Film-Tech Forum ARCHIVE: NEC filter price

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Posted by Stephen Frazza (Member # 2320) on 01-31-2014, 04:09 PM:

I was looking for another source and prices for filters for my NEC's and I found these. Has anyone used this company before. Are they actually legit HEPA filters. They seem insanely cheap compared to what I was paying. Or are they in line with what people are paying.

Air Filter (7"x7") for NEC

Air Filter (3.5"x9.5") for NEC

Posted by Justin Hamaker (Member # 2165) on 01-31-2014, 04:13 PM:

We use those filters, and they seem to work fine.

Just FYI, the filters that come with the projector can be washed and reused - assuming they are the ones with the fabric baffles and hard plastic frame.

Just rinse under hot water, and apply a little dish soap. Run your finger along each fold a few times on each side, then rinse and dry. I don't know how many times you can do this before they fall apart, but it's a better alternative than $36 per filter change (2 each per projector).

Posted by Steve Guttag (Member # 268) on 01-31-2014, 08:11 PM:

There is less air flow through those. Strong was distributing that type of filter but has changed to one that really resembles the original NEC.

Posted by Mark Gulbrandsen (Member # 72) on 01-31-2014, 11:26 PM:

The air filters above are not true HEPPA filters like the original NEC filters are. If you have an NC-900 and you buy the NEC lamp kit you will get the actual NEC heppa air filters with that kit. The filters that Strong used to sell were passable as for filtration but did not fit as tightly into the filter openings as the original filters did. I've seen dome dust leakage because of it. Placng a thin layer of foam tape around the edges of the filters that contact the projector side of the opening fixes that problem. Also, tape the center join of the two lamphouse air filter on top together. That stops any dust leakage there. Except for a few very dusty locatons we have nistalled NEC's, the air filters last remarkably long.

Mark

Posted by Marco Giustini (Member # 4544) on 02-01-2014, 04:51 AM:

There is no point in having HEPA filters if there is no sealing around the filters themselves.

Posted by Steve Moore (Member # 4753) on 02-01-2014, 05:37 AM:

Has anyone got or had a good source of Christie CP2000SB (the large blue machine!) filters, and does anyone know where the "small" filter is? I know where the large "operator side" one is, where the air goes across the light engine, however one supplier said I should be buying the small one too; yet until now I was not aware there was one in those? Anyone come across it's location?

Posted by Marco Giustini (Member # 4544) on 02-01-2014, 06:09 AM:

LAD filter. It's inside the light engine, just in front of the big one. Remove the big filter and you'll see it. It must be white, if it's not it has to be replaced, that filters the air going to the DMDs.

Posted by Mark Gulbrandsen (Member # 72) on 02-01-2014, 12:16 PM:

I agree Marco, Thats why I reccomend the foam tape and such.

Posted by Marco Giustini (Member # 4544) on 02-01-2014, 01:12 PM:

Yes but given the price NEC sell the filters, I would expect a much better design. There is no sealing between the fan and the filters, why the air shouldn't be sucked from the gaps around the panels? They should ask Mr. Dyson, he knows how these things work!

Posted by Mark Gulbrandsen (Member # 72) on 02-02-2014, 12:38 PM:

I think you misunderstood me. I never have any issues with original NEC filters. But over here everyone is using cheap chinese replacements and they do not seal well against the projector. They are about 1/4 the price of the NEC filters and the filter element part is good but the paper frames theya re in are too loose in the filter holders.

Posted by Marco Giustini (Member # 4544) on 02-02-2014, 02:06 PM:

No filter can properly filter air if no gasket is placed around. No matter how good they are. NEC filters come with NO sealing and as you pointed out the lamp ones leave a gap in the middle. For that price range I would expect NEC to better engineer their filters.

Posted by Steve Guttag (Member # 268) on 02-02-2014, 02:32 PM:

I believe the idea on the NEC filters is that they inherently are tight fitting and form a satisfactory seal for what they are doing. They should require one to squeeze them to get in/out.

Is this stuff perfect...no. Barco went to a filter system that lets a fair amount of fine dust in...they will brag about their sealed light engine but that doesn't help all of the mirrors and other optical elements that lead to the light engine.

Christie had decent filtration...except for the lamp, which receives none so the main reflector and UV filter don't get anything either.

