Film-Tech Forum ARCHIVE: How can I depressurize a xenon lamp?

This is topic How can I depressurize a xenon lamp? in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Brian Hogan (Member # 940) on 07-08-2006, 10:41 PM:

before i restate the subject, allow me to explain what i already know about xenon lamps. these lamps contain xenon gas at high pressure (10 atm cold, 30 atm hot) surrounded by a quartz envelope. Lamps must be handled with full safety gear (leather gloves, leather appron and full face shield) whilst using extreme care and respect at all times. mishandling and/or environmental changes may cause the envelope to fail, resulting in an explosion that will send out fragments of the envelope in all directions. This may lead to severe injury or worse.

i am trying to find a way to depressurize a xenon lamp without causing it to be destroyed. i would like to keep this safe version of the lamp in my booth for demonstration. im sure i could get one from osram, but im also sure it would cost a pretty penny.

one technique i can think of would involve making a hole in the hard protective jacket the lamp is transported in. i could then place the lamp in the jacket and postion the nib to be in line with the hole. then perhaps unseal the nib with some sort of tool via the hole. the tool would have to be easy to find and use as well as able to cut the quartz without destroying the rest of the envelope.

any other ideas or thoughts on this topic? has anyone else tried to do this with good results? cheers for the feedback!

Posted by Richard Hamilton (Member # 321) on 07-09-2006, 05:04 AM:

I usually use a hammer [Big Grin]

Seriously, I have never had the need or desire to try. Can it be done? That is for someone else to answer. All the depressurized bulbs I have seen have been new at the trade shows, and I always assumed they were never pressurized to begin with.

If it can be done, try calling Osram. They must have bulbs that were shipped back under warranty and they have no use for. Or send them 1 of yours if they can do it.

Rick

Posted by Paul Van Dusen (Member # 3640) on 07-09-2006, 05:11 AM:

Well, if you've ever had a bulb go blue on you, then you've done it already. Seriously though, the only way I know to do what your asking is by accident by overtightening the clamps on either end of the bulb when installing. Of course, you could always have a demo bulb like ours, still in the protective case. One of the good ones mind you, with the metal clasps. We've been getting the crappy ones held together with velcro lately. [bs]

Posted by Dieter Depypere (Member # 3184) on 07-09-2006, 05:22 AM:

It can be done. But make sure that you protect yourself very well (in case something goes wrong). I have heard that you can snip off the filling tip (bulb into a box, only(!) a little hole with a tube that reaches to that tip, let something heavy fall onto the tip and do not look after). If done properly you will hear a hissing sound.

If it does not matter if the lamp is destroyed, wrap the bulb into its box, use some tape to close it very well and then throw it out of the window (preferably from the 2nd floor and up and of course if nobody is down there [Big Grin]

).
Or wrap the bulb into a strong cloth and use the hammer.

Posted by Matthew Taylor (Member # 2310) on 07-09-2006, 05:34 AM:

There was a thread on this a while back. Here's the LINK to it.

Posted by Mark Gulbrandsen (Member # 72) on 07-09-2006, 12:31 PM:

I've done it this way......

Use a dremel tool with a cut off wheel to grind the extreme tip of the seal off and the gas will slowly leak out. Slowly is better than all at once! This is easy and relatively safe to do just be sure the lamp itself is wrapped in its explosive proof kevlar or what ever it is supplied with and allow the tip to protrude outside the wrap.

P.S. Be sure to still wear ALL of your safety gear when doing this... you could slip and grind the wrong place but the fragments will be contained within the wrap.

Mark

Posted by Alan Gouger (Member # 543) on 07-09-2006, 04:51 PM:

I just watched a program in hi def showing the Osram factory and the making of the bulbs. When they add the gas they dip the bulb into liquid nitrogen until the process is complete.

[ 07-09-2006, 07:20 PM: Message edited by: Alan Gouger ]