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Wow, you are a glutton for punishment on driving. I'm the same way...took a business trip up to Boston about 5 years ago and "swung by" leader evaporator on my way back to the airport. 8O :lol:
Thanks for the tips on the sap lifter. Something else for me to fool around with in the future.
Got my extractor put together. Looks like something out of the boiler room of a submarine. Sure hope it works, I have about 45 minutes of wiring left and then I'll try it out.
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That is one long "swing by " from Boston When you are in Pa. I know that I was camping a few years ago near Rutland so visited Grimm and then said lets go to St.Albins what a hike.
It was fun anyways.
Keith
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Gravity releaser
Your releaser idea will work. The weight of a water column, no mater how large in diameter is equal to .434 PSI per foot of elevation rise. Ten foot high column would equal 4.34 PSI at the bottom. The reason that the diameter of the water column does not matter is that the vacuum is applied over a larger surface area in a larger diameter water column. 29.92" atmospheric pressure (vacuum) is equal to 14.7 PSI, so 2.03" atmospheric pressure (vacuum) is equal to 1 PSI. A perfect vacuum is the lack of any pressure, so 29.92 inches of vacuum is equal to the lack of 14.7 PSI.
The height of the water column needed to maintain 17 inches of vacuum is as follows. 17" vac devided by 2.03 is equal to 8.374 (PSI), 8.374 devided by .434 is equal to 19.29. A 19.29 foot tall water column would be required to maintain 17 inches of vacuum. That height is measured from the the max liquid level in the barrel (the outlet to the storage tank). The volumn of liquid in that 19.29 foot water column would equal 7.07 gal.
Great idea, have fun with the freeze up issue.
R Fox
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Well, so much for figuring out something new! I had my fluid mechanics book out and worked my butt off trying to figure all this out, and behold the great maple trader has everything done!! I'm gonna do a little more figuring and then build this thing saturday. Any words of warning?
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releaser
I built a system simular to this years ago to be used on a milk paper carton filling machine. In worked much like this system except I used a 4 inch stainless steel stand pipe. At the bottom of the stand pipe I installed a 180 degree elbow with a check ball positioned at the end of the elbow. I supplied the vacuum to the top of the stand pipe and the foam would enter the stand pipe aprox 2 ft from the 180 elbow. The foam would go back to a liquid form and start to fill the pipe. Once the the weight of the milk over came the pressure of the vacuum the check ball would lift allowing the milk to enter a recovery line to be repocessed. This system worked for many years until defoamerless valves were developed. I am quite sure either designed system will work and pvc is a probably the most cost effective way to build either one.
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question
This reply/question may be outdated now, but it sounds like the idea is to add more weight to the column of sap using the mainline supply under vacuum. In doing this, the weight of the sap column in the pvc pipe exceeds the weight that the column of sap under vacuum will support, so some of the sap is lost out the bottom due to gravity and transferred to the vat. As more sap is pulled from the mainline, more sap would be released out the bottom and into the vat. I'm just wondering what weight is needed to exceed the weight that the sap column will support. I imagine the diameter of the upright pipe and it's inherent friction plays some role, but it's probably not significant compared to the weight of the sap due to volume. On the other hand, with a larger diameter pipe, there would be more surface area on the top of the sap column to pull on.
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Question/Thought
With the releaser, I'm wondering why the vacuum can pull sap from the mainlines which need to be higher than the column of sap in the pvc pipe. So if it can't pull the sap in the pvc pipe any higher, it must not be able to pull the sap in the mainlines higher. I'm assuming the friction in the two sizes of pipe don't make that much difference. It must be the reason for the pin holes in the mainlines as they curve up.
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Hi Kevin,
Thanks for those links you posted. You really got me thinking now. I have been trying to figure out how to build my own releaser. That twin tank idea is excellent. I will use threaded rod for most of the linkages so I can have a lot of adjustment.
Gary
Monroe, NH
75 taps 71 tubing, 4 buckets(for the kids)
2x6 Small Brothers
Wanting to grow a little
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Looks like I missed out on a lot of spirited debate regarding the gravity releaser concept. We built ours and used it for the 2005 season, and it worked as described. We placed clear sections of tubing on each of the riser mainlines, downstream of the pin holes, in order to watch the sap. What we saw was wicked agitation and sap tornadoes (sap spouts?) surging up the dancing risers. As expected, the sap level in the barrel slowly rose to the point that it reached the hole that drained into the vat.
We never measured the vacuum at the end taps of the system, but when we pulled taps, there was definitety suction. At the end of the season, when we pulled taps, we noticed that we had several major leak points.
We didn't take down the tower and early this year noticed that a deadfall or the wind broke off part of the PVC head at the top of the pipe. We had already decided to abandon the gravity releaser in favor of a submersible sump pump sap ejector in our Zero bulk tank. Since we run a generator anyway in this remote woods to drive the electric vacuum; running the submersible with its float switch was not a big deal. Unfortunately, we didn't get it plumbed in time as evaporator modifications took priority; by the time we had time to finish the work, the good runs were over.
Bottom line: The gravity releaser concept works (not just proven by us, but by others as well). It is a rather inexpensive and passive device (low maintenance, other than fixing PVC), easy to assumble from readily available materials, and a fun lesson in physics and hydraulics.
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Russ,
I think you are heading for a disapointent with your submersible pump idea. Not just any pump will pump agianst the vaccuume. In order to pump out of a vaccuume tank you must have a deep well pump. I know because I have tried it with a sump pump and wasn't able to get any results. Now I run a 1/2 horse 120volt deep well pump and it works great. Try to get the 120 volt ones becuase they are easir to wire up. The 220V 3 wire pumps need a starter or relay switch of some kind. But the 120 v 2 wire ( pluse ground) can be put right on a plug and pluged into a float switch real easy.
Ron