Tank liner?

[Bruce Kilgore]

Hi, Guy's. I was given a 300 gal. sap holding tank. It has some rust on the bottom. I first thought was to paint it with a food grade paint, but I guess they do not make it any more. So I'm wondering if there is food grade sheet plastic? Perhaps I could form a liner. Bruce

[brookledge]

I have seen plastic lined cardboard containers that bascom uses. All they are is a pallet with a big cardboard box with a plastic bag inside and they hold 300- 400 gallons. You may be able to use something like that. The ones Bascom uses have a threaded cap on the top. As far as food grade paint you can still get it from an industrial supply outlet. Like Grainger.

[Teuchtar]

I have a 400gal stock watering tank that got a little rusty. I had turned it over on its side at the end of the season, but the leaf litter that accumulated caused some surface rust to form.
Rust is limited to a couple of patches, maybe 2 sq ft.
I haven't used it for a couple years, but I'll need additional storage this year, so want to press this one into service.
Whats the verdict ? Should I ..
a-scrap the tank
b-epoxy paint ( for $100 cost)
c-don't worry about a little rust, iron is good for you. Won't affect the taste.

Anybody got some experience ?

[markcasper]

I would just scrub it down good, maybe with a scouring pad, and not worry about the rust. The food safety inspector probably wouldn't think this was the best idea. BUT, they have a job to do and they have to find something to check you on, or they wouldn't be doing their job.

Try not to have sap in it during the day when he may show up-in other words, make this the first tank that you boil from at night.

[Sugarmaker]

You can still get the paint but I used some on some buckets ( rust ) and didn't like the epoxy (paint odor).

[maplwrks]

Bruce,
Do you know how much syrup has been produced over the years with rusty buckets? You would be better off cleaning up the spot of rust and using it as is- It will only rust next year- Paint will not stay on it . It's the nature of the beast.

[Teuchtar]

Steel Wool....30 cents
Elbow Grease Nuthin
Not spending $100 ....Priceless

Thanks

[Sugarmaker]

Teuchtar,
Can you give me any hints on the homemade piggy back unit? And does it work better than a steam away?

Regards,
Chris

[sweetwoodmaple]

Wonder how the energy loss compares between the steam off the pans (which you are trying to harness with the steam away) and the heat going up the smoke stack?

I am guessing, depending on the evaporator size (L x W), it is at least a factor of 2 or 3 more energy going up the chimney. We need to figure out a way to harness that, don't you think?

Of course, working with 250 F steam is easier than 600+ F exhaust. Still, imagine a "steam away" , aka open shell and tube heat exchanger, using the exhaust instead of steam? No more 190 F water going into the flue pan, it would be boiling! :wink:

Unfortunately, the creosote would really like that cool surface, so cleaning would be an issue...Oh well.

Brian

[Parker]

To harness the energy going up the stack stretch your arch and ad another flue pan,,,I dont think the stack on my evap got over 400 deg last season (I am going to get a stak thermometer this year) I wonder if too long an arch would affect the draft???

[sweetwoodmaple]

Parker - Yes, I've always wondered about the tradeoffs of a longer arch.

I.E. I hear of those 2 x 10's or 2 x 12's or whatever and wonder what kind of boiling rate they get per square foot. You can probably touch the stack with your hand, but not sure you can get as rigorous of a boil. Maybe a good wood saver helps to make up the difference?

Ok - My idea was to start with a normal size evaporator, take my 3 x 10 drop flue for instance. Then, chop off the back of the arch BEHIND the smoke stack (leave it there) and extend the arch another 6 foot or so and put another drop flue pan and a smoke stack at the end.

Finally, add a damper to the original stack and use it to balance the boiling rate of the original Drop flue pan with the "preheating" pan that was added. Probably need to move the float to the added pan as well.

Sound crazy?

Brian

P.S. Go Steelers! (Sorry, NE fans...can't believe it myself)

[Parker]

Hunh,, never thought of having 2 stacks,,,set up like that,,,,I wonder how that would work,,,,,You going to try it?

