FDT-25W Wall Mounter Ultrasonic Flowmeter
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1. Introduction
1.1 Preface
Welcome to use new modern type transit-time ultrasonic flow meter, please read the user manual
carefully before using. The wall-mounted ultrasonic flow meter is designed to be installed in a fixed
location for long-term flow measurement.
1.2 Features
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Linearity: 0.5%, Repeatability: 0.2%, Accuracy:±1%
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Easy to operate. Good water-proof function.
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Several type transducers for selection, measuring pipe size is from DN15mm to DN6000mm
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Adopt low voltage, multi-pulse technology to improve accuracy, useful life and reliability.
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Powerful Recording Function, record the totalizer data of the last 64 days/64 months/5 years.
1.3 Flow measurement principle
The FDT-25W ultrasonic flow meter is designed to measure the fluid velocity of liquid within a closed
conduit. The transducers are a non-contacting, clamp-on type, which will provide benefits of
non-fouling operation and easy installation.
The FDT-25W transit-time flow meter utilizes two transducers that function as both ultrasonic
transmitters and receivers. The transducers are clamped on the outside of a closed pipe at a specific
distance from each other. The transducers can be mounted in V-method where the sound transverses
the pipe twice, or W-method where the sound transverses the pipe four times, or in Z-method where
the transducers are mounted on opposite sides of the pipe and the sound crosses the pipe once. This
selection of the mounting method depends on pipe and liquid characteristics. The flow meter operates
by alternately transmitting and receiving a frequency modulated burst of sound energy between the two
transducers and measuring the transit time that it takes for sound to travel between the two transducers.
The difference in the transit time measured is directly and exactly related to the velocity of the liquid in
the pipe, show as follows: