changing my ramp?

[tbear]

Hi Everyone,
I've been using a block arch with a 2x4 flat pan. The arch is two blocks high. The fire box is about 19in. deep. Currently the ramp goes (from the back of the firebox) straight up 6 in. (the same height as my grate) then angles up to the the bottom of the chimney. I've also been using a small desk fan to push air in under the grate. It takes awhile but eventually the whole pan boils at a fairly good clip. I'm able to get approx. 10+gph ( if my calculations are correct) depending on wind and weather. I've been cruising the site for several days now (it's a slow time for me) and I've come up with what I think or at least thought is a good idea. I've read so many threads over the past week or so I can't remember why I thought it was so good and I'm having a hard time trying to find the threads that validate the idea. Perhaps I've spent too much time talking to myself. Either way I've decided to throw it out there and hope someone can agree that the idea is sound or rein me in. Maybe a type of preemptive intervention. If I change the ramp to go straight up 12 in. at the rear of the firebox (3in. from the bottom of my pan) then horizontal (2 ft.) to the chimney, then place a couple 2 or 3 pieces of 1 1/2 in. angle iron as baffles on the horizontal (the top of the angle iron would be 1 1/2 in. from the pan) would that put more heat on the bottom of the pan? Thus create a better boil? Thanks, Ted

[Paperman]

Yes get that flue gas as tight to the pan as you can. The bars will also help with add ing turbulance the air to better transfer heat.

[tbear]

That's what I thought too. It's nice to know I'm not just making things up in my head! I think with the change in ramp design and the addition of baffles along with a better air source (a squirrel cage) I'll get a faster more complete pan boil. I love this forum! Ted

[lpakiz]

Ted,
Any non-protected metal in the firebox will have a relatively short life. Make provisions to change it out every so often, guessing once every two years for sure, maybe less, depending on how hot it will get.

[SeanD]

The back wall of the fire box goes straight up to within 3" of the pan and then it goes back to that stack at that 3" height for 2.5'? If I understand it correctly, I'm not so sure you'll get the result you want. I had better luck when I opened up my fire box and ramped up gradually. Heat has a hard time turning corners. I think you'll get a blast of heat right above the firebox and forward, but not past that toward the back. With only four feet of pan, you can have about 3' of it open to the fire with the last 1' down to 3". That's how the bigger rigs are set up.

I think it sounds like your set up is pretty good - especially if you are getting 10 gph from a 2x4. Maybe make the ramp steeper from the 6" point you have now, but I wouldn't block off the back of the pan from the fire box.

Sean

[tbear]

Okay, now I'm back to scratching my head. I was thinking that with such a small arch, air being pushed in by the fan and pulled out by the chimney the heat and gases wouldn't have a choice other than to travel along the bottom of the pan. But I do see how heat might not be good at turning corners. Any other thoughts on this? Thanks, Ted

[Scribner's Mountain Maple]

I have a thought, but with all my ideas, they come with a disclaimer(I am right at least 50% of the time). The thought is that the research has been done on this with the way new arch's are designed. The same concept should apply to a flat pan and your arch design. I think your current set up is pretty good with your ramp design. What I would suggest is to fill in your ramp a little. You could create a pillow like space on your ramp to drive the heat up using vermiculite and a small piece of insulated blanket. This would drive the heat closer to the pan and prevent heat loss under the ramp. Kind of like a larger arch is designed. You could take bricks or similar and create a box perimeter around your ramp and fill it in with a bag of vermiculite (Lowes or the Depot should have this), then cover that with a piece of blanket. Then secure the blanket down with a few bricks on the corners. Just an idea, but I would have to agree that the heat turning the corner may cause an uneven boil. Is there anyway you could test your idea before committing either way.

[twin6]

I'm with Scribner - try to create a ramp instead of a wall - with the same caveat that advice could run true 50% of the time. From my own experience running some larger rigs then designing and building my own 2'x5', you'll maximize heat transfer if you have a shorter firebox, aggressive ramp, then as long a horizontal run as you can create before the heat goes up the stack. Keep the space between your horizontal run and the pan bottom as small as you can while still having a decent draft. Small rigs are fun but one big drawback is that too much heat goes up the stack and doesn't get efficiently transferred to the pan/sap. My 2 cents... Good luck, and don't give up checking threads on this site for sound advice and ideas!

[michiganphil]

The back wall of the fire box goes straight up to within 3" of the pan and then it goes back to that stack at that 3" height for 2.5'? If I understand it correctly, I'm not so sure you'll get the result you want. I had better luck when I opened up my fire box and ramped up gradually. Heat has a hard time turning corners. I think you'll get a blast of heat right above the firebox and forward, but not past that toward the back. With only four feet of pan, you can have about 3' of it open to the fire with the last 1' down to 3". That's how the bigger rigs are set up.

I think it sounds like your set up is pretty good - especially if you are getting 10 gph from a 2x4. Maybe make the ramp steeper from the 6" point you have now, but I wouldn't block off the back of the pan from the fire box.

Sean


I agree with Sean. If your lifting the starting point of your ramp from 6" to 12" for only a 2.5' length of pan, you're going to need more than a desk fan to push the air through. I think you're just going to restrict it. You said you're getting 10+ gph off a 2x4...you can't ask for much more out of a flat pan.

[tbear]

Thanks for all the replies! I think you're right; 10+gph on a good day isn't too bad. I think I'll probably leave it as is for now. I'm sure you know how it is, especially at this time of year, thoughts like "I bet if I____" fill in the blank. Hey! If I put a piece of angle iron on the ramp where it flattens out to meet the chimney would that help to get the rear of the pan boiling better? There I go again! Man, I can't wait for syrup season! Thanks everyone! Ted