High frequency temperature recorder

[Speedy]

I am looking to source a high frequency temerature recorder. It would need to scan at least 5 times per second. So far I have only sourced one that will do one scan per second.

Any ideas?

I picked this forum as I reckon this would be a requirement for measuring temps in an internal combustion chamber.

Speedy.

 

[IRstuff]

Depends on your application, e.g., temperature range, etc.

If you take a thermistor or RTD, you can certainly run that into a 16-bit A/D with 10-100 times the data range you are asking for.

TTFN

 

[Speedy]

It is connected to a K-type thermocouple. Temperature is from room to, I suspect, 400c max.

I have found some software at

http://www.picotech.com

which may do the trick. I'm gettign clarification on this at the moment.

Cheers,
Speedy

 

[zeusfaber]

Have you managed to find a thermocouple with a low enough thermal inertia to make it worth your while logging the temperature at its junction five times a second?

A.

 

[Speedy]

Zeusfaber,
Good point. I was thinking that myself also.
There is also a nice bit of metal in the retainer, which the tip of the probe sits into. All this protection is required for the high temps amd pressure of the explosion.

I was told that it would need to be a least 5 per second. I want to use the same thermocouple on the m/c as I want to see what it is measuring.

Speedy

 

[NickE]

Go Old Scool. Setup a true cold junction or similar electronically. Then get an old true analog chart recorder. Taking a continuous signal on a time base you might be able to resynchronize the recoded signal with the cumbustion chamber events.

If you need to perform math upon the resulting signal there may be a way to make it simulate an audio signal. Then any computer can record it and I think a matlab code could be written to analyze it.

(good luck, this is similar to what I'm going to attempt to do to the signal off of a CCD laser displacement sensor. I'm not sure it will work.)

nick

 

[Timelord]

Speedy,

I had a similar situation once. The only couple we found that responded fast enough (low thermal mass) was a platinum type S couple that was made out of hair fine wire. It was a B#t*h to weld the couple. We had to buy a micro actylene torch and let our welder practice a bit. We let the couple hang out of the insulating tube about 1/8-1/4 to prevent the tube from adding thermal mass. I don't remember our exact sampling rate, but it was fast enough for our application which was measuring a high power laser pulse interaction with a target.

Timelord

 

[btrueblood]

You can get fine wire t/c's in type K too. With a bead size less than 0.05" they have thermal response of better than 1000 deg. F per second, depending on the type of flow past them (heat transfer rate). We used to form the beads using a home-made capacitor-discharge welder.