MFGD Gas Flow Meters merge current technologies with traditional metering

Jun 19, 2019

Turbine, rotary piston and diaphragm gas flow meters have traditionally dominated the UK gas metering marketplace, however new digital technologies including Ultrasonic and Thermal Mass flow measurement are challenging this status quo.

The MFGD Thermal Mass meter manufactured by Siargo – California, is one such design and incorporates proprietary MEMS sensor intelligence powered by a replaceable three year battery, showing flow rate and total flow displayed on the integrated LCD readout.

Featuring increased accuracy and significantly lower installed pressure losses, the MFGD range offers inherent advantages over existing traditional technologies and is available exclusively in the UK via Bell Flow Systems in Buckingham.

Specially designed for natural gas metering, the MFGD is able to reduce traditional un-corrected accuracy losses caused by temperature and pressure variations as these models compensate electronically for the volumetric expansion of gas using patented, advanced MEMS technology.

What is Thermal Mass?

In the example below, the MFGD - MEMS (CMOS) type Thermal Mass flow meter senses flow via the convective heat transfer, flow measurement principle. A micro-heater is placed in the middle of two temperature sensors symmetrically positioned at upstream and downstream points. The cavity below the micro-heater and sensors plays the role of thermal isolation as it is filled with the gas. When the flow passes through the micro-heater, heat is carried away by the flowing medium, with the temperature differences measured by the up and down-stream temperature sensors being directly proportional to the mass flow of the gas being measured.

Thermal mass principle image

Why Thermal Mass?

There are many advantages to this method of air flow measurement.  These type of sensors feature zero moving parts in a nearly unobstructed straight through flow path, which facilitates extremely low pressure drop measurement. Maintenance costs are low and this type of meter is very sensitive at low flow rates, which allows for a high turn-down ratio whilst remaining accurate over a wide measuring range. Insertion style models can also be used in larger pipe sizes, with the option to install via a Hot-tap kit under full system pressure. We recommend placing thermal mass flow meters in dry gas downstream of all treatment filters to prevent sensor degradation.


The MFGD models provide a pulse output and RS232 for remote data logging capabilities and BMS integration. The large integrated data logging memory allows for easy historical download and subsequent analysis. This range is constructed of Aluminium with stainless steel options and features BSP threaded connections as standard, available in sizes DN32 to DN80 with a flow range of 0.1 to 500 Nm3/hr, ideal for light industrial gas measurement applications.

MFGD Thermal Mass Meter

For more information on our thermal mass meters please visit our webpage here or call us 01280 817304.


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