Has anyone added a blower to a 1/2 pint?

[Matt Hatch]

Have a half pint and was wondering if anyone has added a blower ??

[RileySugarbush]

Sure enough.

When I was boiling on concrete blocks and steam table pans on the north side of Riley Lake, RileySugarbushSouth, and friends had a half pint on the south side. Adding a firebrick wall at the back of the firebox and the blower shown here got the rate up around 9-10 gallons per hour.

We all boil together here now and the half pint is being used by a first year sugar maker this season.

[mapleman3]

I moved this to the evaporator forum.

[tappin&sappin]

Knowing what I know now, I'd have a blower on anything I boiled with. Makes a world of difference. Seriously, put one on your half pint.

- Jake

[Dan W]

Jake, I bought your Half Pint set-up a couple of years ago. I put a barrel kit door on it and run a furnace flue induction fan through 2 inch conduit to it. It works great! I am getting 8 to 9 GPH. Are you ready to move up in evaporator size yet? I need a bigger one!

[Turtlecreek]

If you buy jakes I'm in the market for a half pint or something small for next season. If its in good shape I may be interested.

[Dan W]

I was really just joking with Jake. It seems you out grow your equipment every couple of years, I know I have. I am going to seriously try to upgrade for next year though. If I find something I will let you know about the Half Pint.

[Matt Hatch]

Perfect thank you happy boiling

[Brent]

I put a blower on a half pint, a little Fasco 0.7 amp unit and it increased the boil rate buy 30 to 50%. BUT it ate 3 X as much wood.

The flat bottom on the Leader lets most of the heat go up the stack.

[RileySugarbush]

If you brick a back wall up to the bottom of the pan, leaving an inch or so, your boil rate and efficiency will increase.

[gator330]

Any one have an idea about how many cfm blower you want for a small 19"X39" flat pan??

Rileysugarbush

I Like the idea of a back wall, will be putting one in!!!!!

[RileySugarbush]

Like this. I would make the wall even higher, so that the rectangular slot has the same cross sectional area as the stack.

[captaincpfd]

John i have a 2x3 G.H. Grimm do you think that back wall would help me out i like the idea and i would like to do it if you or anyone else on here thinks it would help. If so how far in do i put that back wall from the front of the fire box door. Thanks for your help chad

[RileySugarbush]

I think a half pint is a bit shorter than 3', so I think you are fine. If you have a flat pan, then the goal is to get the flow up and tight against it for as long a distance as you can. The limitation is how much room you need for firewood. Build your wall as close to the door as you can.

I'm sure it will help a lot compared to a full open firebox.

[captaincpfd]

I think a half pint is a bit shorter than 3', so I think you are fine. If you have a flat pan, then the goal is to get the flow up and tight against it for as long a distance as you can. The limitation is how much room you need for firewood. Build your wall as close to the door as you can.

I'm sure it will help a lot compared to a full open firebox.

The firebox is 22"x33 1/2" so if i put a wall in at 18" or 24" i would be ok my wood is cut to 16" how high do i dare go with the wall and one other question if you dont mind the stack is off the back would that be a problem and thank you for your help i'm very thankful i'm a greenhorn at sugaring this year i have out 83 buckets right now. Looking to have fun and enjoy making syrup with my 4 kids. last thing my pan is flat with three dividers in place.

[RileySugarbush]

I'd put it at 18" if your wood is short enough. If you have a 6" diameter stack, the area is 28 sq inches. So a gap of about 1.5 inches should be about right.

Good luck and let us know how it works out.

[Brent]

Any one have an idea about how many cfm blower you want for a small 19"X39" flat pan??

Rileysugarbush

I Like the idea of a back wall, will be putting one in!!!!!

