.

[SeanD]

Good idea putting that thing outside. I can imagine when hour number 8 or so rolls around that racket can get pretty bad. I know no one runs it wide open, but still after hours and hours you must hear it in your sleep.

Sean

[Dennis H.]

Sleep? You don't need no Sleep!

Sorry 82cabby for taking a slight detour here in your post.

[82cabby]

No problem! I'm learning from the conversation. I am debating about how to pre heat this year myself....

[birdmancf]

Glad to see more questions and updates about barrel stove operations. Thanks Dennis H and all for inspiring me to take it to the next level.

My set uplast year had dropped in pans, I'll attach a photo. I always figured the more heating surface versus potential cooling surfaces the better, I'd even stack wood around the outsides of the pans to keep a breeze from cooling the pans/sap. All my syrup produced was darker than I'd made with other rigs since you have to pour to boiled down sap over the scorched area eventually, but the taste was always fine, if not preferred. This year I'll be trying to raise my pans significantly and reduce the scorching, I'm also going to brick it up and add forced air. Can't wait to see how it all works.

[Rick_Seebeck]

I built a rig just like yours and tried it with the pans on top with little success. Dropped them in and wow! Works like a charm. I too planned on upgrading to a new arch and a custom pan but my little rig worked so good that I am sticking with her. I installed a forced draft fan using an old furnace draft induction blower and am up to about 8 gals an hour using two steam table pans. Keep the pans full above the line where they drop in and scorching will not be a problem. My syrup tastes great and is pretty light for a backyard rig.

[82cabby]

I installed a forced draft fan using an old furnace draft induction blower and am up to about 8 gals an hour using two steam table pans.

HOLY COW! 8 gallons an hour is great. How fast do you go through wood?