Pneumatic actuator system considerations
Pneumatic actuator system considerations
(OP)
I am fairly new to pneumatic systems so bear with me here. I have designed a system to use an actuator to move different joint arms. I was considering using a single-action cylinder with a ball valve and regulator to activate the cylinder on and off. Since it is only single acting, would I need to provide a release valve in order for the cylinder to go back to its resting position? Or would it be more feasible to use a double-acting cylinder instead?





RE: Pneumatic actuator system considerations
David Simpson, PE
MuleShoe Engineering
"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
RE: Pneumatic actuator system considerations
RE: Pneumatic actuator system considerations
David Simpson, PE
MuleShoe Engineering
"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
RE: Pneumatic actuator system considerations
You could use a vented ball valve it would seem.
RE: Pneumatic actuator system considerations
See page 4
http://www.omega.com/auto/pdf/SimpValvesguide.pdf
RE: Pneumatic actuator system considerations
David Simpson, PE
MuleShoe Engineering
"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
RE: Pneumatic actuator system considerations
RE: Pneumatic actuator system considerations
If the arms have articulated joints, good luck. It will be very difficult to move the arms without oscillations unless the mass is very low.
Peter Nachtwey
Delta Computer Systems
http://www.deltamotion.com
RE: Pneumatic actuator system considerations
RE: Pneumatic actuator system considerations
And understand this VERY important fact - you control the speed of a pneumatic cylinder by restricting the flow of the air OUT of the cylinder, not IN. That way you always have the whole cylinder under the higher pressure. I have seen SO MANY technicians try to control the speed of a cylinder by installing a pressure regulator on the feed. That doesn't control the speed. It controls the pressure. Size the pressure regulator to achieve the force you need when stopped. Adjust the flow controls to achieve the speed needed during travel.
RE: Pneumatic actuator system considerations
First point - my experience has taught me to use single acting cylinders only when I must, not just when I can, for several reasons. There are really no financial or space savings. Single acting cylinders have to be larger than double acting cylinders of the same stroke to accomodate the internal spring. The cost difference between a 3-way control valve and a 4-way valve is insignificant, or sometimes non-existent. I promise you, the end result of your project will be more satisfying with double acting cylinders and 4- or 5-way valves.
Second point - I mentioned installing flow control valves above. Maybe I should clarify that. Needle valves restrict flow in both directions and are not appropriate for this purpose. Flow Control valves have internal checks valves that allow full flow in one direction and restrict the flow in the other direction. That's why they are ideal for use on pneumatic cylinders. They allow the motive force powering the piston to be at full line pressure. They work best when installed directly in the ports of the cylinder.