Poor man's continuous flow system

[Cjadamec]

To be honest I'm amazed it works at all but it did right off the bat. Complete with pump driven copper coil stack Preheater.

[Mark B]

Could you give a better description of how this works? Thxs, Mark

[Cjadamec]

There is a 12v pump rated at 1gal/min pumping from a 55 gallon barrel.
The pump sends cold sap to the copper coil and a line feeding back into the barrel. The line going to the barrel allows most of the pumps flow to bypass the coil. I adjust valves, one on the hot enough of the coil and one on the recirc line back to the barrel, to control flow of sap into my back pan. From the back pan I have siphon tubes connecting the other pans.
The end result is warm raw sap entering the back and being siphoned forward making what amounts to continuous flow. In a very crude way. I should have run my siphon tubes differently so my 5 steam tables pans ran in series rather than parallel. Will do that next time I start up.

[mol1jb]

What are your siphons made out of?

[Cjadamec]

Pex tubing it's stable at boiling temps just wouldn't be good for very much pressure.

[mol1jb]

Pex tubing it's stable at boiling temps just wouldn't be good for very much pressure.

Looks good. Hows that new arch boiling?

[Cjadamec]

Made some adjustments and added more stack for better draft, it's boiling way better than it had been. Not having to ladle sap from one pan to another is awesome. The 20 bucks for the pump seems like it was worth it so far.

[Thumb Bum]

Can you post a couple of pictures of just the siphons? I was looking into making them out of copper I've never seen them made out of PEX.

[Cjadamec]

They are made from clear 3/4 inch pex tubing that I had leftover from plumbing my house and some metal 90 degree radius supports also leftovers. The radius supports hold the tube in a bend so that the ends stay in the sap otherwise the pex would just lay flat. The metal also protects the tubing from the really hot metal angle iron frame that holds up the pans. I chose the clear tubing so I can see if the siphon gets vapor locked.

The picture is what it looks like but the tubing is longer on the ones I'm using. I cut the tube so that it touches the bottom of each pan and the middle of the bend is just slightly over the top edge of the pan.

I'm already over budget on what I wanted to spend on sugaring this year so I'm making do with what I have on hand as much as I can.

[Thumb Bum]

I am over budget this year myself. Why I hadn't made my siphons yet I may try these out of PEX I've got some red and blue laying around

[Cjadamec]

If you have elbow fittings for the pex that would take the place of the bend support. Fittings were my first choice but I didn't have any on hand. Good luck with your boiling.

[Thumb Bum]

Going to have to be fittings I don't have been to supports

[Haynes Forest Products]

Cjadamec In the plumbing business that valve would be called a tempering valve. Now have you experienced what happens when the pump stops circulating the sap thru the coil when its glowing red? I like your ingenuity and thinking out side the box. Don't ever let someone tell you something wont work unless they can show you the scars to prove it.

[Cjadamec]

Haven't overheated the coil as of yet but one day I'm sure it's in my future. I've got lots of experience in steam plants and ships so I'm used to the saying if it works it isn't stupid. Some days you just need to make it work and 20 fittings and adaptors later you are back up and running.

I still think it's a recirc line, a tempering valve would mix the hot water with cold to change the water temp. My recirc line is bypassing pump output back to the pump suction to control pressure and flow out of the end of the coil. Having the extra valve at the end of the coil gives me fine control of flow into the pans. As a side benefit keeping the coil under a couple pounds of pressure stops the sap from boiling in the coil.

[Haynes Forest Products]

I had a complete boiler set up for my preheater, recirc pump, pressure tank, heat exchanger, pressure relief, auto fill and my coil was inside the flue stack. I forgot to turn on the recirculater pump on and boy things got to rattling before steam started to come out the relief valve. YIKES

[Cjadamec]

As years go by and I'm looking for faster evaporator rates going to a full pressure boiler type Preheater might come into play. That little pump is rated for 100psi....

For now though happy to have all 5 pans at a steady boil and not having to dump ice cold sap into my pans killing everything. I had 70 gallons to start yesterday and had to shut it all down after about 4 hours because my 55 gallon barrel was almost empty. Should get a nice run this weekend so I can get another go at tuning the setup in.

[to100]

So how deep is sap I your pans? How do you take near out and finish? Are you set up in a shack or open air?
How do you prime your pex, do bubbles break you flow often?

[Cjadamec]

Honestly last night was the first time I ran this so I have a lot to hash out about the best way to run it.

I'm set up out in the open no shack just me the evaporator and mother nature. My only taste of civilization is the extension cord bringing power over from my pool sub panel. I use the power for some LED flood lights, the AUF blower, and now the pump (it's a 12v pump powered off a 110v power supply).

