Litre Meter VFF Series Assembly instructions

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Document No LM0670 Issue A Rev 2 November 2017 Page 1 of 15
INSTALLATION, OPERATING
AND MAINTENANCE INSTRUCTIONS
VFF SERIES ROTARY FLOWMETERS
DESIGN & PRINCIPLE OF OPERATION:
These VFF series flowmeters are defined as rotary piston meters of a type as detailed in British Standard
BS.7405:1991 which is a guide to flowmeters. They offer a wide metering range and can measure low and
high viscosity fluids. For most of the flow range the viscosity may be varied with minor effect on the output
characteristic.
Litre Meter provides a standard factory calibration representative of the application in terms of viscosity
and flow rate range. A calibration certificate is provided which details the calibration fluid and viscosity,
together with pulses per litre at a range of flow rates specifically for the application or the total meter
range.
The only moving part of the flowmeter is the rotor which is equipped with a top mounted central magnet.
The rotor oscillation is detected by a sensor or pair of sensors. The interaction between the magnet and
a sensor does not impose drag on the rotor which could otherwise affect the low flow rate measurement
capability. The certificate shows the number of active sensors. The reed-switch sensors are inherently
intrinsically safe.
Typical VFF Flowmeter parts
THE METER MAY NOT BE DESIGNED FOR USE ON WATER – PLEASE CONSULT THE
FACTORY. See
FAT Issues on page 12.

Document No LM0670 Issue A Rev 2 November 2017 Page 2 of 15
Contents
DESIGN & PRINCIPLE OF OPERATION:..............................................................................................1
SPECIFICATION: .................................................................................................................................3
METER CONTENTS DESCRIPTION all as stated on the calibration certificate ..............................3
MATERIALS:........................................................................................................................................3
FILTRATION:........................................................................................................................................3
Meter Size......................................................................................................................................3
FLOW PULSATION: .............................................................................................................................4
COMMISSIONING and START-UP: ....................................................................................................4
MECHANICAL INSTALLATION: ...........................................................................................................5
Application Warnings: ......................................................................................................................6
INTRINSIC SAFETY Exi – Installation notes .....................................................................................7
FLAMEPROOF EExd – Installation notes..........................................................................................7
PRESERVATION ..................................................................................................................................7
RECALIBRATION PERIOD ...................................................................................................................7
HANDLING AND SHIPPING PROCEDURES ........................................................................................8
HAZARDOUS AREA CERTIFICATION...................................................................................................8
FIELD WIRING CONNECTION & OUTPUT ...........................................................................................8
METER MAINTENANCE – GENERAL ...................................................................................................9
METER MAINTENANCE - TROUBLE SHOOTING.................................................................................9
WEEE - Waste Electrical and Electronic Equipment .....................................................................10
Measurement Principle: .................................................................................................................11
What’s a pressure balanced chamber? ........................................................................................11
Key Benefits: ...............................................................................................................................11
FAT Issues ........................................................................................................................................12
On-Site Flowmeter Calibration.......................................................................................................12
On-Site calibration..........................................................................................................................12
Precautions: ....................................................................................................................................12
Flying start and finish.................................................................................................................13
Standing start and finish ...........................................................................................................13
Installation ......................................................................................................................................13
Commence the test.........................................................................................................................13
Calculations.....................................................................................................................................13
Appendix..........................................................................................................................................15

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 0C 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.
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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
F
.L
F
03 and LF.05 40 microns
VFF.LF15 etc and larger 100 microns

Document No LM0670 Issue A Rev 2 November 2017 Page 4 of 15
FLOW PULSATION:
The VFF series meters can be affected by pulsing flow rate particularly if there are severe flow rate
variations in terms of the nominal flow. Sometimes a damping value can be utilized in the electronics to
provide a smoother displayed value of flow rate.
Positive displacement meters ‘follow’ the flow rate changes and therefore may appear to give an unstable
reading. A correctly chosen filter value in the instrumentation may be used to stabilise the meter reading
and/or output.
COMMISSIONING and START-UP:
Before commissioning and start up Litre Meter recommend that this entire manual is
read. Pay attention to these sections:
Mechanical Installation and
FAT Issues.
Understanding the VFF flowmeter, previous customer experience and its operating
parameters will greatly improve any Factory Acceptance Test but also ease
commissioning and initial start-up.

