how to measure temp in an aggresive environment?

[motomartin]

The machine we manufacture needs a temperature feedback control added to it.
Problem is, the part of the machine i need to measure is rotating in mid-air at 800rpm in a mineral grinding chamber.

I've been racking by brains on this one and decided to try a thermocouple to start with ( but open to any ideas ? )

Any ideas where to start, with highly abrasive,dusty,50g environments and how best to get the signal out, bearing in mind that its an extraodinarily difficult situation to monitor ?

TIA

 

[Skogsgurra]

Is it a surface or the dust cloud you need to measure temperature of? Is the dust cloud there constantly? Do you need continuous measurement or, say, one per minute or so? Can the dust be "blown away" locally for about a second without affecting the process?

Gunnar Englund

http://www.gke.org

 

[djs]

If you don't need very high accuracy, try IR temperature sensing. Non-contact, remote sensing. Just need a clear line of sight to the object you are monitoring.

 

[motomartin]

Can't do IR - cos of the dust / mineral / media cloud.

However, its the 'process' of the grinding i need to measure the temp of - actually in the chamber. Can't do it at entry or exits either.

Been looking at Dwyer stuff - but nothing seems suitable yet.

 

[Skogsgurra]

That's why I asked about measuring the dust cloud or blowing it away to measure the substance or mechanical parts. What is the structure of the stuff? Is it a dust, slurry, dough or what?

Gunnar Englund

http://www.gke.org

 

[controlnovice]

How about wireless?

I know there are many level transmitters that are now wireless, but not sure about temperature. It's not normally something I would do if I'm using the signal for control - I'd only use it for indication, but it's a possibility.

The temperature element could be placed inside wherever you like. The housing could be built to handle the environment. The receiver could be located outside of the environment.

Another downside would be changing the batteries every so often. So if this is a continuous process, forget about it.

 

[ilan7]

We do use standard (comertial) wireless system to measure the temperature insibe the rotating part of a generator.
The system it rotating in 1,500 rpm with the generator rotor and transmite the temperature (4 channels) to an outside reader.
If soung interesting, please write and I will look for and send the full details. System quite expensive.
Leave a note here or at: iarie@yahoo.com

 

[IRstuff]

I think that you'll find that the "dust" is less of a problem than you think, particularly for a long wavelength infrared pyrometer operating in the 8-12 micrometer regime.

TTFN

 

[ScottyUK]

Hi ilan7,

Does your system - or can it be configured to - detect ground faults on the rotor between the rotor bars and the rotor forging? We have a lot of troubles with our existing GF monitor system: power supply conditions aren't great, shaft speed is 3000rpm, lots of heavy current, high voltage etc. Sounds like you might have addressed some of this already.


----------------------------------

One day my ship will come in.
But with my luck, I'll be at the airport!

 

[Rheinhardt]

Hi Motomartin

I notice you havent given a temperature range indication.

Here is a link with with usefull wireless temperature technology.

http://www.security-and-alarms-1st.com/temperature-alarm/wireless-temperature-monitoring.htm

And a nice one operated with batteries and updates every 10s not bad for monitoring. Batteries last about 2 years they say pending on your pulse delay

http://www.generalcommunications.com/wireless_sensors/sensor_temperature.htm

Hope it helps

Rheinhardt



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