Up untill now I have only batch processed hadn't even thought far enough ahead to think that I could draw off this setup. It wasn't until I saw it working that I realized what I had built. I just didn't want to manually move the sap around. I will probably still batch process basically, but the hamster is slowly spinning the idea wheel and I may try to finish on the evaporator at some point.

I started the prime when everything was cold by filling the tube with sap sticking my fingers over the ends and putting them in the pans. That worked well untill it didn't. I had to reprime a couple of times after everything was hot by basic doing the same thing. A lil tricky to be sure without scalding myself. Vapor lock is the death nail of all siphon tubes and I know I can find a work around I just haven't yet.

I wouldn't say I had to prime often as long as it was running steady it just kept going. I think I caused more problems by changing things than I would had if I just left it alone.

When I let it run the way it wanted to my my back pan was running at around 5 inches deep, middle pans around 4", and the front two over the fire were around 3". My steam pans are 6 inches deep. When I let it run that way and kept the fire steady it seemed to run pretty good.

[wobbletop]

I'm interested in more details about the stack preheater. I had tried doing this before, but the sap always scorched in the tube.

What is the flow rate into the pan? What pump did you use?

My next attempt I was thinking was to have a pump to continually circulate the sap from the storage tank through the stack coil and back to the storage tank and repeat. Only when the pan required more sap, would I divert the preheated sap to the pan. Theoretically, if I could adjust the diversion to match the evaporation rate, it could be run without much interaction. As I run out of sap for the batch operation, I would switch to plain water running through the stack coil to prevent anything burning inside the coil. It could also then produce some warm water for cleanup.

Thanks for posting your setup!

[Haynes Forest Products]

Wobbletop One thing you need to do is when you run out of sap is chase it with clean water. Even a small amount on the inside will smell like a forest fire. I get some sap/syrup that will jump out of my pan and when it hits the arch it will wake you out of a deep sleep with gripping fear your burning the shack down. doesn't take much.

[Cjadamec]

I'm using THIS (https://www.amazon.com/gp/product/B01N75ZIXF/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1)pump from amazon. You can run the pump of a 12v battery or you can get a power supply (https://www.amazon.com/gp/product/B00GU63ICU/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1)which is what I did.

You don't want to heat up your storage container that's just begging for any unused sap to spoil and make a mess of your tank.

Instead of pumping warm sap back to the storage tank its better to send cold sap back to the storage tank. In the picture you can see how I put a tee fitting in and a valve to control the flow that goes back into the tank. There is another valve right before the sap goes in the pan. To set it up and adjust flow it goes like this:

Both valves wide open
Start pump and get flow
Close the valve on the tee just enough that you get a solid stream of water into the pan. This should be a very small adjustment.
Adjust flow into the pan with the valve near the pan. This valve can be anywhere from wide open to almost closed depending on how much flow you need to meet your evaporation rate. You want to make sure you have at least a steady drip going into the pan or you will overheat the sap in the coil.

With 2 valves setup like this you have infinite control of flow of sap into your pan. From super slow trickle to max flow from the pump.


To flush the coil with this setup I get a 5 gallon bucket of clean water ready to go. I shut off pump, then put the pump suction into the bucket of clean water. Shut the valve on the tee and open the valve going to the pan wide open. Direct the outlet of the tube away from your pans (I have a flexible piece of tubing the last 18" or so going to the pans so I can just point it onto the ground). Turn the pump on and pump the water thru the coil. After flushing open up the tee valve and let the coil drain onto the ground. You now have a clean coil that will dry out.

I'm using push to connect fittings (https://www.amazon.com/gp/product/B072HR2QQG/ref=oh_aui_detailpage_o02_s01?ie=UTF8&psc=1)that I can remove from the copper when I'm done. I remove them so there is no chance of them melting.

My copper tubing is 3/8" OD tubing 25 feet long. It could be longer but 25 feet fit the budget.

[wobbletop]

Thanks for the details!

I was only using 1/4 copper tubing before so 3/8 would probably be better at absorbing the heat and not scorching. Also, I would plan on only heating the sap I would plan on batch boiling. No risk of sap spoiling in the storage container.

Any idea of the temp of the sap after your preheater?

[Cjadamec]

At medium boil rates the sap out of the preheater gets too hot to let it run on your finger. When its cranked up to full boil and there is a good stream of sap going thru the preheater it gets warm probably around 90-100. It's warm enough so it doesn't kill the boil in the pan.

If I get a chance next boil I will work on getting some temps. So far with everything so new it's been a handful to keep an eye on everything.

