Syrup Pan boils too strongly - should the pans be swapped?

[user587]

First year on new homeade evaporator have boiled 4 times, it runs nicely - except… whenever we get halfway to syrup (boiling 3-5 F above water) we have to keep the firing to a modest level to keep the foam down. We’ve been using the prescribed procedure for defoaming (a couple drops into the entry point of each pan with each firing, tried oil and butter), and additionally we’ve tried lots of things in the syrup pan when the foaming comes on (butter, olive oil, pam cooking spray, canola oil). The defoaming aids help for sure, but ultimately we always end up tuning the fire down (turning off the over-fire air, and sometimes even the under-fire air) to keep the foaming down. No matter what defoaming aid we use (and how much), if we really load up the wood box and crank up the air, the foaming heads out of control.

The boil on the flue pan is OK, but not great. When the front pan is boiling nicely (under control, modest wood loading, low amounts of air) the rear pan boils in at the front of the drop-flues very strongly (5-6” geysers), but it’s only at the front of the flues. The long flues are not really boiling, they just carry the bubbles away from the front. When we’re running hot (first hr of boiling only to avoid over-foaming the front pan) we also get a little geyser at the exhaust end of the flues, probably due to the small dam near the exhaust end of the flues. But the entire length of the flues there is little or no boil (although it is difficult to see in the steam hoods and with the preheater)

We’re boiling about 25 gph, seems we should be doing better. It is painful to have to constantly keep the wood loading modest and also to throttle down the air. We are a bit cautious, being new at this.

Hindsight being 20-20, I think the design should have had an angled rear wall in the firebox. The firebox is 32” deep, the front pan is 36” deep, so the fire does not see the flues until it’s over the edge, and moving down the "hallway" flue. I may change the firebox to have an angled rear to give the fire and the flue runs a line-of-sight to each other. But right now, I REALLY do not want to tear apart the arch, grinding, cutting, welding, during the season. Don’t have the materials, etc… (although during the off season, this project is on the list).

What if we switched the flue pan to be at the firebox and put the syrup pan near the stack? It’s pretty easily done, the only thing to deal with would be the steam pipe but that’s simple duct work. There is 6” between the fire stack and the pan, so I can easily install a heat shield (have one already, actually) to avoid the stack heating the front of the pan (has not been a problem with the flue pan, especially with low stack temps). Obviously this would put a nice section of the flues right over the fire, (there is enough height in the firebox for this) which give a great boil in the flues. A small airdam could be added just past the syrup pan (with an open area just larger than the 8” stack area of 50 sq. in) to keep/reflect heat to make sure it boils at the syrup pan.

I’ve searched for and read a MT thread or 2 on this, but the info was pretty sketchy – I don’t recall any posting from anyone who has done it themselves (mostly legends and stories). It seems to me the main risk would be not getting enough boil at the syrup pan, and ending up with syrup in the flue pan (not pretty) but hopefully the exhaust can be managed well enough to get enough boil in the syrup pan.

Should I try to switch the pans? Is there something I’m missing?

Reference info:

- The area around the flues is approx. 1.6x the area of the 8” stack. The open area at the small dam behind the flues is approx. 1.4x the area of the stack

- Syrup pan runs about 1.5" deep.

- Stack temp 300-400 F. (300 when comfy in the front pan, 400 when risky in the front pan)

- Drop flue pan 2x5, flat syrup pan 2x3. Flues are ¾” wide with ¾” space between flues, 10 drops. There is about 1/2" to 3/4" air under the flues.

- Sweet in the flue pan (cooled down and measured today) is 5.75%. (5.5 at entry, 6 at exit, presumably mixed during the overnight cooling). Incoming sap. approx. 2.5%, so I’m guessing that while boiling, the sap moving from front to rear would be about 9% (2.5 – 9, average 5.75). (what should it be with a 2x3 and 2x5 pan configuration?)

