sap ladders

[WestWind]

I'm in the process of setting up a part of my woods with approx 400 potential taps. Unfortunately, it slopes away from the sap tank and I have to use a series of sap ladders. I have a 2 hp Busch R5 type pump running about 27" of hg @ the releaser. How many ladders can be I have? I heard a max of 3; ideally, I'd like to have 5. Is this doable? What does it depend on? Any advise would be greatly appreciated.

[Thompson's Tree Farm]

I have moved sap through as many as 6 ladders. It will work. You lose some vacuum at each ladder so the most remote trees will not have optimum vacuum. I was doing it with 20 to 22 inches of vacuum so 27 will work even better. I tried to keep each lift at 8 feet or less as they were easier to work on that way.

[CharlieVT]

I'm in the process of setting up a part of my woods with approx 400 potential taps. Unfortunately, it slopes away from the sap tank and I have to use a series of sap ladders. I have a 2 hp Busch R5 type pump running about 27" of hg @ the releaser. How many ladders can be I have? I heard a max of 3; ideally, I'd like to have 5. Is this doable? What does it depend on? Any advise would be greatly appreciated.

From my experience, running four sap ladders in series, you can get it to work, meaning it will move the sap. But at the expense of vacuum at the tap.

I have an old rotary vane dairy pump, modifed with oil flood, which runs at about 22mmHg.
Four sap ladders in series in the system. The first ladder is made of two six way manifolds, the second ladder one six way, the third, a four way manifold, and the last a three way.

Vacuum drops progressively out the system to where there is only about 14mmHg at the taps beyond the last ladder.

One of the maple sages said that a sap ladder is the last option you want to consider for moving sap because of the costs in vacuum loss. That said, it can help you tap trees that you would otherwise not get to.

My suggestion would be to build your system out to the first couple of ladders and see how it works. You can test off season with one drop in a bucket of water to see how the fluid moves through the system. If you have two ladders in series working well, add the next.

I look at the movement of sap up through the ladders and the vacuum level at drops beyond each ladder.

I use an automotive type vacuum gauge that I can just plug into a drop or a stubby to quickly spot check vacuum levels.

HTH

What I wonder about: The trade off of vacuum level versus sap transport isn't something easily calculated. At some point, the drop in vacuum in the system may reduce sap yield to the point at which additional trees on the system does not acutally increase sap yield due to the loss of production due to vacuum loss. That is to say, there might be some point at which fewer trees with higher vacuum would yield more sap than would more trees at lower vacuum even if the sap ladders are moving sap through the system. This is something that currently available data might allow us to estimate. Using data from a graph charting sap yield increase vs vacuum levels, it might be possible to determine at what point additional trees added by a sap ladder doesn't actually increase sap yield on the system. Anyone done this?

[maple flats]

I did it using a 30 cfm pump at 19" on a 410 tap total bush. I have 3 ladders, a 30", an 8' and a 9'. They are not in series. My farthest out one is feeding a 1" main and I only get 14" vacuum at the far end. Some points to remember, each ladder costs some vacuum and if you introduce a small leak you lose even more. However, I got to add 75 taps on the 30" ladder, 34 taps on the 8' ladder and 41 taps on the 9' ladder. Without the ladders, I'd lose 80 of those taps. You just need to decide if the cost in vac is worth the gain in total taps.

[BreezyHill]

Westwind,
I run 3 ladders to elevate one section 48'. Past that there will be another 55 feet of ladders added to get sap from further away to the current ladder system.

The limiting factor is the amount of vacuum you have and how tight your system is.
Sap is able to be lifted 12" for every inch of mercury vacuum you have, minus 20%. The 20% is just my adjustment for system comfort and speed of sap in the risers.

The length of the risers is the length of the rise not the height of the top mainline off the ground.

The amount of vacuum needs to be measured at the ladder site, not at the releaser. The 27 at the releaser is great, but if you only have 16 at the ladder site you will not get a 18' ladder working.

The number of taps into the system is also important as each riser has a maximum capacity. I use 13 on a 5/16 riser and use 6 way stars only. If I only need 3 of the stars I use the ones that will balance the sap flow best and cap the other three.

The relative levelness of the star is also important as you need the gas bubbles to be evenly distributed between the lines used.

To speed the flow you may need a leaker added to the end of the line. If you have a tight tubing system a leaker will be a huge benefit to getting a higher vac reading past the ladder. If you have a leaky system then the leaker will have no benefit.

Back flow is often seen on a leaky system or a star that is not level and air is rushing up on line and sap is going back down in one or more of the other lines.

Ladders have a few basic rules. If you follow these rules you will have success. Fail to follow these rules and they will fail.

Feel free to ask any questions. There are no stupid questions.

I have been working with ladders since the late 70's. They are a tool that nearly every tapper can use.

Ben

[BreezyHill]

The expense of vacuum on my ladders is less than 1" depending on the ladder size. The bottom of the 14' there was no drop, at the bottom of the 2 nd ladder, 16' lift was less than 1" from what releaser reading and 3rd ladder showed a total loss of less than 1.5" from what the releaser was reading.

Often systems that have an expense of vacuum or consumption of vacuum inches is due to the system is not properly sized with sufficient risers. The frictional area of 5/16 tubing is much more than the mainline...thus why a tubing riser is preferred to a large mainline riser as the frictional area helps the riser work with less expense of cfm.

The expense of cfm is what is consumed by adding a leaker. I have found that by adding a leaker I can increase the vacuum amount due to the speed of the sap flowing thru the ladder. Slugs of sap in a ladder has the same reduction of vacuum as it does in a mains. You want to keep the sap flowing at a consistent rate to maintain vacuum.

