can vac. uphill ?

[maplefarmer]

I am running a mainline along the top of a river bank and some of the trees closer to the water will either have to be tapped from high off of a ladder, or is it ok to run a vac. uphill ? would not be straight up but would have small rises to get to mainline.

[Russell Lampron]

Although it isn't ideal it will work. I have some taps like that in my system.

[sjdoyon]

I am running a mainline along the top of a river bank and some of the trees closer to the water will either have to be tapped from high off of a ladder, or is it ok to run a vac. uphill ? would not be straight up but would have small rises to get to mainline.

It will work on vacuum.


3x10 Inferno Arch
4,000+ Taps
7,5 HP Vacuum pump
Lapierre 600gph RO
3 SS 1500 gallon tanks
24x32 Sugarhouse

[Dale Mahalko]

Vacuum is not a pull. It is a push. Atmospheric pressure (the weight of the air above us) does the pushing.

1 inch of mercury equals .49115 pounds per square inch

-- 25 inches of gauge mercury is 12.2 psi .... 28.1 ft column of water
-- 15 inches of gauge mercury is 7.36 psi .... 16.9 ft column of water

The column height that atmospheric pressure can lift, is a maximum limit, and as this lifting limit is approached, the flow of the liquid will steadily decrease, from gushing, to a stream, to a dribble, to just a static column that stays at the same height continuously.

Vacuum gauges are measuring relative to whatever your current atmospheric pressure is. The relative measurement can never go below the absolute pressure. So at 10,000 ft above sea level, it would simply not be possible to achieve a gauge vacuum of more than about 21 inches of mercury, even with a perfect vacuum inside the pipe.

Also the atmospheric air density overhead changes due to heating and cooling, which is why barometric pressure changes over time.

--------------
Sea level is "1 atmosphere", which is "14.7 psi", or 29.9 inches of mercury

1 cubic inch of water weighs 0.036127 pounds

14.7 psi can lift a column of water up to 33.9 ft in a perfect vacuum.
(14.7 psi / 0.036127 lbs per cubic inch = 406 inches tall / 12 inches/ft = 33.9 ft column of water)

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If you are higher than sea level, then atmospheric pressure will be progressively lower, and so will the maximum achievable gauge vacuum measurement.

At sea level ................... 14.7 psi air pressure ... 29.9 inches mercury
1000 ft above sea level .... 14.2 psi air pressure ... 28.9 inches mercury
2500 ft above sea level .... 13.4 psi air pressure ... 27.3 inches mercury
5000 ft above sea level .... 12.2 psi air pressure ... 24.9 inches mercury
10000 ft above sea level .. 10.1 psi air pressure ... 20.6 inches mercury

[Dale Mahalko]

Also, you can lift using vacuum for more than the max water column height, but you have to keep releasing to atmospheric pressure with vacuum releasers, in a step pattern up the slope.

25 inches mercury ... lifting out of a 100ft deep valley:

lift 20 ft, goes into a vacuum releaser, which dumps into a collection tank with a vent to atmosphere and a float ball over the drain.
lift 20 ft, goes into a vacuum releaser, which dumps into a collection tank with a vent to atmosphere and a float ball over the drain.
lift 20 ft, goes into a vacuum releaser, which dumps into a collection tank with a vent to atmosphere and a float ball over the drain.
lift 20 ft, goes into a vacuum releaser, which dumps into a collection tank with a vent to atmosphere and a float ball over the drain.
lift 20 ft, goes into a vacuum releaser, which dumps into a collection tank at the evaporator.

This gets expensive with all the releasers and collection tanks, which each need to be inside a box to keep out bugs and critters.

Also if an upper-step releaser fails the next lower collection tank will overflow and dump onto the ground.