Single pipe sap ladders; observations and questions

[Gary R]

I am new to vacuum this year. I've read the Ontario study. Single pipe, double pipe and star ladders are about equal. I've read comments from others on here that they did not think double pipe had much more benefit over single pipe. Here is my set up and what I'm observing. I do not know if this is typical or if I have some sizing issues. I have 102 taps, 3/4" main line. Total distance of about 850'. I have single pipe ladders, two 5' and one 14'. The 14' gets me high enough to cross 100' uphill and releaser - tank height. All my ladders are 1" pvc. I have 27" at the pump, 26" at tree side of releaser, 20"+ at end of main line. Sap is running well and I am happy how things are going. The question; I initially had some freeze up issue during the cold weather. It got warm and I thought I was still having the freeze up problem. I based this on going to the 14' ladder and watching and listening to the pipe. I have a couple of laterals that enter the main line just in front of the ladder. Easy to see sap flow in the laterals. I would see sap flowing fast in the laterals and hear a lot of sap going up the ladder. The ladder would actually shake. Then it would stop and no sap would flow. I noticed that this seemed normal in my system. This cycle would occur over a few minutes over and over and I'm getting sap dumping from the releaser. At the end of the main line my vac level will sometimes drop to 12", with no sap flowing in the laterals. Then the vac level would slowly go back up to 20" and sap would flow fast into the main line. This cycle would occur over a few minutes. Is this normal? Maybe my pipe sizing is wrong? I have check valve taps which is good. My sap does a lot of moving and stopping

Any comments or suggestions would be greatly appreciated.

Thanks

[Haynes Forest Products]

Vacuum levels will drop when large amounts of either air or liquid fill in the void. SO could it be that you get a good run of sap with air that travels down the line into the ladder causing the shaking and the vac levels lower decreasing the vacuum reading at the releaser and then because the sap shot into the releaser vacuum can transfer back out into the woods past the ladderand they rise again.

[Beweller]

Why do you make the ladder larger than the main line?

[Gary R]

Beweller, I only did it because I thought bigger was better. The study did use a single pipe the same size as the main line. The two pipe ladders, both pipes were the same size as the main line. I might have caused some inefficiencies the way I did it. I'm hoping for more input. I'd like to make this the best it can be. I may have made a mistake.

Here's the study

http://www.ontariomaple.com/index.php?action=display&cat=38&doc=2004_summary_sap_ladder_project-Final_Rep_June_2304.pdf

[red maples]

its better to do 2 pipes in stead of 1 so if you have a really heavy run your gonna need that extra pipe. just put a valve in 1 side so you can shut off 1 side when you have a light sap flow.

[sapman]

I've tried shutting one side off, and even on light runs it still seems to work better for me to leave both open.

[Gary R]

Back on 3/3 I changed all my ladders to two type. Only cost $42 and two hours labor. No valve was put in either pipe. The pipes are 3/4", the size of my main line. They are operating the same as my original single pipes. Vacuum goes from 20 to 12 to 20 at the end of the mainline. Sap does the same also. It surges to the releaser the just sits in the lower mainline with no movement. Things are working good. I just got 2.5 gal. per tap in less than 24hrs. What could I get? Has anybody actually observed the sap movement? Has anybody tried the sap lifting system that CDL sells? I don't recall if there is a flapper in their tank. I do see how it works. It looks just like the manifold on a releaser that keeps vacuum on the line when it's dumping. Any thought's appreciated.

[Housewright]

Gary
I have a 3/4" line with two single pipe ladders both about 6' hgt. Length of line is 200'. It pretty much did the same as what you describe yours doing.
I spent a lot of time trying to figure out what it was doing as the guage at the end would drop to 15" and all the lats seemed water logged. If I pulled the last tap that little shot would make the main cear its throat and the guage would jump to 25.
Finally decided I was spending way too much time watching the Rockola.
If the sap is coming in just let it do its thing. I think if your using ladders your going to lose some at the end period.
I was thinking of changing from single to double mid season so its interesting to hear your results.

[maple flats]

I have all 2 pipe ladders, same size. I like watching the sap climb. I too have decided to leave the valve open, as both seem to work well and equally.