valve control

[Dost]

Hi
I am trying to monitor a control rig via a mobile device.the rig consist of 1 inch diameter copper pipe through which air is passing at rate of 120 cubic litre per hour.I wish to control this flow of air proprtionaly using either acutator or a solenoid void.I came to know the there is no proptional solenoid valve avaialable .in that case my only option is an actuator.my question is which type of actuator can do this job and also can an actuator can be interface with labview using 7.1 if yes than which NI card should i use please do reply me.

[MogaRaghu]

Since you want proportional control of air flow, by default you should use an actuator that can regulate. Like for instance ball valves have poor regulation and are good only for open/close applications. A sluice gate type of valve can provide regulation and you can have a hydraulic / pneumatic cylinder controlling the gate position. You can then control this cylinder with a proportional solenoid valve. And if you have a linear position transducer linked to the cylinder rod, you can then control the gate in closed loop. The proportional valve in turn can be controlled with command from the Analog Out of a regular multifuunction card like the 6024-E.

These are generic guidelines basedf on the little inputs that you had given.

Raghunathan

[Brian_Beal]

Mass flow controllers are available that will do this, unless there is something in your application that I am missing. I have used ones from MKS before. They are available with different I/O, but typically the setpoint is controlled with a 0-5 VDC signal, and mass flow is output as 0-5 VDC. There is also the ability to directly control the valve.