Proportional flow valves
Proportional flow valves
(OP)
Hi, I was wondering how do i convert one of those solenoid pneumatic 2/2 control valves to a proportional flow pneumatic valve. I was hoping to use a range of 0-5V to determine the flow rate of the valve. I understand that there might be some electronics involved. So far what i have learned is that i use a Pulse width modulated driver and feed in the voltage into it to determine the duty cycle.
The varying duty cycle should determine how much the valve moves in or out. I am not too sure about whether this concept would work.
Can anyone help me with this?
Thanks
The varying duty cycle should determine how much the valve moves in or out. I am not too sure about whether this concept would work.
Can anyone help me with this?
Thanks





RE: Proportional flow valves
1) Does the 2/2 refer to a two-way two-postion valve, -actually it may be 3-position?
2) How would your pulse width modulation determine duty cycle with voltage being fed in?
3) Are you trying to turn this valve fully off-on and to proportionally control it via the counts on-off? A counter with a feed-back loop using a PLC might be an idea.
Please explain.
ttracewicz@atsspartec.on.ca
RE: Proportional flow valves
2) Burr Brown is giving out demo boards of their PWM driver for solenoids/motor. I've got one of them right now. Basically they enable the duty cycle to be tied to a varying voltage. the input signal should have a range between 0-5V, other ranges can be done with additional components. sorry if i was not clear on this
3) I'm trying to see if it is possible to open the valve in steps, like quarter, half, 3 quarters and then full, closing it repeatedly many times would not be an option if the valve is rather big . Flow would hopefully be in steps also.
I learned that some companies use a PWM signal to control their proportional valves also. Sometimes there is also a feedback loop tied to the circuitry to ensure linearity but on the cheaper models, i think linearity is from selection of the return spring in the solenoid valve.
I was wondering if there had been any success in converting normal 2/2NC valves as proportional valves still cost a bit more.
I did ask one company whether its possible. I think it was Alcon valves in the UK and they said it was not. I checked the ASCO Posiflow valve catalog and saw that some of the internal components were modified for proportional valves. But the overall design was basically the same. Thats why I was wondering if was possible to do so
Thanks
RE: Proportional flow valves
RE: Proportional flow valves
Thanks again
RE: Proportional flow valves
RE: Proportional flow valves
Got to http://www.fpweb.com and look at the Designers Guide under Valves Directional control to see the manufacturers that listProportional valves.
Also you can look up the company address and phone number in another section.
Regards:
Bud Trinkel
http://www.evansville.net/~fluidpwr
Bud Trinkel
fluidpwr@evansville.net
Fluid Power Solutions
33+ years experience in hydraulic and pneumatic circut design, troubleshooting and training.