The Alicat MCD Series Bidirectional Mass Flow Controller precisely and rapidly controls mass flow rate, volumetric flow rate, and pressure of process gases in two flow directions via customized high-speed proportional control valves. The dual-valve design pairs a dedicated inlet valve with a dedicated exhaust valve, allowing a single MCD to control upstream and downstream flows, as well as positive pressure or backpressure in both open and closed systems .

The MCD Series produces volumetric and mass flow data that is fully compensated for changes in pressure and temperature and corrected for the user's STP. Flow ranges are available from -0.5 to +0.5 sccm through -3000 to +3000 slpm full scale with 200:1 turndown. Accuracy for bidirectional controllers is ±(0.8% of reading + 0.2% of total span from positive full scale to negative full scale) with ±0.2% FS repeatability and less than 100 ms control response time.

The MCD Series features large integrated displays with user-accessible setpoint control and PID valve tuning without need for a computer. It comes with 30 selectable gas calibrations and both analog and RS-232 digital communications. Extensive customizations are available, including Class 1 Div 2 CSA/ATEX ratings for use in hazardous environments. The series is also available with corrosion-resistant wetted materials (MCDS Series) or low pressure drop (MCDW Series).

The MCD Series is used in a variety of industries, from scientific research and gas analysis to leak testing and environmental monitoring. Dual valves, multi-variable measurement and control functionality, multiple gas calibrations, and a 200:1 turndown ratio allow an MCD to be used as a universal control element, replacing several application-specific devices.