Document No LM0670 Issue A Rev 2 November 2017 Page 5 of 15
MECHANICAL INSTALLATION:
The end user of the equipment shall be responsible for the following actions during the installation of
the equipment to ensure compliance with the Essential Safety Requirements (ESR) of the PED Directive
97/23/EC and 2014/68/EU. The relevant requirements of the PED are listed below:
PED
ESR Ref
ESR Requirement Compliance Requirement
2.3 Provision to ensure safe handling and
operation.
The method of operation specified for
pressure equipment must be such as to
preclude any reasonably foreseen risk in
operation of the equipment. Attention must
be paid, where appropriate, to the following:
Devices to prevent physical access while
pressure or vacuum exists.
Surface temperature
Decomposition of unstable fluids.
It is the end user’s responsibility to ensure that the equipment
is sufficiently protected from additional stress due to traffic,
wind, earthquake loading, corrosion, erosion, fatigue,
decomposition of unstable fluids, reaction forces and
moments which result from the supports, attachment, piping
etc. Pressures that exceed the meters maximum rating shown
on the calibration certificates, Temperatures that exceed
those shown on the calibration cert.
The end user shall ensure that the flowmeter is installed in a
properly designed system with access limitation in place if
required.
It is the responsibility of the end user to assess the expected
surface temperature of the meter once in service, and if
necessary, take the necessary precautions to avoid personnel
coming into contact with the equipment.
The end user should assess the risk and take any steps
necessary to avoid the meter coming into contact with
unstable fluids.
2.4 Means of Examination.
Pressure equipment must be designed and
constructed so that all necessary
examinations to ensure safety can be carried
out.
Litre Meter VFF Flowmeters are designed so that all critical
parts are contained within the meter body and cannot be
examined while in service. The end user should refer to the
operations and maintenance instructions supplied with each
meter.
2.5 Means of draining and venting.
Adequate means must be provided to avoid
harmful effects such as water hammer,
vacuum collapse, corrosion and
uncontrolled chemical reactions.
It is the responsibility of the end user to ensure that the meter
is installed in a well-designed piping system to avoid such
hazards.
2.6 Corrosion or other chemical attack.
The meter has been designed using materials that should not
result in severe corrosion problems. It is the end user’s
responsibility to monitor any change in the process medium
that may cause concern.
2.7 Wear. It is not expected that the use of the meter for flow
measurement will give rise to any abnormal wear problems. It
is the responsibility of the end user to maintain the condition
of the process medium.
2.9 Provisions for filling and discharge. It is the responsibility of the end use
r
to avoid hazards during
filling and discharge.
2.10 Protection against exceeding the
allowable limits of the pressure
equipment.
The meter must be installed in a well-designed piping system
with adequate protection against excessive pressure. – see
also 7.3
2.12 External fire. The meter has no special accessories for fire damage
limitation. It is the responsibility of the end user to provide
adequate fire-fighting facilities on site.
7.3 Pressure limiting devices, particularly for
pressure vessels.
The VFF meter has no integral pressure limiting devices. It is
the responsibility of the end user to ensure that it is installed
in a well-designed system so that momentary pressure surges
are limited to under 10% of the meter’s maximum allowable
pressure.

