Temperature Control

Google "kiln controllers". There are lots of them out there.

You have not specified the required temperature range of furnace to decide the type of thermocouple required.Because it is tempering furnace your requirement may be between 400°C - 900° C . Chromel Alumel ( Ni Cr - Ni ) thermo couple will be good enough and any good make of Pyrometer ( Temperature controller) available in the market calibrated to this thermocouple will suit your purpose. check this link.

http://www.eurotherm.com/products/custom/

the water heater elements will probably burn up in free air, use a electric range temperature control their are inexpense Perry

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Perry You are right those heating elements cannot be used in free air .He has to use suitable heating elements that are designed to work in free atmosphere. He can better depend on oven heaters not water heaters. If the requirement is proper tempering job then uniform and correct temperature is required in the furnace otherwise tempering will not be proper and the very purpose of tempering in furnace will be lost.

Dear Abstract02,

For a start buy an in-expensive controller which can take thermocouple inputs and out-puts a signal through a triac to control the current through the Electric Heater, if the system runs sucessfully, then keep one extra controller for standby or then buy one of the renowned makes available in your city.

Best Regards,

Naseem Aziz

Be sure to use a temperature controller that has been certified for electrical safety as well as reliability. For example, the Listed controller would come with a manual which states if it has been tested for reliability, and can be traced to it's Certification lab, etc.

Software or PLC controls are, to date, not considered to be reliable for safety / temperature control.

Check out a Cal 3000 or Omron they make several. All so as some one else stated the water heater element will burn out in free air.

Go to ebay and search for temp. controller. There is a guy that sells cheap digital controllers with k type thermo probes for around 50 bucks. I build glass furnace, annealers and heat treat ovens when the pipe fitting work slows down and have had good service from these controllers. there are also usually alot of name brand controllers on e-bay as well. I have bought some of these for as little as 10.00 in the past.

pipewelder

please get name or web sit for controlers

There are much better methods of building a kiln. Think turbine.

It sounds like you are describing a heat treating furnace. They are not the same.

www.budgetcastingsupply.com

Look up heating controllers.