CV's and Dropline changing

[palmer4th]

I was wondering if anyone can explain why people are saying changing drops can be beneficial if your using check valves? I thought the point of the check valve was to prevent sap in the line from re entering the tap holes, thus no bacteria from the lines should enter the hole??? what am I missing?

[mapleguy]

Interested in hearing some comments on this. I've been using cv's with old drops and have had unbelievable success and I'm all gravity too.

[WESTMAPLES]

yeah im interested in hearing what others have to say on this topic also. maybe dr Tim could shed some light on the subject.

[CharlieVT]

[QUOTE=palmer4th;239026]I was wondering if anyone can explain why people are saying changing drops can be beneficial if your using check valves? I thought the point of the check valve was to prevent sap in the line from re entering the tap holes, thus no bacteria from the lines should enter the hole?,,,,QUOTE]

Here's some Proctor research published in Maple Digest in 2010:
http://www.uvm.edu/~pmrc/aging.pdf

A quote from the above article: "Based upon that work, as well as
our own previous work (Perkins 2009, Perkins unpublished), we anticipate that
CV adapters will show significant improvements in sap yields when used on old
drops as well as when used in combination with new drops."

If there is research that specifically compares new CVs on new drops to new CVs on old drops, I don't recall seeing it. Anyone have a link to such a publication?

[palmer4th]

That is a good article, I thought there was a newer article also published in the maple digest. I may be mistaken but I thought from the information I have read they are saying for the highest sap yield you have to replace the tap and drop? (I know there are lots of factors involved in deciding when drops need to be replaced).... My question is if you use a new CV spouts every year how can your sap yields go down in comparison to using new CV's and new drops drops. I understand that if your not replacing or cleaning your tubing the quality of your sap could suffer. However if the check valve is working properly why would it matter if its brand new tubing or old tubing?

[DrTimPerkins]

I was wondering if anyone can explain why people are saying changing drops can be beneficial if your using check valves? I thought the point of the check valve was to prevent sap in the line from re entering the tap holes, thus no bacteria from the lines should enter the hole??? what am I missing?

There is an article in the current Maple News with information about dropline replacement interval if you are NOT using CV adapters or spouts. While there have been several papers written with related info, and I've specifically addressed this in many presentations, I can't at the moment think of something easy to point to that answers your question about changing droplines with CVs. With that in mind, see the attached figure (below). It shows sap yields in 4 sections of our "main bush" area over the 2013 season. All were dual-conductor systems on one common pump (separate releasers so we can quantify the sap volume) running an average of 25.7" Hg over the season....and not shut off at any point during the season. The different sections have droplines that are new (0 yrs old), 2 yrs old, 4 yrs old, and 10 yrs old. All were tapped with CV2 spouts at the same time and operated exactly the same. There was no significant difference in sap yields on these systems, with sap yields averaging 30.5 gal/tap. There is no apparent slowdown of sap flow (as we would expect with contaminated systems without CVs) right through the end of the season. In a nearby section of our woods with 8 yr old spouts/drops (non-CV spouts), we got 23.5 gal/tap. In short, age of dropline had no impact on sap yield if using CV spouts, at least out to droplines that were 10 yrs old. At that point it might begin to make sense to replace droplines just due to tubing or fitting breakdown. This would be indicated by breakage or tubing coming off fittings.

8686

[CharlieVT]

Isn't it pretty amazing that a bunch of sap suckers can ask a question online, and shortly get our own resident PhD maple-ologist to reply? Sweet! ;)

Thanks to you Dr. Perkins.

[WESTMAPLES]

thank you dr Tim, that was everybit of information I was looking to have answered . I like to read your responses, they always make sense out of hard to answer questions.

[cur dog]

Wouldn't the best numbers be taken from a bush that shuts its vacuum off, during periods of freezing weather. When the vacuum never stops, it seems you would get good results on regular spouts. Is there data available showing a bush using CV's with new and older drops, and an on, off vacuum routine, like many producers use?

[sjdoyon]

thanks Dr. Perkins, we're coming on our fourth season with our CV drop lines and wasn't looking forward to replacing them next summer. We now can wait a few more years.