Document No LM0670 Issue A Rev 2 November 2017 Page 6 of 15
All positive displacement meters are independent of pipe-work effects, and therefore valves, bends, tees,
etc may be mounted directly onto the flowmeter process connections and the pipe size varied also.
However, to provide optimum performance the meter body should be installed vertically with the process
connections to a horizontal flow line. Screwed anchorages are provided on the underside of the flowmeter
to support the meter and avoid pipe strains, etc. Signal connection is made via a junction box on top of
the flowmeter or via the display. Vertical access should be provided for the field cabling connection and
for maintenance purposes. Litre Meter do not recommend the meter is installed for vertically downward
flow. The calibration certificate will confirm calibration orientation, if non-standard.
Care should be observed on start up to avoid high pressure drops across the flowmeter. The flowmeter
can be specified with several rotor materials including carbon, titanium and stainless steel. There is a
risk of the rotor or chamber damage if a high pressure drop or a high acceleration across the flowmeter is
experienced. Typically, this may be caused by:
wAir in the line
wOpening a valve too quickly
wPurging with compressed air (or steam)
wA sudden introduction of fluid into an empty pipe
To prove the flowmeter is functioning without being installed in the line, it is possible to blow gently
through the meter depending on meter size. You may be able to hear the rotor rotate and see the flow
display.
Ensure that any dangerous fluids that may be in the meter are removed before this test. Please
do not use an airline as the rotor may be unknowingly damaged.
Blocking and Bypass valves should be installed if it is necessary to do preventative maintenance on the
flowmeter without shutting down the flow system. The Bypass valve can be opened before the Blocking
valves allowing the flow to continue while removing the flowmeter for service.
Important: All flow lines should be purged prior to installing the meter. To prevent possible damage to
the meter, install the meter ONLY in flow lines that are clean and free of debris.
Upon initial start-up of the system a spool piece should be installed in place of the flowmeter so that
purging of the system can be performed to remove all particle debris which could cause damage to the
meter internals. In applications where meter flushing is required after meter service, care should be taken
as to not over-speed the meter, as severe meter damage may occur.
Gas bubbles in the system will create measurement errors. These are purely volumetric meters.
Application Warnings:
Do not exceed the maximum temperature stated in the client data sheet
Do not exceed the minimum temperature stated in the client data sheet
Do not exceed the maximum pressure stated in the client data sheet. End user must ensure that a suitable
device is fitted to prevent it from being exceeded.
No pressure surges to be allowed exceeding the maximum pressure stated in the client data sheet.
Only when correctly installed should the system be started. Operability must not be compromised during
installation.
Misuse can be avoided. Please see the Essential Safety Requirements above.
Identified Hazards: Valves and pumps that induce shocks into the system etc.
Ensure glands are sealed and tightened, ensure Exd window is fully screwed down particularly in high
humidity areas
The customer should not change the fluid without notification as this may damage the meter or invalidate
PED certification (Pressure Equipment Directive).

Document No LM0670 Issue A Rev 2 November 2017 Page 7 of 15
INTRINSIC SAFETY Exi – Installation notes
The reed-switch sensors do not require individual certification as they are classed as "simple apparatus".
No marking of the meter regarding intrinsic safety is required under the relevant code. Reed-switches are
covered under the Harmonised European Standards Clause 1.3 of EN50.014 and BS.5501 Part 1. These
refer to devices that do not generate or store more than 1.2V, 0.1Amp, 20 microJoule and 25 milliWatt.
They may be installed in a hazardous area relating to a classification EEx ia IIc T4. The reed-switch contact
rating is 1VA with a switching voltage of 24V ac/dc with contact arrangement normally open form A. For
the display please see the separate display instructions.
There is a technical construction file TCF004 containing an assessment against ATEX Directive 94/9/EC
Annex 2 for installation as equipment Group II Category 1G EEx ia IIC T5 Tamb = -40°C/+60°C. Suitability is
confirmed by ignition hazardous assessments for both electrical and non-electrical equipment.
FLAMEPROOF EExd – Installation notes
Mounted directly on the meter or indirectly is the IP66/IP68 enclosure providing rate and total display.
Please see separate instructions.
Pulse Output: Without a display the raw output may be utilised externally via the junction box.
PRESERVATION
Please note these flowmeters are generally constructed externally in stainless steel with stainless steel
instrument housings. They are designed to be at least IP67 and are, therefore, suitable for mounting
outside to that limit. We would normally recommend that the lowest temperature be –20°C. Please
contact factory if this is likely to be lower. We would also recommend that no fluid be left in the flowmeter
if there is a likelihood of the fluid freezing or setting. If some fluids leave residue, we recommend that
these are thoroughly cleaned out before the units are stored. They will be shipped drained of calibration
and test fluids. If they are to be left for extended periods of time without fluids, then the humidity should
be controlled and either a preservative used inside the meter to prevent any corrosion effect or fully dried.
Please ask the factory for advice. If the display cover is removed, we recommend maintaining the humidity
at less than 40% RH to prevent component corrosion. We do not recommend that demineralised or de-
ionised water is left in the meter for more than a few days. In some rare cases, there has been some attack
on close-fitting surfaces. Either ensure the line is empty of fluid or use a preservation fluid.
RECALIBRATION PERIOD
Recalibration periods of flowmeters are based on industry standards. In industrial applications,
depending on the industry, periods of 6 to 12 months are recommended. Litre Meter advise the user to
seek out data relating to the process, other components within the process and the usage of the meter. If
the measurement is critical then the recalibration should be more frequent than a non-critical rarely used
device. In the absence of any other data Litre Meter advise an annual check and to vary the future
calibration periods depending on results.
If it has remained unused, then no recalibration will usually be necessary. It is wise to check that no fluid
has settled in the measurement chamber that might alter the way the rotor rotates or even cause slight
corrosion where two metal surfaces have been in close contact. Once cleaned the performance should
remain unchanged.