Over all, I much prefer the changeable filters over the wire mesh ones. They do a much better job of keeping the fine dirt out.

We are toying with adding a "pre-filter" to Barco projectors to cover the inlets to see if it cuts down on the dust/dirt and grime. Lets face, it, most do not clean the wire mesh filters very well. This is particularly true if the popcorn oils can make their way to the projectors.

Posted by Marco Giustini (Member # 4544) on 02-02-2014, 02:56 PM:

The NEC filters I use don't need to be squeezed to stay in place and they are actually loose. The fan is on a different chassis, that means that air can actually be sucked from the gap between the panels. Check R320's design: the fan and the filters are in the same compartment. And filters have gaskets.

No, if no gaskets are used you cannot expect "hepa" filters to work, no way. No matter how tight frames are, dust will pass anyway.

Posted by Mark Gulbrandsen (Member # 72) on 02-03-2014, 03:41 PM:

Marco, Thats why I reccomend the foam tape thing. The NEC filters do fit tighter but not what I'd call quite tight enough.

As for Barko... How many of their light engines are actually still sealed? None of the Barkos I've installed lately have sealed light engines and I remember them saying they were moving away from that because of cost. Hepa could also rescue Barko as well if they were smart enough to actually include them on their projectors. The only cleaner I know from experience that's safe to use on front surface mirrors is Panchro Lens Cleaner

This is probably why they made their projectors put out more light at least initially was to compensate for optics getting dirty down the road.

Mark

Posted by Gavin Lewarne (Member # 5397) on 02-04-2014, 07:34 PM:

The filtration on our Barck DP2k-12c is remarkably poor

The cleanable wire mesh filters are very slack in the housings (tried 2 sets) and some things that should be filtered, are not

I clean them every 2 weeks but that doesn't stop a fair amount of that fine powdery dust getting inside

Posted by Marco Giustini (Member # 4544) on 02-05-2014, 03:40 PM:

Mark,

I got it, and I may do it next time. I'm just saying that for the money they ask it would be nice to find some gaskets ON the filters themselves!

How do you recognise if the light engine is sealed or not?

Posted by Dave Macaulay (Member # 813) on 02-06-2014, 05:49 AM:

One clue whether the light engine is sealed is if it doesn't have a LAD fan blowing into it.

Posted by Marco Giustini (Member # 4544) on 02-06-2014, 06:09 AM:

Barco do not have LAD on their light engines. Never had.

Posted by Dave Macaulay (Member # 813) on 02-06-2014, 06:28 AM:

Exactly. Barco has has a "sealed" light engine. The first "digital" projector I saw was at Imax, a DPI unit I think (?) that had a lot of HEPA filters and a lot of fans. You were almost expected to have a clean room if you needed to open the brain case. It had dust spots visible on screen... but I'm sure that there had been many Imax staff opening the thing to peer at the workings.
I recommend Barco for dirty environments (ie drive-in booths) because of the sealed light engine.

Posted by Marco Giustini (Member # 4544) on 02-06-2014, 12:17 PM:

Ok, but I'm quoting Mark:

quote: Mark Gulbrandsen
As for Barko... How many of their light engines are actually still sealed? None of the Barkos I've installed lately have sealed light engines and I remember them saying they were moving away from that because of cost.

Then my question: how to you recognise a sealed Barco engine from a non-sealed one?

Posted by Mark Gulbrandsen (Member # 72) on 02-07-2014, 02:37 PM:

Marco... I just installed a used DP-2000 and it DID NOT have a sealed light engine. In fact the projector was so dirty all over inside that I had to literally dismantle the entire projector and clean everything in it, prisms included. (Job Security!) It's easy to tell a sealed light engine from one that is not because a sealed engine is inside it's own metal housing. On an open light engine you can see the glass prism's, heat sinks, cooling hose, formatter boards, etc. And when the lamp is lit you also see the three primary colors.

Mark

Posted by Marco Giustini (Member # 4544) on 02-07-2014, 03:34 PM:

I'm afraid you are mistaken Mark,

The metal housing has nothing to do with the light engine being sealed or not.
When Barco say the light engine is sealed it means the DMD are in place without air gaps, there are gaskets around them and no air is allowed inside.

