check valves on gravity

[SPILEDRIVER]

any advantage to putting the check valve on a gravity system?? if so would you install them at the usual upward angle or at a straight 90???

[spencer11]

all my gravity is on CVs. use the regular upward angle. it has the same advantages that it would with vac. since gravity creates some natural vacuum it does the same thing. ad it cant hurt to have them as it migh(and does) leangthen hole close up.

spencer

[fresh spout]

seems hard to believe that it is worth the investment for a check valve strictly for a gravity system. They were designed for vaccum, so why spend the extra money. The best investment you can make it to put a fresh spout in every year. Other companies make very economical spouts that make it much more friendly on the pocket to replace each year. New spout means you are not introducing last years bacteria to a new hole, and studies have proved that you will gain higher sap yields each year if you do replace your spout.

[northwoods_forestry]

Yes, I'd be wary too of using check valves on gravity. There may be some slight advantage in preventing sap recoil, but that's not nearly as likely with gravity as it is with vacuum. The check valves also have a tendency to gum up and stick. Vacuum seems to overcome this and pulls the ball out, but it might close off a gravity tap.

[ronr]

Looking at the graph on the top of pg. 11 of the Cornell study linked below, it would seem they are worthwhile.


http://maple.dnr.cornell.edu/pubs/2011%20Maple%20Tubing%20and%20Taphole%20Sanitation %20Research.pdf

[adk1]

THis is what I believed too. I will say that I ahve alot of them leaking. Mostly through the tap hole. I did tap when the wood was still somewhat frozen. I then installed the CV's listening for the "thud" or difference in sound. THen I installed the stubby. I would use a 1/4 turn/twist to seat the stubby in the CV. I would then give it a light tap.

Unfortunatly, after my first small run, I went around looking for leaks. I found alot of leaks via the taphole. SO i tapped the CV in farther, but did not take the stubby off first. Didnt even think about doing that. So now my stubby is inserted farther into the CV...Dont know if this is ok or not. I am sure it will be harder to take off at the end of the season, but would like to know if the ball has come out or something clogging my stubby...thoughts?

[DrTimPerkins]

Sounds to me like you either A) pounded them in too hard and split the wood (fairly easy if frozen) or B) your holes aren't round. By pounding them in harder you likely just exacerbated the problem. There is at least one other ongoing thread on this topic at the moment http://mapletrader.com/community/showthread.php?16231-Plastic-Spout-Questions Improper tapping is one of the easiest ways to lose sap (and thus $).

Whether or not the CV will be economically "worth" using depends largely upon the age (and thus microbial contamination level) of your dropline. If it is more than 5-6 years old, it is likely that the CV will be economically advantageous (and more so than a regular replacement spout).

[adk1]

to what depth should the CV be installed in the hole. The non check valve similar spout stated 3/8-5/8". that does not seem like alot at all

[DrTimPerkins]

On gravity 1.5-2.5" depending upon the size of the tree. On vacuum 1-2" (1.5" is typical) depending upon the size of the tree.

[wiam]

On gravity 1.5-2.5" depending upon the size of the tree. On vacuum 1-2" (1.5" is typical) depending upon the size of the tree.

Just clarifying. Do you mean that is how deep to drill?