Gravity Releaser?

OK guys, bear with me here. We've played with pipeline and vacuums for a few years, but never used a releaser. We have Zero brand dairy bulk tanks for our sap tanks in the woods; these bulk tanks were designed to hold a vacuum. We have a vacuum fitting in one hole on top and a manifold for the mainlines in another hole on top. We got a good deal (free) on a 900 gallon SS cheese vat that we want to use for a sap tank, but now we need a releaser device. Cheap is good, free is better. Our evaporator engineer has tested a gravity-based releaser... no moving parts. I'm hoping someone can apply some engineering or experience to his idea, and maybe improve upon it...

Imagine a 3" PVC pipe, about 20'-22' long, mounted vertically inside the bottom half of a 50 gallon drum, with the bottom of the pipe supported 2-3" off the bottom of the drum. The drum would be along the outside of the vat, with an outlet pipe about 2" from the top of the drum running into the vat. The vacuum line from the pump would be connected to the very top of the 3" PVC pipe, with the top totally sealed. 3/4" mainline fittings would be 3-5' down from the top. The extra 3-5' between the sap inlets and vacuum fitting are the safety buffer to help prevent sap from getting into the pump. You run your 3/4" mainlines up to the fittings. He suggests a pinhole at the bottom of the mainlines as they begin to curve upwards in order to allow a small amount of air in to carry up the sap. The way this works is that you start out with the drum full of sap in order to form a seal at the bottom of the PVC pipe. You start the vaccuum and it will draw up some of the sap from the drum and create a vaccuum in the mainlines. Sap will be drawn up the mainlines and into the PVC pipe, increasing the column of sap in the pipe. Eventually, the weight of the growing sap column can no longer be maintained by the vacuum, and gravity will cause some of the sap to be released from the PVC pipe via the 2-3" gap at the bottom. Once the sap level gets to the drain pipe in the drum, it will begin draining into the cheese vat.

My question is not so much a matter of *if* this works, since he already has one of these working at another producer's operation. My question is whether anyone has heard of or seen something like this, and if there is a better design that does not require the high vertical lift. Naturally, a wider PVC pipe will reduce the height required, since the operation is dependent upon the weight of the column of sap. He started with 3" PVC since there apparently is a direct relationship between 1' of 3" PVC = 1" of vacuum.

So, how much sap weight can a vacuum support? If a foot of 3" PVC is required for each inch of vacuum, then can I assume that 1" of vacuum can support 1.5"*1.5"*PI*12"*0.004329 gallons/cubic inch* 8.333 lbs/gallon = 3.06 pounds of liquid? If 17" of vacuum is desired, then the weight of the column will be 17'*3.06 lbs/foot, or 52 lbs at equilibrium? If this is the case, then can I assume that a pipe that is 8" wide would only need to be 6' high (2.86' for the sap column + the 3' safety buffer)? Mr. Wizard, help!!

[Russ]

Sorry guys, I forgot to log in before posting the previous message.

[syrupmaker]

I can't find the emoticon with a guy waving his hand over his head?

Wow Russ.... i have never heard of anything such as that but it does sound interestingly possible. :idea: I'll have to reread your post and draw it out on paper to put it into perspective.

Back to ya shortly :wink:

Rick

[Maple Hill Sugarhouse]

post edited

[Russ]

Kevin:

The mainline fittings go into the PVC pipe, 3-5' from the top. The vacuum line goes into the PVC at the very top. The drum is not sealed at all, it is merely there to provide storage for the start-up sap (priming sap?) required to seal the bottom of the PVC pipe. Otherwise you would just be sucking air in from the bottom.

Hope this helps clarify the design.

[Maple Hill Sugarhouse]

post edited

[themapleking]

YA WHAT HE SAID :wink: :roll:
I've talked to farmers and syrup makers that use zero tanks. They have colapsed tanks with 17" vacuume or more. They run 15" vacuum in the tanks at the farms milking. Word of warning.