Christie is blowing laminar air to the DMD surface to keep them clean (they say. I say to keep them cool!).

All Barco engines are sealed, maybe the old ones were more sealed, having an aluminium box around them, but that does not change the fact that they are still ALL sealed.

Posted by Mark Gulbrandsen (Member # 72) on 02-07-2014, 05:39 PM:

Well, according to the Patent they only use sealent tape. (Shaking head). I wonder how long that will last. You still have the output face of the prism that gets dirty irregardless because of the poor air filtration.

Posted by Marco Giustini (Member # 4544) on 02-08-2014, 02:42 AM:

It would last more than an open gap! [Smile]

Posted by Carsten Kurz (Member # 5396) on 02-08-2014, 07:35 PM:

I think Barco even quotes a sealed light engine for their cheapest 10Sx/8Sx machine.

- Carsten

Posted by Marco Giustini (Member # 4544) on 02-09-2014, 04:15 AM:

Baro light engines are all sealed. I know the Christie 2210 is sealed as well.
Not sure about NEC but I have an instance where because of bad management lots of dust has entered the light path, I could focus it on a piece of paper moving the focus all the way back. Projector ruined (red halos on black), only solution to replace the light engine - according to NEC.

Posted by Mark Gulbrandsen (Member # 72) on 02-09-2014, 06:34 PM:

Actually open gap light engine is very easy to clean with the right cleaner and cleaning tissues. I;ve had to clean older Christie engines several times beause of operation without filters. And yes, you have to pull the engine out to do it. With different amounts of expansion of the glass between the three primary colors one would think that air gapped engines would be the best way to go. I know that Christie very slightly sacrifices perfect focus of one primary color (they taught and showed us that in advanced training) because they can not get the prism the exact right length and still have it converge properly. Never saw that issue from Barko or NEC though.

Posted by Marco Giustini (Member # 4544) on 02-10-2014, 04:14 PM:

What Christie told me to explain the slightly misconvergence of RED is that because of the different wavelength it won't - and cannot - be perfectly aligned with the others.

I thought it made sense at the time.

Posted by Steve Guttag (Member # 268) on 02-10-2014, 04:41 PM:

Yes...it is red and all of them have it to some degree.

When I converge I tend to not converge Blue To red ever...they are at opposites. I go Blue to Green and Red to Green. If Blue is fixed...do green to blue first then red to green.

Posted by Mark Gulbrandsen (Member # 72) on 02-11-2014, 06:19 PM:

Marco...

I don't think it actually has to do with wavelength. It has to do with it not being able to be in focus perfectly. Some slight physical shortcoming in the relation of the red prism to the other two.

Posted by Lance C. McFetridge (Member # 95) on 05-30-2014, 10:17 AM:

How much are you paying for the filter kit for a NEC 2000C projector with specifications close to original? I understand the manufacturer had done away with the plastic frame filters which were OEM. Any truth to that?
Thanks
Lance

Posted by Mark Gulbrandsen (Member # 72) on 05-30-2014, 02:45 PM:

I've never seen a plastic frame filter in any NEC and I've installed gobs of them. The factory filters are of much higher quality than the Chinese versions. But because NEC wants so much $$$ for them everyone has switched over to the Chinese version. Generally, the Chinese filters for NEC are under ten bucks each.

Mark

Posted by Gordon McLeod (Member # 33) on 05-30-2014, 03:12 PM:

I am testing the stainless steel filters now in the NEC and Christie

Posted by Mark Gulbrandsen (Member # 72) on 05-31-2014, 09:53 AM:

Why? The openings are so large they pass large bugs and even moths! It's like the filter that will never ever clog up though... but other than sheets of paper and tools what will it actually filter out?

You got to be kidding...

Posted by Marco Giustini (Member # 4544) on 05-31-2014, 11:53 AM:

Mark, those are not Barco's filters or if they are they are not the current ones.

Posted by Carsten Kurz (Member # 5396) on 05-31-2014, 12:09 PM:

Yes, the Barco/Kinoton filters are completely different, but these pictures from Mark show the ones that Gordon mentioned for Christie and NEC I think. Looks like a joke to me.

- Carsten

Posted by Mark Gulbrandsen (Member # 72) on 05-31-2014, 12:23 PM:

Yes, that's the NEC filter. Like a coarse woven door screen basically. It's gonna let everything right on through.