There is an article in the current Maple News with information about dropline replacement interval if you are NOT using CV adapters or spouts. While there have been several papers written with related info, and I've specifically addressed this in many presentations, I can't at the moment think of something easy to point to that answers your question about changing droplines with CVs. With that in mind, see the attached figure (below). It shows sap yields in 4 sections of our "main bush" area over the 2013 season. All were dual-conductor systems on one common pump (separate releasers so we can quantify the sap volume) running an average of 25.7" Hg over the season....and not shut off at any point during the season. The different sections have droplines that are new (0 yrs old), 2 yrs old, 4 yrs old, and 10 yrs old. All were tapped with CV2 spouts at the same time and operated exactly the same. There was no significant difference in sap yields on these systems, with sap yields averaging 30.5 gal/tap. There is no apparent slowdown of sap flow (as we would expect with contaminated systems without CVs) right through the end of the season. In a nearby section of our woods with 8 yr old spouts/drops (non-CV spouts), we got 23.5 gal/tap. In short, age of dropline had no impact on sap yield if using CV spouts, at least out to droplines that were 10 yrs old. At that point it might begin to make sense to replace droplines just due to tubing or fitting breakdown. This would be indicated by breakage or tubing coming off fittings.

8686

[palmer4th]

Thank you for a quick reply Dr and for taking the time to explain your research with all of us!!! I was just trying to figure out this whole replacement thing and the benefits of CV's. If the research shows a difference in sap yield between using old drops with new CV's and using new drops with new CV's well then I would question the effectiveness of the CV. If the CV does its job I would think the yield should be the same?

[DrTimPerkins]

Wouldn't the best numbers be taken from a bush that shuts its vacuum off, during periods of freezing weather. When the vacuum never stops, it seems you would get good results on regular spouts. Is there data available showing a bush using CV's with new and older drops, and an on, off vacuum routine, like many producers use?

We did that for several years. The criticism from some folks was that if we kept the vacuum on all the time then the CV spout would not be effective and a regular spout replaced annually would yield the same results. That is definitely NOT the case. The CV spout still outperforms regular spouts under those conditions.

[BreezyHill]

Dr Tim is there a link that we can use to see the data results on the vac on off system. I find it very interesting to compare the data for days and to see the result.
Thanks Ben

[Tmeeeh]

Is it safe to assume that there would be still "no significant difference in the sap yields" if the same experiment were done the same way except for using CV1 instead of the CV2?

[Mark]

What do you do with the dropline after the season? Do you remove the spout?

[DrTimPerkins]

Dr Tim is there a link that we can use to see the data results on the vac on off system. I find it very interesting to compare the data for days and to see the result.

No. The results presented are typically averaged for the season, which is the "norm". It is extremely rare (for almost any scientific experiments....not just these) that the entire data set is published. Generally results are analyzed and presented in some summarized form (graph or table)....typically to save space in whatever way it is being published.

[DrTimPerkins]

What do you do with the dropline after the season? Do you remove the spout?

I assume you mean with systems with a CV spout or adapter. There are several ways to do it. With a CV stubby and adapter you would either plug the adapter into the pin on the tee, or with a separate plug. With the CV2, you would either put it into a cup-tee, or cut the spout off the drop and plug the dropline into a tee or with a plug.

[Mark]

I was thinking of the CV2. Does the spout fit that tight that it has to be cut off?

[unc23win]

I was thinking of the CV2. Does the spout fit that tight that it has to be cut off?

They come off harder than you would think. I have one on my desk and I can not pull it off. Anyhow I think for better results next season cutting them is the way to go you don't want to stretch the line cutting is probably faster and yes the drop will get shorter. For this reason I started making all of my drops longer plus using the Data from Tapping Calculator DR. Perkins shared.

[Mark]

They come off harder than you would think. I have one on my desk and I can not pull it off. Anyhow I think for better results next season cutting them is the way to go you don't want to stretch the line cutting is probably faster and yes the drop will get shorter. For this reason I started making all of my drops longer plus using the Data from Tapping Calculator DR. Perkins shared.

I do too many to be cutting them off. I would go with more of the CV1's but am worried about them being discontinued since there is a new one out.

[unc23win]

I hear you. In my experience they come of hard and if you stretch then line the (maybe) they won't seal next season. With the CV1s research says there is minimal leaking and yes they could get disconnected (maybe) but once again they come off harder than you would expect as well. Anything seasonal is going to involve more labor or at least labor that is different than the norm, however that labor will be made up for by production.

[Buffalo Creek Sugar Camp]

Has anybody heard anything about the CV-1 coming out in a clear version?

[ennismaple]

I've heard that Leader is looking at it but it will require a new mold as the poly spouts cool differently.

[Gary R]

The February Maple Syrup Digest has data from testing at Cornell. It shows good results changing drops and taps verses CV's. There are different environmental circumstances though.

