Kneisley Xenex L-2000 Manual (and correct ventilation amount)

[Matthew Hidy]

Hello,

Does anyone have a manual for a Kneisley Xenex L-2000 Lamphouse (not the Xenex II) that they'd be kind enough to share?

My first item of interest is regarding whether I am meeting appropriate ventilation spec for use with our 2000W bulbs. Right now I am drawing ~150 cfm at each lamp.

Thank you,

Matthew Hidy (on behalf of Cornell Cinema)

msh274@cornell.edu

[Tony Bandiera Jr]

I don't have a source for the manual unfortunately, though John Eickhof Who is a forum regular, may have one. I will reach out to him and refer him to your post to see if he has one.

I can tell you that 150cfm is far too low, most 2k lamphouses require 350-400cfm or so per lamphouse for safe operation. You also do not want too MUCH airflow, as overcooling can affect arc stability and also thermally stress the lamps.

A good rough guide is the lamphouse should never be more than warm to the touch, and the aperture plate, gate and trap area should never be so hot that you can't touch them for less that say 5-10 seconds.

[John Eickhof]

hello, is your lamphouse yellow and resembles the xenex II ? if so the airflow should be 150-200 cfm at the exhaust outlet on top, kneisley recommended a 300 cfm exhaust for two lamphouses, i will look through my library for the proper manual for you, otherwise, most data for the xenex II is applicable for the L-1000 & L-2000 except the mirror is a cold dichroic coated glass type on your unit and the II series uses a cold metal reflector.

[Mark Gulbrandsen]

Kneisley always spec'd way too low of CFM in their manuals. They did not include pushing the air a distance up a 6 or 8 inch pipe, It was exactly the same way with their console. This is probably why Kneisley had issues with Xenex 2's burning the Dichro metal reflectors. The glass reflectors never failed like that.

[Matthew Hidy]

Thanks all for your info.

The lamphouses aren't excessively hot, but I believe they would be better off running a little less warm. We're reworking the ventilation to accommodate a severely under-ventillated digital projector, but want to take the chance to improve the ventilation of the 35mm lamps now too (as I suspected that we should). It sounds like 200 cfm would be a satisfying target for each. Incidentally an old facilities blueprint shows the system was designed for 200 cfm at each Xenex.

John, the lamphouse is a light green/grey and is resemblant of the Xenex II, but I notice differences such as the vent stack set more towards the rear and a blower that draws in from the rear (above the anmeter) instead on my unit. Thank you for taking the time looking for a manual. I appreciate it!

[Gordon McLeod]

It was specified as 150cfm per lamphouse (and that would be acutal measured cfm not fan size. You can over cool the lamp in the Xenex1 very easily and get a rather unstable flicker

[Tony Bandiera Jr]

Gordon, I still agree with Mark that they underspec'd the requirement, especially for a 2k or higher lamp. Knisley wasn't exactly a stellar product in any form. Especially the horrid 500w rectifiers with exposed coils on the bottom that loved to melt floors.

I would install an exhaust blower with adjustable speed (preferably by adjustable drive pulley) that can get let's say 300-350 cfm at each lamp, and if it turns out that flicker rears it's ugly head, just drop the flow down a bit.

Better to overcool a bit rather than undercool IMHO.

[Mark Gulbrandsen]

I never overcooled any xenon lamp even with larger blowers than were called for. And I put in gobs of lamps and consoles.

[Gordon McLeod]

Because the Xenex1 has the exhaust vent directly over the actual arc area of the lamp it is a issue of a cold spot forming on the envelope. I probably installed more Xenex1 than any other lamphouse over the years and have had flicker and spotty blackening when over cooled

[Mark Gulbrandsen]

Gord,
Considering that the temperature immediately in front of the cathode reaches 10,000 degrees plus f. I still find it hard to believe a lamp can be over cooled. Cooled down too quickly is possible. I ran up to 4500 watts in Xenex 1's and 2's with a 1200 CFM.fantech and never had any flickering. None out of smaller lamps either. If there is any major flickering substitute in a different rectifier. Kneisley rectifiers only measure marginally good. And the single phase units are lots cleaner than the three phase units.