[Russ]

Thanks for the warning... that hasn't been a problem so far, but I don't know how much vacuum is typically on our systems. We have to get better at monitoring that.

[wdchuck]

Hey now here's an idea i can get into- cheap and apparently effective! Does it really work though? I get the physics of it, but I'm left wondering if there's something left out of the equation that would screw up the whole operation. Some assumptions\questions.........Lets say its going to freeze hard overnightand there's that sap in the mainline that's going to stay there due to the height of this contraption- how about putting a T up to the releaser and a valve to let things drain out overnight? How 'bout if you build the version of this with 8 or 10 inch pipe so it is significantly shorter- that way you dont need T and valve if you can still run your mains into the releaser with slope. Am I on the right track here and most importantly, will it work as well as the expensive "store bought" releasers, because if it does, I'll start tomorrow. More thoughts, guys?

[Maple Hill Sugarhouse]

post edited

[mapleman3]

We need a releaser thats 1/3 - 1/4 of the price of the big boys. that way us smaller guys don't have to put out a small forture for vaccum, also a small user friendly vaccum pump to, that lets say max 200 taps!

[powerdub]

Haven't you seen the new leader catalog? They have that great new 8 cfm flood vacuum system for 1000 taps or less. Olny one problem though. The darn thing cost a that small fortune mapleman3 is talking about. $2199. That is crazy!! I know a guy that just bought a travini (?) 3 hp water cooled pump for around 1400. I think they can the cost down on this stuff for sure.

On a different note I have done the invent it thing and in the case of the releaser I think I am going to go the route of time tested small fortune. I have lost a lot of sap trying it the other way and in this case I enjoy the piece of mind knowing it is working since I can't be there to watch it. I wish you all the luck though, and who knows, we could be seeing the start of a new invention that will earn you millions 8O :D .

[mapleman3]

Your right, it has to start somewhere!

[Russ]

Well guys, remember that the guy here is Wisconsin already has one of these in production. US patent laws favor the first to use, not the first to file.

Kevin, I forgot to add the "Ts" in the drawing I posted in my album. As someone here mentioned, you don't want the sap to pool in the mainlines when the vac is off. We plan on putting a tee or wye in the mainlines where they begin to slope up; the tubes off those junctions will drain into the vat.

The woods that we plan on using this in is far from commercial power, so we run the vac motor off a gas generator. We can guesstimate the amount of gas needed for the desired duration of operation; when we start the vac, we'll seal the ends of these drain tubes with flappers or tethered balls. When the vac quits, the flappers will open or balls fall out and the mainlines will drain via gravity.

I posted a few other, older pictures of our operation in my album as well. I'll take new ones either at our test boil or definitely next spring during the season.

[Maple Hill Sugarhouse]

post edited

[Maple Hill Sugarhouse]

post edited

[WESTVIRGINIAMAPLER]

Kevin,

For future reference, if you will go to the website and put your mouse in the address bar and right click and then click on copy, you can then go to your post and click paste and it will put the exact address in the post. Submit the post go to 2nd website, copy and then go back and edit post and copy 2nd address.

Sure will make life a lot easier! :D :D

[Maple Hill Sugarhouse]

post edited

[mapleman3]

Kevin.. If you want to do it right, be sure to pick up one of those left to right weight deflectors.. attach it to a gold plated kanuter valve using the right sized muffler bearing wrench!! that'll do it I'm sure!! 8)

[Maple Hill Sugarhouse]

post edited

[mapleman3]

Tell ya what, if you can get that thing to work, you could probably make a fortune, it's amazing what they get for some plastic tubes, plastic cement and O-rings. the main thing is .. can it withstand the Vacuum, negetive pressure sure is an amazing thing, look at what it does to an 18 wheeler stainless milktank if the milk is let out with out venting, implodes like a tin can. I had drawn up a few things too but got nowhere fast, I couldn't think of how to overcome the vacuum and when it did, how to have it close tight enough to start it again.. all with being able to not have the vessel implode 8O :lol: :wink:

[Maple Hill Sugarhouse]

post edited.

