I. Review
1.1 Overview
use of low-frequency excitation current value of plus
or minus two and a new excitation circuit, so that machine power
consumption less than 10VA.
output current with the isolation, no additional
features select pieces of isolated current (ie, does not require
isolation plate).
converter circuit board with SMD components Chip
technology, compact and robust, install easy to use, more suited to
a more severe vibration conditions, the occasion to use (such as
grouting, slurry pump pressure measurements the working
environment, etc.).
converter between the circuit board with the flat
cable connection, interchangeability strong, Assembly and
Disassembly convenience, range sensor matching transformation and
simple to use great convenience for debugging).
meter high stability and good reproducibility.
1.2 Measurement principle
The measuring principle is based on Faraday's law of
electromagnetic induction. Namely: conductive liquid in a magnetic
field for cutting magnetic line of force campaign, the conductor
generated induced voltage, which induced voltage is:
U = RLDZBvD
RLDZ = instrument constant
B = magnetic induction intensity
v = measurement of the average velocity inside the pipe section
D = inside diameter of measuring tube
Measuring flow, fluid flow perpendicular to the flow direction of
the magnetic field, sensing the flow of conductive liquid out of an
average velocity (that is, volume flow) is proportional to the
voltage, thus requiring the flow of the liquid tested with a
minimum conductivity. The induced voltage signal through two
electrodes in direct contact with the liquid detection, and
transmitted via cable to the amplifier, and then converted into a
single output signal. This measurement has the following
advantages:
1. Measuring tube without prominent parts, therefore, no additional
pressure loss.
2. Because the signal in the whole space filled with the formation
of the magnetic field, which is the pipe cross-section on the
average, therefore, from the electrode plane to the sensor plane
between the upstream end of straight pipe required for a relatively
short length of 5 × DN (DN for the catheter internal diameter).
3. Only pipe lining and the electrode contact with the liquid under
test, therefore, a reasonable choice as long as the electrodes and
lining materials, can be achieved by anti-corrosion, wear-resistant
requirements.
4. Sensor signal is a linear relationship between average velocity
into a precise voltage.
5. Survey results and velocity distribution and fluid pressure,
temperature, density, viscosity, electrical conductivity (not less
than the minimum conductivity), etc. independent of physical
parameters, so high accuracy, reliable work.
Second, technical data
2.1 RLDZ installation of the form
RLDZC a body installed with the sensor and
converter
RLDZF sub-size sensor and switches
installed separately
2.2 The sensor parameters
Matching sensor diameter DN10-DN500
Working pressure DN10-DN50 4.0MPa
DN65-DN125 1.6MPa
DN150-DN500 1.0MPa
Ambient temperature 500C
Medium temperature of a body 1200C
Sub-size 1800C
Protection class IP65, IP67, IP68
Electrode structure standard electrode
Scraper-type electrode can be cleaned (DN 350)
Electrode materials, lining materials,
selected according to the measured medium
Shell plate spray paint (or stainless
steel shell)
Flange standard, flange material based on
user selected GB9119 (or DIN2501, JB/T81)
2.3 Electrical Parameters
Conductivity: 20 S / cm
Measuring range: 0 ~ 0.3m / s
0 ~ 10m / s
Output current signal: 4 ~ 20mA DC Load
500
Power Frequency :48-63Hz
Power Supply Voltage: 220VAC (+10% / -15%)
(or 110VAC)
Power consumption: 10VA
Time constant: 3.5s (fixed settings)
2.4 Accuracy index
Measured value ± 1% (M, V) measured
velocity V 0.5m / s
Measurement of 1% (M, V) +0.001 m / s
measured velocity V 0.3m / s
Repeatability <± 0.5%
Temperature effect the amount of 0.5% /
100C
Power supply voltage affect the volume of
0.1% / ± 10%
