High temperature containment CCTV cameras?

[krajesj]

Hello,
I have need of a high temperature CCTV camera for monitoring the area around the RCP loop area. The ambient temperature I'm told is about 150-160 degrees F.
Right now we have a 1/3" color CCTV camera with PT and an 8-24mm zoom lens mounted in a fabricated metal housing box controlled from a remote controller outside the loop area. We were burning up cameras, then I found that almost every off the shelf camera is only rated for ~120 degrees max. Our lenses also experience "browning." What causes this? Is it related to high temperature, radiation exposure, or both?
I've seen very sophisticated nuclear grade auxiliary cooled units as for refractories, etc. I've also seen Peltier cooled cameras (best solution so far), but Peltiers draw LOTS of current I'm told. Maybe a housing within a housing filled with coolant?
Is there a lower priced solution to the refractory camera style? Is there an off the shelf camera good for higher temps? I'd like to compare some ideas with everyone about this. Any experience?
Thanks,
krajesj

 

[vpl]

krajesj

If you haven't already, you should post your question in another forum - probably underthe electrical engineering area.

Patricia Lougheed

Please see FAQ731-376 for tips on how to make the best use of the Eng-Tips Forums.

 

[henerythe8th]

Have you considered "purging" the camera for cooling. "Purged and Pressurized" is a common technique to meet flammability requirements, but also transports heat...

 

[krajesj]

I'm not sure I understand what you mean by "purged and pressurized". Please explain.
Steve

 

[StuartB]

I think the browning of the lens is due to radiation, not heat. High radiation does that to glass. The best solution is to use pure silica glass, it's less prone to this.

What are you really trying to tell with the camera? Is it possible that you could use some other sort of instrumentation or indication?

 

[krajesj]

Thanks for your reply, StuartB,
I don't think I can get anything for lenses other than the standard off-the-shelf lens glass.
The cameras are being used for reactor cooling pump leak detection. They are about 15 feet from the RCP's and are zoomed in to get the best overall presentation. I'm kinda' stuck with the camera lens and camera, it seems. I'm looking for a way to cool the whole assembly, as the ambient air is ~160 F. but the camera guts are only rated for ~120 F. max. The lenses I feel I can do nothing about, they will last two or three refuel cycles. The cameras won't make half of one cycle.
Thanks,
Steve

 

[AlphaT]

StuartB is right about the glass browning. It's radiation induced, and you need special "non-browning" glass to avoid this. You could devise a shielded casing for the cameras using this glass to reduce rad exposure to the lens, but that's hardly low cost. Probably easier just to replace cameras or lenses.

For temperature, 120F is probably about max for commercial cameras, base on my very quick check of catalogs. One solution is to put a light casing or can around the camera and feed cooled air to the casing to keep the camera cool. If you can feed relatively cool air into that metal housing box you mention, that could do the trick.

Another trick is using periscopes or fiberscopes to remove the temperature sensitive portions of the system from the hot (thermal) area. Unfortunately, this is not a low cost option either.

As just an aside, if you're getting a lot of "snow" in the picture, this is typical of CCD cameras in rad environments. Shielding the camera body or relocating out of the rad area is typically the solution.

Hope this helps
Carl

 

[henerythe8th]

With regard to the "purged and pressurized" that I mentioned previously...
...it does not sound as if you really need the "pressurized" if you are currently using the camera in that environment. "Purged and pressurized" is a method of preventing fire in an explosive atmosphere (ie. a flam gas environment. By purging the oxygen out of a system the ability to support combustion is removed, but the temperature must also be limited so that the outside of the system does not get hot enough to cause combustion, too. By purging a system you are replacing the "air" in the system, typically with "pure" nitrogen, if the nitrogen continues to be added to the system then it carries heat away with it. If the circumstances that you are working in would allow you to add nitrogen then a simple "one-way" valve would allow you to vent into that atmosphere. If you can not add gas to the atmosphere where the camera is operating then you could use two "hoses"--one to supply gas, the other as a route out. Hope that lends some insight! Post again if you have questions...

henerythe8th