Mark

Posted by Marco Giustini (Member # 4544) on 05-31-2014, 07:04 PM:

Are those for the lamphouse inlet? Maybe NEC decided filtered air was not needed for the lamphouse. Obviously those are just for preventing someone from dropping items in the projector.

Posted by Mark Gulbrandsen (Member # 72) on 06-02-2014, 06:25 PM:

Marco...

They are available for all styles of NEC filters. I would never use them around here. In this Desert area there is way too much dust and dirt.

Mark

Posted by Bertha Zeng (Member # 8539) on 11-03-2014, 06:58 AM:

the link that you posted i saw that .thats not true hepa ,but you can make it in customized filter as the same size and in real HEPA efficiency.

Posted by Mark Gulbrandsen (Member # 72) on 11-03-2014, 11:41 AM:

I have tested ALL the available filters for NEC over the long term and the filters sold my MIT are by far the best. They fit really tight and seem to seal much better than any of the others out there. AS a result all of my customers will be using the MIT filters or the original NEC filters which always worked fine.

The following images are of a projector that has run with the crappy Strong filters for about three years. Note that the top of the light dump heat sink is nearly plugged up. This entire light engine had to be pulled and cleaned including the area between the light input prism and the actual light engine prism itself. It's not too difficult to pull a clean microfiber rag though that area and get the crud out. The light engine prism itself is sealed in a way similar to how Barco seals theirs. None the less there is a fan right above this engine blowing anything that can manage to get into the projector right into the light engine proper.
That internal fan absolutely needs a heppa filter on it to obviate this sort of issue and I am working on getting a filter that fits it.
Customer was lucky this was only dust and not mixed with popcorn oil or it may not have been possible to clean it on site.

After cleaning it up....

Even the heat exchanger itself was about 60% plugged up. A straw taped to a shop vac clears this crud out easily.

Posted by Gordon McLeod (Member # 33) on 11-05-2014, 04:11 PM:

Well i don't know where you got that Chinese Filter from but the ones we bought dont look like that
They have a very fine interior matrix mesh between the two outer screens
so far we have noticed no increase with internal dust compared to the original Christie and NEC filters we used in the past

Posted by Mark Gulbrandsen (Member # 72) on 11-06-2014, 10:14 PM:

That's the one Strong supplies. You will learn the hard way after running with the mesh filters for several years! NEC charges $2500 USD JUST to clean a light engine and they have to be cycled through Strong or MIT. May as well add to all your grief you claim you are having...

Mark

Posted by Justin Hamaker (Member # 2165) on 04-23-2015, 06:24 PM:

Just curious to see if anyone has found a suitable 3rd party replacement for the NEC NC2000C filters. Specifically I would like to find the hard plastic frame with cloth baffles which can be washed and reused.

Posted by Steve Guttag (Member # 268) on 04-23-2015, 07:17 PM:

Strong's NEC filters are not OEM and I think the same is true for MITs. I doubt you are going to find many that want to make washables...nobody wants to clean them and those that do clean filters often do a lousy job. And a clogged filter is very bad. At least with a new filter, you know it is cleaned.

Posted by Mark Gulbrandsen (Member # 72) on 05-07-2015, 11:13 AM:

quote: Justin Hamaker
Specifically I would like to find the hard plastic frame with cloth baffles which can be washed and reused.

Shaking Head! These are Heppa Filters, they can't be washed.

Mark

Posted by Leo Enticknap (Member # 534) on 05-07-2015, 11:28 AM:

quote: Steve Guttag
I doubt you are going to find many that want to make washables...nobody wants to clean them and those that do clean filters often do a lousy job. And a clogged filter is very bad. At least with a new filter, you know it is cleaned.

At the risk of veering slightly off topic, I got a K & N cotton-based, reusable, washable air filter for my car last year after hearing an infomercial for them on my local radio station. They're a local business - factory five miles down the road - and so even if the thing didn't live up to expectations, at least I'd be supporting local jobs. And at $65 for the filter compared to $15 for the 10,000 mile disposable ones, it'll pay for itself in two years at the rate I drive, even if it doesn't deliver any fuel efficiency benefit.

