High-Pressure Mass Flow Controller for Gases, Ex-Protected style

  • ATEX approval Cat.2, Zone 1
  • High accuracy, excellent repeatability
  • Virtually pressure and temperature independent
  • Operating pressure / delta-P up to 350 bar
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Intrinsically Safe Gas Mass Flow Controllers for High Pressure / High Delta-P

Bronkhorst® EX-FLOW Mass Flow Controllers (MFCs) are suited for precise gas flow control in ATEX Zone 1 hazardous areas. The flow meter part and the control valve of the MFC should be connected (via separate cables) to a power supply with galvanic isolation / preamplifier / readout system (located in the safe zone) which contains a controller board to complete the control loop. See Bronkhorst® E-8000 Series.

EX-FLOW model F-231MX covers flow ranges from 10...500 mln/min up to 0,2...10 ln/min (N2-equivalent) at operating pressures up to 350 bar and max. 350 bar pressure difference (ΔP).

The intrinsically safe measuring head of the flow meter is tested according to ATEX 114 Directive 2014/34/EU and approved under EC-Type Examination Number: KEMA 01ATEX1172, protection II 2 G Ex ib IIC T4 Gb.
The intrinsically safe valve coils are explosion proof certified and available in two options (ATEX certification only):
Coil XB: protection II 1 G Ex ia IIC T6 / protection II 1 D Ex ta IIIC T80°C
Coil XC: protection II 2 G Ex eb IIC T4 / protection II 2 D Ex tb IIIC T130°C

Technical specifications

Measurement / control system
Flow range (intermediate ranges available)min. 10…500 mln/min
max. 0,2…10 ln/min
(based on N2)
Accuracy (incl. linearity) (based on actual calibration)± 1 % FS
Repeatability< 0,2 % RD
Turndown ratio1:50 (2…100%)
Time constant5 sec.
Control stability≤ ± 0,1 % FS typical
Operating temperature-10 … +65 °C
Temperature sensitivityzero: < 0,05% FS/°C; span: < 0,05% Rd/°C
Leak integrity, outboardtested < 2 x 10-9 mbar l/s He
Attitude sensitivitymax. error at 90° off horizontal 0,2% FS at 1 bar, typical N2
Warm-up time30 min. for optimum accuracy
2 min. for accuracy ± 2% FS
Mechanical parts
Material (wetted parts)Stainless steel 316L or comparable
Pressure rating (PN)350 bar abs
Min. ΔP6 bar dif.
Max. ΔPup to 350 bar dif.
Process connectionscompression type or face seal (VCR/VCO) couplings
Sealsstandard: FKM/Viton®;
options: EPDM, FFKM/Kalrez®
Ingress protectionIP65
Electrical properties
Output signal15 … 20 mA (linear)
Terminal connection, cable gland M16x1,5
I/O signals via PS/Readout (located in safe area)analog: 0…5 Vdc, 0…10 Vdc, 0…20 mA, 4…20 mA;
digital: RS232, PROFIBUS DP, DeviceNet™, Modbus RTU or ASCII, PROFINET, EtherCAT®, FLOW-BUS
XB-coilCoil voltage max. 28 V/110 mA;
295 Ohm at 20°C
XC-coilCoil voltage max. 24 V;
65 Ohm at 20°C, Pmax = 9 W at 20°C
Electrical connection
Ex-proof measuring headTerminal connection, cable gland M16x1,5
Control valve coilcable gland M20x1,5
Control valve options
External actuator options to be connected to the controller
Certification for hazardous areas
Approvals / certificates

Technical specifications subject to change without notice.

For dimensional drawings and hook-up diagrams please visit the product page on our website


EX-FLOW brochure
Manual EX-FLOW meters and controllers - ATEX
Manual EX-FLOW meters and controllers - IECEx
Manual EX-FLOW meters and controllers - TIIS
Manual EX-FLOW meters and controllers - KCs
Hook-up diagram
MFM Measuring Head
Dimensional drawing
Dimensional drawing F-230MX-F-231MX-F-232MX