check valve or not

[Mapleman03]

Ive got about 250 taps all gravity, is it worth putting in leader clear check valve taps??? Used leader clear seasonal spouts last year had good luck with them.

[shane hickey]

The clear taps are throw ways meaning replace them every year I personally wouldn't use the clear ones had to many issues the ball freeze in the hole and some of them the ball was oval and restricted the flow of sap coming out of the tree.

[adk1]

I run the older black CV spouts on my gravity operation. Of course you need the stubby spout to. I throw away the cv every year and get new ones. I would highly recommend using some form of cv spout. your season will last longer.

[stoweski]

Dr. Tim made a presentation at Verona this year and convinced me to change to CV2's. CV2's are the new, clear checkvalve spout. Im on gravity, which he only touched on but made it clear that a CV is going to stop the reverse pressure of the tree sucking the sap out of the lines. Steve Childs also had a presentation on similar info and reinforced the use of CV's.

Not sure what presentation it was said but the old, black style is the CV that the ball sticks. The clear CV spouts are fine. Anyone else chime in on that?

[spud]

Ive got about 250 taps all gravity, is it worth putting in leader clear check valve taps??? Used leader clear seasonal spouts last year had good luck with them.

It would only cost you $100.00 to try and I think it's worth the try.

Spud

[sjdoyon]

We use the black check valves and have not had a single problem. I was told the first year on the market, the small balls were getting sucked out of the valve. The plastic fins were too soft but probably more of an issue for high vacuum producers. Issue was corrected.


Dr. Tim made a presentation at Verona this year and convinced me to change to CV2's. CV2's are the new, clear checkvalve spout. Im on gravity, which he only touched on but made it clear that a CV is going to stop the reverse pressure of the tree sucking the sap out of the lines. Steve Childs also had a presentation on similar info and reinforced the use of CV's.

Not sure what presentation it was said but the old, black style is the CV that the ball sticks. The clear CV spouts are fine. Anyone else chime in on that?

[adk1]

I have never had a problem with the black cvs. I always rattle the spout before I install it on the stubby. If I hadent just installed everything 2 years ago including investing in 200 plus stubbies I may have gone the new clear polycarbonate spout. However, I think it's much quicker installing the black cv than having to use your tubing tool to install every clear cv

[stoweski]

The clear CV's don't require a tubing tool to install. They just slip right on. Yes, if you invested in other parts it doesn't make sense to switch... Until you're ready to replace them (maybe from tree rat damage, eh ADK???).

[adk1]

Hey no kidding. I didn't know that they went on by hand. That's cool. I was wondering about each year shortening the length of your drop. Haha

[Sugarmaker]

Check vales co not allow back flushing of the line other than that they should work OK. I just changed 200 drops (out of 600) on our gravity systems and used the std Leader tree saver, no cv, but I flush all my lines after the season.
Regards,
Chris

[Maplewalnut]

I didnt think there was any data from using check valves on gravity? Last I knew Dr Tim always referred to studies Steve Childs was doing on gravity vs check valve but not sure anything was published, maybe I missed it. Dont get me wrong I use check valves on my vaccum bushes but does the check valve give any better performance than a new throw away spout every year on gravity???

[SWEETER CREATIONS]

We have been using the old black cv s they work fine for us. Just ordered another 1000 on friday should arrive today. Anything that makes the season longer is worth it to me. In the end last year we ran 66 days.

[DrTimPerkins]

I didnt think there was any data from using check valves on gravity?

We have never done any research with CV spouts or CV adapters on gravity. They were originally designed and intended to be used with vacuum.

That said, sap backflow can occur in gravity systems during freezes. Steve Childs (Cornell Maple Program) has done some work with them on gravity tubing systems. You'll have to dig around to find his research....some of it is on their webpage, some of it has been in "The Maple News." Gravity systems clearly show similar types of patterns to vacuum systems. However, because the sap yields tend to be considerably lower with gravity than with vacuum, the same patterns mean similar increases in the % of sap yields, but not nearly the same amount of sap yields. In other words, getting 15-25% more sap (as an example) from a gravity system with a baseline average yield of 8 gal of sap/tap means a whole lot less than getting 15-25% more sap from a vacuum system with a baseline average yield of 20 gal sap/tap. Thus the entire economic calculation is also different, and the total $ benefit is smaller and more marginal. That isn't to say it isn't there....it is just smaller, harder to detect, and in some years (like 2012) might even be slightly negative.

Same basic type of relationships hold true for using new spouts and for replacing droplines. They can provide varying levels of benefit, but on gravity systems the benefit is naturally smaller, and the economic gain is correspondingly smaller (or negative in some years).