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Author Topic: Lamphouse exhaust booster recommendations Chris Hipp Phenomenal Film Handler Posts: 1462 From: Mesquite, Tx (east of Dallas) Registered: Jul 2003 posted 03-15-2004 07:06 PM                     I am looking to install an inline booster for our lamphouses with 3k or higher bulbs(3k-6k). They are currently pulling at about 400CFM according to one of our engineers. I do not have a meter so I cannot confirm that. Question is how much is too much, is it possible to overcool a bulb? I am thinking around 700-750 cfm would more than enough for the 6k houses and around 550-600 for the smaller bulbs. Thanks in advance.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 03-15-2004 08:09 PM                     WOW! only 400cfm on a 3kw lamp...thats insane at best. 900 cfm would be more like it and would give you good lamp life. 900 cfm is the smallest amount I reccomend for 2 to 3kw. Even more for larger lamps...thats a boatload of BTU's to get rid of! I've never been able to overcool a lamp although with alot of cold air entering a booth it might cool down too fast after turning it off. As for sucking the air out of a booth, it certainly is possible to do that. Ask your HVAC dude to see how much air is entering the booth before upping the CFM on alot of exhaust blowers. Mark Mark @ CLACO  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 03-16-2004 06:12 PM                     It may not be possible to draw more than 500cfm if the lamphouse vent is 6" due to the static pressure on your fan Also the air intake to the lamphouse needs to pressurize it to the level of the exhaust. Also the booth will need sufficient fresh air introduced so the exhaust can suck out that volume of air of the booth will end up with a negative air pressure  |  IP: Logged Chris Hipp Phenomenal Film Handler Posts: 1462 From: Mesquite, Tx (east of Dallas) Registered: Jul 2003 posted 03-16-2004 06:35 PM                     I think you guys might be onto something with the low pressure in the booth. Any time we open a door it is like you are standing in front of huge fan. I will look into that first.  |  IP: Logged Daryl C. W. O'Shea Film God Posts: 3977 From: Midland Ontario Canada (where Panavision & IMAX lenses come from) Registered: Jun 2002 posted 03-16-2004 06:38 PM                        Which way? You should have positive air pressure... air blowing out of the booth.  |  IP: Logged Chris Hipp Phenomenal Film Handler Posts: 1462 From: Mesquite, Tx (east of Dallas) Registered: Jul 2003 posted 03-16-2004 07:04 PM                     The air comes into the booth.  |  IP: Logged Daryl C. W. O'Shea Film God Posts: 3977 From: Midland Ontario Canada (where Panavision & IMAX lenses come from) Registered: Jun 2002 posted 03-16-2004 07:06 PM                        That sucks.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 03-16-2004 08:08 PM                     Never had a problem in a modern multiplex situation where you didn't have enough air entering the booth,nor in creating a negative air pressure. In a small booth that is very tiny this could be a problem, although for me it has not. We recently added a two screen addition to a theatre we built a number of years back and the local inspector was concerned about creating a negative air pressure in the smallish individual booths but he checked with the architect and all was ok for 900 cfm. Also you are definately NOT limited by the size of the exhaust hose or by the intake size on the lamphouse as what happens with a high draft blower in that the air velocity increases drastically. And that is the desired effect you want anyway. It will actually spin the seal cooling fans at a high rate without them being powered on! Lamphouses and consoles we have cooled this way typically yield 10,000 hours(not my choice to run em that long though!) from a 2kw lamp. 3 and 4kw last as long as 4000 hours. Mark @ CLACO  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 03-16-2004 08:53 PM                     If you take the exhaust requirments of a larger booth makeup air is a big cost very few theatres provide a proper positive air pressure  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 03-16-2004 08:59 PM                     I absolutely agree with you on the positive air pressure thing. I can't think of a booth with positive air pressure. Almost all theates I've been involved with have simple airflow HVAC systems that use either outsode air or recirculate it depending on outside conditions. But most booths are supplied with way more than sufficient air flow to accomodate a number of large exhaust systems. Mark  |  IP: Logged Jack Ondracek Film God Posts: 2348 From: Port Orchard, WA, USA Registered: Oct 2002 posted 03-16-2004 09:07 PM                        quote: Also the air intake to the lamphouse needs to pressurize it to the level of the exhaust. Not sure how you'd go about this, Gordon. It may