Depressurize a xenon arc lamp?

[cjep]

I want to depressurize a 7 kW xenon arc lamp bulb (15 bar pressure) but I'm not sure how to do it safely. I'm thinking about putting it in a drill press and drilling it through its protective plastic housing but I don't know if that's the best. Is there a way to do this without it blowing and has anyone done this that can share any tips?

[cvanc]

Find the manufacturer online and download the data sheet and MSDS.  One or both should have specific info on how to vent the lamp.  Be careful, I deal with smaller xenon lamps than yours and they can really go boom.  DO NOT invent your own method of venting...

[T3sl4co1l]

I have to wonder if there's a xenon recycling service... yes, it stays in the terrestrial atmosphere, but it's at such low concentration, it's not terribly cheap stuff...

Tim

[Brumby]

15 bar is not to be messed with - especially with glass shards as the shrapnel.

Create a weakness in the glass envelope and that thing will explode.

[amyk]

It makes me wonder how they got the pressure into them in the first place, but this might be a way of releasing it:

Put it in a pressure vessel that can withstand 15 bar, pressurise it (so that the pressure inside and outside are nearly equal), make hole, slowly depressurise.

Edit: 15 bar is a little over 200psi, which is not that high of a pressure for things like steel tanks, although still quite scary to work with...

[tesla500]

To fill these lamps, they cool the bulb with liquid nitrogen, pour in liquid xenon, then seal off the pip while the bulb is still cold and the xenon is liquid. When it warms up the xenon evaporates and pressurizes the lamp.

My friend works in a movie theater, they just put them in their case and drop them to depressurize them before putting the remains in the trash. These are one of the few types of arc lamps that don't have any hazardous materials.

[TheWelly888]

At work I sometimes change the Xenon arc lamp used in endoscopy illumination. The metal part of the lamp housing has a small closed off tube about 3mm diameter and 5mm long sticking out. That can be cut with a hacksaw until you hear the gas being released, then you can just treat it like an ordinary lightbulb.

There may be something like that on your lamp.

[Supercharged]

It might not be the safest or correct way, but defenetly the funnyest:
tape a small explosive charge (e.g. from some firework) onto it and detonate it from a safe but enjoyable distance

[m98]

What about shooting it with a sniper gun from a safe distance?   

[chris_leyson]

At least Xenon doesn't pose any toxicology risks, it is sometimes used as an anaethsetic, unlike neon which is an asphyxiant.

[djQUAN]

Photonic induction showed how in one of his vids, around the 9 minute mark.

[Stray Electron]

It might not be the safest or correct way, but defenetly the funnyest:
tape a small explosive charge (e.g. from some firework) onto it and detonate it from a safe but enjoyable distance

   A friend of mine actually holds the US Patent for doing something very similar to that in air bags.  ULTRA fast inflation!  They use little tenny, tiny, detonators that were originally made for US military.  IIRC they only contain about .09 grams of explosive. All you have to do is to give the pressurized diaphram a shock and it will instantly rupture.

  I'm not sure that a fire cracker would produce a sharp enough shock but I'll bet that a primer from rifle cartridge would if you could find a way to ignite it at a safe distance.   When he and I were kids we actually tried things like this. But not today! You'd end up in jail faster than you could say DHS!

[cjep]

I actually want to save the glass bulb for display this time so I wonder if that's even possible to do.
I always wear protective gear handling these and have probably destroyed 40 or so the last couple of years (we have to before we get rid of them), mostly the safe way throwing it to the ground in the protective casing and sometimes stupid ways with air guns and stuff like that. It's a Ushio DXL-70BA if anyone wonders.

[TheWelly888]

^^
There may be something in the metal contacts housing or on whatever is hidden by the gloves that gives access to the xenon gas.

[mikeselectricstuff]

Dremel with diamond cutting wheel perhaps, with suitable explosion protection of course!

[KM4FER]

The post about how the high pressure xenon tubes are made gave me an idea.

If we consider xenon to be near an ideal gas then maybe we could use the ideal gas law to lower the pressure making the process less dangerous.

Since the pressure inside the tube is a direct function of temperature

P = nRT/V

then by lowering the temperature we can lower the pressure.

If at room temperature, 24C or 24 + 273 = 297K, the pressure is about 200 bar then cooling the bulb in a dry ice alcohol bath to -78C, or 195K would reduce the pressure to 195/273 * 200 = 143 bar.  Still dangerous.

Now if you had access to liquid nitrogen then the pressure could be reduced to 77/297 * 200 = 52 bar.  Much better.

earl...

[amyk]

The problem with just making a hole at room temperature is like popping a balloon - the pressure is so high that any small defect in the envelope rapidly gets forced apart by the gas trying to escape.

Using the same equation with the numbers the OP has posted (15 bar at room temperature) gives ~3.9 bar for the liquid nitrogen case, which is incorrect because xenon becomes solid before that. The question then becomes how to cool it to that temperature without inducing thermal stress, and how to open it once it gets to that temperature (the glass will become very brittle)

I still think increasing and decreasing the pressure of the outside is easier than trying to cool it.

[KM4FER]

OOPs,   Sorry about the 200 bar vs 200 psi mixup.  Brain didn't fully engage.

What is the bulb made of?  Is it borosilicate glass or maybe fused quartz?

Knowing this would help in determining what is needed to cut/drill it and how thermal conductive it is.

earl...

[Brumby]

I was wondering if you could find a spot where you could set up an arc and leave that to erode a hole through the envelope.  You know - the sort of thing they warn you NOT to do with a plasma ball.

[TerraHertz]

Trying to get the Xenon out without breaking the bulb, is almost the same problem as I have. I'd like to salvage the Xenon gas from about 10 big lamps I have, and end up with the Xenon, uncontaminated, in a pressure vessel. I have some suitable gas storage containers (see pic) but how to go from A to B ... I have no idea. Well, not yet.

Freezing the Xenon with liquid nitrogen seems like it might be useful. But then making a hole in the glass, and letting the Xenon evaporate and escape, into a previously evacuated space, without mixing with the nitrogen, then pumping... oh hey, if that pressure sphere was cooled with liquid nitrogen, the Xenon evaporating from the bulb would re-freeze in the tank.

Hmm...

[Alexei.Polkhanov]

Put them in a pressure vessel, vacuum it, them shake the vessel. Then pump all gas into a much smaller vessel with a high pressure pump and filter. Dump the glass, and you are done.

+1 this one.
You can add metal balls and crush multiple bulbs at once!

[chris_leyson]

That would be a cremulator then with the added metal balls, wouldn't it be cheaper to just buy Xenon ?

[Alexei.Polkhanov]

Water!
No need for vacuum pump. I forgot how we do it in chemistry - instead of pumping out air upside down container filled with water can be used to prevent contamination of gas by air. Bulbs will have to be broken up while submerged in water directly below the bell. You start with big container completely filled with water and turned upside down and then pump out gas with a tube as it appears on top.

[chris_leyson]

Nice one Alexei  water seal, old school, at least someone thinking physics 

[T3sl4co1l]

Mind that the xenon is under pressure, so you'll just get a mess (of water and maybe a little glass) if you do it in open air.  You'd need a sealed container, but indeed, with enough shaking, the xenon and glass will part ways and settle to opposite ends of the container.

Tim