Document No LM0670 Issue A Rev 2 November 2017 Page 8 of 15
HANDLING AND SHIPPING PROCEDURES
The systems are packed entirely within wooden or cardboard boxes suitable for protecting the units
during normal handling. We would recommend that they are kept in these boxes for as long as is
practicable until they are finally required. One note of caution: please do not lift or handle the meters by
solely lifting the display, glands or cables. If the display cover is removed, we recommend maintaining
the humidity at less than 40% RH to prevent component corrosion.
HAZARDOUS AREA CERTIFICATION
Please consult the instrument manual for details.
FIELD WIRING CONNECTION & OUTPUT
Please see separate FlowPod Installation and Operating Manual LM0662 (or another
instrument manual)
Refer to drawing depending on what has been supplied. The correct drawing is supplied with each order
and can be accessed via the website url. The url is given on the quick start instructions and the outside
of the flowmeter and instrument.
FlowPod drawing:
C7310 2 wire or C7311 for 4 wire
VRGS drawing
Refer to drawing depending on what has been supplied. The correct drawing is supplied with each order
and can be accessed via the website url. The url is given on the quick start instructions and the outside
of the flowmeter and instrument.
Fluidwell drawing – see Appendix
Caution:
Meter disassembly, assembly, modification etc should only be carried out by
qualified personnel.

Document No LM0670 Issue A Rev 2 November 2017 Page 9 of 15
METER MAINTENANCE – GENERAL
This unit should not require regular maintenance providing the installation precautions above are taken
into consideration. The warranty will not be invalidated if the cap is removed to inspect the rotor and its
chamber. Document LM0638 lists all the possible failure scenarios and resolutions and to some extent,
probabilities – see also the FAT Issue section in this manual, p12.
METER MAINTENANCE - TROUBLE SHOOTING
1. If the display or receiving equipment fails to register pulses, first check the display and/or the
receiving equipment by shorting out a pair of input terminals to check for function. (This duplicates the
action of the reed switch). Access is gained to the sensor through the process described below: If the
reed sensor is tested for continuity please ensure a
maximum of 10mA (0.01A) is applied.
1.1.1. Undo the display cover.
1.1.2. The display disc assembly will then be
loose enough to remove, just held by a ribbon
cable. The sensor will still be attached and
connected to one of the terminal blocks (TB2).
1.1.3. Remove the wires from TB2. Connect
two new wires to TB2 using Sig1 and Set2.
Short these two wires together a number of
times – this duplicates the action of the reed
switch. Help is available at the factory. If the
shorting makes the display count, then it is
likely there is either a problem inside the chamber or with the sensor itself.
1.1.3.1 To replace the sensor undo the nut to
loosen the existing sensor.
1.1.3.2 Gently undo the sensor body to remove
the sensor.
1.1.3.3 Replace with the new sensor ensuring
that a) the sensor is located at the bottom of
its hole and b) the nut locks the sensor in
place
1.1.4. Reassemble ensuring that the sealing O-rings are
kept in place and wiring is re-connected.
1.2 If the instrumentation responds then the next step is to check the wiring between the
reeds and the display (which may also contain a pulse repeater such as a galvanic isolator used
for intrinsically safe systems). (
Integral display– ignore this step )
1.3 If shorting the field wire connections sequentially produces a result at the display, then
it is likely there is either a problem inside the chamber or with the sensor itself (less likely). (See
para 1.1.3 above for assistance on this)
1.4. The first check avoids breaking down the liquid seal of the flowmeter.
1.4.1 Undo the M8 nut and undo the reed sensor. Moving a magnet in front of this will duplicate
the action of the flowmeter. Replace if necessary. Tighten the nut ensuring the reed