be possible with lamphouses like the Ultra-80, but there was no such attempt with older models like the X-60 series. The Xenex Pup didn't have a blower in it at all, if I recall right... so anything provided up the stack would create a vacuum in the lamphouse, wouldn't it? I'm also pretty sure you aren't getting 600cfm out of that little blower on the side of a Super Lume-X. About the only way I could think of would be to have enough make-up air being forced into the booth to create a positive pressure in the whole room, with all exhaust blowers on. Assuming the intake vents on the lamphouse could handle the cfm's that you're looking for, that would be about as close as you'd get to equalling what the stacks would be pulling. ??????????  |  IP: Logged Paul Konen Jedi Master Film Handler Posts: 981 From: Frisco, TX. (North of Dallas) Registered: Jun 99 posted 03-16-2004 09:08 PM                     Chris, I could show you what I did in my booth. I found a device (inline duct fan) in the Grainger catalog that would help. When a DLP was joined or tapped onto the existing exhaust stack, it wasn't pulling enough air out. Also, when it was windy, the backflow would throw down the exhaust failsafe and kill the bulb. Anyway, added this exhaust and it helped quite a bit. Also, it has helped when on Friday night, the roof motor goes out and it can be temporarily installed to exhaust the air out into the booth space.  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 03-16-2004 11:08 PM                        For those who don't know, "positive air pressure" is recommended for film handling areas, so airborne dirt from outside is not "sucked" into the projection room. In other words, the system should be balanced so that when you open the door, the air flows outward. Incoming air from the HVAC should be well-filtered. High Efficiency Particulate Air filters (HEPA) are available at moderate cost, capable of efficiently filtering airborne dirt particles as small as a micrometer in size. (e.g., 3M Filtrete, Purolator, etc.) It's already been suggested that having a dedicated air source for lamp cooling would be a good lamphouse design feature, and make it easier to maintain the proper projection room environment.  |  IP: Logged Jason Burroughs Jedi Master Film Handler Posts: 654 From: Allen, TX Registered: Jun 99 posted 03-17-2004 10:16 AM                     I'm not sure about Chris's location, but this is certainly true at the AMC Grand, which is the prototype for their currently gigaplexes. The booth is part of the return system. Air is drawn from the auditoriums and into the booth, from there the HV/AC system draws the air and redistributes though a high velocity vectored duct system by use of various controlled dampers etc. The booth as no HV/AC system of its own, and relies on the air, complete with particulate matter, from the auditoriums for cooling and heating. This creates a negative air pressure in the booth to start with, add to that 10 exhaust fans running in the same room, and you end up with a pretty healthy inflow of air from open doors etc. AMC MAY have changed this method since construction of the Grand, but I doubt it.  |  IP: Logged John Walsh Film God Posts: 2490 From: Connecticut, USA, Earth, Milky Way Registered: Oct 1999 posted 03-17-2004 01:11 PM                     This has become a big issue with our circuit... Almost always during construction, the HVAC people are not told what is required by the projection people, so the booth is not properly set up to provide the correct amount of air. We have booths with 13 projectors in one room. Times 900 cfm each, that is an incredible amount of air that we pay to cool or heat, then immediately throw it away. Note that in some states, making the booth part of the return system is not allowed; the air must be dumped outside. This is because mixing all the air confuses the fire alarm if there is smoke. Some lamphouses seem to be more 'cooling' efficent than others: I'd be interested in knowing what make lamphouses Chris uses. Totally agree with Mark and Gordon about making sure enough air is coming into the booth. Other suggestions: We have consoles where the manufacturer put an exhaust fan on the top of the console, presumably to help. However, this fan had less cfm flow than the roof-top fan, so it actually reduced the airflow. You might want to check yours, and/or be sure the booster fan is greater than the roof fan. Change the ducting from the roof to the projector (or even just a section) to the largest size you can. Just like resistance in a wire is less with a larger gauge, a larger duct will allow the air to flow easier. This photo looks dumb, but it sucked like crazy. Consider getting a cfm meter; it should specifically state it can measure in cfm's. I have an Extech 407114. Although a good idea, none of our booths have positive air... we'd go broke...  |  IP: Logged

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