It did live up to expectations - very pleased with it. Acceleration feels slightly better, and the car went from just passing the smog test before last to passing the last one very comfortably. The manual does stress that regular and thorough cleaning is important to maintain performance, though.

I'm guessing that it would be possible to make these things for DLP projectors, too, but the danger would be people simply not taking them out and cleaning them, followed by impeded air flow, overheating and cooked DLP arrays. I'm further guessing that in a professional installation situation, it's cheaper to buy new disposables every few months than to pay someone to remove, clean and reinstall reusable filters.

Posted by Justin Hamaker (Member # 2165) on 05-07-2015, 02:50 PM:

quote: Mark Gulbrandsen
Shaking Head! These are Heppa Filters, they can't be washed.

Do they not work if they are washed? I have done this for several cycles and they seem to be working just fine. They are collecting just as much dust as the disposable paper filters we've used.

Posted by Mark Gulbrandsen (Member # 72) on 05-08-2015, 06:47 PM:

If they are still working after washing your's are likely not real Heppa Filters. The light engines on NEC are not sealed and the blower immediately above the light engine should really have it's own Heppa on it. Having a light engine cleaned because of dust and popper oil leakage can cost you $2500 at Strong! I have had to pull those that were using the cheapo Strong paper filters and clean what had already built up. Bu the amount of prism cleaning that can be done in the booth is limited.
The filters on these projectors are of the utmost importance. Even the crappy filters from Strong leak dust. I've switched all my customers over to the filters from MIT which are tighter fitting and seem not to have dust leakage at all.

Mark

Posted by Justin Hamaker (Member # 2165) on 05-08-2015, 08:42 PM:

Mark, here are a few pictures of the filters. I don't know if the NEC projectors still come with these, but they came in the projectors we installed in 2010 and 2011. As I said, I have washed these a couple times using a mild dish soap. So far the filters are intact and show no signs of wear.

Posted by Mark Gulbrandsen (Member # 72) on 05-16-2015, 09:37 AM:

Still shaking head. You're the guy that changes his oil, runs the old oil through a paper towel to "clean it" and then puts it back in the engine. You have a $60,000.00 projector and you're worried about 30.00 worth of filters.
[Roll Eyes]

Posted by Marco Giustini (Member # 4544) on 05-16-2015, 05:11 PM:

Some HEPA filters can be washed, not sure about NEC ones - not that it really matters since there are no gaskets to prevents unfiltered air to flow around them - but I second Mark here on the 60k/30 thing!

Posted by Monte L Fullmer (Member # 2797) on 05-16-2015, 05:59 PM:

quote: Mark Gulbrandsen
old oil through a paper towel to "clean it"

..Remember many moons ago when there was an aftermarket oil filter where one could insert a roll of "T.P." in it so one didn't have to buy new filters when doing oil changes?

There was a small town operator over here running a dollar house and he would wait until the vertical bulb in that ORC console would be pitch black since he couldn't justify spending $800 bucks for a new bulb when it was time to be replacing bulbs at at the allowed time over warranty hours..and that 1.6K bulb would have well over 14k hours on it-image was flat, flickering and burnt seal ends!

Posted by Mark Gulbrandsen (Member # 72) on 05-16-2015, 09:17 PM:

Monte,

You probably remember that I flat out refused to do that guy's conversion because he's such a cheap skate. He had to pay someone to come in from the east coast! [Razz]

Marco, I actually include rolls of very thin foam tape with my filter orders. That seals things up pretty well. I have my customers stick it around the edge of the filter then lay them in place. Also, the MIT filters fit the available space much tighter and have less leakage to begin with. I don't even bother with the filters from Strong any more.

Mark

Posted by Gordon McLeod (Member # 33) on 05-16-2015, 11:06 PM:

well mark i have had the metal filters ( and they are not the ones you pictured) in our machines and i can definetly state they are as clean inside as they were with the original factory supplied filters
so so much for that baloney

Posted by Steve Guttag (Member # 268) on 05-17-2015, 06:50 AM:

Gord...are you comparing same-same? That is, Mark shows the results of desert air. What is the air like in the booths you've made the comparison? Was it clean air to begin with? Was there a popper near by to give that sticky nasty oily crap?