- Simple copper preheater in the steam hood, (10) 4’ long runs of ½” copper. Not sure of the sap entry temp, sometime it burns the fingers, sometimes not)

Thank you in advance for your thought and advice!

http://i1103.photobucket.com/albums/g478/user587/Arch%20Construction/th_0212111156b.jpg (http://s1103.photobucket.com/albums/g478/user587/Arch%20Construction/?action=view&current=0212111156b.jpg)

[Southtowns27]

How foamy is "out of control?" It's normal for near syrup to look really foamy even though it really isn't. The "foam" in the last two compartments in the syrup pan of my evap nearly comes over the partitions. It's normal. Just keep up regular use of defoamer. The commercial "Atmos" stuff is the way to go. 1.5" deep is plenty of depth so I don't think you need to worry about running it dry.

[user587]

How foamy is "out of control?" It's normal for near syrup to look really foamy even though it really isn't. The "foam" in the last two compartments in the syrup pan of my evap nearly comes over the partitions. It's normal. .

Wow - I've not been comfortable with foam that high. The left 2 pics below are what we call "good boils" but the right pic is nearly trouble in one section. We've found that when there is a foam like that, it seem to slow the progression to syrup - like the foam traps the steam and reduces boiling.

A local syrup maker (1200 taps, non-MT) has been very graciously helping me. when I visited his boil recently, it looked like the 2 on the left - no build-up of foam, the top of the liquid is visible.

Now I'm a bit confused - If I boil and get foam up the the dividers (5" high) it seems scary to me!
http://i1103.photobucket.com/albums/g478/user587/Boiling%20Pics/th_0303111234a.jpg (http://s1103.photobucket.com/albums/g478/user587/Boiling%20Pics/?action=view&current=0303111234a.jpg) http://i1103.photobucket.com/albums/g478/user587/Boiling%20Pics/th_0303111138a.jpg (http://s1103.photobucket.com/albums/g478/user587/Boiling%20Pics/?action=view&current=0303111138a.jpg) http://i1103.photobucket.com/albums/g478/user587/Boiling%20Pics/th_0303111039a.jpg (http://s1103.photobucket.com/albums/g478/user587/Boiling%20Pics/?action=view&current=0303111039a.jpg)

[Southtowns27]

The pic on the right is what mine looks like ALL the time, sometimes even "foamier." (is that a word??) Doesn't seem to affect anything. I pulled 16 gals of syrup off mine in 8 hours yesterday. I'm running only 1" in my front pan (you said you have 1.5") so I don't think you have a problem.

[red maples]

nah I don't like foam!!! my boil rate goes down with foam!!! and it pushes all the syrup to the front pans. then mixes back once you add defoamer... it also throws off your floats. I recommend keeping the foam to a minimun.

keep and even boil defoam I would have defoamed that pan once it starts to rise like that. take your eye off of it for a momment boom over flow. especially with that shallow pan mine is very deep.

just my 2 cents

[adk1]

nah I don't like foam!!! my boil rate goes down with foam!!! and it pushes all the syrup to the front pans. then mixes back once you add defoamer... it also throws off your floats. I recommend keeping the foam to a minimun.

keep and even boil defoam I would have defoamed that pan once it starts to rise like that. take your eye off of it for a momment boom over flow. especially with that shallow pan mine is very deep.

just my 2 cents

Also remember that every time your use defoamer, it draws syrup into that area for some reason.

[Maple Hobo]

Some foam is normal, too much foam is bad.
If the boil gets too hard it can allow a air bubble under the sap in the bubble and scorch you pan.

Keep up the heat and run your pans a little deeper (using floats?). Experiment a bit, you'll find the sweet spot and then you'll have to adjust it for how sweet your water is from that point.

Too deep and you'll take a lot longer to boil off the water.

All I can speak too on this...lol

[buck3m]

I am no expert but somethings not right. Too much foam must be a bad thing or there wouldn't be all that defoamer sold and all the talk about keeping the foam down.

It make no sense to me that you're only getting 25 gph yet your syrup pan is foaming out of control. You said "But the entire length of the flues there is little or no boil (although it is difficult to see in the steam hoods and with the preheater)" No boil in the flue pan? Seems like some arch design problem as you've surmised.

I suppose there's the risk of damaging your flues with wood if you put your flue pan over the fire box, but to tell you the truth that's probably what I'd try for this season just to see how it works.

Hopefully more of these guys with a lot more expertise will have some insight.

[Maple Mist]

you might need more stack . too much heat under front pan means not enough stack. stack temp on wood 600 degrees and up.

