Imaging Through Bullet-proof Media
Imaging Through Bullet-proof Media
(OP)
Hi all,
I am a thermal imaging neophyte, so please bear with me. I hope someone can help. The situation is this...
We have a fixed-mount infrared video camera (Electrophysics Corp.) mounted above, and looking down into, an automobile shredder. The video image is used to enable the shredder operator to see through copious amounts of steam into the throat of the shredder so that he can see what he is putting into the shredder. We have the camera housed inside a substantial (read HEAVY) enclosure with a piece of expanded metal (1/2" mesh) covering the opening through which the lens looks down into the shredder.
The problem is that occasionally a piece of shrapnel will be shot up out of the shredder and make it through the mesh, striking the face of the camera lens. This, of course, destroys the lens.
Does anyone have any better ideas on how we can protect the camera lens and prevent it from being destroyed by flying shrapnel? We were thinking about using some type of bulletproof glass. Will this work? If so, what type do we need? Any other suggestions?
Much appreciated,
John R.
Cincinnati, OH.
I am a thermal imaging neophyte, so please bear with me. I hope someone can help. The situation is this...
We have a fixed-mount infrared video camera (Electrophysics Corp.) mounted above, and looking down into, an automobile shredder. The video image is used to enable the shredder operator to see through copious amounts of steam into the throat of the shredder so that he can see what he is putting into the shredder. We have the camera housed inside a substantial (read HEAVY) enclosure with a piece of expanded metal (1/2" mesh) covering the opening through which the lens looks down into the shredder.
The problem is that occasionally a piece of shrapnel will be shot up out of the shredder and make it through the mesh, striking the face of the camera lens. This, of course, destroys the lens.
Does anyone have any better ideas on how we can protect the camera lens and prevent it from being destroyed by flying shrapnel? We were thinking about using some type of bulletproof glass. Will this work? If so, what type do we need? Any other suggestions?
Much appreciated,
John R.
Cincinnati, OH.





RE: Imaging Through Bullet-proof Media
RE: Imaging Through Bullet-proof Media
Again, Thanks!
RE: Imaging Through Bullet-proof Media
You might also need to look into hard carbon or diamond coatins to minimize chipping and gouging of the window itself.
TTFN
RE: Imaging Through Bullet-proof Media
Jack
Jack M. Kleinfeld, P.E.
Kleinfeld Technical Services, Inc.
Infrared Thermography, Finite Element Analysis, Process Engineering
4011 Hillman Ave
Bronx, NY 10463
718-884-6644
866-884-6644 toll free
212-214-0919 fax and voice mail
JKEngineer@aol.com or JKEngineer@KleinfeldTechnical.com
come see what we can do for you: http://www.KleinfeldTechnical.com
Jack M. Kleinfeld, P.E. Kleinfeld Technical Services, Inc.
Infrared Thermography, Finite Element Analysis, Process Engineering
www.KleinfeldTechnical.com
RE: Imaging Through Bullet-proof Media
What about using some sort of periscope? Suggestions?
Thanks again.
--John R.
RE: Imaging Through Bullet-proof Media
You could try just a single 45º fold mirror to keep the cost down. You might try to find a high polish flat, first-surface mirror to experiment with first
TTFN
RE: Imaging Through Bullet-proof Media
How about using highly polised stainless in place of glass mirror in this periscope apparatus. I have several "stainless" inspection mirrors that are very durable. You could probably make it yourself. I've made belt buckles using ss pipe and tubing then polished them to a "blinding" finish using ordinary jewelers rouge.
Kind regards,
Roy Gariepy
Maintenance and Reliability Dept.
Dorlastan Fibers LLC.
Goose Creek, South Carolina USA
RE: Imaging Through Bullet-proof Media
Not sure, really just throwing out a quick thought.
RE: Imaging Through Bullet-proof Media
RE: Imaging Through Bullet-proof Media
If I can be of further assistance, please feel free to contact me.
John Snell
Snell Infrared
http://www.snellinfrared.com
RE: Imaging Through Bullet-proof Media
I looked into the plastic material available from infraredwindow.com and in fact I have a sample of the material. We are going to experiment with it by inserting(weaving is more accurate) it into a 15 lines/inch mesh grid of kevlar & stainless steel thread. We've done some preliminary tests and it will stop a pellet from a pellet gun 10 feet away.
As for the thermal mirror concept, I must admit that I like this approach better because it places the camera lens out of the direct 'line of fire'. I assume that we could simply use a flat piece of thick aluminum and set it at the appropriate angle to reflect the scene into the camera? However, would it not also deflect any shrapnel directly into the camera lens? What about using two mirrors in periscope fashion? The only drawback to that is that it makes our IP67 rated camera enclosure somewhat larger.
Comments appreciated!
--John R.
RE: Imaging Through Bullet-proof Media
Jack M. Kleinfeld, P.E. Kleinfeld Technical Services, Inc.
Infrared Thermography, Finite Element Analysis, Process Engineering
www.KleinfeldTechnical.com
RE: Imaging Through Bullet-proof Media
Thanks JKEngineer. Often times it helps to have someone like yourself ask the basic common sense questions! Helps me to pull my head out of my .... er, sand!
Cheers,
--John R.
RE: Imaging Through Bullet-proof Media
Jack M. Kleinfeld, P.E. Kleinfeld Technical Services, Inc.
Infrared Thermography, Finite Element Analysis, Process Engineering
www.KleinfeldTechnical.com
RE: Imaging Through Bullet-proof Media
to intercept moving particles while attenuate the IR
only with acceptable amount.
<nbucska@pcperipherals DOT com> subj: eng-tips
RE: Imaging Through Bullet-proof Media
RE: Imaging Through Bullet-proof Media
I like the mirror idea. I'd suggest installing the mirror on a mounting so that if the shrapnel hits the mirror it will definitely flop out of the way. Vwalla. No reflected projectile. Let it hinge on one or two bolts using bellville washers to act as axial springs. Use lock tight on the threads though. We build a camera made for use in splattering areas but I can't mention that on this forum, or can I? Ours is however, only for visible light. Your IR camera (I assume it is sensitive beyond 1200 nanometers i.e. 1.2 microns) won't see through our optics. What wavelength are you using? Are you band limiting the light to the camera in any way?
cameraman1
RE: Imaging Through Bullet-proof Media
also, forget kevlar, it will stop blunt objects but sharp or pointed objects go thru it like a knife thru butter.
RE: Imaging Through Bullet-proof Media
Thank you all for your thoughtful and unique suggestions. I do appreciate it.
Eyec... you are correct, we actually do only look at what goes into the shredder. It just so happens that the best angle to see what goes into the shredder is the one that looks down into the shredder. We have to use IR since the whole shredder feed area is surrounded by steam, especially during the colder months.
Since late September we have been experimenting with a prototype lens protector that consists of a stainless steel mesh screen sandwiched between the expanded metal and the camera enclosure lens opening. It is approx. 10 mesh and actually is a piece cut from the side of a McDonald's french-fry fryer basket. It seems to be working well. The contraption has taken three direct "hits" from shredder shrapnel and has so far successfully protected the lens.
Again, thanks to all.
--J. Ruble
Cincinnati, OH
RE: Imaging Through Bullet-proof Media
I recently worked out a problem for a client dealing with ir measurements of molten steel and determining when the pour goes to a slag state. The imaging equipment was protected from an environment more harsh than the one you describe and is working. You might contact Bill Barron Sr. of Williamson ir. They make environmental housings for their scanners.