[Maple Hill Sugarhouse]

post edited

[Maple Hill Sugarhouse]

post edeited

[Russ]

If you go to my album, you can see a crude drawing of the gravity releaser that has been discussed here. I talked to the user of the system last night; here are the specs that go with the picture:

- 3" PVC tower is 30' high.
- Four 1" mainline fittings are 5 feet down from the top of the PVC tower.
- Barrel is a 55 gallon drum, cut in half.
- A 1/16" hole is drilled at the beginning of the upslope on each mainline to allow the vacuum to grab some air to lift the sap.
- They run 20" of vacuum at the pump.
- It takes about 15 gallons of sap in the barrel to prime the column, plus have some left in the barrel to prevent sucking air from the bottom of the PVC tower.

My brother has attempted to build a 8'high 8" wide PVC tower, but recent research on how vacuums work may indicate that a wider column does not make a difference in the height required. Plan B is to have a 30' 3" tower built by next weekend, so we can test that as well. As I stated earlier, I will post our findings and perhaps some pictures as well.

[Mr Bill]

The gravity releaser is a clever idea. Unfortunately, you can't get something for nothing in this world and this is no exception.

If the trees are significantly below the height the mainline connects into the releaser pipe/tower, you will not have much vacuum at the trees.

So, if the tower is 25 ft. tall,
the ground is flat so the tower/pipe base and tree bases are all at the same elevation,
the main line connects at the 22 ft point,
20 in-Hg of vacuum is pulled at the top of the tower
and the trees are tapped 3 feet above the base,
then when the mainline is full and dumping into the releaser tower, the vacuum at your trees will only be about 3 in-Hg.

It's just like trying to run a drop line uphill. With sap, roughly 1 inch Hg of vacuum equates with 1 foot of height. If the drop line runs uphill to about 18 feet elevation difference and the vacuum at the top of the hill is 20 inches of mercury (in-Hg), then you will only have about 2 in-Hg of vacuum at the tree tap.

If the releaser tower can be positioned at the bottom of a hill such that the mainline connection to the pipe is at or below the elevation of the taps on the trees, then there won’t be any compromise in vacuum at the trees. Of course you wouldn’t need a vacuum system either since with full tubing that runs to the base of the tower, the gravity flow could pull 20 in-Hg or better anyway.

With respect to the notion that using a bigger diameter pipe will allow it to be shorter, unfortunately it doesn't work this way. Vacuum is a pressure – that is force per unit of area. The height a given vacuum will raise the sap in the pipe is irrelevant to pipe diameter. Sure, the fatter the pipe the more the sap weighs but since vacuum is a pressure, the fatter the pipe the more area the pressure has to work on and this offsets the increased weight exactly. Sorry.

[brookledge]

Physics 101 good point

[Russ]

I'll concede on the wider diameter pipe point. As for the rest of the concept, with the 30' PVC tower and the rest of the design, I have been told that it does work. I'll have to check on the slope versus level ground point; our implementation will be on a slope. We still want to apply vacuum to improve the flow, and will utilize Kevin's vacuum booster design to help in that regard as well. I thought sap ladders were a crazy idea too, until I heard of all the people that are using them. I guess it's wait and see.

I better get to bed. I'll be up at three; son #1 and I are headed up to the sugar shack (210 miles) for the test boil tomorrow. Got the camera and camcorder packed already.

[mapleman3]

210 miles 8O you must stay there the whole sugar season :?: WOW my hats off to you Russ :wink:

[Brian]

I have about 60-70 taps below the sugar house and also to far down for a sap ladder. They run gravity into a tank, so I am going to hook vacuum from the releaser and run 1 inch plastic down to the upper side of the main line and put in a check valve at the bottom of the main line and i hope as the sap runs down and fills the main line, in time the weight of the sap will overtake the check valve and dump some sap every once in awhile. Then at night when the vacuum is off it will dump out.