Document No LM0670 Issue A Rev 2 November 2017 Page 10 of 15
sensor is held at the end of the sensor hole.
2. If it is seen that there is no sensor output by the above procedures and it is certain that flow is
taking place, then it is possible that the rotor has become jammed due to the presence of a foreign
body/particle. The sensor output may be a continuous ‘low’ state or a ‘high’ closed contact state
of signal if the magnet is stationary under a reed switch. The meter may be disassembled in the
following manner.
Ensuring that the line pressure is off, and the line is drained as necessary, remove the socket cap
screws of the flowmeter cap (the sensor may be left in place during this procedure). The top cap
can now be removed from the flowmeter body. [In some instances, the rotor is exposed. If not,
the rotor can be accessed by undoing the socket cap screws presented.] It is likely that the rotor
is stuck. Extract the rotor vertically (taking care that the operator is not contaminated with the
process fluid). Observe both the rotor and the rotor chamber for debris or particles. Clean both
the rotor and the rotor chamber. With the rotor free from the flowmeter, the rotor can be placed
against the top cap. Run the rotor in a circular motion to check the output from the sensor system.
Ideally this should duplicate the action of the rotor in its chamber. Having verified that an output
is taking place, the rotor can be replaced in the rotor chamber. Replace the rotor and check that
it oscillates freely. Ensure that the O-ring is undamaged and place it in its groove in the top cap.
Reassemble the top cap taking care to tighten the socket cap screws. If applicable, re-assemble
the top cover, bracket and enclosure.
3. Check that suitable filtration is present in the upstream pipe work to the flowmeter. Employ a
smaller micron mesh filter if necessary.
If appropriate see the separate instruction for the display unit.
WEEE - Waste Electrical and Electronic Equipment
Litre Meter Ltd has a formal product disposal Take-Back and Recycle Program in Europe that complies
with the European Union Directive 2012/19/EU on waste electrical and electronic equipment, also
known as the "WEEE Directive".
This program provides self-service instructions for ease of use product take-back and recycling.
Equipment that is returned through this program will be handled in an environmentally safe manner
using processes that meet or exceed the WEEE Directive requirements. This program is for Litre Meter
customers who have Litre Meter and other manufacturer's flowmeters that have been supplied by Litre
Meter that have reached the end of life.
WEEE - Please contact us to initiate a return request. See our policy on the website.

Document No LM0670 Issue A Rev 2 November 2017 Page 11 of 15
Measurement Principle:
Figure 1 Measurement Principle
The flow causes the rotor to move within the measuring chamber. This movement is sensed, giving an output
representing an increment of volume flow. The rotor is basically a disc shape with an annular groove on its
underside capable of holding and transporting flow from the chamber inlet to the outlet. Some fluid is also
transported in a cavity formed between the rotor outside wall and the chamber wall. A centre 'peg' under the rotor is
constrained to run in a circular groove in the body. A web (or plate) in the body is engaged with a slot in the rotor
and this modifies the rotation to that of an oscillation as flow passes. It is this oscillation that produces the
compartmentation of the fluid into 'positively displaced pockets'. The top of the rotor is equipped with a powerful
magnet directly above the 'peg' that is on the underside and so this also has a circular path which allows it to
engage and disengage a reed switch sensor located in the top cap above. A volt-free contact closure output signal is
given for each oscillation which represents a volume increment. The fluid is transported in a 'positive' manner
always. The typical metering repeatability is better than 0.2% and a meter accuracy of 1% actual reading is usually
obtained over a substantial flow range. For lowest flows the meter will under-read the actual flow in a consistent
manner. This allows an improved wide-range system accuracy to be gained using a linearising electronics
instrument such as the Litre Meter FlowPod.
What’s a pressure balanced chamber?
Extensive testing by Litre Meter in 2005 proved that leaks occur over the top of the rotor at higher
pressures. This is due to minute distortions of the cap. For example, at 700bar the cap moves by just
0.02mm in the centre. Increasing the bulk of the cap still produces this movement. The effect on meter
performance was the creation of a leak path for fluid that avoided the positive displacement of the rotor.
This was equivalent to about a 3% inaccuracy at 700bar. Because of this Litre Meter designed a special
pressure balance chamber for its VFF flowmeter so it could operate at extreme pressure and at low-flow
rates. The pressure balance chamber acts as a barrier, protecting the internal measurement components
of the instrument from the high pressure conditions, preventing them from expanding and contracting
under the immense pressure. All VFFs over 414bar are fitted with this technology. It is identified by the
letters PBC in the calibration certificate.
Key Benefits:
wNo distortion of the chamber at higher
pressures.
wNo measurement inaccuracy due to
pressure.
wEnables selection of optimal materials
for the chamber to match the rotor i.e.
PVD coated stainless steel.
wEnables selection of optimal materials
for the pressure vessel. i.e. super
duplex stainless steel
wEnables construction of a duplex
bodied flowmeter – duplex material does not lend itself to the tolerances required in machining
the chamber.

