Mass Flow Controllers (MFC) are constant mass flow devices which will maintain a constant flow rate against a changing or high backpressure. To set a constant flow through a device one can connect the output of one or more MFC directly to the device. If you want to set a flow rate to several devices, then you either utilize a MFC on each device or set up a manifold that delivers gas to several devices. Using multiple MFCs allow one to change the composition of the supply gas to a common manifold. If one is utilizing a common manifold and using needle valves or rotameters to set the flow through each device, a constant pressure is required at the manifold. The gas coming into the common manifold (a constant flow rate from one of more MFC) must be converted to a constant pressure behind each rotameter, otherwise if you change one rotameter, then all rotameters would be affected. To achieve a constant pressure from a constant flow one uses the G262 Blow Off Valve to maintain a constant backpressure on the MFC’s and a Pressure Regulator to provide a constant pressure to the common manifold. The Blow Off Pressure would be set somewhere above the Pressure Regulator’s level and a small amount of gas would be constantly blowing off or wasted. One would set the total MFC flow rate slightly above the total common manifold flow rates to maintain the Blow Off and Pressure Regulator’s settings.

Producing Area:Canada