Steam hood

[Maplewalnut]

Probably a stupid question but I have to ask. I was under the impression that the steam hoods had an exhaust fan mounted in them to help pull steam up and out. The more I read it seems like the hood just acts as a collection 'funnel' as the steam rises? And a preheater sits within the hood and heats as the steam rises through it Someone just answer without laughing and let this post sink to the bottom!

[RileySugarbush]

No fan is needed. The steam stack works like a chimney and pulls the vapor up the stack. It can be so efficient it pulls extra cool air in and the preheater won't work well, so a damper needs to be added. My 2x3 hood has a 6" stack that runs up into the cupola, about 10 feet long. It is balanced pretty well, meaning no steam escapes around the base of the hood, but enough is held in the hood to preheat the sap to 190F or so. I was ready to add a damper but didn't need it.

[maplesyrupstove]

Maplewalnut there are pictures in my preheater album in yahoo photos

[Fred Henderson]

A steam stack out thru the roof with a good draft will also hlep lower the boiling point of water. Because it lowers the atmosphere pressure inside the hood.

[Breezy Lane Sugarworks]

I've always wondered how hard it would be to seal up a hood and put vacuum in it some how????? Just something I've been trying to think of for a bit.