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This topic comprises 2 pages: 1  2 
 
Author Topic: Xenon lamp cooling
Josh Jones
Redhat

Posts: 1207
From: Plano, TX
Registered: Apr 2000


 - posted 04-25-2001 10:03 PM      Profile for Josh Jones   Author's Homepage   Email Josh Jones   Send New Private Message       Edit/Delete Post 
here is the scoop...
I have a Kniesley L-100-3 lamphouse that I recently acquired. I ran it for a 3 hour period one night and the room became quite warm. would it be safe to flip the exhaust blower around so that it blows air out instead of in? I want to run the hot air up a hose and out of the room. A friend of mine I talked to said that should be ok so long as you blow a little air over the ends of the bulb, but never on the glass. A vision of a big muffin fan blowing on the cathode and reflector comes to mind.
what do you think?

Josh

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Michael Cunningham
Expert Film Handler

Posts: 186
From: Anchorage, AK
Registered: Nov 1999


 - posted 04-25-2001 10:11 PM      Profile for Michael Cunningham   Email Michael Cunningham   Send New Private Message       Edit/Delete Post 
Um, I think your friend is a little off, unless I'm not understanding something... The way lamphouse cooling is supposed to work is that air is pulled from the booth, travels all around the bulb, and then is sucked out of the top of the lamphouse and exhausted to the roof. My Strong lamphouses have a top-mounted blower that pulls air down from the booth just behind the refelector where it travels throught the center hole, around the bulb. It also has an intake fan at the front which blows cool air onto the front of the bulb. Hot air is then piped to the roof through a vent rising from the center of the lamphouse, just above the center of the bulb. Hope this helps you.

-Mike

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John Walsh
Film God

Posts: 2490
From: Connecticut, USA, Earth, Milky Way
Registered: Oct 1999


 - posted 04-25-2001 10:19 PM      Profile for John Walsh   Email John Walsh   Send New Private Message       Edit/Delete Post 
I would not advise doing that. Usually the air flow has been designed to go in a certain direction. Besides, do you really want to have to modify the lamphouse with a muffen fan? I assume the lamp is so small that there's not top exhaust.

Is there an air vent somewhere in the lamphouse? Maybe you could adapt a hose to fit there. Old lamps used to have a sort of large, upside funnel above them to gather heat and vent it outside.


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Josh Jones
Redhat

Posts: 1207
From: Plano, TX
Registered: Apr 2000


 - posted 04-25-2001 10:24 PM      Profile for Josh Jones   Author's Homepage   Email Josh Jones   Send New Private Message       Edit/Delete Post 
This is a 500 watt Kniesley l-100-3 lamphouse. It seams safe to me because the bulb never had any airflow on it before, and the only parts that were really air cooled were the reflector and the cathode stud. Besides, this way wont natural convection aid a little too? before air entered the top and exited the bottom, opposing natural convection. It was designed this way, but wouldn't my way run cooler?

Josh


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Aaron Sisemore
Flaming Ribs beat Reeses Peanut Butter Cups any day!

Posts: 3061
From: Rockwall TX USA
Registered: Sep 1999


 - posted 04-25-2001 10:49 PM      Profile for Aaron Sisemore   Email Aaron Sisemore   Send New Private Message       Edit/Delete Post 
You may also want to be concerned about running lamps not exhausted to the outside as some xenon bulbs can generate ozone in operation and its toxic when concentrated. Additionally, bulb life is lengthened greatly if the lamp is properly cooled and exhausted.

Aaron


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Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000


 - posted 04-26-2001 01:47 AM      Profile for Paul G. Thompson   Email Paul G. Thompson   Send New Private Message       Edit/Delete Post 
Josh, John is right. So is Aaron about the exhaust.


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Scott Norwood
Film God

Posts: 8146
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99


 - posted 04-26-2001 07:52 AM      Profile for Scott Norwood   Author's Homepage   Email Scott Norwood   Send New Private Message       Edit/Delete Post 
Is outside exhaust really an issue with the smaller xenon lamps? I would think that it wouldn't be a major issue with 1kw and smaller. I never had a problem with heat or (I hope) ozone when running two 1kw 16mm projectors in a smallish booth, with no outside exhaust.


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Jeff Taylor
Jedi Master Film Handler

Posts: 601
From: Chatham, NJ/East Hampton, NY
Registered: Apr 2000


 - posted 04-26-2001 08:06 AM      Profile for Jeff Taylor   Email Jeff Taylor   Send New Private Message       Edit/Delete Post 
IMHO, Scott's right. I know even "Ozone Free" xenon's generate some, but let's face it, LOTS of people run 500-550 watt xenons in portable machines with no outside venting. Furthermore, from what I've seen the forced cooling on these short arc horizontals is really directed at the anode and cathode and not "blanket cooling" of the entire envalope. Obviously the lamp and lamphouse manufacturers know best (I hope), but in this size range I don't think it's all that much of a problem.

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John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000


 - posted 04-26-2001 08:33 AM      Profile for John Pytlak   Author's Homepage   Email John Pytlak   Send New Private Message       Edit/Delete Post 
In a xenon lamp, ozone can be generated by the high voltage ignition (corona ionization) and by strong UV (ultraviolet) radiation breaking down oxygen molecules. "Ozone Free" xenon lamps have special additives in the quartz bulb to reduce the amount of short UV radiation, but still can produce some ozone.