[user587]

You said "But the entire length of the flues there is little or no boil (although it is difficult to see in the steam hoods and with the preheater)" No boil in the flue pan? Seems like some arch design problem as you've surmised.


Sorry, I was not quite clear. There is a very good boil at the front of the flues - geysers 5-6" above the liquid level. But beyond the first 6" it's difficult to see any additional boil (although visibility is poor) except again at the tail end of the flues, where there are small (1-2") geysers at times.

[user587]

you might need more stack . too much heat under front pan means not enough stack. stack temp on wood 600 degrees and up.

Do you mean stack length or dia? The stack is 8" dia, with a 42" long tapered (rect. to round) base stack and then about 12' more round stack.

thanks - Scott

[Maple Mist]

hopefully someone with a rig your size will chime in with there stack size and length

[Brent]

Also remember that every time your use defoamer, it draws syrup into that area for some reason.

old school of thought was to put the defoamer in at the entrance point of the pan. As commented above, that will draw the liquids back to the point where you apply the drops. I was visiting a progressive local sugarmaker and he said to do the opposite. Put the drops in near the draw off point, so the flow on the bubble collapse is in the direction you want it to go ... towards the draw off.
That's what I did last year and it worked great.

[Dave Puhl]

It looks like to me that you have alot of heat on your syrup pan which is ok to a point...how is the foam in the sap pan...this is white in color ..if you have sap foam add more defoamer...on my 2x6 I use more than a few drops...is your sap pan really jumpin..some times mine will boil/jump to the top....your set up is new is your arch bricked up correctly.... is there smoke coming out or is it clear once it gets going....cant tell by the pix...make sure your syrup does invert to the center....get the flow going by drawing off a little and add to the sap side...

[3rdgen.maple]

A few things for you to take into consideration and dont get mad at me you asked. lol First off I would skip all the off the shelf grocery store defoamer substitutes and get a bottle of Atmos defoamer. I add a couple drops where the raw sap enters the pan every hour. I never had a pan look like that and I can push 40gph on my 2x6. Next thing is (this is where the mad thing comes in) your syrup pan is to shallow and you should not have a wall blocking off the firebox. It needs to be a ramp, that wall is holding the heat up front and not getting the max heat to the flue pan. If you angle the wall so it ends about 18 inches into the flue pan you are going to up your gph by alot and you wont have to baby the fire. Put the heat in those flues and less under the syrup pan, the flues are what is going to get you gph.

[twofer]

I logged on tonight to start this same exact thread!

I'm running a 2.5'x10' Inferno and I'm having the same exact problem. After 8 hours of boiling I start to get foaming in the syrup pan that won't go down even with adding defoamer to the last partition. Like you I am able to keep the foam down if I open the door and allow the syrup pan to boil at a very modest rate.

Here's a list of things I have tried over the past two days with no success. After 7 hours of boiling the foam starts to build up.


Cleaned syrup pan of all nitre. You can see a light buildup that you can push around with a metal spatula but it looks nothing like the picture of the heavy deposit in the North American Maple Syrup Producers manual.
Reversing pans every three hours
Leveled pans (maybe a 1/16" out of level)
Loaded wood farther back in the chamber
Increased defoamer application rate to 4 drops every 10 minutes in flue pan float box
Ran syrup pan 1.5" deep


I'm at a loss for what to try next. I don't know if the sap is bad from sitting in the tanks but it's clear as day and making dark amber???? I don't know if the Atmos defoamer (purchased this year) I have is bad and isn't working??? I don't know if the nitre buildup is just that bad and the syrup pan needs to be cleaned after every 7 hours???

At this rate there is going to be sap on the ground here in Michigan if I can't get a decent boil rate going for an extended period of time.


A few things for you to take into consideration and dont get mad at me you asked. lol First off I would skip all the off the shelf grocery store defoamer substitutes and get a bottle of Atmos defoamer. I add a couple drops where the raw sap enters the pan every hour. I never had a pan look like that and I can push 40gph on my 2x6. Next thing is (this is where the mad thing comes in) your syrup pan is to shallow and you should not have a wall blocking off the firebox. It needs to be a ramp, that wall is holding the heat up front and not getting the max heat to the flue pan. If you angle the wall so it ends about 18 inches into the flue pan you are going to up your gph by alot and you wont have to baby the fire. Put the heat in those flues and less under the syrup pan, the flues are what is going to get you gph.

