Biocide or additive for gate coolant loop?

[Jim Cassedy]

Nice pics. I assume there is still a submersible pump in the
bucket, and the radiator is the first stop for the warm water
after the projector?

Yes. There is a submersible pump in the bottom of the bucket.
The flow is: Bucket--> Gate/Trap--> Radiator --> Bucket

[Brad Miller]

In case anyone has a failing pump from the goop build-up, the pumps BLS used in those little buckets are:
Little Giant NK-1 submersible pump #526003
https://www.amazon.com/dp/B000CDRZWG

Personally I prefer to put a chiller on the line, but few venues would be willing to put forth the extra expense.

[Jim Cassedy]

<edited> In case anyone has a failing pump from the goop build-up, the pumps BLS
used in those little buckets are: Little Giant NK-1 submersible pump #526003

Hey Brad- Do you know where the little fan/radiator assemblies came from? I was once looking
for something just like that for a non-theatrical related project. I saw some similar ones online
a while back but that particular model was really exactly what I was looking for.

[Steve Guttag]

My favorite additive is Tyfocor (not Tyfocor-L...which is much easier to find). It is clear and only need a 1:5 Tyfocor to Distilled Water mix. My favorite pump/heat exchanger was the one that the MarkVII DCinema projectors used (Barco and Chrisite). Thermotek made them and they were called the HX50-4.

Screen Shot 2025-03-20 at 10.41.06 PM.png

You only have about a liter of coolant. It seals up well so you don't have evaporation. If you lose flow, it will sound the alarm. It was quite pricey and it is long out of production (if you look up Thermotek, they have no record of it now). They were definitely the best of the non-chilled options.

I never liked the submersible ones. You are heating up the water that the pump sits in. The plastic tubs then act as insulators keeping the heat in.

Strong/Ballantyne had their circulator that was a metal tank and the pump sat outside of the tank with the impeller pulling from the top so the sediment would settle.

For when you really want to keep the gate/trap area cool, chillers are the way. I have to thank Larry Shaw for pointing me towards Remcor. When it was in production (a theme here) the CH250 was pretty killer. Again, a bout a liter of coolant is all you needed as the reservoir was jut a section of 4-inch PVC pipe on the side of the unit. If you set it to 18C (about 65F) you got a good combination of a cool running gate/trap without condensation.

Screen Shot 2025-03-20 at 10.51.46 PM.png

[Ryan Gallagher]

Tyfocor appears to just be Ethaline Glycol type anti-freeze. Better in all ways except for the toxicity compared to PG. Both are waste that has to be disposed of properly, so if it had better bio-cide properties I might consider it.

I also have thought about the insulative properties of the plastic tank with the submerged pump. Not really an efficient design for dissipating heat! And kinda kills my idea of using an agitator pump 24/7 too. Of course the original design was not really to dissipate it, but just have a massive enough water source to sink it, and prey it cools off over night before the next shift. I'm unsure how much heat a UV-C sterilizer would add to the system, but also wouldn't have to be on during films, could just be part of a clarifying cycle on a timer or something.

Those active chilled/compressor coolers are fancy. And excessive! If I was running 7k lamps in a drive in it would be tempting though. Honestly though I'm not sure the thermal design of the Century trap coolers are efficient enough to justify such things. It might keep the human touched parts cool... but for cooling the film itself i've seen archive posts discussing certain installs with other projectors that use cooled air nozzles aimed more directly that seem far more targeted in design.

And correction, my memory was incorrect on our lampage. We are running Ushio UXL-40SC currently, so only 4K. The whole water cooling debate might be academic. The Super80 OEM specs were 4200w max. I'm guessing our JJs were sourced from somewhere that ran larger lamps, and hence came with the optional coolers, and so they got hooked up here too. My main benefit to keeping them in use appears to be for film trap handling comfort when cleaning between reels, and for when there is no heat filtering in our 70mm setup.

[Ryan Gallagher]

If I was to endeavor to build my own bucket style radiator version these oil coolers seem like the closest approximation to Jim's photos that are still somewhat affordable. This one is 110v, but there is a cheaper/smaller 12v one too. Then there is the whole market of PC water cooler radiators too. Still got the issue that you are dealing with annoying submersible pumps unless you get fancier in your build.

