Back Pressure/Vacuum on Buckets

[danfredw]

Been thinking about this one for a while, not 100% sure how to describe it. When using gravity taps on buckets and you have a really good seal on the tubing hole + lid, is there any concern about the sap not wanting to flow into the bucket because it's having to displace air? If your spiles were just the metal ones with hanging buckets, then there's no concern about air displacement, but when you have that great seal, for the sap to go in the bucket, there has to be enough pressure, or the internal contents needs to be displaced.

I think to some degree, this may fall in line why vacuum works better than gravity. On days where it flows great, typically later in the season, I put my doubts aside, but early in the season, I always question this (or maybe I'd get even better flow on those days). I saw one person post that they'd create a tiny pin hole in the lid or top side of the bucket to maybe alleviate this, but I'd rather not do this just because I love knowing that my buckets maybe get blown sideways, I won't have a chance of it leaking while I'm not home. Is there any logic on making that small pin hole in the bucket/lid?

I tried to search for the answer but no luck. I know there are a lot of other variables for when it runs, but I still feel this might be a viable question on any day. Thanks!

[TheNamelessPoet]

NOT in the top of the bucket. Water will get in when it rains. I am not on vacuum, but I would think it would be the same issue of running water.

If you want to add a hole. put it just below the lip of where the top snaps on. You are right tho, it can be risky if it blows over.https://uploads.tapatalk-cdn.com/20200219/8492dbcb730ee39caf55581dd11bef5c.jpg

[buckeye gold]

I think your concern is valid. I noticed one day the flow into mt float box wasn't what it should be and my sap in the pan was getting low. I had screwed the lid on tight on my head tank and not realized the vent on the lid was pushed shut. When I unscrewed the lid I heard air hiss as it rushed in and my flow jumped right up. When I used buckets I just snapped two sides down to make lids easier to get off and they would vent. Yes they leaked if they fell over

[maple flats]

If your taps and drops are 5/16 and your tubing enters the bucket but does not extend below the sap in the bucket, don't worry, the sap can and will pass the gases (looks like air) in the tubing. However, if you use 3/16 tubing the sap will not pass the gases and it can form a slight vacuum. On buckets this is not generally considered good unless the fall from the tap to the bucket is more than just 2-4 feet. If you have a side hill with the bucket 5-6 or more feet below the tap, you can produce a little vacuum but when the tree freezes again it will pull sap back in thru the tap unless you use CV taps.

[Super Sapper]

You should have the buckets vented. Sap runs because of a pressure difference and in theory you could equalize it with a tight lid. If the bucket would tip over in the wind there could not be much sap in it anyway. I built a wooden "box" to put the containers in and have not had any blow over not matter how much wind. The box is just an open frame with the boards across the bottom extended out a little to make it stable.

[danfredw]

Yes, I'm on 5/16 drops. No, the tubing isn't generally in the sap as the hole is in the very top on the side and it even likes to curl upwards.

I'm hesitant to drill holes, so maybe I'll try the 'crack the lid' idea, but I do think when I often want to do this, I am in a period where there hasn't been much flow nor is there much sap in the bucket. I live in a very windy area, even in the woods, so I've had buckets on their side a few times.

I'm guessing you built that wooden box for when you were on buckets and not anymore with 325 taps. That sounds like far too many supports to build. I've put some nice fieldstone down as a support for the buckets because I'm also on a hill for half my taps and that has seemed to help.

I'll maybe test it out with some and see if I get different flows but now it's cold again and nothing looks to run for a few days.

[Z/MAN]

I drill a hole into the lid slightly smaller then the old blue 7/16 taps. I then force the blue tap thru the hole in the lid. Place the bucket at a slight angle (tap side up) and have NO problem with water getting in. I place a flat stone on top of the buckets and that keeps them from blowing over in the wind. I snap the lids on three sides and leave the fourth (on the down side of angle I place the buckets at) unlatched. It is still tight but unlatched, easy to open but nothing can get in. By putting the tap in the lid you can easily switch buckets for transporting or cleaning. This system has worked flawlessly for me for years.

[fisheatingbagel]

This is what I started doing this year as an experiment. Drill slight undersize holes in the lid for 5/16 tubing so rainwater can't leak in. The lids sit on top. I haven't had any problem with lids blowing off, so I don't use a weight - that also allows air to pass between the lid and bucket. I extend the tubing into the bucket so it's almost touching the bottom. I use CV spouts to keep sap from being drawn back into the taphole. I want to minimize the taphole exposure to air to see if the holes remain viable for longer than regular metal spouts. So far so good, although all taps are still running good. The proof will be at the end of the season after a warm spell when the metal tap holes have dried up.