I've been using Atmos defoamer and when it is added to a partition that is foaming it has no effect. He might be experiencing the same problem I am.

[Treetapper]

Good lookin rig. You will get it worked out. That's part of the fun of building your own. Good luck!

[user587]

A few things for you to take into consideration and dont get mad at me you asked. lol First off I would skip all the off the shelf grocery store defoamer substitutes and get a bottle of Atmos defoamer. I add a couple drops where the raw sap enters the pan every hour. I never had a pan look like that and I can push 40gph on my 2x6. Next thing is (this is where the mad thing comes in) your syrup pan is to shallow and you should not have a wall blocking off the firebox. It needs to be a ramp, that wall is holding the heat up front and not getting the max heat to the flue pan. If you angle the wall so it ends about 18 inches into the flue pan you are going to up your gph by alot and you wont have to baby the fire. Put the heat in those flues and less under the syrup pan, the flues are what is going to get you gph.

Thanks for taking the time to respond - and I'm definitely not mad (although perhaps a bit frustrated). regarding a ramp on the arch - I came to the conclusion that I wish I had built a ramp. However, I'm loath to change it mid-season - lots of cutting, welding, grinding ig the sugar house now does not sound fun. (that's why I've been thinking about venturing into the uncharted dark world of swapped pans)

I ordered some of the commercial defoamer, should be here Monday late. I might try bacon also...

When you say the syrup pan is too shallow, do you mean liquid level (1.5") or pan sidewall height (7", if I recall correctly)

Thanks!

[Southtowns27]

I still don't think either of you guys actually have a problem. Mine runs the same way and always has. I've never scorched the pan and I'm currently making "fancy" grade syrup. Next boil I'll have to take some pics of it since no one wants to believe me...

[3rdgen.maple]

user587 I was thinking the height of the pan. If it had higher sides it wouldnt be as big a deal if it foams up. Mine has something like 14 inches or so. I recall the foaming being a problem for others as well. I have never experienced this problem but am also wondering if it is just what nature is giving you at this point in time and if it will just go away on its own in due time. I do know you should be able to just cram that firebox full of wood and be more concerned of getting it hotter rather than cooler. I gave up last night as I couldnt get a good boil. Temps outside dropped and snow started to fall and went from a raging boil to wasting wood and fighting the darn thing. Sometimes it is what it is and just have to try another day.

[RileySugarbush]

I'd look closely at your air flow. If possible increase your stack size. You mentioned cranking up the air but I don't recall seeing what blower you had on there. For what it's worth, our 2x6 has a small steep walled firebox with a 200 cfm blower and have never seen this. I think the stack is 10" dia and we run probe temps at the stack base of around 1600 and boil 40 to 45 gph. So something is clearly wrong. I'm thinking much highar air flow will increase total energy but blow the highest temps further back toward your stack and away from your syrup pan.

[user587]

I'd look closely at your air flow. If possible increase your stack size. You mentioned cranking up the air but I don't recall seeing what blower you had on there. For what it's worth, our 2x6 has a small steep walled firebox with a 200 cfm blower and have never seen this. I think the stack is 10" dia and we run probe temps at the stack base of around 1600 and boil 40 to 45 gph. So something is clearly wrong. I'm thinking much highar air flow will increase total energy but blow the highest temps further back toward your stack and away from your syrup pan.

The blower is the research-paper recommended one from Grainger, except the paper suggests 1/2 hp for 2' wide arch, and I have a 3/4hp. I forget the cfm rating, but it's the paddle fan type that creates a few inches of water column. It is fed under and over the fire, each can be independently throttled from zero-to-full open. 2" PVC feed the under-fire, 3" PVC feed the over-fire. It moves a lot of air.

[user587]

user587 I was thinking the height of the pan. If it had higher sides it wouldnt be as big a deal if it foams up. Mine has something like 14 inches or so. I recall the foaming being a problem for others as well. I have never experienced this problem but am also wondering if it is just what nature is giving you at this point in time and if it will just go away on its own in due time. I do know you should be able to just cram that firebox full of wood and be more concerned of getting it hotter rather than cooler. I gave up last night as I couldnt get a good boil. Temps outside dropped and snow started to fall and went from a raging boil to wasting wood and fighting the darn thing. Sometimes it is what it is and just have to try another day.