Haven't been here in awhile, but it's nice to see you guys are up to the same old same old. While you'all spend lots o'money trying to figure out how to make something that works, your spending money you could spend on the real deal. But if you must experiment, why not work on something that has a chance of working? Build an electric releaser. There is nothing simplier to build, and have a decent chance of working than that.
:lol: :lol: :lol:

[Maple Hill Sugarhouse]

Where the heck have you been? Pounding rocks?

Kevin:

You're funny. No I haven't been pounding rocks, just didn't have the internet on. Needed a break ya know. This internet thing can be adictive.
Anyway you'll hear from me once in awhile. I always have some insight to share, good or bad. I'll leave it at that. :lol: :lol: :lol:

[Russ]

The gravity releaser works! A modification in the design allows for either gravity flow or vacuum operation. More details to follow; absic diagram is in my photo album. Low cost, no moving parts, a miracle of physics. No idea how much vacuum we're pulling; the gauge says 14", but we think the gauge is faulty. Good vacuum at the end taps, based on feel and sap movement.

[mapleman3]

Great job russ, and cool reserch too, may have something there!!!

[sweetwoodmaple]

Thinking about this releaser a little more...

Appreciating that the laws of physics and gravity are constant, I was wondering how the 3" tower works.

Wonder if the secret to success is in the small holes at the base of the main lines before they go up 25' into the main 3" tube?

As someone stated earlier, if it was truly a 25' water (sap) column, there would not be much vacuum at the taps. But if the holes introduce air, now it's an air and water mixture column which has a much less specific gravity than pure water. Therefore, the 25' column would allow vacuum at the taps yet the sap would condense once it entered the 3" column.

Guess you better oversize your vacuum pump in this scenerio as well?

Brian

[sweetwoodmaple]

Alright Russ and Kevin - what was the final verdict on this? Were you able to get some vacuum at the trees or not? If so, how much?

As was mentioned earlier, could you use a PVC swing check at the bottom of the 3" column to start out with when there is no sap, then when the column fills up, the check would release from the pressure of the water and open. You could then have a bypass to let the sap out at night past the check. McMaster carries the zero pressure PVC swing checks that have a rubber seat.

Another comment after reading this again...you can pull the same water column height, no matter what the diameter, that is correct. But, your CFM and corresponding Vacuum pump HP will limit how much volume you can pull at at time. Therefore, the smaller diameter will rise faster that the larger diameter, but still the same height in the end.

I need to decide whether or not to build one of these or my design for a standard releaser.

Thanks,

Brian

[Maple Hill Sugarhouse]

post edited

[Maple Hill Sugarhouse]

post edited

[sweetwoodmaple]

Was just reading that when I bounced back on the Trader and saw your post. Google is great. (except in China, :wink: )

What's better on the sap ladder concept is looking up how a coffee maker works. http://home.howstuffworks.com/coffee-maker4.htm.

This is why you can inject some air and the sap can travel up. Called a water boiling pump, only we are injecting the air without heat, but still using energy created by the vac pump. Buoyancy is what helps the water up, riding on the bubbles. Aquarium filters work under the same concept. As this article states, smaller lines might tend to allow the liquid to rise higher than larger diameter lines.


On the current ladder concept of 5/16 stars and a dry line bypass, it sounds like the bypass could be a hindrance on lift of sap, but a bonus on transferring the vacuum down the line to the next taps. The only way around it is to inject the air WITHIN the ladder (poke tiny holes in the 5/16 lines). Or, is it the fact that the sap really doesn't start to flow up the 5/16 lines until the sap level in the tubing get's high enough to start to plug off the bypass tube Tee in the lower ladder? Otherwise, wouldn't the air flow just go through the dry line and not help the sap up the 5/16 lines?

So, all this begs the question, are you really limited by the 1" HG = 1 ft of total sap rise in your sugar bush? If you had a zillion HP and CFM to work with (therefore, lots of energy into the system), couldn't you pull sap up indefinately as long as your ladders never exceeded 18' or whatever for each one?