The little Fasco with the 0.7 amp motor would make my half pint run so hot the bottom of the stack glowed dull red after the sun went down. Boiled a fair bit faster but ate enough firewood in 3 weeks to heat my house for the winter. As a matter of interest, the 2 x 6 raised flue I have now eats the same amount of wood and boils about 5 or 6 times the GPH of sap

[steve J]

I have a 2x3 from Mason and that back wall idea looks good. Were you able to buy a block that size or did you have to custom pour one?

[RileySugarbush]

Brent,

One possible cause of that is that the blower was blasting the heat straight out the stack. That is the purpose of the back wall to the firebox. With or without the blower, fuel efficiency is increased when the combustion gasses are forced near the bottom of the pan and are not allowed to escape without contributing to the evaporation.

[quial100]

I see what you have done with the half pint and the back wall.

Q. Would this work on a arch that ramps up to the stack?

I have a small arch 19"x39" just added a blower. There is room to stand a fire brick on edge two across and still leave 2" from the top, to the rear stack plate. all just at the end of the pan.

Q. Is the concept of the wall to push the heat up and back across the bottom of the pan also slowing it from a fast exit out the stack??

[tappin&sappin]

Dan W... glad to hear the half pint is treating you well. Your doing good w/ that blower, I used to only get 5-6gph out of it from what I remember.

My 2x6 w/ no preheater and a combustion fan is giving me about 25gph right now.

If I can find a 2.5x8 or 3x10 for the right price, my 2x6 will be on the market.

I will of course post it for sale here on the trader in the classifieds section if I choose to sell it. :)

- Jake

[RileySugarbush]

Quail,

For a wood fired arch with a blower, having a vertical back wall to the firebox maximizes heat transfer to the pan, which is the goal, right? You want as narrow a path for the flue gases as you can get away with, which is limited by eventually choking off the draft/flow if you get too tight. I propose that keeping the flow area constant and equal to the area of the stack is a good place to start. Keep the wall as close to the front of the arch as you can and still get wood in. I believe the sloped flue are a legacy of natural draft arches and are not optimal.

This is all just my opinion, but it makes physical sense to me anyway. Applying these principles I am getting 45gph out of my 2x6 even though it has too big a syrup pan. This year I am adding a bit of air injection over the firebox to try and do a little better and save some wood.

For your second question, the added restriction will reduce the air mass flow rate, but it will actually be moving at a higher velocity since it is a smaller flow area. The gain is that more of the heat in the gases are close to the pan for better heat transfer.

[gator330]

rileysugarbush

Thanks for the info!!!! (Quail is my dad, I was at his house when I posted my Questions he was logged on....) Sence then I have come home and put in the vertical back. I've seen arches with this before All makes a lot of sence!!!! Just hearing it from some one makes it all a little better in my mind. Thank you again. I will see if it all warks this weekend when the sap flood hits the north east!!!!! The blower is a little 80 cfm 4 in duct blower that I fastened to tine throught the ash door. Looks as if it will work.

[RileySugarbush]

Gator,

That sounds good. If you really want to try something interesting for all of us, how about this?

Get a sheet of steel, about 1/8 thick and as wide as your arch and set it on the top of the wall so that it projects back toward the stack to keep the narrow slot as long as possible, maybe to within 2" of your arch back. Someone posted a photo of something like this with the corners cut off to force the flow to the outside edges. Have it wide enough to project forward over the firebox an equal amount. That back firebox wall position has been determined by the wood length/grate size. If your firing door is low enough so chucking in wood won't hit this plate, then you may see a remarkable increase in evaporation rate.

Make sure the plate can't fall off mid boil. That would ruin your day!

[Mac]

Some one was asking about a back wall in a 2 x 3. Here is what I did, just used full fire brick... cut em to fit then added some support brick behind it, in case I heave a piece of eastern hop hornbeam to hard. and it hits that back wall has some guts to it... I left just under 3" to the pan... mabe I should go higher... I got 8gph with H2o on a test fire with out really stoking it.