Posted by Mark Gulbrandsen (Member # 72) on 05-17-2015, 10:20 AM:

Around this area even the Barco's with metal filters are basically ineffective. In fact the stuff that gets through is so fine it is like the consistency of talcum powder. Doesn't affect the prism but it DOES affect and shorten the lifespan of just about everything else in the projector.

You keep running see metal filters Gord because eventually I'm going to get a good laugh. Those prism's are not sealed and NEC charges $2500 USD just to dismantle and clean one.

At least I can't make fun of you re-using your motor oil since you don't drive. [Big Grin]

Mark

Posted by Brad Miller (Member # 2) on 05-17-2015, 12:25 PM:

In dealing with theaters all over the US, I can absolutely vouch for the booth environment dictating if rewashable filters should even be an option. I've seen some Barcos with rewashable filters brought to the point of useless when we are called in to investigate.

Too many theater owners say "nobody sees the booth, so I'm not spending a penny on it" and foolishly murder their equipment (and presentation quality) in that mindset.

Posted by Mark Gulbrandsen (Member # 72) on 05-17-2015, 05:57 PM:

Exactly Brad!

And the metal filters don't murder the equipment right away, they do that over time... I always say... What you don't see in there today will for sure be in there tomorrow.

Mark

Posted by Mike Blakesley (Member # 26) on 05-17-2015, 09:36 PM:

quote: Brad Miller
Too many theater owners say "nobody sees the booth, so I'm not spending a penny on it"

I have said that quote, but I was talking about painting the concrete booth floor (which is pretty ugly, but who cares?) We change our filters religiously.

Posted by Steve Guttag (Member # 268) on 05-18-2015, 05:47 AM:

One thing to watch out for on concrete floors is that they are sealed up. Concrete can shed dust otherwise (rather easily).

Posted by Leo Enticknap (Member # 534) on 05-18-2015, 11:38 AM:

quote: Brad Miller
In dealing with theaters all over the US, I can absolutely vouch for the booth environment dictating if rewashable filters should even be an option.

Absolutely - how much crud is in the air determines how much crud gets caught in an air filter, and thus how often that filter needs replacing or cleaning.

Shortly after moving from England to the US, my wife asked me to investigate why our home HVAC system wasn't working properly - the air flow through the ceiling ducts was very weak. Home air cooling systems are simply unknown in Britain (climate too cold to need them!), and so I had to start by reading up online about the basics of how these things work. "HVAC 101" took me to the panel air filter in the furnace unit. It was totally and utterly black - filter replaced, strong blasts of cold air restored.

When I asked the guy at Home Depot how often one is supposed to replace these things normally, his reply was that it depends almost entirely on the air quality where you live. At the bottom of the Inland Empire valley, where the smog settles = every 4 to 6 weeks. Up in the San Bernardino mountains (e.g. Arrowhead or Big Bear) = every year to 18 months. Drive up there and look down, and you can see the smog hanging over San Bernardino - a lovely brew of desert sand, dust, exhaust fumes and the output of the various industrial facilities in the area, Ontario Airport, etc (SB has been found by one study to have the lowest air quality/worst pollution of any metro in the US). It's all being sucked into everyone's HVAC filters, hence why you need to replace them so frequently.

Posted by Monte L Fullmer (Member # 2797) on 05-19-2015, 05:14 PM:

It seems apparent that these digital units should have been installed in a "clean room" surroundings.

For some of these installs are just plain horrible to witness when it comes to clean surroundings when it comes to dusty conditions.

Posted by Mark Gulbrandsen (Member # 72) on 05-25-2015, 04:02 PM:

quote: Monte L Fullmer
For some of these installs are just plain horrible to witness when it comes to clean surroundings when it comes to dusty conditions.

Yes, and that's the primary reason for using NEC projectors in places like this. They won't get dirty inside, at all and equipment will likely last longer as a result.

Mark

Posted by Mike Blakesley (Member # 26) on 05-25-2015, 10:24 PM:

That's true. Forsyth is "dustville" to the max due to the railroad, mostly (lots of areas that aren't paved near the tracks), plus the city loves to spread sand during the winter and not pick it up until late April, so that's even more dust. And our building is 85 years old, so all of that adds up to our booth can get dusty -- but our projector is spic-n-span on the inside.

Posted by System Notices (Member # 2357) on 08-27-2016, 08:47 PM:

It has been 459 days since the last post.