I only used 25 feet of tubing so if you need more heat you just need more tubing. Wrapping the tubing tight to the stack with the insulation also makes a big difference.

Other details are I have an 8 inch stack and according to the magnetic temp gauge my high fire is around 500. At 500 my front two pans are solid bubbles and the middle two are violently boiling and the back is a rolling boil.

[jdircksen]

I came across this thread and I'm really interested in the siphons between steam table pans. I run 3 pans side by side (long sides touching) and would love to add sap on one end only. Currently I add fresh pre-heated sap to all 3 pans at the same time. It's been 2 years since this thread, so have are you still using the siphons?

[Sugar Bear]

My recent experience with the siphon tubes is that they work well in a non boil environment but the more you are boiling your sap the more likely/sooner the siphons fail.

I.E. they do not work well in a rapidly boiling pan of sap as the tubes get air logged from the rapid boil rather rapidly.

I don't think their is a solution to this problem unless boiling you sap slowly is an option.

You can do well from a pre heater pan to a boil pan with the siphon, because typically your pre heater pan will not be in a rapid boil.

[Cjadamec]

I'll give an update to this after a couple of seasons of steam pans and siphon tubes.

It was a lot of work and baby sitting to keep the siphon tubes working and free of air locks. When it was working it was nice but when I had the rig running at full temp and a hard boil I would end up spending half my time using a ladle to transfer sap from pan to pan.

I kept trying to get creative and find ways to keep the tubes from air locking but I wasn't willing to put any money into fittings, because in the end I knew the siphon tubes were a hold over until I bought a real pan.

Setting up a gradient in your steam pans makes the end of the batch easier to finish and I liked seeing the change from clear raw sap to amber sweet. I had issues with sugar burning on the upper edge of my final pan because me pans were set fully in the fire. I'm sure it darkened my finished product but I never tasted any burnt flavors.

Again like the siphon tubes the steam pans were the cheapest way I had to increase my boiling rate without buying a real pan. They worked great for what they are but between the burned sugar on the edges and boiling over and spilling of sap I'm sure I lost most finished product during the cooking than I want to think about.

I was very happy with my pumped preheater with the re-circ loop to control flow. I was able to get very hot preheated sap and control the flow rate into my pans. Because it was pumped and their was pressure in the preheat tube I never had any issues with burning of sap in my stack preheater.

For this coming season I bought a 4x2 divided pan from Bascoms. Its shiny and new and I'm excited to use it. It was also $425 dollars that I didn't have available to spend in the last couple of seasons.

Would I do the siphon tubes again? Sure I would it was fun and creative. I learned a bunch while doing it. I also "feel" like it improved my boiling rate. I really have no data to back that up. It sure did keep me busy though.

Am I happy to throw them in a corner and let them collect dust while I use a real divided pan setup? You betcha.

[jdircksen]

Thank you guys for the info. I've read through a couple threads and the consensus seems to be that they take some tinkering. One of the other threads suggested a petcock valve and hand primer (opposed to sucking with your mouth) to get the air out of tube. Like you said though, it's just more money invested when I plan to get a pan next year anyway.

[DougM]

For what it's worth, our second evaporator was an old Champion that used siphon tubes. Maybe it will help, you can get an idea of how they were built in the photos below. At the bottom of the first photo you can see how the bottom of the tube sits in a little cup, not on the bottom of the pan.

No doubt this was a tricky system to run, we definitely had to keep an eye on the siphons. But it did work. Good luck

20475 20476 20477

[Ohio Maple Blaster]

Sorry to say, but this was such a smart setup, I had to copy it! Was only 17 degrees last weekend, so the lines kept icing up on me. However, this week it’s running perfect for my setup! Thanks for working this one through! It is a little noisy, especially the reverberation in the stack. I’ve got hose clamps keeping it snug, and ceramic around the coil, and that seems to help dampen it. 20981

[Cjadamec]

Nothing to be sorry for. I think it's awesome that you like the setup and it's working for you.

It is certainly noisy from the reverberations in the stack but that's a function of the small reciprocating pumps. They are just noisy, but they are cheap and they work. I've done the same as you to try and quiet it down but like you it only helps a little. The noise is just a trade off for sap that is near boiling going into the pan which is worth it to me.

One of these days I will work on getting a pressure gauge plumbed into the system. I think that would really help in getting the valves adjusted correctly.

[Ohio Maple Blaster]

Been tooling around with it, but it’s been money all day. 36 degrees in, 185 out. Got it to quiet down by pumping from a bucket and not the barrel. But you’re right, I’ll take a little noise for the added efficiency all day. Measured the flow rate to exactly 4gph.