Hi,

We need to install an instrument inside our gas fired curing ovens that will continuously measure and transmit its internal temperatures. I am looking for a complete data system with an enclosure containing up to 5 wireless K thermocouples that can resist temperatures of 600 deg F continuous and excursions of up to 1500 degrees F. (there might be a short fire of duration up to 15 minutes in length. The enclosure specs could be similar to the box used in an aircraft flight data recorder. However, the antenna would have to protrude I guess and be high temperature survivable.

Thus, what I would like to put into this enclosure is a wireless temperature transmitter that will take the output of up to 5 conventional thermocouples and send this to a base station for real time data analysis. The challenge seems to be the high temperatures since we have found a system that transmits well but is incapable of handling the temperatures.

Does anyone know of such an enclosure and could it work as I hope? If you have a complete system with the thermocouple transmitter, etc. that would be even better.

Thanks,
Glassy
Guardian Fiberglass

 

Hello Glassy

I do not know of anything that will do what you
want. However I know they make retractable thermowells. These are used quite a lot in sulfur recovery furnaces in refineries. Another method is to install windows into the side of your oven and use an infared unit to monitor temps. I have use them before in high heat applications and they work quite well.

Sometimes your process is quite dirty and your windows will get dirty. You can overcome this by introducing a slight purge air into the window port. Most window glass has high melt tolerance.

The above system would be out of furnance and gives you easy access for maintenance and none of the fuss of the high heat issues.

Hope this helps
Mark

 

Have you considered using infrared devices to meassure temperature.

At a glass company we were able to withstand over 1100ºC continuosly, but for certain areas in the middle of a 160tn/day oven of molten glass four feet deep, there was the need to determine surface temperature. We did so with infrared devices that scanned the surface.

If you need help, please email me

[email protected]

 

Just put your TC's in the oven where you want them, run them out through a suitable port and then to your device. Your going to spend endless engineering manhours finding an enclosure and antenna to meet these needs. In fact I don't know many enclosure which will withstand the 600 to 1500 Deg temps you mentioned and for the cost involved, you can put in the TC's, wire it up, have it on the air (so to say) in one day.

Good luck - do the simple cost effective solution and go home and have a beer and call it a day!

M Hyatt
Techncial Consultants
[email protected]

 

Hello Glassy
No electronic devices will survive the temperatures you are talking about. The highest working temperature is in the order of 180°F. A wireless device like the one you describe would need to be powered by batteries. No battery could survive the high temperatures.
Perhaps you were thinking that your enclosure could have some special insulation so it could keep cool on the inside. The problem then is that the thermocouples would condust heat into the enclosure causing the contents to fry.

The standard solution to your problem is not wireless. You will need to use long ceramic sheathed thermocouples that extend through the refractory wall of your oven. This type of thermocouple is readily available from thermocouple manufacturers. The thermocouple will have a connection head than needs to be sufficiently far away from the outside wall so that it stays relatively cool (say, less than 200°F). Your thermcouple extension cables (also called compensating cabel) connect to these head and run back to your instrument panel which is hopefully in a cool clean area with no noxious fumes.

An alternative to the above arrangement is to use infrared devices mounted outside your oven. You would need large access holes in the oven wall for the infrared devices to look through.

Regards
Jamie Downs
[email protected]

 

I have seen similar things done in ovens using an insulated box with a data logging device inside. no reason you could not add a wireless ethernet systm inside the box.

Bob Peterson

 

Howdy,

I think the infrared device would need a water-cooled jacket for protection from the heat. And be sure to consider distance-to- spot size ratio and field of view.

Take care,
Fred Chwalek

 

Hi,

The wireless sytem you found might be the one to meet our applications. We need the sensor operating in a range between -50 and +200 degrees Celsius near the high voltage transmission lines. Is it possible you can provide more detailed information about the system you have found?

Thanks and best wishes,
Ponlee
MPI
[email protected]

 

The solution is possible.

What is the time duration??????? If possible pl give the temp-time profile as expected.

Jkapoor

[email protected]

 

Hi,
You may want to check out two offerings from Nomadics, Inc. First the TCProfile Six Channel Temperature Datalogger. It is a PCMCIA card and interfaces with a laptop/palmtop. If the computer is networked, data can be made available to anyone on the network.
Also, http://www.vigilink.net offers an industrial maintneance/montoring system that provides collection/aggreation and wireless transmission over 2 miles LOS.

If you have questions, please email me.

Thanks,
Rick Cope

 

Are you saying the hot glass will not effect the IR temperature reading - at all? What IR device have you used successfully, and are you able to detect temperatures to +/- a few degrees C?

Thanks. Dave