Shurflo shortcomings and how to overcome them

[jmayerl]

I switched to the 4008's last season because I couldn't get max vac with the 2088's. I would also look for small leaks or possible a tapped tree that is hollow. ( I had a healthy tree that I once hit a dead spot in the wood. I also have only used the recirc line once and that was a marginal day last week, still maintained 28"

[RileySugarbush]

I switched to the 4008's last season because I couldn't get max vac with the 2088's. I would also look for small leaks or possible a tapped tree that is hollow. ( I had a healthy tree that I once hit a dead spot in the wood. I also have only used the recirc line once and that was a marginal day last week, still maintained 28"

This is fascinating to me. I have not been able to achieve those levels at the pump reliably. You are talking about the vac at the manifold, right? I will have an extra 4008 and will try again in my shop, with exactly the same setup as you and see if i can replicate your results. Out in the bush, with any significant number of bubbles, (no big leaks, the sap is moving at a steady, reasonable rate and no obvious leaks on any fitting) I just can't get those levels fo vac.

if these pumps work this well, a half a dozen $90 pumps could replace a liquid ring pump and releaser on a 1000 tap bush.

[RileySugarbush]

OK OK! I will admit it doubted you guys. I had tried what I thought was everything to get my pumps to pull a nice vacuum. In fact, some attempts looked almost exactly like jmayerl showed in his video. But no good results. My system was tight, in fact I couldn’t get it to work even in the shop!

But after your “encouragement” it tried again and this time increased the length of the 1/2” inlet hose a little bit and it worked! I’m not sure why that tiny change made such a big difference but I thank you for holding my feet to the fire. I’ll try it out in the bush today and see if it works as well as my complicated contraption and will report back.

[L&msugarbush]

Would love to see some more pictures of that Shurflo setup and weather it worked out for you or not? I also did the Shurflo pump last year and had some good success but wasn't getting the vacuum like you weren't

[Biz]

I found an easy to test if the pump and fittings around it are tight. Just make up an adaptor to a 1/8" hose barb on the pump inlet side, and get a short piece of small hose to fit it, 2mm, 2.5mm, or 3/32" will fit (a piece of chainsaw fuel line might work), then put the hose end into a bucket or water or sap and test for vacuum. I did this on two indoor demonstration units a couple weeks ago and was able to pull 25" of vacuum on both units. No messing around with needle valve settings. This small tubing would probably work well for a recirculation line too, without reducing vacuum too much. I did not have luck using 3/16" tubing for this test, it won't draw enough vacuum unless you use a really long piece.

Dave

[DrTimPerkins]

I would respectfully suggest using a piece of Tygon tubing (readily available at Hardware stores in various diameters...usually purchase by the foot) instead of fuel line. Fuel line tubing (even before it is used) has a strong odor and is definitely not food grade material.

[DrTimPerkins]

if these pumps work this well, a half a dozen $90 pumps could replace a liquid ring pump and releaser on a 1000 tap bush.

While you might be able to get decent vacuum this way, what you'd find is that a LR pump (or some other pump with higher CFM) would likely become a far better choice at a certain point.

The amount of sap you get from a tree is linearly proportional to the difference in pressure inside vs outside (in the tubing) the tree....basically the old 5-7% more sap per 1" Hg vacuum (incidentally, that rule was established by PMRC about 20 yrs ago and confirmed later by Cornell and more recently by Centre Acer). However the ability to reach higher vacuum levels is dependent upon the ability to evacuate the tubing of air, both from leaks and from gases produced by the tree, in order to achieve those vacuum levels. While diaphragm pumps have the benefits of simplicity, low cost and need no releaser, they are vulnerable to even very small leaks and warm temperatures due to their inability to move gases out of the tubing system fast enough. This style of pump is made to move liquid, not air. Thus they are very inefficient at removing air from the tubing system, and suffer anytime there is a leak or high gas production from trees (warm weather). Their inability to move air also makes leak detection more difficult when leaks do occur. A leak on a tubing system with a higher CFM pump is considerably easier to find.

Of course...it all depends upon how the tubing system is designed and implemented. You certainly could compartmentalize the system to reduce mainline use and try to optimize it for use with multiple diaphragm pumps on 1,000 taps, but it would not be anywhere near a standard system.