I think the bottom line is that under perfectly sealed conditions, the most you can bring water up is 29", so you MUST have air for any of these concepts to work. It's the placement or timing or ? of air that maybe allows the injector that D&G sells to be better at lifting the sap.


Brian

[sweetwoodmaple]

P.S. Gee, it's too bad the UV light wasn't up for grabs on stuff like this. I know, this is too easy! :D

[Maple Hill Sugarhouse]

post edited

[sweetwoodmaple]

ZZZiiippp. Ouch, that hurt! :oops: Kind of like being at the end of the chain of people grabbing the electric fence, I guess.

Alright, I get the concept on 34'. 14.7 psi divided by 4.3 psi per 10' of water head. Hence why you can get 450' up, with around 100 psi. Don't think air plays much part there, besides scrubbing the tubing.

So, ok on the roughness call, but I've thrown the red flag on the bypass (not meant to be a pun). Seen the new leader catalog yet? What about that vacuum ladder that they sell in there? Just a small tank with a vertical line, then a bypass. How does that work?

Should I be removing the vacuum bypass on my ladders? Maybe I'm mixing up my theories by # of 6 way stars per # of taps and having a bypass line. Are they depending on differential area between (6) 5/16 lines and say one 1" line? Guess I could always use it for a large gage port. :D

Brian

UPDATE: Just talked to Leader. The bypass is only for washing. Guess I have to lose a time out on that one... :cry:

[Maple Hill Sugarhouse]

post edited

[sweetwoodmaple]

Yeah, Brad is who I called twice today. He said, from his experience, that after 14' of ladder height (either in a single or multiple ladders), that you have to put in an air leak to get any higher. He suggested that I put a small hole in my lowest ladder at the very end of the line and give it a try.

I asked about the whole theory on sap ladders and air, and he is still under the impression that the air/water mixture has less specific gravity, so therefore does not necessarily hold up to the rule of a maximum of 34' or so total lift. I guess the gravity releaser still lives, though you or Russ still haven't answered my original question about how much vacuum at the taps using that type of releaser. 8O I'm afraid it would not be enough to run my ladders?

Also talked to him about the new sap lifter. He wasn't very revealing in how it worked. So I guess both of you are tight lipped on this one. :wink:

I'm wondering if you are running into pressure drop issues when using straight water with no air. In a 5/16 line, you can't get very much flow without building up back pressure. I am speculating that if you lowered the flow rate (like it would take all day type flow rate), you would be able to reach the top. But, with all the benefits of your snazzy air/water tubing washer, who would want it any other way? :D

Guess I'll have to open the window while the sun is shining to get that "UV light", eh?

[Maple Hill Sugarhouse]

post edited

[sweetwoodmaple]

Aren't we, in the end, just creating a "maxed out" sap ladder here with the gravity releaser? The only way I can see to keep good vacuum plus use the gravity releaser is to bring the line in straight at the top of the 30' column so that the vacuum is maintained in to top of the main line and the sap falls down into the 3" PVC that goes down to the barrel. The problem is...I'll be getting a nose bleed putting everything in, unless i have a valley to work with or dig a well.

And, I'm a little confused since your sketches with Russ showed the main line coming in at the bottom then turning upward to the top of the tower (with a hole drilled at the bend upward). Are we assuming there is some vacuum left after pulling the sap and air up 20' ? Or are you assuming that if you are pulling it up 20', you still have 10' or so worth of vacuum to spare?

My mechanical/electrical releaser is looking better all the time...

I suppose you could do two vacuum pumps or plumb up some way to act like two systems from a single pump. One to pull up the sap into the releaser and one to supply vacuum to the taps.

[Maple Hill Sugarhouse]

post edited

[sweetwoodmaple]

...Works the same way. Hence why Brad talked about 30' being about the limit.

So, is that why the gravity releaser posts kind of died out? Think I'm dizzy from running in circles here...

