Thread: Where to buy a pressurized tank?

A simple & safe way would be to design a series of parallel, small diameter tanks, made from schedule pipe. This has a very high burst pressure. Add schedule end-caps & piping nipples - weld end-caps to pipe section.

Go out & chat to a local pipe-fabricator. In the west, these are easy to find - not so sure about Thailand.

Originally Posted by watterinja

A simple & safe way would be to design a series of parallel, small diameter tanks, made from schedule pipe. This has a very high burst pressure. Add schedule end-caps & piping nipples - weld end-caps to pipe section.

Go out & chat to a local pipe-fabricator. In the west, these are easy to find - not so sure about Thailand.

Sounds tricky to me, especially the bit about talking to the pipe fabricator. Most of these ppl didn't study their trade, take a look at the welders.

Like I said before, Go and buy a used air compressor, or a new one if you want, but one with a large enough air receiver to do your job, put your discharge fitting in the bottom, say in the place where the water drain is located, fill as full of product as you want, set the compressor shut off switch to the pressure that you need on your product and start it up and all automatic til you need to refill with your chosen liquid.

Then when you are finished with your experiment you will have an air compressor that is still useful as an air compressor.

Originally Posted by Smithson

the important thing is that it will pump the solution, rather than air, into the bamboo.

Why don't do just that , pump air into the bamboo?
Should work if you have filled the bamboo with borax solution.

Originally Posted by lom

Originally Posted by Smithson

the important thing is that it will pump the solution, rather than air, into the bamboo.

Why don't do just that , pump air into the bamboo?
Should work if you have filled the bamboo with borax solution.

Interesting idea, but not sure if it would work. A fair bit of solution is required. The tank system allows many poles to be done at once.

Originally Posted by Thetyim

Originally Posted by Smithson

If it isn't too heavy it could be posted,

It weighs 3.5 kilo but I think it's too small for you.
It's 40cm long and about 14cm in diameter.

Safe working pressure is 1.34Mpa which , if my maths is right, is 194 psi

Thanks for the advice, I've found a place selling old fire extinguishers and there's info on the net for converting them, although not for liquids, it's still helpful.

Once it's drained, is this 100% that there is no pressure in the tank? I'd hate to get it wrong.

^
Mine was a dry powder filled one.
After the kids had sent it off there was no pressure left in it but a load of powder so open and clean it outside.

Originally Posted by Thetyim

^
Mine was a dry powder filled one.
After the kids had sent it off there was no pressure left in it but a load of powder so open and clean it outside.

It looks like the extinguisher won't be able to hold enough liquid. I'm now considering the tanks that are used on water pumps. According to the info on side of the tank, they are capable of holding pressure up to 4 bar.

I've found a stainless steel one that holds about 25 liters, hopefully this will do the job, the poles I'm treating are 9 meters long.

Alternative source would be a scrap yard and look for a brake cylinder from a truck

Originally Posted by Happyman

Alternative source would be a scrap yard and look for a brake cylinder from a truck

Back home it'd be worthwhile, but my mrs has a saying, "2nd hand more expensive than new". Second hand crap that is thrown away at home is selling for 80% of the price of the new things.

Originally Posted by Happyman

Alternative source would be a scrap yard and look for a brake cylinder from a truck

Must mean an air receiver from a truck with air brakes, but that would not be of a size to do what you want either.
And yes, a water pressure tank from a well pump would do you just fine, just do not exceed the pressure stated on the tank.

Thanks for the help, everything is ready, except I need a filter. This will be placed between the tank and the splitor. The idea is to catch suspended particles within the solution, as these will block the ends of the bamboo.

Any suggestions for making a suitable filter? 2" PVC pressure pipe would be suitable, however I'm not sure what material to fill it with. I needs to filter fine particles without reducing the pressure. Any ideas?

Originally Posted by baldrick

any obstruction is going to cause a pressure drop , even straight pipe causes a pressure drop over length.
a good idea will be guages at both ends of your filter so you can accurately work out what pressure you are injecting at. it will also tell you when the filter needs to be cleaned.

This is correct, actually it's difficult to see how a filter would work, it would either cause major pressure drop or the pressure would push than suspended particles thru.

normally in industry you will have across the filter - and normally 2 filters - allowing for bypass , isolation and removal.

basic - a dial pressure gauge at input and output
normal - a differential pressure switch which will toggle an alarm when the diff pressure setting is reached.
good - A diff press transmitter to the DCS which allows a trend log and also alarm , shutdown switches , this will also have guages and a diff press switch as separate backup.

^ Thanks Rick, I managed to get a filter with a very fine mesh which will have to do for the time being. Don't know how good it will be with suspended particles, but don't think it will cause much pressure loss. It's a type that is used with sprinkler systems. The present set up is simple, not really sure how important the filter is.

There are some filters for water which can take pressure up to 4 bar, but not sure what sort of pressure they can maintain on the output side.

running a pilot plant you can expect to have to try different things - theoretical calculations normally don't scale to reality.

just be careful with your pressure vessel - it is a good idea to have a safety relief valve ( PSV ) on all pressure vessels - you can calibrate and test it with a guage and a hand pump.

if you are using oil or hydrocarbons it is advisable to get the correct thread tape for fittings or else it will leak if you just use normal plumbers thread tape.

Originally Posted by Smithson

Also need a 'hydrometer', if anyone knows where to get one.

Ordered my from a home brew company in Australia.

The Country Brewer - More Than Just A Home Brew Store!

Thanks for the help.

I got everything together and tried it on the weekend. The tank, valve, hoses etc. were fine, but the fittings on the ends of the bamboo are a real nightmare. We used an old motorbike inner tube, to join the bamboo and 4" PVC. This was tightened with hose clips. Below are the main problems.
- The pressure pulls the fitting away from the bamboo.
- It wasn't possible to get a seal between the bamboo and the inner tube. Unlike PVC, the bamboo doesn't have a smooth surface. I tried putting a heap of teflon tape around the bamboo, but the hose clips weren't strong enough and broke.

So there are a few adjustments needed.

- I need to find some kid of rubber fitting to join the PVC and bamboo, it needs to fit bamboo from 3" to 5". Something tapered and flexible would be good, but it must not balloon when pressurized.

- I need to find really strong clips to replace the hose clips and something to help seal the rough surface of the bamboo.

- I need to find some way of clamping the bamboo and fittings together so they don't pull away from each other.

Any ideas?

Below is a pic of what I'm trying to achieve, you can see they are using some kind of steel fittings.


Ben, regarding the info on mud, this is something I'm also interesting in. I've seen nice places with mud walls with bamboo truss roofs. For the cost of the bamboo, it depends, transport is a big factor - I'm lucky enough to have bamboo growing on my property and very close by.

I also like the open spaces and bamboo is ideal for this.

can you make a groove in the end of you bamboo so the hose clamp can sit in it - file one out

and more hose clamps means more surface area gripping which will make it tighter