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Brand: Mobrey
Mobrey 131 Vane Operated Flow Switch for Air Flow
Description
Vane operated flow switch for air and gas duct flow detection
The Mobrey 131 is a vane operated flow switch for air flow in ducts, with a switching range of 2.5 to 12.5 m/s (500 to 2500 ft/min). A vane in the duct moves a microswitch, and the set point can be adjusted between 2.5 and 12.5 m/s by control springs that are accessible with the instrument in place. The datasheet lists oil and gas, chemical, petrochemical, refining, power and food industry applications, and describes ATEX and IECEx certified flameproof enclosures.
Technical specifications
| Parameter | Specification |
|---|---|
| Medium | Air flow |
| Range of adjustment | 2.5 to 12.5 m/s (500 to 2500 ft/min) |
| Vane ranges | 5 to 12.5 m/s with 115 mm square vane; 2.5 to 6 m/s with 180 mm square vane |
| Maximum flow | 17.5 m/s or 12.5 m/s, depending on vane, see datasheet |
| Process connection | Duct mounting (code Y) |
| Ambient temperature | -25 C to +60 C; special build to -60 C |
| Process temperature | 0 to 60 C |
| Enclosure | Flameproof, IP66; H gravity die-cast aluminium-silicon alloy, K sand cast grey iron; light grey epoxy finish |
| Wetted parts | Mild steel backplate, stainless steel counterbalance, aluminium (V) or stainless steel (W) vane |
| Electrical entry | M20 x 1.5 ISO or 3/4 NPT internal, single or dual entry (codes 0, 5, 3, 6) |
| Contact codes | SPDT or DPDT general purpose (02, 03), SPDT or DPDT gold alloy (04, 05) |
| Electrical rating | General purpose 5 A at 110/250 Vac and 2 A at 30 Vdc; gold alloy 1 A at 125 Vac and 100 mA at 30 Vdc |
| Terminal block | Non-pinching, cables up to 2.5 mm2 / 14 AWG |
| Dielectric strength | 2 kV live parts to earth; 500 V across open contacts |
| Weight | Enclosure H 4.6 kg; enclosure K 9.4 kg |
| Datasheet revision | TDS.131.F, December 2022 |
Approvals and certification as printed
The datasheet states CENELEC and ATEX certification by Baseefa for use in Zone 1 hazardous areas as EEx d IIC, and IECEx approval to IEC 60079-0 and IEC 60079-1 for Exd IIC. The temperature classes and ambient limits are printed with different values in different sections of the document (for example T6 and T4 with -60 to +40 C and -60 to +80 C in the enclosure table, and -40 to +60 C and -40 to +85 C under approvals), and the certificate references use the older Baseefa and ITS naming. Always confirm the marking and certificate number on the nameplate of the unit supplied.
Selection and ordering
The model code is 131 followed by the enclosure (H or K), electrical entry, wetted material (V aluminium vane or W stainless steel vane), range code (V1 or V2 switching options), contact code and process connection Y. Choose the 115 mm vane for higher velocities and the 180 mm vane for low velocities. Moving parts are treated with a water-repelling lubricant before leaving the factory, and the datasheet recommends occasional inspection and re-lubrication so the vane stays free. Intrinsically safe circuits operate at low voltage and current, so gold contacts are recommended. The switch is not suitable for electrical isolation.
Documents and quotation
To quote, send the duct size, air velocity set point, process temperature, enclosure, cable entry, contact and electrical load, and the zone and gas group. The datasheet is an older issue, so confirm current construction and approvals with the manufacturer before ordering.
The manufacturer document is attached to this page and listed below. Seven Star LLC is an independent supplier in Muscat and can quote against the model code, quantity and delivery location. Browse more instruments in Flow Indicators & Switches, or see the Mobrey brand page.
Datasheets & Documents
- Datasheet Mobrey 131 vane operated flow switch datasheet TDS.131.F (December 2022) Download
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About brand
Mobrey is a British brand of level and flow instruments with a long history in process measurement. Emerson acquired Solartron Mobrey from The Roxboro Group in 2005 and ran it as Mobrey Measurement, and in 2019 the Mobrey line passed to the UK company Delta Controls, whose Delta Mobrey business now issues the product datasheets. The range covers float and displacer level switches, ultrasonic and hydrostatic level transmitters, solids level switches and vane flow switches.
Seven Star LLC is an independent supplier in Muscat. We list Mobrey level instruments for process plants and utilities in Oman and the GCC.
Mobrey company profile
| Origin | United Kingdom |
|---|---|
| Current owner | Delta Mobrey Ltd (Delta Controls), since 2019 |
| Former owner | Emerson (Mobrey Measurement), 2005-2019 |
| Product families | Float and displacer level switches, MLT100 displacer transmitter, DMSP400 ultrasonic transmitter, 9710 hydrostatic transmitter, solids level switches, vane flow switches |
Milestones
- 2005: Emerson acquires Solartron Mobrey and renames it Mobrey Measurement.
- 2019: Delta Controls takes over the Mobrey product line from Emerson.
Mobrey product series
Level transmitters include the MLT100 SMART HART displacer transmitter, the 9710 submersible hydrostatic transmitter with 4-20 mA and the DMSP400 ultrasonic level and flow transmitter.
Level switches include the MVLSF magnetic vertical float switch with the MHLSC horizontal switch chambers, the PLS rotating paddle switch and the DMS vibrating fork switch for solids. The 131 is a vane operated flow switch for air flow.
Float switches are mounted in external chambers so they can be isolated for service, displacer transmitters measure level and interface in process vessels, and vibrating fork and rotating paddle switches suit silos of powders and granules. Hydrostatic transmitters such as the 9710 sit at the bottom of open tanks and wells.
Where Mobrey instruments are used
Level measurement and alarms on vessels, separators and tanks, open channel flow, bulk solid silos and hoppers, and air flow proving in ducts.
Mobrey products we list
Ordering Mobrey instruments: what we need
Send the model, process medium, pressure and temperature, connection, range or switching point, electrical output and any hazardous-area certification required.
Facts checked against Emerson and Delta Controls announcements and Mobrey datasheets, October 2026.
Browse Mobrey products by category: Level Instrumentation.
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Frequently Asked Questions
What does the Mobrey 131 detect?
Air flow in a duct, using a vane that actuates a microswitch.
What velocity range can be set?
Between 2.5 and 12.5 m/s (500 to 2500 ft/min), using the control springs.
What enclosure protection does it have?
Flameproof cast enclosures with IP66 protection, in aluminium-silicon alloy (H) or grey iron (K).
Which vane materials are offered?
Aluminium vane (code V) or stainless steel vane (code W) on a mild steel backplate.
Which approvals are mentioned?
ATEX and IECEx for Zone 1 Exd IIC; confirm exact marking on the nameplate because sections of the datasheet differ.
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