My fear with foaming is not running over the sides (I've never let it get near that), but rather running dry at the bottom of the pan. I'm boiling inside a building, no breeze, and usually about 60 degrees around the evap. I made a few tweaks, will boil again today hopefully with better results.

[Flat Lander Sugaring]

hummm what am I doing wrong< I don't get foam, good or bad. I just talked about this last night with a person and I already can't remember what he said:(

40 to 45 an hour on a 2x6? wow is there a steam away on it?

[KenWP]

What happens if you cut down the under fire air and increase the over fire air. Does the over fire air blow towards the stack or is it blowing the heat to the side of the fire box whick keeps the front pan to hot and not move the heat towards the flue pans. The under fire air could be directing the flames up against the syrup pan to much.

[RileySugarbush]

Those are the rates we have achieved for the last three tears using under fire air only with a 210 cfm low pressure blower through very open ducts and grates. Firing with fine split dry fuel every 5-6min and a base stack temp of 1500 - 1600 F measured with a Condor probe. This isn't very fuel efficient but it sure evaporates a lot of water.

User 587: Maybe try this experiment. Increase you underfire air dramatically and dont worry about over. Can you combine both ducts to under the grate? Sacrifice efficiency for rate and increase the air flow total. If the grate has restrictive nozzles this might be a problem. I believe you have a very hot fire but not enough total air flow to extend that hot combustion back to the flue pan.

[twofer]

The blower is the research-paper recommended one from Grainger, except the paper suggests 1/2 hp for 2' wide arch, and I have a 3/4hp. I forget the cfm rating, but it's the paddle fan type that creates a few inches of water column. It is fed under and over the fire, each can be independently throttled from zero-to-full open. 2" PVC feed the under-fire, 3" PVC feed the over-fire. It moves a lot of air.

We share even more in common with this problem. I also went with the research paper but I ended up using the 1/2 HP blower that they recommended.

Last night we made it five hours into the boil before we had to shutdown because of the foaming. So far the only thing that seems to help is cleaning the pan so I'm cleaning the pan for the third time after making only 13 gallons of syrup.

[Southtowns27]

Ok, I got some pics from last night. This is what my front pan looks like ALL the time. Always has, both on this rig and my old 2x6. Maybe it's just the way my sap is, I don't know. Anyway, the liquid level in the pan is about 1.25". The "foam" is dang near to the top of the partitions. Defoamer has little to no effect on it. I've never scorched the pan.
I said it before, but I really don't think you guys have a problem.
http://img.photobucket.com/albums/v621/Southtowns27/Maple%20Syrup%202011/Picture021.jpg
http://img.photobucket.com/albums/v621/Southtowns27/Maple%20Syrup%202011/Picture020.jpg

[user587]

Making progress now. Tried every defoamer known to mankind (including now bacon, and Atmos (sp?) from Leader. When it's foaming, nothing will take care of it except toning down the fire.

But - today I scoured the pan before boiling and had a great day - foaming was very limited and could be easily managed with almost any defoamer, - we only needed it a few times (maybe 1-2 times per hour, if that). I had "cleaned" the pan before each boil, but this time I scoured it raw.

Also to address the non-ramped arch, I removed a couple rows of firebrick (gaining 1.25") and chamfered the back wall firebrick to allow a slightly better transition from firebox to the flue run. Also added some baffles/heat shields hanging just under the front pan to reduce the heat transfer to the front pan, allowing more to the back. Made the baffles block more of the center 2 compartments, so now the 4 front compartments boil very equally.

With no foaming today, we played with the firing - fired heavily with small wood every 7 minutes, and lots of air over the fire, modest air under the fire. Boiled 84 gallons in the last 2 hours, 42 gph. I think there is more improvement left if I can get better contact from the fire to the flue pan, and we may play with the firing schedule some more also. I'm still interested to try swapping pans, but for now the honest 42 gph will be OK I guess.

