flow controllers/ regulators

[thryll]

I would like to be able to regulate the amount of free flowing air through some pipework. I am using a vacuum in order to draw the air in. Does anyone know of a company which sells a regulator which can work with ambient room pressures and regulate/control fairly small flows 5-30 Lpm cost effectively ? thanks

 

[hacksaw]

rotameter suppliers can help you. they have small flow controllers that work in conjunction with the rotameter and are adjustable. you can also do it manually with a rotameter and the built-in needle valve.

However, if you are needing better than 1% control then you have to go with a mass flow controller (they are not cheap).