Thank you for purchasing the Model FT3 Thermal Gas Mass Flow Meter and
Temperature Transmitter from Fox Thermal Instruments. The Model FT3 is
one of the most technically advanced flow meters in the world. Extensive
engineering effort has been invested to deliver advanced features, accuracy
measurement performance and outstanding reliability.
This Instruction Manual contains the electrical and mechanical installation
instructions as well as details for programming, maintaining and
troubleshooting the meter.
This manual is divided into the following sections: Introduction, Installation,
Wiring, Operation, Maintenance, Troubleshooting, Appendices, Glossary and
Index.
Theory of Operation
The Model FT3 is an innovative Thermal Mass Gas Flow Meter and
Temperature Transmitter. It is microprocessor-based and field programmable.
The FT3 thermal sensor operates on the law that gases absorb heat. A
heated sensor placed in an air or gas stream transfers heat in proportion to
the stream’s mass velocity. There are two sensor elements connected to
a balanced bridge circuit. One sensor element detects the gas temperature
and a second element is maintained at a constant temperature above the gas
temperature. The energy applied to the heated sensor to maintain a constant
flow velocity. The FT3 flow meter maintains accurate flow measurement over
a large temperature and pressure range.
Mass Flow
The Model FT3 measures mass flow; an advantage over other flow meters
which measure volumetric flow rate. Volumetric flow is incomplete because
temperature and pressure are unknown and must be measured separately.
For example, the mass flow of a gas depends on its temperature and
pressure. As temperature and pressure changes, the gas volume changes
but not its mass. Therefore a device measuring mass flow is independent of
temperature and pressure. The Model FT3 provides a direct measurement
measurements required.
4
Introduction
Scope
Model FT3
INTRODUCTION
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Calibration
Validation
I/O Description
Product Description
Mass Flow
Welcome
Flow Calibration
