I’m thinking about building some automation with my coffee roaster: http://www.thepeoplesroast.com/huky/. One of the key parts of this would be automatically controlling the gas flow (propane)…after some Googling I can’t figure out how to best go about mechanically controlling the gas valve.
The burner I have is simply an outdoor burner, roughly equivalent to a single burner on your stove top. It’s controlled by a single circular valve which I can only assume is a needle valve on the inside.
What should I look for to either:
connect a stepper motor to the existing valve
replace the existing valve and connect with something else which has a stepper motor integrated
If you just need to turn the gas on and off, without the need to regulate the flow, look for a solenoid valve. If you need a motorized valve (more likely to be a ball valve), I would image that to be quite expensive, as it needs to be pretty well built to be gas tight. I’d be weary to couple a stepper to the existing valve, as these things can exert pretty high torque and if something goes wrong, might rip your valve apart…
I’ll actually need to regular the gas flow…the automation will be controlling the heating rate via flame regulation, so I need a needle valve for that. I have found a few natural gas valves with stepper motors for the fireplace industry, but it seems like there isn’t anything standard for propane valves.
Here’s a crazy idea - no clue, if that has been done before or if it makes sense for your application - but what if you used a solenoid valve and operated it in a pulse-width-mode sort of fashion? So, you simply turn it on and off in quick succession and the rate (or pulse width) at which you do that, determines how much it heats.
I think the problem there would be that the flame would go out when the solenoid valve turned off. I’m not super familiar with solenoids but if my basic understanding is correct they’re boolean, in that the propane would be on or off, right?