110cooler.png

https://www.amazon.com/dp/B0D9VZDC9W

[Steve Guttag]

The purpose of water cooling the gates/traps is for the metal, not the film. Metal expands with heat and aperture plates will even warp into the film and blister it (naturally, it depends on the plate, trap design, and lamp in use). You don't want the most critical part of the projection process changing dimensionally through heat and you don't want the thermal cycle it. Secondarily, you don't want the gate/trap transferring their heat to the film. Your best bet on keeping the film cool is your lamp system and its alignment.

My rule of thumb was, 3KW and up, I water cooled. 2KW and below, air cooled. 2500 was on the bubble. Above 4KW, I preferred chilled water or filtered "city water." With Kinoton projectors and their delrin gate parts, particularly on the 16mm machines, I would move to chilled by 4KW as that is an awful lot of heat on such a small area. In fact, I wouldn't go above 4KW on 16mm on Kinoton and 2KW on other machines.

As for your JJs having water cells...ALL 70mm machines had them, standard. It is presumed that 70mm was going into the biggest houses that use the largest lamps.

Before they made the Ultra-80, they used the Super-80 up to 7KW. The reflector and lamp adapters are the same. The difference is the intake blower is better on the Ultra-80. If your exhaust is good enough (800cfm), it should handle 7KW. Truth be told, the light you get above 4KW is a set of diminishing returns as the arc keep getting bigger but the efficiency goes down. Rarely does it pay to go above 6KW.

[Ryan Gallagher]

The purpose of water cooling the gates/traps is for the metal, not the film. Metal expands with heat and aperture plates will even warp into the film and blister it (naturally, it depends on the plate, trap design, and lamp in use). You don't want the most critical part of the projection process changing dimensionally through heat and you don't want the thermal cycle it. Secondarily, you don't want the gate/trap transferring their heat to the film. Your best bet on keeping the film cool is your lamp system and its alignment.

My rule of thumb was, 3KW and up, I water cooled. 2KW and below, air cooled. 2500 was on the bubble. Above 4KW, I preferred chilled water or filtered "city water." With Kinoton projectors and their delrin gate parts, particularly on the 16mm machines, I would move to chilled by 4KW as that is an awful lot of heat on such a small area. In fact, I wouldn't go above 4KW on 16mm on Kinoton and 2KW on other machines.

As for your JJs having water cells...ALL 70mm machines had them, standard. It is presumed that 70mm was going into the biggest houses that use the largest lamps.

Before they made the Ultra-80, they used the Super-80 up to 7KW. The reflector and lamp adapters are the same. The difference is the intake blower is better on the Ultra-80. If your exhaust is good enough (800cfm), it should handle 7KW. Truth be told, the light you get above 4KW is a set of diminishing returns as the arc keep getting bigger but the efficiency goes down. Rarely does it pay to go above 6KW.

Good to know on the Super80s being the same except for exhaust. Once I redo our stacks (to mitigate our lack of dampers and condensation risks) I'll make an effort to measure our CFM. I suspect we are on the adequate side to go brighter if need be. Understood on the diminishing returns. Our switchers are probably the limiting factor right now, have quite the variety.

4K has been what they always ran in these houses, presumably someone actually took a measurement at some point way back in the day, but there is a chance they just put the biggest lamps they understood to be supported in them and called it good. Picture looks good to my eye, but no idea if we are on the SMPTE spec or not for brightness. Much better since I re-aligned the lamphouses as best as the mis-matched soundhead hangers allow until I get time to put my replacement hanger on the hacked one.

Is there an economical spot meter for doing reflected light brightness measurement? I got a couple harkness meters but I don't trust their calibration and they are really best for A to B to catch changes.

Using your practices our booth definitely would have been water cooled. I hadn't even considered a direct line to city water and drain. Fancy. No drains near by though so that route would be a project!

[Ryan Gallagher]

Welp, determined part B of my problem is that one of the loops seems to be air-locking either at the block, or at the hose high point just before the drum.

When I remade them I left off the return tube inside the drum, I liked being able so confirm flow rate by sound/sight. But perhaps that was a mistake, when pumps are off gravity and/or a bit of syphon action will drain a good length of the return tube.

Weirdly only one loop does not recover fully when pump is back on, perhaps the one that doesn’t also has an air leak near a fiitting, but a bit hard to locate visually cause I used the semi-opaque fiber reinforced hose.

I did at least confirm flow failure is not due to a blockage, it will flow through the projector for a period when reversing the in/out connections before locking up again.