OT: Non-contact temperature measurement of chrome

[kamenges]

We have a customer asking us to measure the temperature of a moving chrome covered roll that is near room temperature. We aren't allowed to paint any surface of the roll or alter the surface in any way. The heating on the roll will occur over a fairly small cross-machine strip of the roll face but that location can be changed by the operator at will.

We are looking into various IR solutions but so far nothing looks promising. If anyone has any thoughts on good suppliers feel free to suggest. But this is likely kind of cost sensitive so if the cost ends up over $1000 that may be an issue.

One other thought we had was to make a low volume void in a block of Delryn and install a thermocouple so the head protrudes into the void. We would then mount the block close to the roll surface (0.005"-0.01" gap or so) and let the thermocouple/void heat up by radiation. Does that seem like something that would work?

Keith

 

[TheWaterboy]

Can you get to the inside of the roll and mount something in there with a brush or even RF connection?

 

[JeffKiper]

Have you looked at Ircon infrared?

 

[TheWaterboy]

Just had an Epiphany. Mirrored surfaces are a problem for IR not because of emmissivity which can be adjusted for, but because of reflection. If it could be completely enclosed in dark I wonder if that would make a difference.

 

[I_Automation]

A customer of mine has a hot roll laminator with a hard rubber surface coating over a steel roller with a heating rod inside..


They have a thermocouple on a (probably 14 gge) stainless steel plate that rides on the surface of the roll with some tension for good contact. The thermocouple itself does not contact the roll, but is very close to it and reads the temperature of the stainless plate. The temperature controller is calibrated to read the roll actual temperature and it is reliable.



The machine is over 15 years old and the rollers don't need replaced because the thermocouple plate wore into them, so a chrome roller should last.

 

[kamenges]

JeffKiper, no I haven't but I will take a look at what they have.

TheWaterboy, you are correct about the reflections, especially when trying to detect a temperature so close to ambient. I will have to see what is out there for short focal length sensors. The other concern I guess I have would be if the shielding takes on then radiates ambient temperature. Will that pollute my readings.

I_Automation, someone has been dragging a piece of steel along another piece of steel for 15 years without causing any wear? That is truly impressive. I could get another 300,000 miles out of my Saturn if GM would have gotten that one figured out. Didn't the friction of this throw the reading off or was the temperature high enough that frictional heating didn't matter?

Thanks guys.
Keith

 

[nehpets]

I've used these in the past.
https://www.ifm.com/na/en/product/TW2100?tab=documents


Steve

 

[I_Automation]

I_Automation, someone has been dragging a piece of steel along another piece of steel for 15 years without causing any wear? That is truly impressive.

Mo. Steel on hard rubber. The rolls don't need replaced because of the steel rubbing on it - they get replaced about once a year for other reasons. (cuts, pitting, separation, etc)

 

[danw]

We have a customer asking us to measure the temperature of a moving chrome covered roll that is near room temperature.

I'm curious.

a) rough dimensions of the roll. 1" diameter? 20" diameter? 10 feet long?

b) What does 'moving' mean?
0.1 RPM?
1 RPM?
10 RPM?
100 RPM?
1000 RPM?

C)

The heating on the roll will occur over a fairly small cross-machine strip of the roll face

I'm not sure what 'cross-machine strip' means.

Is the intent to see a hot or cold spot along the circumference of the roll, so as it rotates it is cold, cold, cold, warmer, warmer, warmest, less warm, less warm, cold, cold, cold?

Or to see a change in temperature along the length of the roll?

 

[kamenges]

Originally posted by danw:

Originally Posted by meninges

Gotta love auto-complete.

It is a 12" diameter roll running at roughly 220 RPM (700 FPM). The roll is 12" wide but only a 1" "lane" of the roll is used at any given time. This "lane" could be anywhere across the width of the roll, however, meaning whatever we select we need to be able to position in the cross-machine direction. This lane is where the material work is being done and where the heating will occur. It will be where the temperature is at its highest. We are fairly confident that the temperature of the lane will end up fairly uniform around the circumference of the roll.

Keith