| 摘要 |
<p>A fluid mass flow controller (20) includes a control circuit (70, 72, 74, 76, 80) connected to pressure sensors (46, 48) for sensing the differential pressure across a restrictor (56) for controlling a valve (40) to control the fluid mass flow rate to a setpoint. The control circuit (70, 72, 74, 76, 80) compares the differential pressure with the downstream pressure at a measured temperature with a data set of a gas passing through the flow controller (20) over a range of differential pressures and downstream pressures and adjusts the flow control rate accordingly. The flow controller (20) includes a two part body (22). The flow restrictor (56) may comprise an orifice or nozzle but preferably comprises a sintered metal plug having a predetermined porosity for the expected materials and flow conditions to which the flow controller (20) would be exposed.</p> |
