Thermal mass or Coriolis: which mass flow meter
Both give you mass rather than volume, but they get there by completely different routes — and that difference decides accuracy, cost and what fluids you can put through them.
Two routes to mass
Most flow meters measure volume. Mass flow meters measure mass, which is what you usually actually want, because mass does not change when temperature and pressure do. Two technologies dominate, and they work on entirely different physics.
Thermal mass meters work on heat transfer. A heated element sits in the flow stream; as fluid passes it absorbs heat, and the rate of heat transfer is directly proportional to mass flow rate. It suits low flow rates and gas measurement, and it is simple, compact and comparatively inexpensive.
Coriolis meters use the Coriolis effect. Fluid moving through an oscillating tube induces a phase shift in that oscillation, proportional to the mass flow rate. Because the measurement is direct, it works regardless of the fluid's properties — which is what makes Coriolis so versatile across viscous and dense fluids, and lets it report density alongside flow.
Thermal mass
BROIL's thermal mass meters are built around measurement accuracy that holds at low flow rates, where many technologies start to drift. The sensing design minimises deviation, so industries working to strict measurement standards get results that stay consistent rather than needing constant re-checking.
Response time is the second strength. These meters adjust quickly when flow conditions change, which matters in a dynamic process where the rate genuinely fluctuates — you get to correct in time rather than after the fact.
Installation is flexible: various orientations and configurations are supported, so fitting into existing pipework is usually straightforward. They are compatible with a wide range of gases, including aggressive and corrosive ones. Typical duties are gas flow measurement in HVAC systems and precise dosing in manufacturing.
Coriolis
Coriolis meters measure mass flow rate and density in real time, with an uncertainty that can be better than 0.1%. That level of precision is why they are chosen in pharmaceutical, food processing and chemical work where the tolerance is genuinely tight.
They also handle high-viscosity fluids, which frequently defeat other technologies, and stay reliable under high pressure and high temperature. Fewer moving parts than most alternatives means less wear, longer service life and lower maintenance frequency, and the construction resists corrosion in harsh applications.
Compliance is part of the picture too. Certification to ATEX and IECEx means the meters can be deployed in potentially explosive atmospheres — relevant in oil, gas and petrochemical work — and legal metrology approval supports fair trade and measurement accuracy across jurisdictions.
Comparing them
| Thermal mass | Coriolis | |
|---|---|---|
| Principle | Heat transfer from a heated element | Phase shift in an oscillating tube |
| Typical accuracy | Good; limited at very low flow and with viscous fluids | Excellent across a wide flow range |
| Purchase cost | Lower initial price | Higher |
| Installation | Simpler design, easier to fit | More complex setup and calibration |
| Maintenance | Fewer moving parts, less frequent attention | More sensitive to fluid property change; regular calibration |
| Media | Best suited to gas | Wider range, including corrosive and viscous fluids |
Choosing between them
If the duty is gas, at moderate flow, on a budget, thermal mass is usually the sensible answer and the easier install. If the tolerance is tight, the fluid is viscous or dense, or you need density as well as flow, Coriolis earns its higher cost.
The cost comparison is worth doing properly. A lower purchase price is only part of total ownership — factor in installation effort and the calibration interval before deciding. And check media compatibility early, because that is the constraint most likely to rule one technology out entirely.
Full specifications are on the thermal mass meter page, and Coriolis units are listed in the shop.