[steve J]

I like what you did with your mason rig. I currently dry brick my rig every year because I must be able to move it our of the way after the season. So I need to figure out how to make a similar wall that I can take out after the season maybe useing sheet metal?

[johnallin]

Steve,

I did a back wall on my half pint, up to within one course of brick to the pan.
I then laid bricks on top of the wall with about 1" between them to further concentrate the heat before it goes up the stack. Played around with it until I got the results I wanted. Works great.

From what I see, you may be able to lightly mortar and break it out at the end of the season. Just a thought

[Uncle Tucker]

I gave this some thoughts a couple of years ago. I first idea was to duplicate a house wood stove by putting a baffle on top of the firebox. I put 1/4” steel from the top of the wall to 2 inches short of the front of the arch. The thought behind this is that flames are the hottest near the end. So have the flames snake under the pan and burn under the pans instead of in the stovepipe.
During the test boil the first problem I had was when loading wood I hit the steel plate back and it blocked the smoke stack off (smoke from every crack on the arch). The second problem was that the radiant heat from the coals was hotter than the flames, so I had shielded the heat with the steel plate. So, I totally removed the steel plate. I noticed most of the heat went over the center of the wall.
The final adjustment I did was to cut the corners off the steel plate and cut the plate just as long as the wall. This worked great to push the fire to the back corners of the arch and this is how it stayed for two seasons until I sold the evaporator.
I hope these pictures help http://picasaweb.google.com/uncletucker/HalfPint#5216991468694765170 , http://picasaweb.google.com/uncletucker/HalfPint#5216991444158422018 .

[Greenthumb]

when you got the the 1/2 pint tricked out what was your boil rate. It looks like a great set up.

[Brent]

when I got mine going with the blower and as Leader put in the instructions, a flame wall near the back like has been discussed here . .. I think roughly 10 to 12 GPH.

[Uncle Tucker]

I never had a blower on mine. I would get 6-8 GPH. I had a blower for it but I sold the stove before got to try it.

[steve J]

I am going to try and put something together quickly for my 2x3. Is there any reason why I could not use a cement blocks to quickly make this back wall? Also I noticed that someone mentioned a blower I do not have a blower would installing this wall still be useful without a blower?

[RileySugarbush]

The wall helps with or without a blower. You can make the wall a little higher with a blower since the system is less sensitive to the increased resistance to flow. I think many have used about a 3" gap between the wall and pan.

Cement blocks will work for a season, they just loose all strength at the high temperatures. Late in the season they may break if you toss the wood in too hard.

[Brent]

As noted above, I think there is a risk the cement blocks would crack / crumble. Not a big loss but not neat.

A blower will give you hotter temps and a faster boil but it will use
a disproportionate abount of wood.

You may get a 30 to 50% increase in the boil rate but use 2 X the
woold. If you've got more wood than you need, go for it.

You will get the same results with less wood if you can put a pipe or
two above the wood , pointing downward, to create turbulence.
See http://www.uvm.edu/~pmrc/ (http://www.uvm.edu/%7Epmrc/) They actuallay suggest something like
80% of the air should be above the wood and only 20% coming up
through the grate.

[steve J]

Well I ran my 2x3 with the wall installed and found it boiled hot up to the face of the wall. The center flow was boiling almost to the back of evaporator but no boil onthe back of the draw off channel until you got in front of the wall. Do you think if I lowered the wall a little under the draw off Channel I might get a little more heat to that back corner ?

[johnallin]

Steve,
I have a back wall on my half pint as per Leader's instructions, but I only went up to where another course of brick would be about 1½" from the bottom of the pan. I then used 1/2 bricks just laying on the top of the wall and left spaces of about 1" between them and kept moving them around until I found what worked for me.

As expected the pan boiled fastest where the opennings were. If I leave a brick out under the draw off channel the fire seeks that hole and the pan boils like crazy there. Keep playing with it and you should find something that works for you. Problem for me is that I havn't cemented them in yet and keep knocking them off the wall.....