Compressed air powered water pressure

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  • Thread starter bigyabbie
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  • #26
Then the next best option would be to use a pump, keeping a large tank air tight sealed would be very unrelaible especially in an earthquake prone location and the tropical climate wont help much either.

I use a 12v pump at my workshop, I have an old oil burner and use it to heat up water and pump it though pipes at my workshop. A couple of old car batteries along with a solar panel and I rarely have to charge them either and in the UK we dont get a huge amount of sun. You would probably need larger or more pumps with more batteries but the system could be kept topped up with solar or mains supply for when you need it. You will also find you can use the batteries maybe for emergency lighting also when the power is out at night etc.
 
  • #27
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Hi
your first suggestion of having a water tank that you pressurise with air pressure might end up being a lot more expensive than you think. YOu will basically need two pressure vessels. The first pressure vessel will be the water tank and the second pressure vessel will be the air receiver. If you are having a hard time picturing the water tank as a pressure vessel just ask yourself what it is filling up with as it's water level is dropping. That's right, it's filling up with compressed air. I live in south africa, so I quote south african law. In these here parts a 2000 Liter tank with 4 bar water pressure is classified as "SEP", which means that it needs to be built to sound engineering practise. Not a big deal if you know what you are doing. A 2000 liter vessel under 4 bar air pressure is a category 3 pressure vessel. that is a big deal. The reason why I'm making this distinction is that there was somebody that made a statement in a previous comment. He said something to the effect of just use air to pressurise the water tank to the same pressure that the local municipal water pressure would pressurise it to. It's not that simple. Air pressure and water pressure are two completely different things. Water pressure is not dangerous. Air pressure is incredibly dangerous.

What colours are prison clothes in Taiwan? Is it a bold fashion statement? Would you like to make a bold fashion statement? If you build something that is illegal and somebody dies, where do you go? These questions are for introspection...

A category 3 pressure vessel involves a lot of paperwork and legalities and pressure vessel codes and government inspectors and Approved Inspection Authorities, designs that have to be stamped by professional engineers and verified by Inspection Authorities after the Professional Engineer has signed it off. Even the sheet material that you buy has to conform to a pressure vessel code. This is not something that you can DIY your way through. If you really want to go this route get a quote from a reputable engineering company in your vicinity. Make sure you sit down before you open it though.
You're better off building a water tower. If the first one collapses due to an earthquake, just build another one. Get a quote for the pressure vessels and then get a quote for the water tower and calculate how many water towers you can build for one compressed air system as has been mentioned in the opening paragraph. I dare you...



How many stars does your accomodation have? 5 star, 2 star?
 
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  • #28
Did i miss something or has nobody mentioned a ram pump? Throw a water tank on the roof of each bungalow and you’ll have 40 psi no problem. A ram pump basically turns flow into pressure, so 10’ head could give you like 70 psi, but use the excess pressure to either pump the waste to a lower tank for treatment or to generate power with inline micro hydro generators.
 
  • #29
berkeman
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Did i miss something or has nobody mentioned a ram pump? Throw a water tank on the roof of each bungalow and you’ll have 40 psi no problem. A ram pump basically turns flow into pressure, so 10’ head could give you like 70 psi, but use the excess pressure to either pump the waste to a lower tank for treatment or to generate power with inline micro hydro generators.
Welcome to PF. :smile:

It's been a while since I read through this old thread, but I don't think the bungalo roofs are built assuming the extra weight of any significant water storage. Maybe out near the edges where the load bearing walls can supply more support, but you also have the seismic issues that the OP mentioned.

Also, could you maybe post a sketch of what you are proposing with the ram pump?
 
  • #30
hutchphd
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Did i miss something or has nobody mentioned a ram pump?
A ram pump is not a viable solution here. It uses a lot of low head water to pump a little (maybe 5%) of the flow to high pressure. Where they are appropriate they work very well....my brother in Maine has supplied his house for 45 years this way and it is like free money.
 
  • #31
berkeman
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A ram pump is not a viable solution here. It uses a lot of low head water to pump a little (maybe 5%) of the flow to high pressure. Where they are appropriate they work very well....my brother in Maine has supplied his house for 45 years this way and it is like free money.
That's very interesting. Could you maybe post a diagram of how that works? (Or recruit your brother to draw the diagram...). Thanks :smile:
 
  • #32
hutchphd
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When he built it (1970's) I had never heard of such a thing and was suitably impressed by his engineering diligence (not bad for an MD!). They are decidedly not new, but are very clever. Now there are lots of good explanations online:

The downhill flow builds up until turbulence causes a flap valve to slam shut and it squirts the water hammer into a little local pressurized holding tank via a one way valve. Repeat.
He rebuilds it every couple of years and in between it just thumps away like a slightly metallic heartbeat in his little semi-underground spring house. His house tank is about 80 feet above the ram pump. Any overflow pumped waters the garden.
 
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