Pyrometer

The really nice thing about the analog pyrometer is you dont need a power source for it to work. A lot of gas forges are being built with atmospheric burners and its nice to put the whole thing on a cart and be able to roll it outside or take it with you and use it where no power is available.
 
Thanks for the info JCaswell. I just purchased one of their temp. controllers. I have a pretty good oven that I made but it only has an on/off switch with a temp. display. Up to now I've been controlling heat and soak with the on/off switch. If I can figure out how to wire in this new temp. controller it will be a huge improvement.
 
If it is an electric oven you have the controller operate a solenoid switch or relay to turn the oven on and off. If you hook the controller up to a gas forge, you install an electric solenoid valve in the gas line and operate it from the controller. It will turn the forge on and off to maintain temperature +/-10-15F.
Stacy
 
Stacy, I'd put a needle valve in parallel with the solenoid valve to go from high to low flame, instead of completely shutting off the gas.
You want some flow of gas through the burner into the forge at all times, else you get a chimney effect where the hot gases go back out through your burner.
If you do shut off the gas on a forge, you need to also shut of the air path out into the burner.
 
Thanks Howie.
I should have explained that the simple setup I gave was for an atmospheric forge. On a blown forge it is necessary to have a small flame going. A bypass needle valve does this. The air gate may also need adjusting to keep the flame right at the desired temp.
Stacy
 
I have a bunch of heat treading "blankets" from the heat treaters that heat treat our high crome pipe welds and some other sever service welds. They are composed of pink ceramic tiles about a inch by an inch and a half and a quarter thick. They have 2 holes in each and they are strung togeather on high nickel resistance wire. to form a flexable blanket. They usually run on about 40 volts so if I place 3 of them in series I will have the correct drop for a 110v circuit theat wi ll draw less than 30 amps. I plan to wrap them arond a piece of 4" piece of heavy walled stainless and insulate with kaowool and use it as a high temp salt ht. I can get all the piecies at work as we go thru lots of stainless. Its amazing what people will help you with when you show them a nice damascus knife and tell them about how it is made.
 
bladsmth said:
Thanks Howie.
I should have explained that the simple setup I gave was for an atmospheric forge. On a blown forge it is necessary to have a small flame going. A bypass needle valve does this. The air gate may also need adjusting to keep the flame right at the desired temp.
Stacy
Click to expand...

:confused:
I don't run a controller on my forge, but I do have a few blown salt pots with controllers (essentially modified, upright forges). I have found no need for a needle-valve arrangement as described on the high-temp units (the heat in the unit ignites the gas when it comes back on easily and smoothly enough.) I do have a needle valve as described on a long 'low-temp' vertical and a 'low-temp' horizontal unit because you need a pilot light for re-ignition.
Unless I'm missing something I don't see how I can be getting a chimeney effect back through the burner since the blower is always on. :confused:

If everything in the shop worked as trouble-free as the salt pots, I'd be happy. :)
 
Joe, I mentioned the chimney effect primarily for those using venturi burners.
In a blower burner that always has the air running, all you have to worry about is re-ignition, so the bypass keeps the flame on.
Re-igniting a venturi burner using the forge heat isn't really a great idea either, as you might have a flash when the gas gets turned from full off to full on. Better to have it idling, too.
 
thanks for the help guys. i was outbid on that kiln pyrometer. the bid was more than i was going to spend. im kinda glad tho because if i had won the bid i was going to have to buy it and i wouldnt have been able to get some of the stuff i did today.
 
howiesatwork said:
Joe, I mentioned the chimney effect primarily for those using venturi burners.
In a blower burner that always has the air running, all you have to worry about is re-ignition, so the bypass keeps the flame on.
Re-igniting a venturi burner using the forge heat isn't really a great idea either, as you might have a flash when the gas gets turned from full off to full on. Better to have it idling, too.
Click to expand...

Hmmm,
Perhaps a forge application would benefit from an idling circuit (I wouldn't run a controller on a forge for reasons expressed earier), but on the 'ol blown blown salt pots, I've never had trouble going from full off to full on. Any given afternoon, one might cycle several hundred times and never fail to reignite smoothly. :o
 
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