Mass Flow Controllers & Meters


MCT–Series: Stream Switching Gas Mass Flow Controllers

Reduce your inventory and clean up your workspace with Alicat MCT-Series Stream Switching Gas Mass Flow Controllers. Dual valves located upstream allow you to switch your gas source. Dual valves located downstream make it possible to run two separate processes on a single source of gas. We’ll use your application parameters to customize your valve and PID tuning to ensure that it delivers fast and stable control, in all directions.

  • Versatile. Use a single gas source for two separate processes, or switch between separate sources for a single process. Select another gas calibration as you switch sources or define your own gas composition with COMPOSER™.
  • Connected. Easy integration into your digital industrial network with Ethernet/IP, EtherCAT, DeviceNet, Profibus, Modbus (RTU and TCP/IP) or serial communications options.
  • Durable. Backed by annual recalibrations and our limited lifetime warranty, an Alicat instrument will keep your process running smoothly, even in challenging environments, for years to come.

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  • Available ranges: max 0–5000 SLPM; min 0–0.5 SCCM
  • Steady state control range: 0.01% – 100% of full scale
  • Standard accuracy calibration, NIST-traceable: ±0.6% of reading or ±0.1% of full scale (most products)
  • Optional high-accuracy calibration, NIST-traceable: ±0.5% of reading or ±0.1% of full scale (most products)
  • Repeatability: ±(0.1% of reading + 0.02% of full scale) (most products)
  • Typical control response timet: as fast as 30 ms
  • Warm-up time: <1 s
Operating conditions
  • Compatible gases: 98 (MCT) or 130 (MCTS) pre-loaded selectable gas calibrations; additional mixtures definable with COMPOSER™
  • Operating temperature: –10°C to +60°C
  • Full scale operating pressure: 160 PSIA
  • Proof pressure: 175 PSIA
  • STP/NTP: user–selectable (defaults: 25°C & 1 ATM (STP); 0°C & 1 ATM (NTP))
Model variations
  • Switching valves located upstream (MCT–Series)
  • Switching valves located downstream (MCT-Series with DS in the adder codes)
  • Switching valves located upstream and downstream (MCT4-Series)
  • Aggressive gases (MCTS–Series)
Model variation: Corrosive gases (MCTS-Series)

Instruments in the standard MCT series are also available with an optional “S” configuration (MCTS) for use with corrosive gases. In this configuration, we upgrade the valve to 303 stainless steel, the sensor to 316L stainless steel and the elastomers to FFKM. Some corrosive gases require 316L stainless steel throughout the flow path, and in this case we can upgrade both the valve (type PCA) and flow body to 316L for full scale flow ranges of 20 SLPM or less.

Valve options

Your mass flow controller may be customized with one of the following valving options to ensure optimal performance under your expected process conditions.

  • MCT: small proportional control valve for flow ranges of 20 SLPM and below
  • MCT with PCA designation: high-performance proportional control valve used for some applications with higher pressures
  • MCPT: small proportional control valve with the largest orifice (not available for corrosive configurations)
  • MCRT: nearly frictionless large Rolamite proportional valve for flow rates of 50 SLPM and above
Build options
  • Communications protocols: analog, RS-232, RS-485, DeviceNet, EtherCAT, Ethernet/IP, Modbus RTU or TCP/IP, PROFIBUS
  • Displays: monochrome or color; integrated or panel-mount
  • Process connections: NPT, SAE, AN, BSPP/G, welded compression, or VCR/VCO fittings
  • Elastomers: Viton, FFKM, EPDM, Silicone
Performance options

Alicat’s MCT-Series uses small proportional valves for control at lower flow rates and is suitable for use with non-corrosive gases.


Alicat’s MCTS-Series uses small proportional valves for control at lower flow rates and is suitable for use with corrosive gases.


Continuous operation of a bottle-fed process

In the upstream configuration, you can use an MCT to continuously operate a bottle-fed process. When the bottle pressure drops below your threshold, simply switch your input to the other stream and its full bottle. As that bottle feeds your process, you can exchange the emptied bottle on the first stream for a fresh one.

Multi-source calibration of an analyzer

Calibrate a gas analyzer that measures concentrations of pollutants in ambient air with stream-switching at the inlet. Three separate calibrated bottles of air and greenhouse gas mixtures lead to the three inlet valves of an MCT. An additional proportional valve on the outlet side controls the flow rate of each stream when it is needed by the analyzer.

Feeding multiple analytical processes from a single source

In the downstream configuration, an MCT can be used to feed two wholly separate analytical processes from a single source of gas. You could sample ambient air and send it to two separate analyzers on an alternating schedule. Or you could supply two separate processes from the same bottle of nitrogen, each with fully proportional flow control.

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