3000 psi nitrogen flow

You need a regulator.

Thanks eriew.

From what I understand a regulator controls the pressure. I need to balance the pressure into the small tank up to the source pressure.

A needle valve would work but I want to make this idiot proof.

thanks again

If you are filling your bottles on an assembly line and need to do it fast, you might try immersing the bottles in a tank of water to soak up the heat of compression. Scuba tanks are often filled this way. It also makes the process safer for when a bottle decides to explode. 3000 psi can cause considerable damage and injury.

How many bottles are you filling at a time?

Hi Tom,

One bottle at a time. It's a maintenance item.

Simplicity is key so that the operator does not have to go through a long procedure. Certainly there will be a proceedure considering the pressures involved. But simple is safe.

Thanks

Guy

You are going to have trouble finding an orifice that small.

V=.0125 cuft

P = 3000 psig P1 = 3000 (1-1/e^†κ) At the initial flow the tank would fill in one Time Constant (Tk). The actual result will be approx 63% fill in one Tk and 99.99% in 5 time constants.

Vol x compression factor = atmos cuft so .0125cuft x 3014.7/14.7 = 2.564 ftcu.(atm)

Then the orifice diameter for a 100% full flow orifice = .051/.2t = .255/t = d²

d= √.255/tsec at 30 seconds the orifice would be .092 dia.

at 20 seconds the orifice would be .113 dia

Please let me know how close we come. Tom

Tom,

This is great! Thanks.

I will review your comment closer and will definately comment on our final results.

Thanks again,

Guy

Hi Guy

I used equations for compressed air so the difference between the density of hydrogen and air will produce a marginal difference.

Please excuse my comment about not being able to find a small enough orifice. Before doing the math it seemed that this would fill extremely fast. After math, I should have erased that comment. You can plug a fitting and drill a hole about 3/32 to 1/8 through it for a quick and dirty, but safe all things being equal, test.

I'm pretty sure you will be close enough to make the final orifice more to your liking.

It is good to read that you know the difference between a regulator and an orifice.

The nitrogen which comes in at 3000 psi at what ever temperature, squeezes the one atmosphere of air inside the bottle until tears come. If there were any combustible gas in the bottle you might have a diesel experience. Just as a second thought you could draw a vacuum on the bottle to get rid of the bulk of the air and reduce the chance of anything combustible being there and super heated. Then close off the vacuum and fill with nitrogen with impunity and little recognized heat.

Please do let me know what you find in fact. Tm

there was an explosion is an ethylene plant in europe with this same thing. The operator was putting a ne pressure gauge in service. The type with a bourdon tube and about 6" in diameter. As per the proceedure, the bordon tube was purged with N2 to make sure there was no O2 (very bad stuff with ethylene). The gauge was screwed on and the operator open the vale as fast as possible.

The N2 in the tube compressed and the temperature rose to over 800F. We know it was 600F because that is the autodecomposition temperature of ethylene at 1000 psig. The ethylene autodecomposed and traveled down the line blistering paint until it was hot enough and the pipe ruptured.

Hi vicini

Thank you for sharing your knowledge of high pressure/high temperature highjinks. Hope no one was injured during that education process.

We occasionally provide small regulators for Oxygen service. Those who Oxy clean the gauges are far fewer than those who Oxy clean regulators. Those bourdon tubes must be tricky little critters to clean and remove even the idea of oil and combustibles.

We don't need more entangled regulations to drive manufacturing away. It is good to see guy's like Guy taking care of business.

i don't see anything relating to energy in your equation and energy is heat. The first poster is on the right track.