Pressure control valve

[wjbzone]

I use a analog/digital IO board (DT9802 from datx.com) connected to my computer (DT Measure Foundry software) to measure flow rate and switch relays.

I want to use a couple of channels on this board to control pressure in a supply line. (setpoint / feedback loop)

I am looking at using a air actuated control valve like this one:

http://www.badgermeter.com/pdf/valves/941570.pdf

Is this type of valve a good selection and if so, what hardware is typically used to control the air pressure to this valve?
(any suggestions welcome)
Bill

Now I r 1

 

[CMfgE1]

Badger is a good quality valve. You will need an I/P (current to pressure convertor) and a point on your IO board.
The valve I/P will get its signal from the programmed pressure.
The computer will send a 4-20ma signal to the I/P which will put out a 3-15psi signal to the valve. You will need and air supply of 20 psig for the I/P (inlet supply). Connect the outlet of the I/P to the inlet of the valve and your done. Now connect the analog out of the IO board to the I/P. If you would like more info on the control loop. feel free to ask in this post.

I looked at the specs of that system and it looks like you have 2 analog outputs. As long as one of them is free you should be all set. You will need a pressure transmitter to monitor the pressure you want to control ( I assume you know this already) As far as the programming, I have never worked with this setup (data translation) or software.

ABB (

http://www.abb.com/global/abbzh/abb...=us&m=9F2&c=26DBE8EACADEB6BEC1256D3700451553)

and Bellofram (

http://www.marshbellofram.com/belfram/products/electro/type1000.htm)

are 2 good suppliers of I/P.

Good Luck!!!







Quote: "Its not what you know, its who you know"
Everythings a learning experience-Everything

 

[wjbzone]

Thanks CMfgE1

That I/P was what I was looking for. At least to get me further along.

My IO board has 2 analog outputs. Both free. My pressure transmitter will be located downstream from the valve. I will need to see what this software can do to setup a control loop. Some kind of PID system I hope.

I plan to use the other analog output for temperature control.

Bill



Now I r 1

 

[ilan7]

Actually in order to install a pressure control loop you do not need any controller any more. You can buy the pressure transmitter with a controller option (if you buy from SMAR (

http://WWW.Smar.com)

this feature is a standard in most pressure transmitters) or you can buy the I/P + Positioner with the same option (from Smar, Simense, ABB and others).

 

[rmw]

Unless you already have pneumatic instrumentation in the plant, and a dedicated instrument air system (remembering my motto that "clean dry instrument air" is an oxymoron) I would use an electrically operated valve.

Regular plant air is not suitable for instrument service due to grime, moisture and oil, to name the most serious culprits.

ABB has already been mentioned and another good source for electric valve actuators is

http://www.jordancontrols.com/

This type actuator will accept an analog control signal, and can usually send you an analog feedback signal (in addition to the one it uses for its own brain.)

You would need to select the right valve for your application, and they can custom adapt it to your valve.

rmw

 

[jsummerfield]

Lots of industrial control valves are pneumatic. Most pneumatic valves and transducers work well even when the air fails to comply with industry standards for dew point. Clean, dry instrument air is better for pneumatic signals.

John