# free air compressor known as trompe, but multi-stage

#### GodofPecking

##### Songster
I have bought some pipes to arrange into a trompe, but I don't want to dig a hole or go too high, so I wonder has anyone done a two or three stage trompe to get higher air pressure ?

I'm using the excess pressure in the tap water to run it, as I have no stream.

#### Nardo

##### Free Ranging
5 Years
I have bought some pipes to arrange into a trompe, but I don't want to dig a hole or go too high, so I wonder has anyone done a two or three stage trompe to get higher air pressure ?

I'm using the excess pressure in the tap water to run it, as I have no stream.
You may have looked here already, but check out the post from Brian White - a little more than halfway down the page of this link:
https://permies.com/t/16261/Mollison-Trompe-alternative-energy

#### GodofPecking

##### Songster
I had not seen that previously. Brian White's post is great because it nails down the circus of why one reader's test rig had low output, rather than allow people to be discouraged. He's doing well. The psi is determined by the height difference between the water output and the surface of the (still) water in the bubble separation chamber. He's closest to that. The reader was using about 1 meter difference.

The pressure I have to work with is considerable because I'm using tapwater. I don't need all that pressure which is in the water supply mains because I'll just use an elevated water tank to supply water to the house and garden after I've used up the excess pressure by making compressed air.

I have a pressure gauge on the household mains water supply, it reads a little over 75psi or just over 500kpa which is equal to 50 meters high. (50 yards high) So it could fill a tank that high, and I could use that for the input and then use a tank for the output at 5 meters high (5 yards high) to supply the used fresh water to the house and yard.

Feet of Water = PSI x 2.31
PSI = Feet of Water x .433
mH2O value = kPa value x 0.101972
1000 kpa = 101.972 meters head

It is not practical to use a tower or tunnel 50 meters high or deep, so stages must be built,

#### Nardo

##### Free Ranging
5 Years
I had not seen that previously. Brian White's post is great because it nails down the circus of why one reader's test rig had low output, rather than allow people to be discouraged. He's doing well. The psi is determined by the height difference between the water output and the surface of the (still) water in the bubble separation chamber. He's closest to that. The reader was using about 1 meter difference.

The pressure I have to work with is considerable because I'm using tapwater. I don't need all that pressure which is in the water supply mains because I'll just use an elevated water tank to supply water to the house and garden after I've used up the excess pressure by making compressed air.

I have a pressure gauge on the household mains water supply, it reads a little over 75psi or just over 500kpa which is equal to 50 meters high. (50 yards high) So it could fill a tank that high, and I could use that for the input and then use a tank for the output at 5 meters high (5 yards high) to supply the used fresh water to the house and yard.

Feet of Water = PSI x 2.31
PSI = Feet of Water x .433
mH2O value = kPa value x 0.101972
1000 kpa = 101.972 meters head

It is not practical to use a tower or tunnel 50 meters high or deep, so stages must be built,
Ambitious! Good luck. Keep us posted.

#### GodofPecking

##### Songster
thanks. I think ill make a series of small tromps. The air intake for a trompe can be enclosed so that air enters via a pipe rather than straight from the atmosphere. Mixing the air and water has been made trivial in my application by those water aerators you put on household taps, especially kitchen taps. So I'm arranging a plumbing t-piece to have water enter one way through a tap aerator and air enter through the side.

The output of one trompe enters the air intake of the next, stepping air pressure up using progressively higher pressure water.

It should be possible to extract 50 meters of head, or air pressure, using a tower which is a small fraction of the height. Is this not true, if it is, perhaps an example can be found, or someone knows of one...

I should be able to make a compressor which has no moving parts except water, which uses no power except the excess pressure of the water supply, and costs no more in parts than the pipes, tanks, and their supports. It should be no higher than a little more than a water tank, and not require digging.

#### GodofPecking

##### Songster
I wonder how the reduction in volume of air effects the trompes which are not open to the atmosphere, So I wonder who might have built one,

#### 007Sean

##### Becoming Ridiculously Awesome
I wonder how the reduction in volume of air effects the trompes which are not open to the atmosphere, So I wonder who might have built one,
I'd like to know that too!

#### GodofPecking

##### Songster
drawing and hypothesizing is easier than building on a budget right now, so I would think an air bubble would form in flooded airtubes if installed as drawn. the bubble extending from the lower trompe's water output level to the upper trompe's air intake. the airtube could become an alternate water path, so i guess it can loop up to the top of the tower, or above the top trompe to stop water flooding it while waiting for bubbles.

oh yes, maybe.

#### Nardo

##### Free Ranging
5 Years
GodofPecking,
I'm following this and I just got to work so let me mull a bit. The thing is, I'm a hydraulic mechanic for Bosch, who is one of, if not the premier, hydraulic pump manufacturers in the world. The Germans (we are based there) have an unbelievable amount of data and knowledge. Anyways, I'm thinking that a great many of your questions really pertain to, and can be answered by, hydraulic applications. That is really exactly what you are doing, it's just that we use oil rather than water, which is moot, since water is sort of the whole word HYDRAULIC. LOL. Anyway, let me dig some. Our whole demon in life is keeping the air OUT of the systems...

#### Nardo

##### Free Ranging
5 Years
So just a quick post, we're thinking but right off - and you may have considered this - the reservoirs need to be consecutively smaller. Or your water 'column' I'm going to call it, needs to become more condensed (or compressed) as you go to increase the pressure as the flow changes.