[Sugarmaker]

Just changed 2/3 of our drops and spouts, still using std 5/16 black spouts and 30 inches of Max Flow for drops. Will see if there is a difference in sap quanity. If I do this again I am just going to cut off the old spout and use a new CV on the old drops. That's 2 years away. But the data seems to say even on gravity with older drop lines, the new CV out performs. I have an idea how I Can rinse the tubing using check valves, so that will be a trial in the future.
Regards,
Chris

[DrTimPerkins]

The February Maple Syrup Digest has data from testing at Cornell.

Actually, this was not really a Cornell Study, although it was written up by Mike Farrell as the science advisor. I believe it appeared in The Maple News (not the Maple Digest). These results are based upon some work done by a sugarmaker. The sites varied somewhat, and used different pumps in some cases. It is not what I would consider by any means to be a scientific study, and the interpretation of the results is therefore rather difficult, which makes conclusions based upon this work quite challenging.

[Gary R]

Sorry Dr. Perkins, but I read it last night in the Maple Syrup Digest. The article was by Steve Childs. There are some details missing but it looks like Cornell has been testing for a few years.

[DrTimPerkins]

Sorry Dr. Perkins, but I read it last night in the Maple Syrup Digest. The article was by Steve Childs. There are some details missing but it looks like Cornell has been testing for a few years.

Ah....my mistake. I thought you were referring to the other one.

[Homestead Maple]

Check this study out by Stephen Childs of Cornell University. There are a number of scenarios changing drop lines, types of adapters, etc.

http://maple.dnr.cornell.edu/pubs/2013%20Maple%20Tubing%20Research%20Report.pdf

[PCFarms]

I had a quick question about replacing droplines: If we are on a 3-year rotation of replacing droplines, does it makes sense to replace the T as well as the dropline? We are using seasonal spouts.

[DrTimPerkins]

We always replace tees when replacing drops. If you try to cut the tubing off the tee, a certain percentage of them will have microleaks no matter how careful you try to be. Under high vacuum you'll spend your time chasing these leaks and cutting them out anyway. Turns out to be faster and more economical to just replace them. For gravity or low vacuum it is probably less critical.

[mainebackswoodssyrup]

We always replace tees when replacing drops. If you try to cut the tubing off the tee, a certain percentage of them will have microleaks no matter how careful you try to be. Under high vacuum you'll spend your time chasing these leaks and cutting them out anyway. Turns out to be faster and more economical to just replace them. For gravity or low vacuum it is probably less critical.

100% agree. Just the time you spend messing around with a used tee makes it worth the $0.20 aside from the potential lost sap yield if you scar the tee. Once you have your woods on a rotation schedule, we've found it easier to go through the bush to make repairs on the 1st pass while lugging all the fittings and items needed then go through a 2nd time just to do the drops. We make our drops in the shack ahead of time where it's warm. May seem like it takes more time to go through the woods a 2nd time but we've found it actually saves time. Drops can be done very quickly, takes about the same time to replace a drop as it does to drill in a tap doing it this way.

[GeneralStark]

I used to agree 100% with the change the T philosophy when replacing drops. Now I'm not so sure...

This winter a fellow producer turned me on to using a tool made by Pruno, that when properly used, enables one to cut the drop off without scarring the barbs on the T. It takes practice to get the technique right but it can be very quick to change drops when you get good at it. I don't have a picture of the tool handy but you can see it here in their catalogue. https://www.atelierpruno.com/documents/Pruno_CATALOGUE2020_EN.pdf They call it a "stripping plier" but I have heard it referred to as a "splice tool".

It's on pg. 10 of the catalogue (pg. 6 of the PDF) and the code # is 71200 or 71210. It's hard to see in their photo but the blade of the tool has a profile cut into it that is nearly identical to the barb profile on a tubing fitting. When you close the tool on the T (Drop) it cuts the tubing parallel to it so you can then get the drop off. Because of the profile on the blade, the barbs are not contacted with the blade unless you really over do it.

I did an experiment this season and replaced about 100 drops using the method described with the Pruno tool, and another 200 with the conventional two handed tool cutting out the T method. I didn't find any issues with micro leaks when leaving the T intact. Once again, it does take practice to get it right but it does seem to be a viable option for drop replacement without removing the T. I did find it faster once I got the hang of the tool. I would remove a bunch of drops and then go around and replace them. Two people could really cruise with one removing the drop and the other putting on the new one.

While I do replace drops on rotation, I often have to also replace them due to animal damage. In this case I always replace the T and damaged tubing as I'm cutting out tubing anyway. I do now plan to continue leaving the T intact though for annual replacement after my experience this season. I haven't found any studies that suggest leaving the T will reduce the benefit of drop replacement as far as taphole sanitation goes with 5/16 tubing. But, I'm not sure that anyone has closely studied it.