Need to measure up to 1200 degrees F - help

In summary, the conversation discusses different options for measuring temperatures up to 1200 degrees F, specifically in the context of building a kiln for annealing glass. While the original poster suggests using a rod and trial and error method, it is suggested to use a thermocouple and a temperature control module for more accurate and controlled measurements. The conversation also mentions the importance of selecting the correct type of thermocouple and ensuring that the heater control contacts are properly sized. The original poster also shares their success in finding an analog pyrometer at a low cost and plans to invest in a temperature controller when building a larger kiln in the future.
  • #1
jgravatt
Does anyone have any thoughts about how I could measure temperatures up to 1200 degrees F? I could buy a pyrometer or piece one together with a thermocouple and multimeter, but just wondering if there is an easier way to do it.

Thanks,
Jeremy
 
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  • #2
At 1200F it is probably easiest to use a thermocouple. What is the application?

http://www.omega.com/toc_asp/subsectionSC.asp?subsection=A01&book=Temperature
 
  • #3
I built a kiln to anneal glass, but I need an accurate way to measure temperature so I can set up a firing schedule. I suppose I could use a small 3 mil rod and if it slumps then the box is too hot, but that takes a lot of trial and error.

Jeremy
 
  • #4
Originally posted by jgravatt
I built a kiln to anneal glass, but I need an accurate way to measure temperature so I can set up a firing schedule. I suppose I could use a small 3 mil rod and if it slumps then the box is too hot, but that takes a lot of trial and error.

Jeremy

Usually, kiln applications do use thermocouples. The page linked shows some options in your temp range. Also, you can buy temperature control modules very cheaply now. They can read the thermocouple directly [no amplification] and they also provide discrete contact outputs for simple on/off control. They can also provide one or several temperature zones and ramp schedules [allowing for a controlled ramping up or down of the temperature as is also often required]. Omega [linked] or nearly any industrial electrical supply house sells these controllers. You should be able to purchase one for about $60 - $80.
 
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  • #5
Two additional notes: If you buy a controller make sure that it is compatible with the thermocouple type selected [most likely type J, K, or E in your case]. Nearly any controller accepts types J and K, but any other selection could create a compatibility problem with some low cost controllers.

Next, you need to be careful about the contact rating for an inductive load like this. I assume that your heater draws about 15 amps at 110 or 220VAC. This could exceed the standard contact rating of 10-15 amps for purely RESISITIVE loads. You need to oversize your heater control contacts by at least 50 - 100%. You can also buy relays with magnets inserted that act to quench the back EMF discharge; thus protecting the contacts from damage. [Edit: strike that comment. True but not really applicable here]. The kiln may also have an intervening contactor that makes this a moot point.
 
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  • #6
Thanks for everything. I fould an old analog pyrometer with a type k thermocouple on an auction for $12. Hopefully it will work, anyway it will be worth the risk of $12. As for the controller, I won't get one until I build a larger kiln - probably within the year as my current kiln works fine. Thanks.

Jeremy
 

1. How do I measure temperatures up to 1200 degrees F?

To measure temperatures up to 1200 degrees F, you will need a specialized thermometer or pyrometer that is designed for high-temperature measurements. These instruments use different types of sensors, such as thermocouples or infrared technology, to accurately measure high temperatures.

2. Can any regular thermometer measure up to 1200 degrees F?

No, regular thermometers are not designed to measure such high temperatures and may not provide accurate readings. It is essential to use a thermometer or pyrometer specifically designed for high-temperature measurements to ensure accurate results.

3. What are the risks of measuring temperatures at such high levels?

Measuring temperatures at 1200 degrees F can be hazardous, as it involves working with very hot objects or environments. It is essential to take proper precautions and use protective gear, such as heat-resistant gloves and goggles, to avoid burns or other injuries.

4. How do I calibrate my high-temperature thermometer?

To ensure accurate measurements, it is crucial to calibrate your high-temperature thermometer regularly. This can be done by comparing the readings with a known reference temperature, such as an ice bath for lower temperatures or a standard melting point for higher temperatures. If needed, the thermometer can be adjusted accordingly.

5. Are there any factors that can affect the accuracy of high-temperature measurements?

Yes, several factors can affect the accuracy of high-temperature measurements, such as the distance between the thermometer and the object being measured, the emissivity of the object's surface, and any external factors, like drafts or air currents. It is essential to follow the manufacturer's instructions and consider these factors to obtain precise results.

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