[Sugarmaker]

You guys got some wild ideas keep them coming. I like the thought of getting as much heat as possible out of the stack heat. When we have a6 foot red glow out the top of a 20 foot stack I know we are loosing a lot of energy. These rig and arch designs haven't changed in 100 years! I would love to get 30 % increase in boiling rate by channelling the hot flue gasses thru tubes in a super charged preheater. Does it matter if the sap is boiling? Isn't that what we want to do at some point anyway??? :idea:

More questions than answers!
Chris

[WESTVIRGINIAMAPLER]

If you put a blower on an evaporator and cranked it up, I think I could run a 2x16. It is amazing how far the blower would push the flame back thru if you have the proper size stack! :D

[Teuchtar]

Chris asked about my homemade piggyback, so here goes.

This project was started for the 2004 season. Still a work in progress.

I fabricated a stout open top box from aluminum, and it has a sealing surface to the top of the flue pan. Into that box fits my 24 x 24 sugar pan. Under the sugar pan, there are internal baffles and gutters that pipe the condensate back to a 5 gal bucket. Sap doesn't touch the aluminum. only condensate. I used aluminum because I can't work SS.

Flue pan is 4 feet long, piggyback pan is 2 feet long. This leaves me room for a hatch to keep an eye on the flue pan, as well as drop in the defoamer.

The sugar pan was my evaporator prior to purchasing the 2 x 6. Its lain there unused for a couple of years, so didn't cost me any extra.

I have a sump pump in the bucket to pump the hot condensate up to a storage tank in the sugarhouse loft.

The flue pan steam will heat that sugar pan up to 185 in a few minutes. The pan is open to air, so hot sap is able to evaporate, but doesn't boil.

Sap level in the pan is controlled by a float switch running an electric sap trasfer pump. Pump is a stainless pump used for beverage fountain.

This year, I have added a sparger blower and air pipes to the piggyback. That will foam up the pan and help to evaporate more sap. I have the hardware made up, but have not tried it yet. The sparger and air pipes will get the evaporation rate up a bit, but I probably won't get as high as the commercial units.

Expenses so far:
Sugar pan $200 15 years ago.
Aluminum: Salvaged from scrap
Sealer and gaskets $25
Sparger: $60 new, on eBay
Pump and motor $75, new on eBay
Tubing $20
Float switch for pump $20

project costs to date, $200 ( excluding pan)

Let me know if you are interested in the performance test results or a photo etc.

[Sugarmaker]

Duncan,
I emailed you before I read this. This was a excellent discription and I bet there will be othere wanting to see pictures of this setup. This must be a nice unit! The bubblers sound like they will help too! That switch is in the hot sap? I like the Idea of saving the condensate I may think about that this year and pump it into a holding tank for use cleaning the evaporator at a later date. I have nerver tried it but several folks in our association say the distilled water really helps clean the pans at the end of the season.

[Teuchtar]

Before the addition, my stack temp was high enough to melt the zinc galvanizing, which happens at 725 wall temp, with exhaust approaching 1000 deg. Big waste of heat. And a rusty stack.

The new arch extension drops that exhaust temperature to 450 deg. My cobbled up blower pushed that back up to 525 deg, and caused a lot more excitement in all the pans. The blower is a surplus unit "liberated" from a large Xerox copier, with some homemade ducts. Measured output is 190 cfm.

I still need to make a few adjustments to the smoke path. I have too much clearance under the flues, but thats easily fixed by closing up with some dry sand.

My new arch extension sets right on top of the old arch, right where the smoke collar attaches. D&G are kind enough to bolt that collar in place, so its easy to remove, then attach the extension, and re-use the collar at the new place where the flue attaches. I had to move the rig 6 ft forward so I could keep the stack in the same location.

Theres a nasty Z-bend in the gas path between the two flue pans, but I can fair that out with sheet metal flow guides. That should improve the draft. Then I still need to seal up a few air leaks that seem to be causing some dilution further back in the gas path. I picked up some thermocouples this summer, so should be able to measure the infiltration of air, and improve things a little.

My stack was about 26 ft before the addition, so I always had plenty of draft and no need for a blower before the addition. But that extra gas path resistance tells me I need the blower.

My Air tight door will be on order tomorrow. I am going with a custom made door fitted with stove gasket. Still need to figure out how to make the closure device.

Brian, somewhere I came across documentation that says you should see 3 gal/hr per sq foot on a 7" flue with ideal firing. So the 3x10 should reach 90 gal per hr. Then boost that with the Steamaway.

My chats with some of the experts says that the arch extensions are effective, but don't boil with the same fury that the from flue pan does. I guess its all a matter of gas path design.

[Teuchtar]

Typo, last para:

same fury that the front flue pan