MEASUREMENT & MONITORING
CHALLENGING THE STATUS QUO
BELL FLOW SYSTEMS
MFGD GAS FLOW METERS MERGE CURRENT
TECHNOLOGIES WITH TRADITIONAL METERING
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.
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PECM Issue 39
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.
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.
www.bellflowsystems.co.uk