Document No LM0670 Issue A Rev 2 November 2017 Page 3 of 15
SPECIFICATION:
ACCURACY: The accuracy of the flowmeter can be determined by the change in the pulses per litre value
over a flow rate range selected from the calibration certificate. It should be noted that linearising
electronics can follow the characteristic of the flowmeter thereby improving the overall system accuracy
output of flow rate and totalisation. For severe pulsing flow, linearisation of the flowmeter signal may be
impractical and two data points only should be used for minimum and maximum flow rate of the
application.
PRESSURE RATING: The maximum service pressure is shown on the flowmeter calibration certificate. This
meter conforms to all aspects of the Pressure Equipment Directive.
TEMPERATURE RATING: The minimum and maximum service temperature is shown on the flowmeter
calibration certificate. If the minimum fluid operating temperature is to be below 0C discuss this with
the manufacturer. The ambient temperature can range from -40°C/-40°F to +75°C/+167°F (dependent on
instrumentation).
LIFE RATING – Sensor: Litre Meter have carried out life testing on the latest reed sensor. At the current
and voltage of a Fluidwell display they have successfully lasted over 15 billion operations representing 30
years continuous running at over maximum flow rate.
METER CONTENTS DESCRIPTION all as stated on the calibration certificate
1. Flowmeter body or module with rotor chamber is as per the stock code.
2. The rotor.
3. O seals are provided to seal the pressure parts.
4. The top cap together with a number of bolts.
5. A single sensor is held in place using a simple M8 nut.
6. A male union protects the sensor assembly and is sealed with an O-ring for environmental
protection to IP68. A cable with M8 electrical sensor connection connects to the display.
7. Optionally: A display integrally mounted on the union or separate through a junction box.
MATERIALS:
In most applications Litre Meter use PVD coatings. These give stainless steel and titanium parts a
distinctive anthracite grey colour. They provide excellent mechanical properties giving each flowmeter
the capability of lower flow measurement, extended maximum flow and increased life. The actual coating
material is not disclosed but is applied to a chromium nitride base layer. Extensive testing with an LF15
running at 90 l/hour for over two years show no signs of wear and achieved lower flow measurement. The
PVD coating will improve the life expectancy of the meter for normal operation and will improve the
flowmeters ability to withstand overrunning for short periods. Please note, that even with the PVD coating,
long periods of overrunning will accelerate the wear process and result in poor performance or in some
extreme cases may lead to meter failure.
FILTRATION:
Positive displacement flowmeters do contain close tolerance moving parts and this applies to the VFF
series flowmeters. However, Litre Meter has performed extensive independent and customer tests that
show the VFF series is relatively immune from particles. Together with over 30 years of operating data Litre
Meter recommends the following:
Meter Size Filtration recommendation
VF
.L
03 and LF.05 40 microns
VFF.LF15 etc and larger 100 microns
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