Thermal Flow Switch Monitors

Our thermal dispersion flow switches are specifically designed for the harshest of applications in liquid or gas. They are both ATEX Exd certified and SIL2 rated.

Thermal dispersion technology measures  the temperature difference between an active (heated) RTD and a reference (un heated) RTD. This is greatest in a no-flow condition and decreases as flow increases, cooling the heated RTD. Changes in flow velocity directly affect the extent to which heat dissipates and, in turn, the magnitude of the temperature difference between the RTDs.


  • FLT93L

    An "in line" design, for low flow applications in gas or liquid.

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  • FLT93S/F

    Bespoke designs for a wide range of applications, pipe sizes from 1 ½ to 1m diameter.

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  • FS10i

    The FS10i is a low cost, thermal flow monitor for liquids & gases, SIL2 compliant, ATEX certified with no moving parts.

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  • FLT93B

    A basic, general purpose flow switch for pipe sizes of > 1 ½"

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  • Analyser / Sample flow monitoring

    The advanced Model FS10A Analyser Flow Switch/Monitor represents the best-in-class, solution for continuously verifying flows within liquid or gas process analyser sampling systems.

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  • AwiEco, Single Channel Biogas Analyser

    Allison Engineering are the exclusive UK representative for Awite Gmbh. Awite are the market leader in Germany for Biogas and Bio-methane analysers with hundreds of successful installations.

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  • FS10A

    The FS10 has been specifically designed for use in process analysers for liquid and gas flow detection.

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Our Calibration Facilities

N.I.S.T traceable calibration facilities , the most sophisticated of any manufacturer of thermal gas mass flow meters.

FS10A – Calibration Movie

How to calibrate the FS10A in the field – Watch the movie

FS10A – Features Movie

An overview of the Key Features of the FS10A analyser sample flow monitor – Watch the Movie