When you first come into a room where there is ozone, the pungent odor is unmistakable. (The nose is very sensitive to the smell of ozone). After breathing it for a while, you become desensitized and may not notice it anymore, but may have side-effects like a headache, sinus pain, or eye irritation.

If there is enough ozone to notice the odor, better ventilation is needed. Ozone is good in the upper atmosphere because it helps shield the earth from excess ultraviolet radiation, but it is NOT good to breathe it.

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion


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Randy Stankey
Film God

Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99


 - posted 04-26-2001 09:03 AM      Profile for Randy Stankey   Email Randy Stankey   Send New Private Message       Edit/Delete Post 
I 'd say that it's possible to OVER ventillate a lamphouse.

I have been told that it's not a good idea to open the lamphouse right after running the lamp. The idea is that the rush of cold air can cause the lamp to crack and break. (Thermal shock)

It then follows that if there's too much cool air comming into the lamphouse because you've beefed up the fans, you could cause the same thing to happen.

I vote for leaving the lamphouse as it is and just getting some outside ventillation in the room. Maybe just some kind of exhaust fan? The booth at the college I worked at had an exhaust for the lamphouse itself AND an exhaust fan hooked up to a thermostat. The room is also used as a follow spot booth during stage shows. (Yes, they were carbon arc.)

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John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
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 - posted 04-26-2001 09:18 AM      Profile for John Pytlak   Author's Homepage   Email John Pytlak   Send New Private Message       Edit/Delete Post 
Excessive or uneven cooling of the lamp can cause arc instabilities (flicker) and deposits to build up on the cooler areas of the quartz envelope of the lamp. Follow the lamphouse manufacturer's recommendations regarding venting. Keep all air intakes to the lamphouse clean and clear, and be careful not to misposition any baffles or ducts within the lamphouse.

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

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Scott Norwood
Film God

Posts: 8146
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99


 - posted 04-26-2001 10:52 AM      Profile for Scott Norwood   Author's Homepage   Email Scott Norwood   Send New Private Message       Edit/Delete Post 
What does ozone smell like? Is it the same kind of smell that is produced by xerox machines and laser printers (which also produce ozone)? If so, then I certainly didn't have any problems with it, even when running two 1kw lamps (probably the "ozone free" type) in a not-very-well-ventilated booth. I'm sure that lamp life probably would have been helped by better ventilation, but I wasn't in a position to make that decision.

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Aaron Sisemore
Flaming Ribs beat Reeses Peanut Butter Cups any day!

Posts: 3061
From: Rockwall TX USA
Registered: Sep 1999


 - posted 04-26-2001 11:28 AM      Profile for Aaron Sisemore   Email Aaron Sisemore   Send New Private Message       Edit/Delete Post 
Randy: why would ANYONE want to open a xenon lamphouse up right after turning it off? even in the most heinous of emergencies, i would wait at least ten minutes for the bulb to cool before even thinking of opening the door(s) to access the lamp.

The only time I have seen a problem with there being too much ventilation to the point of affecting lamphouse operation was in one location with a CFS console that had its main cooling blower sieze (the one in the rear that is ducted directly to the bulb) and the exhaust was so good that the vane switch that normally cut the power when the fan stops was being held closed by the exhaust alone!

Scott: its difficult to describe but ozone smells a little like a 'burnt mustiness' and is unmistakeable once you get a good whiff of the stuff. Malfunctioning neon gives off quite a bit of ozone as well, that is where I have received the best idea of what it smells like, especially when the neon is indoors and the ozone ends up in the projection booth :O

Aaron

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John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000


 - posted 04-26-2001 11:40 AM      Profile for John Pytlak   Author's Homepage   Email John Pytlak   Send New Private Message       Edit/Delete Post 
Scott: Yes, the high voltages used to attract the toner in electrostatic copiers and laser printers do generate ozone. Likewise any AC corona discharge, as around an old TV high-voltage flyback transformer or neon sign. Sometimes, you can smell it outside during a lightning storm. If you ever built a Van De Graaf generator, Tesla Coil, Jacob's Ladder, or other high voltage electricity demonstrator for a science fair, you've probably smelled ozone.

"Mr. Wizard" says you can easily generate ozone by CAREFULLY (we're talking THOUSANDS of lethal volts here ) bringing the output leads of a neon transformer close together, until there is a corona discharge or "St. Elmo's Fire" between the two leads (be careful not to let an actual spark jump between the leads). The pungent smell of ozone will live in your mind forever! (But don't accidently kill yourself doing this experiment ).

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion


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Tom Sauter
Expert Film Handler

Posts: 163
From: Buffalo, NY, USA
Registered: Sep 2000


 - posted 04-26-2001 12:36 PM      Profile for Tom Sauter   Author's Homepage   Email Tom Sauter   Send New Private Message       Edit/Delete Post 
Scott: all Eiki xenon lamps are listed as ozone-free so you can relax

That "copier smell" is ozone. Another way to smell it distinctly is to run your hand along the front of your TV while its on. You'll feel yourself pick up static, and after covering the entire screen you'll smell it on your hand.

The last time I smelled ozone after a thunderstorm was when lighting hit my house!

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