[Maple Hill Sugarhouse]

post edited

[sweetwoodmaple]

Not sure if it was a single lift or a combination. Might have been per lift. He was throwing around higher numbers so it might have been per lift.

My UV light went out a few hours ago. Will have to wait another 12 hours or so for it to come back on. (ok, I've beat that to death)

Brian

[sweetwoodmaple]

...One other thing while i was talking to Matt the other night.

As seen in the latest Leader catalog and Matt's letter, he made 940 gallons of syrup last year, and about 700 of that was fancy from 5000 taps.

So what, you say? :?

(He only drains his tubing every year, doesn't clean it with one of those fancy washers. 8O :P :P )

What say you, Kevin?

I should add that he does let some sap run on the ground at the beginning of the season.

[Maple Hill Sugarhouse]

post edited

[sweetwoodmaple]

One of secrets, as you mentioned, is that he boils sap the day it comes in if possible. That kills those boogies alot faster without letting them grow. Does create a hectic season if it just runs a little at a time.

I imagine your setup will be better if you have to let the sap sit for a number of days before boiling.

For Pete's sake, Kevin, learn the home row (aka touch typing). :D :D Can't believe you hunt and peck all these long posts. 8O 8O

Here you go, man. http://www.senselang.com/

We can suck alot more information from you if you learn to type faster!!! :wink:

Take Care and see you in a week or so. Thanks for all the info.

[Maple Hill Sugarhouse]

post edited.

[sweetwoodmaple]

...They had typewriters back then? :lol: :lol:

Sorry, just couldn't resist.

[Maple Hill Sugarhouse]

post edited

[sweetwoodmaple]

Wow, you're not as old as I thought! :wink: I only got you by a few years.

You grab the posts so quick that you don't give me a chance to "polish" things up. I'm not trying to slip something by you, honestly.

Do you get a notification when someone responds or are you on this thing constantly?

Of course, maybe if I hunt and peck, my fingers wouldn't get ahead of my brain and I wouldn't have to do corrections after the fact.

[Maple Hill Sugarhouse]

poste edited??

[Maple Hill Sugarhouse]

post edited

[sweetwoodmaple]

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.

[brookledge]

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

[5foxfarm]

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

[Toby]

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?

[Dale Westrick]

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.

[small_operator]

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.

[small_operator]

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.

[small_operator]

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

[Russ]

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.

[maplehound]

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

[Russ]

Hmmm... we have a few months to ponder that. We tested it under vacuum and it seemed to pump ok.

[tmccrumm]

I investigated this type of system 20 years ago, problem is, as the column of sap gets higher in the tube, all your vacuum energy is being used to hold up the column of sap, and very little vacuum gets to the trees, esp. if you have a pinhole ther to insert air.

[ryebrye]

... This is a very old thread, I know, but I'm curious if anything has been tried with this in the past 8 years or so.

(I also disagree with the last post - the vacuum pump doesn't expend energy to lift a column of sap, it removes air and atmospheric pressure is what lifts the sap.)

I have been toying around with the idea of trying out this kind of a releaser.

I have more than 30 feet of vertical drop from my last tap to my collection point, so I was thinking about setting up something with a big column of 3/4" mainline 30+ feet with a vacuum line at the top of it, and at the bottom of that column I'd have a flapper for a mechanical releaser. When the pump first turns on, atmospheric pressure would keep the flapper closed. When the force of the column of sap above it plus the sap coming down the line is greater than atmospheric pressure, it would open the flap a bit and let sap pour out until the atmospheric pressure overcame it again and shut it.

There may be a big fluctuation in vacuum level when this happens - especially if it opens enough to dump the whole sap column... But I won't know until I try it. (But if anyone else has tried it I'm all ears)

I don't really _need_ much vacuum in a mainline as I was pegging vacuum gauges with 28+" on 3/16 last year, so even if this is a total failure I wouldnt miss out on much by just bypassing it entirely and going with just gravity.

... Any thoughts?