Responding to a couple responses, we did play with the under-vs-over fire air, and as suggested the over-fire air makes lots of heat, but it stays more near the front (hence the heat shields). A "colder" fire (less air) will run back more, but the boil in the flue pan is lower due to the colder fire.

Thanks for the tips, it's just-in-time 'cause there is a lot of boiling to be done this week!

[Dave Puhl]

From what i see that is not foam it syrup cooking,....if that makes sense....hot fire you r have going....as long as ypu got the flow you should be ok ...just got done cookin tonight and tried to keep track of canola oil I used...as long as the sap pan was foaming I was giving it a squirt...after several seconds the oil hit it you could hear the boil...listen to and smell your evaporater running....

[PerryW]

I like foam. This is the way I run my front pan:

http://i6.photobucket.com/albums/y235/perryW/th_HPSyrupBoil2Small.jpg (http://s6.photobucket.com/albums/y235/perryW/?action=view&current=HPSyrupBoil2Small.mp4)

[maple flats]

Anytime I have foam like PerryW I run into big problems. Over the years I have discovered that excessive foam is caused by too much sugar sand in the front pan as long as you add a drop or 2 of defoamer in the flue pan at every fueling. I try to never add in the syrup pan except as last resort, while shutting down to clean the front pan. You might also try more stack.
On my rig I have a vertical wall at the back of the firebox up to within 6" of the pan, then a short ramp to the back. Last year I had geyser problems right behind the wall but I made a deflector that sits on the flue pan to keep it in the pan. Now I can push as hard as I like, the geysers are deflected back into the pan and I get a good boil all the way back on my 6' long flue pan. To know if sugarsand is getting to be a problem try 2 things, one= run a cleaning brush in the offending pan while boiling, if it does not slide easily you have a coating of sugar sand, two= watch your boil rate, a decided drop with all other things being equal means you have sugar sand insulating the pan (and adding to the foaming problem)
When this happens I shut down, when the fire is out I drain the pan, add white vinegar, let set (warm it if not getting warm) and wait for 15-20 minutes, then brush, the sand will come off. Rinse very well with clean fresh water. Then get beck to boiling, a new clean pan will boil very nicely. If I need to do this during a boil it takes about 75-90 minutes and I am back to boiling. Most of this time is waiting for the coals to burn out. The important part is accurate monitoring of sap in to keep track of boil rate. When I need it I notice a drop of 20% or more in boil rate.
About the ramp, I always had a long ramp on my last evaporator but went to the wall last year when I added over fire air. Last year the boil was so fast just above and immediately behind the wall that I had to slow the boil rate o I lost lots of sap splashing into the hood drain and some running down the side of the evaporator from between the pan and the hood. My deflector stopped that, the deflector is patterned after the one Leader has on a 2x6 I saw the last 2 years on a 2x6 at the Verona show, I don't know if they use it on other sizes but I use one on my 3x8.

[PerryW]

I can get mine to foam like that even with clean pans. It's usually just my evaporator telling me it needs more wood. Open a door and chuck some wood in and the front pan slows down since the hot coals are now covered with wood.

I usually don't have to clean the pans midseason at all (except to clean the sides above the waterline after each boil), but I'm religious about reversing the flow after each boil, so I think that helps to prevent buildup.

Personally, I'm not a big fan of putting a lot defoamer in the syrup pan, since it may end up in the finished product.

With the back pan, when I hear the "rattling" quieting down, I add a couple drops.

[Old-Timer]

# 1 Your running to deep in your front pan, Drop it to 1 in. I
prefer to boil w 3/4 and have for 60 + yrs.
# 2 Increase your stack size by 2 in. or increase the stack height
to get more draft.
# 3 Insulate up 1/2 in from the bottom of your flues the entire
length of the flue pan.
# 4 Stack temp should be 800/1100 deg F
Good Luck

[crackher]

I keep learning every day but when my syrup pan is boiling too hard that mean I have too much fire and coal underneath the syrup pan.
Keep your fire back more and it will naturally cool off the pan, no defoamer.

[user587]

Today boiled again, started with a freshly scoured pan again, and had no problem keeping the foam down with an occasional drop of oil. It appears that the fresh pan does the trick for us.

Still playing with the firing pattern/timing/wood type, heat shield under the front pan, etc...

46 gph average for 5 hours in the middle of the boil.

