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!!

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

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

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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.

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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.

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.

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?

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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!

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 .

Your right, it has to start somewhere!

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.

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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

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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)

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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:

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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.

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.

Physics 101 good point

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.

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

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:

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:

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.

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

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

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

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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