[red maples]

this thread is from 2006. So looking at the past threads they do make Stainless sump pumps for the "electric" releasers.

But anyway I am trying to see why your having a problem. OK so trying to understand, basicially its laid out like this:

vac. pump......releaser collection tank..... 30 ft verticle rise.... first tap going out? is this correct? if so then are you getting sap stuck in the line as it comes down the line over the 30 ft drop? or do you need it to lift up 30 ft? I will read it again. See if I can understand!!??

[ryebrye]

this thread is from 2006. So looking at the past threads they do make Stainless sump pumps for the "electric" releasers.

But anyway I am trying to see why your having a problem. OK so trying to understand, basicially its laid out like this:

vac. pump......releaser collection tank..... 30 ft verticle rise.... first tap going out? is this correct? if so then are you getting sap stuck in the line as it comes down the line over the 30 ft drop? or do you need it to lift up 30 ft? I will read it again. See if I can understand!!??

The idea is that you*might be able to achieve high vacuum without having to have a normal vacuum releaser if you can leverage gravity to help you maintain vacuum in the system and still get sap out of it.

Here'a a really rough diagram of how it might look:

https://www.evernote.com/shard/s163/sh/723b7610-5340-47c5-8c4c-275b872d8a3b/203058b51d376a95efa01b1a5c8cafc3

9989

I don't think you would need a submersible pump at all, gravity should cause sap to gather down the line and once there is enough there to overcome the force that atmospheric pressure is putting on it to cause it to rise up in the air you would have more force inside the tubing pushing against the flap then you had outside the tubing holding the flap closed, so the flap would open a small amount and sap would flow out but air shouldn't (or might not?) flow in.

[red maples]

I honestly don't see how thats possible. here is a perfect example fill a shop vac full of water just before the float shuts off the vacuum now loosen the cap wiht the vac running reguardless of the weight of the water on the cap it will still suck air and not allow the water to escape and if some does escape it will not be enough to clear out the lines while sap is still coming down the line backing up into you vacuum pump line.

the other problems you will have is when the line starts to freeze and backs up into the top line going into the vacuum pump, whenever you introduce any air leaks into the system it creates a cold air gap that will cause freeze points where the air coming in because its not really a closed system the vacuum goes into the releaser and that is the stopping point for the sap. there is no way for the sap to get to the releaser. In theory it will work under perfect conditions and under a constant run but sap is never constant and can run differently even hour to hour, day to day, morning to night. to many variables in sap flow to keep it constant. you can try it but I would say it will only work sometimes. You can try it and I would love to hear how it comes out. When a mechanical releaser dumps the vacuum to the large container is broken or removed allowing the sap to move out then when the vacuum is reintroduced it closes up and continues you really don;t have a consistent way of breaking the vacuum enough for it to work. it would also effect the vacuum in the upper lines as well.

but thats my opinion if you can find the right ratio of weight to vacuum it might and mean might work but I really think its a fine line.

[ryebrye]

I honestly don't see how thats possible. here is a perfect example fill a shop vac full of water just before the float shuts off the vacuum now loosen the cap wiht the vac running reguardless of the weight of the water on the cap it will still suck air and not allow the water to escape and if some does escape it will not be enough to clear out the lines while sap is still coming down the line backing up into you vacuum pump line.

the other problems you will have is when the line starts to freeze and backs up into the top line going into the vacuum pump, whenever you introduce any air leaks into the system it creates a cold air gap that will cause freeze points where the air coming in because its not really a closed system the vacuum goes into the releaser and that is the stopping point for the sap. there is no way for the sap to get to the releaser. In theory it will work under perfect conditions and under a constant run but sap is never constant and can run differently even hour to hour, day to day, morning to night. to many variables in sap flow to keep it constant. you can try it but I would say it will only work sometimes. You can try it and I would love to hear how it comes out. When a mechanical releaser dumps the vacuum to the large container is broken or removed allowing the sap to move out then when the vacuum is reintroduced it closes up and continues you really don;t have a consistent way of breaking the vacuum enough for it to work. it would also effect the vacuum in the upper lines as well.

but thats my opinion if you can find the right ratio of weight to vacuum it might and mean might work but I really think its a fine line.

