Borescope Camera - DIY Hi-Temp Version

[W&KO]

the only off the shelf unit to suit our application is worth $125,000, from memory this one will handle 1500 degrees.

I did find a unit overseas that can handle 300 degrees for a short period of time, 200 degrees for longer time

Problem is I need one to handle 850 degrees for maybe 10sec max.

Sooo DIY it is…….what my chances of success.??

I am aware of a company in the west that uses go-pro’s is a custom made insulated box, they have worked out max time it can be in the environment so they can still read the SD card . The go pro is single use, as it’s destroyed in the process of taking the videos.

I’ll plough ahead to a bore scope……..as we want to see what it’s looking at in real time. I have a few ideas up my sleeve…..

Be interested in members thoughts on how they would approach this build!!!!!

[speleomike]

What do you actually need to look at ?

[BradC]

And how big is the hole?

[W&KO]

What do you actually need to look at ?

We need to check two cross overs in a vertical shaft kiln for build dust which may jab turned into lump.

The next problem will be how do we remove it. Previous designs had air cannons however the manufacturer has moved away from this due to issues the cannon cause.

[W&KO]

And how big is the hole?

The access hole is 232mm x 232mm square x 1000mm deep/long.

The cross overs are maybe 1400 x 800 and arched at the top.

[BradC]

My initial gut idea was something like a conventional borescope inside a stainless tube with a quartz window and some dense insulation like fibreglass between the borescope and the stainless wall. Trying to use the thermal inertia and poor conductivity of the stainless coupled with the insulation to keep the actual borescope cooler.

Kinda like a thick insulating condom.

[W&KO]

My initial gut idea was something like a conventional borescope inside a stainless tube with a quartz window and some dense insulation like fibreglass between the borescope and the stainless wall. Trying to use the thermal inertia and poor conductivity of the stainless coupled with the insulation to keep the actual borescope cooler.

Kinda like a thick insulating condom.

Your thoughts are very much aligned with mine.

I’m thinking off running a thermal couple next to the camera cable so we can monitor temps at the camera

Also considering running ambient air through the pipe….to take heat away.

[BradC]

10 seconds isn't a lot of time, you'd need to make sure the thermal inertia in the thermocouple was small enough to get an accurate reading.

The other thing I thought was using a big enough bit of tube, space the borescope internally with a spider and run a small pipe down the inside to push compressed air into the lens end of the tube to help carry the heat back up the tube.

[workingonit]

Your thoughts are very much aligned with mine.

I’m thinking off running a thermal couple next to the camera cable so we can monitor temps at the camera

Also considering running ambient air through the pipe….to take heat away.

Interesting project. I have a small hobby waste oil furnace, so always interested in furnace stuff.

Sapphire lens higher melt temp. I got several 3 inch dia by 1 inch thick, used, from USA for a few hundred - a nice big window - if you're customising then diamond tooling required (lapidary saw and laps/grinders). Someone will sell something ready made for your size requirements more expense. You melting aluminium? Wonder if there could be a flux effect on sapphire, aluminium oxide? Note I'm not using my sapphire for furnace related matters.

Iced water jacket/coils like convection furnace.

How close have you got to get to the site of interest. Remote port hole with telescopic camera lense set up?

[Ferret]

Was involved years ago with building a borescope that could survive insertion into a blast furnace ~2000C +.

Inconel 600 series alloy tube, think we had a sapphire window, optic fibre and **** loads of water cooling. Worked fine till someone forgot to turn the water cooling on one day.

[speleomike]

And the obvious question .... can the kiln be turned off and hence cooled down for this maintenance?

[W&KO]

And the obvious question .... can the kiln be turned off and hence cooled down for this maintenance?

Well short answer is yes….however we are fully sold across the business therefore customers are at risk..

Taking the kiln down, cooling time, reheat time, on grade time it we would be maybe 2 weeks without production maybe longer. Not call if there isn’t an issue in the crossover…..hence happy to burn a few dollars in designing something for a quick look.

These kilns don’t like full shutdowns even more so when dumping the rock. 10 + years is the target between full shut downs.

[Ferret]

Problem is I need one to handle 850 degrees for maybe 10sec max.

At the temperatures your talking about I'm sure you would get away with an optical fibre down a copper tube with water cooling provided you got the water cooling flow rate right.

Though copper has fairly low melting point it has very high thermal conductivity. Just got to transfer the heat away from it fast enough and it will stay intact. Will last much longer than 10sec too.

Blast furnace tuyeres (the ports through which hot blast is admitted into a blast furnace) are essentially water cooled copper pipes. The blast is ~1200C and the tuyeres protrude into 2000C environments. They last ~3 months provided they only have to cope with radiation. Splash them with molten metal and it's a different story.