[RileySugarbush]

What is the temp at the stack base now? (Probe or surface thermometer)

[user587]

What is the temp at the stack base now? (Probe or surface thermometer)

hi 400's, saw 500 only once. Measured with handheld laser on exterior of base stack (painted black)

Checked the 7 hour average, it was 47 gph. Seems decent to me considering the lack of a ramp - I feel performance can be improved further if/when I get the fire ramped back to the flues better.

[RileySugarbush]

Don't know how that compares to my internal probe thermometer, but I bet you can run it harder with more under fire air and get a higher rate at the expense of fuel efficiency. Like Brandon does on his 2x8. I am not convinced a ramp is needed. I don't have one and my syrup pan overlaps the back wall of the firebox by 8 inches. It does add some flow resistance and may require a stronger stack draw.

[user587]

We share even more in common with this problem. I also went with the research paper but I ended up using the 1/2 HP blower that they recommended.

Last night we made it five hours into the boil before we had to shutdown because of the foaming. So far the only thing that seems to help is cleaning the pan so I'm cleaning the pan for the third time after making only 13 gallons of syrup.

Twofer - for us the key is cleaning the pan. We now clean the syrup pan every firing, and have only occasional foaming, and when it does foam it responds very well to tiny amounts of almost any defoaming agent. 15 minutes with vinegar makes the front pan cleaning very easy. But we still have huge heat in the front pan - we've installed a heat shield between the fire and the center of the front pan to moderate it. We need to fire hard to get a strong boil in the flue pan which is a bit much for the syrup pan.

We're getting 50 gph consistently now, after playing with the firing pattern, etc... but I think we can do better with some arch mods for next year.

[twofer]

I've reduced our depth to 1 1/2 and now the scale isn't building up on the bottom of the pan. So that's one problem down. I also have the firing down so that we are getting more frequent smaller draws and I think that is also helping reduce the scale buildup.

Even with a freshly cleaned pan when we get 4 hours into the boil there is about 1-1/2" inches of foam in the last three partitions. Stack temp is 500°F.

Another thing I've noticed is that the two center partitions seem to be bowed in the center. In the middle of the partition it is ~1/8 deeper compared to outside of the partition where the dividers are welded. Not sure if this is acceptable or not. This is a brand new pan.

[user587]

I've reduced our depth to 1 1/2 and now the scale isn't building up on the bottom of the pan. So that's one problem down. I also have the firing down so that we are getting more frequent smaller draws and I think that is also helping reduce the scale buildup.

Even with a freshly cleaned pan when we get 4 hours into the boil there is about 1-1/2" inches of foam in the last three partitions. Stack temp is 500°F.

Another thing I've noticed is that the two center partitions seem to be bowed in the center. In the middle of the partition it is ~1/8 deeper compared to outside of the partition where the dividers are welded. Not sure if this is acceptable or not. This is a brand new pan.

I think we're finding the same thing with our rigs - with effective air-over-fire the front pan boil is rather heavy. As mentioned before, we added a heat shield (pic below) so we could fire heavily to make lots of steam in the rear pan without over-doing the front pan. It seems to help, and due to the shape/design we evened-out the boil in the 4 compartments.


http://i1103.photobucket.com/albums/g478/user587/Arch%20Construction/th_0318110855a.jpg (http://s1103.photobucket.com/albums/g478/user587/Arch%20Construction/?action=view&current=0318110855a.jpg)

[sugarsand]

I"ve been in to syrup for over 50 years, as my father and grandfather before me. May be we have been doing things wrong all these years but we don"t normally knock the foam down unless it is about to go over the sides. We have always used a dairy heavy cream from the grocery store. One little touch of this will take out all the foam in the syrup pan almost instantly.

sugarsand

[Flat Lander Sugaring]

I"ve been in to syrup for over 50 years, as my father and grandfather before me. May be we have been doing things wrong all these years but we don"t normally knock the foam down unless it is about to go over the sides. We have always used a dairy heavy cream from the grocery store. One little touch of this will take out all the foam in the syrup pan almost instantly.

sugarsand

the thing is if you sell your syrup to a person who is allergic to dairy products it could be bad for that person thats why they make that defoamer product. I'm with you on letting the foam go as far as it can before knocking it down.