Posted by Steve Kraus (Member # 476) on 08-27-2016, 08:47 PM:

Interesting thing about the OEM NEC filters is that the "unwoven" fabric has tiny pores. I don't mean microscopically; you can see them with the unaided eye if you look really closely. I presume they know what they are doing but seems like they would let particulates through. Isn't the OEM filter considered the best?

If MIT could get theirs made with thicker sidewalls instead of card stock akin to index cards, they would be a lot better. They told me over the phone that they get theirs from the same factory that supplies NEC. If they do...they are sure not buying the same ones!

The metal screen filters are mentioned on NEC's own site but for the lamphouse only. If you see dust buildup you must, it says, go back to the regular unwoven filter. I guess that makes sense considering film lamphouses rarely got filtered air.

Posted by Steve Guttag (Member # 268) on 08-28-2016, 09:55 AM:

Having worked with the filters from the manufacturer and the OEMs...they seem to continually evolve. I've seen them with cardboard frames, plastic frames, white edges, black edges, with more pletes, less pletes, dividers between pletes. They all work and fail to varing degrees.

The current MIT knockoff filter set to the NC900 is a dead ringer to the factory installed filters. The MERV rating on the knockoffs are supposed to be the same as the factory (I have not nor have the facilities to test this).

I've seen VERY dirty projectors using the factory filters so they are not a guarantee of success.

The original Strong knock offs were not too good. They were restrictive of air flow, fit too loose (so dirt could go around the filter) but they have evolved their filters a couple of times now and while have thin white edges, plete wise, are pretty much the same as the original. NEC claimes that their edge has a metallic strip on it so that it will do a better job of stopping dirt electrstatically. I have not seen it work dramatically well.

I'd rather see ALL of the projector companies and those that are making aftermarket filters go to what Christie used on their CP2000S/SB series...a filter with a tight-fitting rubber seal around the filter that seals it up better. I dislike the metal mesh filters immensely. They don't filter sufficiently and they expect the end user to clean them regularly. I've found that getting people to change a dirty filter is going to be MUCH easier than getting people to regularly clean the metal mesh well without damaging it.

I think a lot of the filtration problems could be improved by going with a cheap "air register" type filter on the OUTSIDE of the projector and servers (yes servers and anything else with a fan such in crud too). It will stop the popcorn oils from getting in. In a sense, Christie is already doing this with their LAD filter that is really just sitting behind the main filter.

Posted by Mark Gulbrandsen (Member # 72) on 08-28-2016, 08:34 PM:

I have a few customers in very dusty locations placing thin foam tape around the edge of the NEC filters so they seal better. It seems to be pretty effective too. I also thought of having some thin rubber gaskets cut that would go in first then the filter up against them to seal around the edges of the filter. It would work the same as the foam tape but would last much longer.

Mark

Posted by Steve Kraus (Member # 476) on 08-28-2016, 10:23 PM:

I bought two sets from MIT about a year ago so I have the ones with the white card stock frames. I used very thin weatherstrip to help seal the edges and prevent leaks. The adjoining filters I put double stick foam tape between.

I do have my OEM orginals saved. After vacuuming them I did a *very* elaborate washing process with mild dish detergent involving 4 washes (including two overnight soaks), multiple rinses also including long soaks, and a final rinse in distilled water so no dissolved solids in tap water would be deposited as they dry. Whether I ever actually reuse them is debatable but seems like I could. I cannot imagine a theatre being as thorough. FWIW they do seem to withstand careful washing without damage.

I have another MIT set still to use and if they have changed since one year ago, I am tempted to buy some just to see if they've gotten better.

Posted by Mark Gulbrandsen (Member # 72) on 08-30-2016, 09:41 AM:

The MIT filters are the same as they have always been.... It's all I sell anymore. The NEC filters are too spensive for most of my customers that need to frequently change them.

Mark

Posted by Steve Kraus (Member # 476) on 08-30-2016, 02:05 PM:

Where would you even get NEC filters if Strong is supplying something else? And how much are they?

Posted by Mark Gulbrandsen (Member # 72) on 08-30-2016, 05:59 PM:

You can order the NEC filters from an an authorized NEC Parts distributor if everyone else evaporates...

Mark