Electronic Gas Control Servo

jlm · September 10, 2015, 11:11am

Hello,
Thank you for accepting me on this Forum. I am setting up a Stuart boiler for my stationary steam engine. It features a ceramic burner that is gas fired. An electronic valve was bought to monitor the operating temperature in the steam vessel, but requires a servo control with a lever attached to move the valve approximately 90 degrees. I have no idea what I should be buying on this site to accomplish this task.

Advice?

Cheers…John

bdaouas · September 10, 2015, 2:17pm

Hi,

Thank you for posting on RobotShop’s forum.

How the electronic valve is mounted currently ?
Could you provide us some clear pictures showing your current setup ? and the position of the valve ?

Regards,

jlm · September 10, 2015, 9:26pm

Thank you for your prompt reply. Here are two pictures of the diagram set-up and some info on assembly. I do not understand how the valve lever could move 10 to 20 degrees more than the servo arm if they are linked. Wouldn’t the movement be the same since they are permanently linked?
John

bdaouas · September 11, 2015, 3:05pm

Hi John,

From what we understand, initially and before bending the end of the pull rod to link the servo arm and valve lever permanently, you have to setup the servo arm and the valve lever in a way that the valve lever is positioned at 10° to 20° from the vertical position of the servo arm.
In other words your final setup should be like this :
The servo will have two positions, in his first position the lever position should close the valve. In the second position of the servo, the position of the lever should open the valve. Then, you need to bend/configure the pull rod accordingly.
For the servo, you can probably use a standard RC Servo. Like for example this HS-645MG Servo Motor or this HS-755HB Giant Scale Servo Motor. However, to be one hundred percent sure when choosing the servo, you might want to calculate the force required to move the lever and choose a servo that will provide enough torque for it.
From what we see in the diagram, you can probably mount the servo using one of these Lynxmotion Aluminum Servo Bracket.
Finally, for a nicer and more professional finish, you could probably replace the pull rod by this Lynxmotion Ball Link with this Lynxmotion Threaded Rod.
One Ball link will be attached to the Servo arm and another to the valve lever linked by the Threaded Rod between two ball sockets. Whenever you want to change the valve lever position, you can just remove one Ball link by removing its nut.
We hope this helps.

Best Regards,

jlm · September 11, 2015, 5:59pm

Hello Brahim,Thank you so much for your detailed response to my inquiry about controlling the gas valve on my Stuart boiler. Apparently, the pressure, not the temperature of the boiler is monitored by an electronic module (see attachment). When pressure of say 60 lbs. is achieved, the gas valve closes and goes to pilot light mode. I didn’t know that a servo motor was required when I set up the design in the model boiler room. Things are going to be tight. The servo motor may look as large as the gas tank (propane/butane mixture).

I deeply appreciate your assistance here.

Cheers…John

AGFNicole · June 13, 2019, 10:07am

Hi John,
Is the project still on going ?
We are servo manufacturer, we would like to solve the solution with you. thank you