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Allison Engineering

Innovative Solutions for
Process Control

Flow Switches / 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.