Best fire grate height?(OTE)

[Hunt4sap]

What is everyone's best experience with the height from the fire grate to the bottom of their pan, more specifically in OTEs?
Got my grate welded up this afternoon with angle iron and looking for some examples before I mount it in my OTE...
Thanks Matt

[Cjadamec]

My grate sits right around where the sides of the tank start to curve into the bottom. That way I didn't need any brackets to hold the grate up it just rests on the fire brick I have in there to protect the insulation blanket. You want your grate to be easily removable to make cleaning the fire box easier.

I would say my overall fire box is a little less than a 24"x24" cube. There's about 24" from the grate to the bottom of my front hotel pans and about 18"-20" before the arch opens up.

It's not the prettiest looking arch but it works well. Hopefully I can get a coat of paint on it this fall if I can ever find the time to do it. Hopefully the photos give you an idea of the sizes.

[Hunt4sap]

Cool thanks for sharing the details
Here's what I welded up for my new OTE for fire grate above my AUF
18913
Once I mount 2 larger support angle iron pieces ( one front, one back of Firebox) my grate will just sit on top of those( kind of float) to allow some movement when heated and allow for easy removal for cleaning...

[Paddymountain]

With a regular evaporator, you would want around 22 or 24 inches. I had asked this question several years ago when I revamped mine.
Before that they were around 17 inches, and I was always scorching the syrup pan slightly with each use. That problem has gone away
since I lowered the grates to 22 inches. Also a lot more AUF helped my situation too.

[Hunt4sap]

Awesome thanks, sounds like I should shoot for 20"-22" from top of my grate to bottom of my pan then?

[Hunt4sap]

18934
Got angle iron fire grate in and started to brick yesterday!
Getting closer to a test boil...
I ended up with 21.5" from fire grate to bottom of pan, it left about 4" below grate where AUF tube is, thanks to all for there input.

[maple flats]

I can't tell from the picture, I hope the open side of the angles irons points up, not the points. When the open sides fill with ash it protects the grate from enough heat to make it last far longer. Points up and it will sag from the intense heat and then need replacing after the sag gets too bad.

[Hunt4sap]

Yes, points are down(vvvvvv)

[Cjadamec]

That's looking good. It should work well for you. Next thing you need to start thinking about is a pre-heater and how to get an automated feed system rigged up. Adding a small amount of cold raw sap continuously to the pan will keep your GPH rates much higher than periotic additions of large amounts of cold sap.

[Hunt4sap]

It's the ledge above evaporator pan

[Hunt4sap]

Here's a pic of the preheater SS pan on ledge(6"by 8" by 24") I built into OTE above flat pan with 1/2" valve to feed evaporator pan18944
Here's my grate I welded up and got the fire brick put in today, it's finally starting to look like something!!!
18945
18946

[Cjadamec]

Nicely done. Gotta love it when the plan starts to come together.

[reck9953]

I’m getting ready to build an OTE myself and I like your design. The flue pipe is mounted to the rear of the tank? How big is your flat pan? Did you have it made or buy it? If bought where?

[Hunt4sap]

27" by 48"( WF mason)
I test boiled and all worked great!