PID

D

DCbrumley

Joined
Aug 16, 2017
Messages
2
I know this topic comes up numerous times, but this is my first post, and I am fairly new to knifemaking, and I have a question related to setting up a pid on my forge.
My forge is two burner, venturi forge, I worked for an electrician helping him build a room in his shop, and he gave me the forge. First I have the funds to buy a forge, but I would prefer not to do that, second I do not have the welding skills required to make a forge if I did I would make a blown forge.
Now I went through the stickies and did find plans on setting up a pid for a forge, but it was for a blown forge (Nicks plans). If I were to set up a pid on my forge would I simply hook up the pid, and SSR to a solenoid, and thermocouple drill a hole in the forge, put the sheath in a wrap with kai wool, and pop the thermocouple in there, and get powers source?
Anything I am leaving out, missing. I know I am thinking of this in a very, very simple way.
I have not created any schematics or anything, just been trying to gather as much info as possible before I start formulating a plan.
Anyways thanks for the info, and replies, this place has been an enormous asset for me.
 
for a venturi forge, just get a good thermocouple and display and a piece of 4" steel pipe or square tube. cut the pipe so it is as long as the forge, it will act as a muffle and help keep temperature constant. place the end of the thermocouple in the middle of the muffle. it will take a little trial and error, but you can manually adjust air and gas flow so the indicated temperature stays +/- 25F. with most low alloy high carbon steels(1084,1095,80CrV2, O1, 52100), the blades are in the heat for 10 minutes or less. yes, you need to constantly monitor time and temperature, but you would need to do that with a PID controlled electric one because the time inside is so short.
 
The PID plans are mine. They have been redrawn by several folks. The PID sticky has lots of info on them. Yes, you can run the system on a venturi and eliminate all the parts that apply to the blower.

The issue with running simple PID control circuit on a venturi is that it is an OFF/ON system. There is a good size Whoooof when it re-ignites. Not a problem, but unnerving to some folks. The two stage PID system I developed eliminates that. The issue becomes that the low and high are not balanced as well on a venturi as they are with a blown forge. Again, it works, but just a bit less perfectly. Since you have the forge, add the two stage PID control and adjust each stage to get a Hi/LOW that works with your burners.

As pointed out, a muffle pipe is a good idea when doing HT.
 
You must log in or register to reply here.
Back
Top