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Adjusting Flowrate?

Adjusting Flowrate?

Adjusting Flowrate?

(OP)
Hi,
In a simple pipe line, how can the flow rate be adjusted easily? A relief valve can be directed back to the tank in case of an overpressure as a safety. Instead could a ball valve be installed and directed back to the tank and tweaked to adjust the flow rate in the main line? The pressure in the main line can be adjusted with a pressure regulator, so that's not a problem. But it's just the flow rate my main issue.
Thanks for advice / suggestions!
Gabriel

RE: Adjusting Flowrate?

Ball valves aren't intended to be throttling valves (flow control).  Globe valves are generally what are used.

Companies such as OCV in Tulsa make pilot-operated flow control valves if you need automatic control.

Or are you talking about air/gas-phase fluid?

RE: Adjusting Flowrate?

Flow rate adjustment with a throttling valve only works with centrifugal pumps. Never try this with a positive displacement pump!

RE: Adjusting Flowrate?

Depends on how you're getting the fluid into the mainline.  Tr1 assumed you have a pump there, in which case you could bleed pressure (and flow) off your injection line into a tank (or perhaps recirculating it back to pump suction) to reduce the pressure that is driving flow into the mainline, but that may also tend to decrease the flow going to the mainline too.  As the pump runs out farther on its curve you gain flow but lose pressue. If the line diameters and tank and the mainline pressures can be adjusted to split the flow as you require as the pump pressure reduces, you may get the balance you need, otherwise you will have to carefully design the takeoff line and the injection line with properly sized diameters to get the flow split.  If you need accurate control, best way is to put a real control valve on the pump discharge to control what you need going to the mainline and an offtake line to a tank or to recirculation to take the excess.  

Take heed of the other's advice too.

"I am sure it can be done. I've seen it on the internet."  BigInch's favorite client.

"Being GREEN isn't easy." Kermitfrog http://www.youtube.com/watch?v=hpiIWMWWVco

http://virtualpipeline.spaces.live.com

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