Divator tanks, how to separate into 2 x separate tanks

[TerryNZ]

Hi,

greetings from lil ol NZ

We are a technical company that services electronic equipment in remote areas. I want to get some small compressed air tanks set up as blow down tanks that we can carry to remote sites and blow dust and debris from electronic equipment. Currently we use a D size bottle of compressed nitrogen, but I'm getting old and it weighs 20kg so it can be a killer to carry it too far, especially as it is usually uphill and we carry other equipment with us.

I have the chance to buy 3 x Divator MK 11 tank systems. I want to separate the tanks into 6 individual 6-7kg tanks. One tank obviously has the shut-off valve fitted to it, but I want to buy 3 compatible shut-off valves to fit to the other tanks.

I searched the web and downloaded lots of manuals from the Divator site but no luck so far. Any suggestions of what sort of shut-off valve I can fit..? The most I can find is that the tanks are rated to 3,000 PSI and the valve needs to be 'half inch bsp taper model' although I don't know if this is correct.

I will need to get the tanks filled at a local dive shop who are pretty strict so whatever I fit needs to be compliant.

Thanks for your help

 

[TerryNZ]

This link is for a DIVATOR manifold that was listed on Ebay a few years ago. You can click on the picture to enlarge it.

I'm guessing I could either get the same manifold and disconnect the slave tank (but I bet the manifold is expensive). Or get a compatible single tank 3,000PSI rated shut of valve.

AGA Interspiro Divator scuba tank manifold valve NOS (05/11/2009)

 

[Scared Silly]

While these cylinders are small, they are rated at 4500 psi (300 bar) to be full. So while you can find valves you may not get a full fill as most stations will not fill past 3500-3600 psi (240 bar). Fire departments can often go higher. At that is the case in the states. Down under those fills may be possible. So before sinking money into the cylinders and valves I would check on your max fill pressure.

You would better off getting what we call deco bottles. You should be able to find some that are similar in size to the Interspiro cylinders but are full at 3000-3400 psi (~200-240 bar) and come with a std scuba valve. They will obviously hold less gas but should cost less overall.

 

[TerryNZ]

Hi, the maximum fill pressure V capacity is not really an issue, even if I only fill the 4L Divator tanks to 3,000PSI then I still get 1.2m3 per tank which is plenty. A single tank will last up to 5 different site visits. The D size cylinder does 10+ sites, so it is a real overkill to carry.

I can buy a set of 2 Divator tanks for NZ$300 which is GBP140 or US$220, I just need to separate the tanks and fit an approved shut-off valve to the 2nd tank.

The dive shop will only fill to about 200bar but because the tanks are rated to 300bar then I need to fit a 300bar shutoff. What I fit after the shut off is not their concern.. Cheers...

 

[TerryNZ]

However I will look into deco tanks, it depends what is available in new Zealand...

 

[Scared Silly]

I would try and contact Interspiro directly about the valves. You will need valves for both cylinders - you will not be able to use the manifold on just a single cylinder as the line equalizes both cylinders regardless of whether the valve is open or not.

Aluminum deco bottles in states run about $150 with valves.

 

[TerryNZ]

Cool thanks, I was hoping I could just disconnect the the feed line from the slave tank at the valve and put a bung in.

Are deco tanks for oxygen only or can you fill them with compressed air. If a deco tank has a capacity of 19cu ft how much is this in metric capacity at 200bar...

 

[Scared Silly]

No, you not be able to put a bung in to the manifold. You might be able to put a cap on the threaded end (perhaps that is what are talking about). But then you have that end flopping about. And if you notice the manifold typically has a plastic casing around it for protection. So you really want new valves for both cylinders.

Deco cylinders can hold any type gas, air, pure O2, argon, and other gasses as long there is an adapter to fill them.

Damn good question on the metric equivalent. Somewhere around 2.9 liters for the 19 cuft bottle. Here is a chart with some specs in metric: XS Scuba Luxfer Aluminum Scuba Cylinder Specifications
My guess you could get 3-4 jobs out of one cylinders????

AL40s are very common for deco. And at about 7 kilos that should be a nice trade off between size and weight with having enough gas for multiple jobs.

 

[TerryNZ]

Excellent link, really good to have the imperial and metric charts to compare... Thanks

 

[TerryNZ]

One final question...

How much does compressed air weigh..? If for instance the AL40 is 6.9Kg empty what will it weigh when full..? The exact weight is not critical but I am narrowing down the size and type of bottle that I need so I just want to fine tune the details a little more.