High-Pressure Mass Flow Meter for Gases, Ex-proof Style

  • ATEX approval Cat.2, Zone 1
  • Also IECEx, TIIS and KCs certified
  • High accuracy, excellent repeatability
  • Virtually pressure and temperature independent
  • Pressure rating 200 bar
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Intrinsically Safe Gas Mass Flow Meters for high flow rates

Bronkhorst® EX-FLOW Mass Flow Meters (MFMs) are suited for precise gas flow measurement in ATEX Zone 1 hazardous areas. The MFM should be connected to a power supply with galvanic isolation / preamplifier / readout system (located in the safe zone). See Bronkhorst® E-8000 Series.

EX-FLOW model F-126BX covers flow ranges from 1...50 m3n/h up to 7,5...375 m3n/h (N2-equivalent) at operating pressures up to 200 bar.

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.
Other certifications: IECEx (IECEx DEK14.0060) and TIIS (検・第TC21584号).

Technical specifications

Measurement system
Flow range, based on N2
(intermediate ranges available)
min. 1...50 m3n/h
max. 7,5...375 m3n/h

Accuracy (incl. linearity)
(based on actual calibration)

±1% FS
Turndown 1:50 (2...100%)
Repeatability < 0,2% Rd

Time constant

5 seconds
Operating temperature -10…+70°C
Temperature sensitivity zero: < 0,05% FS/°C; span: < 0,05% Rd/°C
Leak integrity, outboard tested < 2 x 10-9 mbar l/s He
Attitude sensitivity max. error at 90° off horizontal 0,2% FS at 1 bar, typical N2
Warm-up time 30 min. for optimum accuracy
2 min for accuracy ± 2% FS
Mechanical parts
Material (wetted parts) stainless steel 316L or comparable
Pressure rating 200 bar abs
Process connections compression type or face seal couplings
Seals standard: Viton®; options: EPDM, Kalrez® (FFKM)
Ingress protection (housing) IP65
Electrical properties
Signal circuit type of explosion protection: intrinsic safety Ex ib IIC, only for connection to a certified intrinsically safe circuit with the following maximum values:
  Ui = 28 V, Ii = 98 mA, Pi = 686 mW
  The effective internal capacitance between:
  Terminals 1 and 3: Ci = 1 nF;
  Effective internal inductance: Li = 0,3 mH
Output signal 15…20 mA (linear)

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
Electrical connection
Ex-proof measuring head Terminal connection, cable gland M16x1,5

Technical specifications and dimensions 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

Dimensional drawing
Dimensional drawing F-126BX

IECEx: IECEx DEK14.0060
TIIS: 検・第TC21584号 (Japanese certification)
KCs: Ex ib IIC T4 (Korean certification)

Bronkhorst High-Tech B.V.

Nijverheidsstraat 1A
NL-7261 AK Ruurlo (NL)
Tel. +31 573 45 88 00
[email protected]

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