Hill Report: Chasing the Bubbles

Guest blogger Bob Page writes:

A simple summary of the three laws of thermodynamics and the fight against entropy.

First Law:  You can’t win.
Second Law: You can’t even break even.
Third Law: You can’t get out of the game.

It’s been two years since I volunteered to help out at Nebraska Knoll during emergencies (Spring showing up in February, staff calling in sick, a big sap run, a restocking panic, or the double edged sword of a big influx of tourists). I have had the pleasure of helping out a little again this year and as before this included a few days of tapping in February, helping to bottle syrup, and stoking the firebox. The one part of ensuring the best possible sugaring season that I had missed out on, and was quite happy to have done so because it sounded exhausting, was looking for leaks in the vast network of tubing connecting 9800 taps to the sugarhouse. Well, dodging that duty ended as soon as the sap started running.

With 900 feet of relief between the sugarhouse and the upper reaches of the sugarbush, gravity does some of the work of getting sap to the sugarhouse holding tanks; however, a vacuum pump does most.  According to Lew, the difference made by maintaining a good vacuum through the tubing system can increase production by 20% or more. There’s a gauge on the strength of the vacuum in the pumphouse and when the sap first started to flow it read a miserable “20.5”psi.  The number needed to be raised to at least “25” psi. This is the general case each year as over 11 months between sugaring seasons all manner of bad things happen to the tubing network. Animals chew on it, maybe because they think it might taste good or because they’re mad about it “being in the way”. There’s tens of thousands of trees in the sugarbush and quite a few will fall down over the year. Add in human error in properly setting taps or drop lines to taps and the opportunities for leaks in the network are endless.

These “leaks” are hard to find until the sap starts running so it’s not like the tubing system can be made leak free before the season starts. It means when the season starts there’s a sleepless-night-type urgency to fix the leaks. This year was the first in several without Ross, a tree-tapping, leak-fixing machine impossible to replace with a single guy and certainly not some half-time geezer. Fortunately, all I would be responsible for is the Morningside section of the network with the new “main guy”, Matt, responsible for everything else.

On my first day Lew got me set up with all the tools and spare parts required to fix most types of leaks. I’m pretty sure there weren’t two dozen different items but it seemed like it. As I looked at everything it ran through my mind that for tapping I only carried a drill and a hammer, and I couldn’t even keep track of those. The odds I would head out in the morning with everything I needed were vanishingly small let alone keeping track of all of them through a full day. Confirming this prognosis, on three of the four days I worked on leaks I got no further than the first leak when I noticed I had forgotten some tool or part. Once it was an obscure part but the other two were a hammer and plastic tubing – the two most used items. What is it with me and hammers! Each time I skulked back to the sugarhouse praying no one would see me, neither item was one I could admit to having forgotten.

In addition to setting me up with the tools, I got a brief tutorial on how to fix leaks on the big black mainlines, the clear blue tap lines, or problems with the taps themselves. Lastly, we headed up to the Morningside section of the sugarbush so Lew could show me how to identify leaks. Seldom would it be as easy as tracking down a hissing noise off in the distance.

Finding a leak starts with looking where a clear blue tap line comes into one of the black main lines and looking at how fast the bubbles in the tap line are moving. I had no idea, but maple trees put out a lot of gas along with sap so lines fill with closely spaced bubbles. The bubbles, if there are no leaks, move slowly. If they move quickly or the tubing looks empty there’s a leak somewhere above in the line. Fairly quickly we found a tap line with fast-moving bubbles and followed up the line until we found where the bubbles were moving slowly. These leaks are always right at the transition. I don’t understand the physics or fluid dynamics of it but that’s the way it works.

Lew helped me fix the leak using two of the more useful tools and ones that I’m pretty sure aren’t at Home Depot. One is a couple of wood blocks linked by a cord, with each block having a groove the diameter of the plastic tubing. The other was a splicing tool. Getting the wooden blocks clamped onto the tubing on either side of the leak is critical because once the few inches of tubing with the leak gets cut out the tubing wants to recoil like cutting a stretched rubber band. If that happens while doing the job alone there’s a long walk back to the sugarhouse to find help.

So, Lew can fix such a simple leak in a minute or two. It will take me 15 the first time as I can’t figure out how to get the wooden blocks to securely hold the tubing in place. My Ph.D. in geology proves to be of no help. Furthermore, using the splicing tool, which has two sets of grips perpendicular to each other, proves a serious challenge to this uncoordinated senior citizen. One part of the tool clamps on the tubing and the other pushes a connector into the tubing. Lew makes it look easy, but in combination the two parts of the tool have me overmatched at first, serving to make me nuts.

I get much better as the day goes on using the various tools, but this work proves to be harder work than just tapping trees. In tapping you get a break at every tapped tree, so you get constant mini-breaks from snowshoeing. Looking for leaks requires slogging along on snowshoes covering 4 or 5 times the distance experienced during tapping, with only 15-20 breaks to fix leaks during the day. I’m cramping and worn out by 2pm. Luckily, I have dogs at home and have a real excuse to quit early.  I fixed probably 20 leaks, from the minor to taps that had fallen out and which could be heard sucking air from 50 yards.

Meanwhile Lew and Matt had been out doing the same and probably at 3 times the rate. I check the gauge in the pumphouse on my return: “21”. I’m totally demoralized.  There’s still lots to do. Any of 9800 taps could be improperly set, any of 9800 connections of droplines to tap lines could be leaking, any of 900 or so tap line connections to main lines could be leaking, a squirrel may have decided to take a chomp anywhere along over 100 km of tubing, or high winds in the night may have felled half a dozen trees.

Within 3 days (including 1 day from Ross!) the entire sugarbush has been checked and the vacuum is up to “25” with sap virtually being sucked out of the trees. I foolishly think the work is done, but I soon learn that without daily vigilance the vacuum will drop as new leaks are constantly opening. It’s entropy! All ordered things move towards disorder and chaos without work done to prevent it. My wife points it out every time she sees my office. The same with the sugarbush tubing network. I’m shocked to find 10 days after I had fixed all the leaks on the 2000-tap Morningside network that at least 10% of the tap lines have new leaks including two serious “hissers”.

I’ve made my minor contribution to keeping the system at “25”, complied with the latest self-isolation guidelines, and passed several pleasant early spring days in the forest.  To top it off, on the way down at the end of my last day I find a hammer! I return with more tools than I had when I started out! It’s a sign but I’m still not sure of what.

-Bob Page