Long airline from Vacuum Pump to Releaser?

[Mr. Red Maple]

I was wondering if anyone has ever made a really long airline from their vacuum pump to releaser and how it worked out? My releaser will be about 2500 feet from the vacuum pump and will be hooked up to about 1000 trees. Planning on using a vacuum pump that does about 35cfm. From what I've read from the tubing notebook this wouldn't work unless I had a huge mainline. It's hard for me to believe this since right now I have just a 1/2 inch airline 800 feet to 300 taps and I get 26 inches of vacuum on the lines no problem. I plan on using 1.5 inch line next year.

I would like to hear what size airlines lines others are using and how long your airlines are to how many trees.

Thanks

[Sunday Rock Maple]

We are going 1400 feet with 1.5 inches with a 60 cfm pump and typically lose about 2".

[Thompson's Tree Farm]

I have a couple of runs between 2000 and 2500 feet. I use 2 inch line and lose about 1 inch of vacuum. Have another line that is just over 1200 feet. Again using 2 inch line and lose less than 1/2 inch of vacuum.

[WestfordSugarworks]

Your main consideration should be not the inches of vacuum that you are reading on the gauge, but the decrease in cfm (cubic feet per minute) that will result from long runs of pipe (which will thus reduce your ability to maintain the high vacuum). 1.5" will be far too small (I'm guessing). The ability of your pump to evacuate air from the system will be really reduced after that long 2500' foot run, and so your ability to evacuate air from the lateral lines and maintain high vacuum at the tap hole will be diminished. Consult the tubing book from Cornell and determine what size pipe you will need to minimize cfm loss at that distance. Right now in the system you have, you are certainly diminishing your potential yield by having only a 1/2" air line. Especially on big sap flow days, I bet your system struggles to move all that air from the mainline and from the laterals and you have a way lower vacuum level at the taphole than what your releaser reads. Vacuum is deceiving and cfm capabilities should really be the focus for sugarmakers. I would replace that airline to a 1.25" or 1.5" right away.

We have two airlines but each are only a few feet long to the releaser. Other sugarmakers that I know like to play it safe by having large air lines (3") to ensure they aren't losing any of their pumps potential. I think that would be overkill for 2500' but I also think 1.5" would be too small. Consult that book, or maybe another sugarmaker who already has it could tell you what the right size would be. I bet 2" or even 2.5" is what you need.

A friend of mine ran 10,000' of 3" airline from his pump in the sugarhouse to his releaser way up on the backside of a ridge. I thought that was probably undersized for such a long run, but they said it was ok based on the calculations that the Cornell book had. Our dry lines are mostly 2" and 3" and this seems to work well for us. I think it's about 2500' of 3" that drops to 2" for the remaining half mile or so.

[Russell Lampron]

I run a 1.25" air line from my SP 22 vacuum pump to my releaser which is 1500' away. I went with 1.25" because that is the size of the outlet on the pump. I don't lose any vacuum from the pump to the releaser but the releaser is slow to recover after it dumps. I have a horizontal releaser that is good for 8000 taps and I only have 700 taps on it. I wish I had gone larger with my air line, the releaser will take a 3" pipe. I wouldn't go that large but maybe 2" would get me a faster recovery time.

[GeneralStark]

As Westford describes, the goal is to be able to remove air from your tubing system as efficiently as possible. Larger diameter pipe will be more effective at this...

Another option is multiple runs of pipe to achieve the desired CFM. For instance, if you already have a 1.25" air line in place, you could add a second to double your capacity.

[ennismaple]

That depends on what type of releaser you are using? If electric you can get away with a smaller transfer pipe than if you're using a mechanical releaser.

We have a 1.25" vacuum pipe that runs 2000 ft to a double mechanical releaser. When the sap runs very well in that woods (about 1900 taps) the releaser dumps every 75 seconds and we can't get more than 16" Hg - because we can't get enough CFM's through the pipe to overcome the air that enters the system every time it dumps. We plan to replace that with a 2" vacuum line and we should get way higher CFM transfer and higher vac levels on high flow days.

[blissville maples]

I run a Busch 5 HP 61 cfm pump. It is 2000 feet to the double releaser through 1 1/2 pipe. From there a one inch line goes another 1800 feet on a fairly flat run with a second one inch line going 900 feet and ninety into the wet line. The pump stays parked on 28.5 as well as the releaser, the vaccum gauge at the end reads 26.5-27 inches