[WestWind]

This site is a great resource; friendly and knowledgeable advice! Thanx to all who responded. Charlie VT, the automotive vacuum gauge is a great idea and the notion of diminishing return of vacuum drop vs. sap transport is sobering. I would think that point of equilibrium is distant since as long as one maintains enough vacuum to lift sap through all the ladders, there is some vacuum at the tap which, though reduced, is better than none. BreezyHill, I currently have 2 ladders and am in the process of installing 2 more. The 1st one, closest to the releaser, is the tallest at about 17', the 2nd and rest are/will be 4-6'. I don't know the vacuum throughout the system, only @ the releaser. I understand now it's important to monitor it as it progresses further into the sugerbush. I also don't know how many taps I'll end up with so i thought i'd build in an overcapacity of 6 way stars at each ladder, just in case... And, yes, some of my stars are tilted.
Your advice, so far, has given me more to work with and more work to do...!

[CharlieVT]

This site is a great resource; friendly and knowledgeable advice! Thanx to all who responded. Charlie VT, the automotive vacuum gauge is a great idea and the notion of diminishing return of vacuum drop vs. sap transport is sobering. I would think that point of equilibrium is distant since as long as one maintains enough vacuum to lift sap through all the ladders, there is some vacuum at the tap which, though reduced, is better than none. BreezyHill, I currently have 2 ladders and am in the process of installing 2 more. The 1st one, closest to the releaser, is the tallest at about 17', the 2nd and rest are/will be 4-6'. I don't know the vacuum throughout the system, only @ the releaser. I understand now it's important to monitor it as it progresses further into the sugerbush. I also don't know how many taps I'll end up with so i thought i'd build in an overcapacity of 6 way stars at each ladder, just in case... And, yes, some of my stars are tilted.
Your advice, so far, has given me more to work with and more work to do...!

With respect to vacuum loss and decreased production, I knew I had seen pretty good data; scoll down to the graph "gallons produced vs vacuum level", from the good folks at Procter research center: http://www.uvm.edu/~pmrc/vacsap.pdf

I suppose a good rule of thumb might be as long as you have at least 15mmHg vacuum at the far end of the system is worth doing. From a paper published by the UNH extension service, http://extension.unh.edu/resources/files/Resource002015_Rep2980.pdf : quote: "A vacuum system must be capable of producing a vacuum of 15” of mercury at the far end of the lateral tubing for it to be considered economical."

[Super Sapper]

Since it is easier to draw up liquid in smaller diameter tubes, would using 3/16" for ladders be something to look at? I know you would reduce capacity for volume but the sap would rise easier.

[DrTimPerkins]

I use an automotive type vacuum gauge that I can just plug into a drop or a stubby to quickly spot check vacuum levels.

While this is the way measuring vacuum on a lateral line or dropline is commonly done, please be aware that it doesn't give you a true reading of what vacuum you are pulling (most of the time) at the taphole. As soon as you pull the spout, all the sap in that lateral line is rapidly pulled into the mainline, leaving it void of liquid. So your vacuum reading should be fairly close to what you have at the mainline junction (minus any frictional losses in the 5/16" line). When the lines are filled with sap, the vacuum level is (typically) somewhat lower, depending upon the sap and the gas flow rate from the tree.

An analogy to this would be if you were trying to measure the pressure within a balloon after you blew it up, and you untied the end of the balloon to do it. Doing so would allow some (or all) of the air to rush out, so the reading you get wouldn't be the same as the balloon initially had in it.

[chrismxz583]

Can a vacuum booster be installed after the sap ladder to help? I am just getting around to trying to install one this year and not sure if that would be beneficial or a waste of time.

[BreezyHill]

The booster tank will be counter productive in a series of ladders; due to the removal of the gas bubbles in the flow that will make the sap rise in the next ladder quicker.

If installed after all the ladders and the flow is uneven or surging then it would be beneficial as it will tend to even the flow and provide a more constant vacuum transfer to the ladder and past the ladder.

A "booster tank" should really be called a balance tank or a separation tank as it does not increase the vacuum...only a pump can do this.

A balance tank is usually located very close to the vacuum pump to have a sizable area that a fluctuation in vacuum level, like when a releaser cycles, will not affect the vacuum level as much and have a balancing effect on the vacuum reading of the system. This will reduce the surges of sap flow in the system. This will increase the vacuum on the system to the tap hole.

Ben

[Millers Crossing]

I started with a large ladder built of 1" main, and 14 on top and 14 on bottom 6-way stars in 2013.
It worked great on an 8cfm, .75 hp oil cooled pump, but I felt like I was leaving lots sap in the woods, because of a pile up at the ladder. I only had 12" of vac after ladders.

I switched to a reverse slope releaser this year, and I am spending a lot time and worry getting the rev slope to work right.

The point was to lift about 900 taps about 10' up, and back to the releaser without losing all that vac.
This a challenging bush because I only have a .75% slope, over 2500' of distance, so losing vacuum with ladders was problematic.

I have gotten the system to work, and I have over 20" vac after the lifter which was the goal, but ice in my return line off the rev. slope releaser has caused the dry line to become the transport line, until pm sun thaws the return line, then it works right. I am considering making my black dry line my return line, to help get the thaw earlier in the day, use the blue sap line for the air, at least while the cold persists.

Rev. Slope is thawed with heat before the run starts each day, but the darn return line has been the problem, forcing sap to travel home on dry line, without the rate I need/want to keep with sap.

Sometimes, the rev. slope lifter loses vac because of sap build-up, and then gets stuck 1/2 open, and major vac loss happens...

I still have star ladders further in the bush, and they are working well, so far during these light runs.

This cold has been causing havoc with start and stop, you really need to be diligent each day with start up and shut down procedures.

1800 taps
3 hp 20 cfm oil vac pump
2x6 Leader
D&G 1000gph 10 brix ro