Another preheater question

[Bucket Head]

Hi Guy's,
The previous thread on preheaters was very interesting as I soon will be picking up a used alum. hood that I have to modify to fit my evaporator. I will also build a preheater for it while I'm reworking it. Like Mapleman3, I too was wondering about sealing seams/joints/gaps. I'm not so concerned about steam leak's as I am sealing the drip rail/ drip rail corners. My question is what have you guy's used to seal your hood's? Will silicone work? Will it hold up to the heat and not want to lift off? I recently was told of DAP brand 100% silicone that several local syrup makers use to fix their leaky bucket's. They use this stuff because it states on the label (I read this for myself also) "Safe for food contact as long as sealant is cured and washed". Has anyone used this on their hoods? What would you guy's recomend? Thank's.

Steve

[Pete33Vt]

I hope it works because thats what I am using to seal all the holes, and gaps on my steam hood.

[Fred Henderson]

You would be better served if you could find a flat fiber gasket material. Something that is safe, You don't need that silcone falling in you product.

[Sugarmaker]

I went and saw some operations with hoods and no sealing to speak of and was impressed. As I said before I would not get to concerned about the air tightness. I fact I think you need some air coming in from some where or you may not get draft. Don't the air tight arches have blowers for forced draft?
I may have some pictures while we are boiling on the web site that show the amount of or lack of steam in the room. (When you get to the picture page click on any one of the four pictures to go to the other thumbnails in that series.

Put your time into designing and building a good preheater with a good condensate removal system and you will gain a little on production.

Now keep in mind that my rig is a antique compared to you guys and the look of my hoods whittled out of scrap stainless pretty well matches the rest of the unit. It sure would not look right if I had real good looking hoods on the old 3 x 10.

Regards,
Chris

[Dave Y]

Chris,
Your may be an antique, but it is a restored antique! Looked pretty good when I saw it. So did the hoods. You did a fine job on it.

[mapleman3]

The question I have in addition to Bucket heads is... how much does the steam drip down the inside of the hood to the condensate removal channel vs the condensate off the stack and preaheter? if I have the pan under the preheater dumping into the channel and out... does the channel really need to be sealed against the hood? I wonder how much would go in between and drip onto the floor? also if we use the silicone I will just run a bead in between the joint so it's not really exposed, but in your case where it's already built maybe someone can silver solder the joints for you?

[brookledge]

99% of the condensate comes from the preheater. You have to have to have a big temperature differential to cause condensation. When your hood is hot and up to temp there is not much condensate from the hood.
When I open my hood and look into the pre heater it looks like there are leaks in the pipes, it runs off that fast. but as far as the sides of the hood virtually none.
Keith

[Russell Lampron]

Like Kieth said most of the condensate comes from the preheater. With my hood alone I get maybe 10 gallons of water after 5 hours of boiling. With the preheater I get about 30 gallons in the same amount of time.

With the brake that you are using can you bend it so that the drip channel is part of the hood and not a separate piece that is attached to it? I haven't measured it but I think my drip channel is an inch deep and the drip tray for the stack and preheater is piped in to that. I have a 1/2 inch pipe fitting on the rear corner that the drip channel drains into. I drain that in to a cut off juice barrel.

Russ

[Sugarmaker]

I agree with both Keith and Russ.
I get a cup full of condensate from the hood and 5-6-7 gallons per hour from the drip channels. I don't have a tray. I have channels under each tube to allow the steam to get through.

Dave Y , Thanks for the comments. I still drool over those shiny rigs but i am to cheap to own one in the near future. The price of syrup is going to have to go up a lot.

Regards,
Chris

[WESTVIRGINIAMAPLER]

You will get some condensation running back down the stack due to the constant barrage of cold air hitting it and the temp of the stack gets cooler the higher it gets. My drip tray sits underneath the stack and is wider than the stack and catchs all the stack condensation too.

My drip tray is 1" square aluminum channel that is welded and the frame for my hood is aluminum also with 26 gauge stainless making it very lightweight. I killed a lot of birds with one stone on my hood as my drip tray is the entire length of the flue pan hood and it has a 90 degree lip on each end bent down that sits in the aluminum channel. The takes care of all the condensation from the preheater and also strengthens the hood. I have stainless brackets bolted onto the preheater pan that adjusted up and down with stainless bolts and have about 4" of adjustment on each one. The drip pan is really heavy gauge stainless, 11 gauge or heavier so it is strong enough to hold the preheater without any sag or bow.