Yeah, I probably will try it primarily because I don't have much to lose. 90% of my taps will be getting vacuum from 3/16 and gravity

(I'm only going to have around 100 taps on this system this year)

To avoid sucking air I might have it drain into a trap of liquid and then into the tank so that it will have a little more pressure to overcome but when it does overcome it, it will be opening into liquid and not air...

This specific setup might not be the right way to do it, but it sounds like from this ancient thread that some people have done it in the past.

It will be fun to play around with at least.

[Super Sapper]

Why not just replace the tubing after the last tap with one or two runs of 3/16" run down to your collection tank?

[ryebrye]

Why not just replace the tubing after the last tap with one or two runs of 3/16" run down to your collection tank?

The latest thought I have is even simpler than what I was proposing before - I'm thinking of having the mainline under vacuum and on the downward slope, and then connecting the vacuum to the mainline high up on it (so it's higher than a 33 foot vertical rise for the sap to get to where the vacuum is being applied) and the force of the atmospheric pressure would cause the sap to back up in the line until enough sap collected that it would naturally drain out the bottom of the tubing. I could use a flapper on the bottom to help it maintain vacuum until it gets primed, or I could leave it open and use liquid to prime it - but in either case I don't think I'll need the straight vertical tubing I was thinking of earlier - the column of sap in the 3/4" mainline will keep it from sucking air, and the weight of the sap will push sap out the bottom of it in a steady stream.

I could have the mainline step down to a couple of 3/16 lines and it would probably work too, but it will be easier I think to just keep the 3/4 mainline going down the hill. The advantage of going down to a smaller tubing size would be that I would require less sap to prime it, but the disadvantage is that it would take longer to drain when I want to drain it before a hard freeze etc - it can take a long time to drain a 3/16 line. I don't expect to have any vacuum leaks in the mainline part, so even after I turn off the pump it would not have an open flow of air to flush out the 3/16 drain lines.

I'll think about it more though.

[Super Sapper]

I'm new at the tubing and will be using teh 3/16" for the first time this spring, but why would you want to drain it during a freeze? When it warms up to thaw the trees for the sap to run the tubing will thaw out also and the lines will be primed and you will have the vacuum right away. Using the 3/16" would also eliminate using a vacuum pump and releaser.

[maple flats]

Ben and Judy's Sugarhouse in West Edmeston, NY had one of these at one time. I was there a few years ago for a Glen Goodrich tubing seminar. After the seminar we walked one of their sugarbushes. Mounted right at the back of a garage, behind the sugarhouse was a PVC contraption, likely 30' or so high. I asked what it was and they said they had used it as a releaser at one time. They explained it, but being so long ago I don't recall details. They did say that the vacuum would pull the sap up in the vertical tube and at some point it would get a slug of air in it, that let the sap all fall out into a barrel on the bottom. The barrel had a drain tube to drain the excess to a sap tank. Then the process would repeat. Sounded neat but sadly I din't even have vacuum at that time and didn't pay close enough attention to what Ben said.

[ryebrye]

I'm new at the tubing and will be using teh 3/16" for the first time this spring, but why would you want to drain it during a freeze? When it warms up to thaw the trees for the sap to run the tubing will thaw out also and the lines will be primed and you will have the vacuum right away. Using the 3/16" would also eliminate using a vacuum pump and releaser.

You don't want to drain the tubing after a freeze. You want to to stay full. If you have a period of several days above freezing when the sap slowly stops running (even with the vacuum) then it will eventually drain itself.

It takes a bit of time to get a full column of sap. I believe having done form of vacuum would lessen the time to establish the column of sap. I would still set it up for 3/16 gravity (put a bunch of trees on one lateral to get a full column to establish, etc)


You can do just fine on 3/16 with no pump. I'm just playing around with other things this year.