Document No LM0670 Issue A Rev 2 November 2017 Page 12 of 15
FAT Issues
TheFactoryAcceptanceTestcanbethefirsttimethemeterisrunafterbeingdespatchedfromthe
factory.Herearesomecommonproblemsencounteredandtheirresolution:
1ThemostfrequentlyusedFATfluidiswater.Thiswon’tdamagethemetersatall,butit
doeshaveaverylowviscosity.Therearetwosignificanteffects.Firstly,themeterwill
probablynotmeasureaslowastheflowratesachievedattimeoffactorycalibration.
Thecalibrationviscosityistakentobetheviscosityofnormaloperation.Secondly,ifit
doesoperateatthelowestflows,thentheaccuracymaybegreatlyreduced.Itislikely
tounder‐readbyupto30%.ThesolutionistochangetheFATfluid.Theadditionof
glycolorreplacementbyglycolfortheFATisquitecommon.
2Dirtinthesystemishardtoavoid.Evenwithfiltrationat40or100micronsitisstill
quiteeasyforpotentiallyblockingparticlestobeheldinthepiping,evenafterflushing.
Wewouldrecommendthemeteristakenoutoflinebeforepipeflushing.Itemslike
PTFEtapeandtheremnantsofthreadlockingcompoundswillpreventtherotorfrom
turning.However,therotorandchambercanbesimplycleanedbydisassemblyand
washing.
3Installationattitudecanbedifferentfromoriginalcalibration.Themetersarenormally
calibratedinahorizontallinewiththemeterinstalledupright.Ifadifferentorientation
isadvisedoruseditwillbenotedonthecalibrationcertificate.Therewillbesomesmall
functionaldifferencesifthemeterisinstalledonverticallyupwardfloworupsidedown.
LitreMeterdonotrecommendthemeterisinstalledforverticallydownwardflow.
Performanceattheverylowestflowsmaybecompromisedunlesscalibratedinthe
correctorientation.

AnerroranalysissystemisdescribedindocumentLM0638,VFFFaultFinding.
On-Site Flowmeter Calibration

ThisproceduremustbeintegratedwiththeapprovedHealthandSafetypolicyatsite.

Thepurposeofthissectionistooutlineageneralcalibrationprocedureforvariousflowmeters.Itwillmakespecific
referencetovolumetricflowmetersbutmostoftheprinciplesareequallyapplicabletootherflowmeasurement
technologies.TheimportantconsiderationisthatthereisaccesstothereadingoftheMeterUnderTest(MUT)anda
sufficientlyaccurateunderstandingoftheactualflowrate.

On-Site calibration
Theaimofthiscalibrationtechniqueistoprovidedatatotheusersuch
thattheinstrumentationcanbeadjustedtoshowthecorrectflowrate
and/ortotal

Thiswillbedoneby
omaintainingaknownflowrateand
omonitoringtheoutputoftheMUT

Precautions:
Flush/Cleanpipingpriortoinstallingthemeterorany
pipeworkchanges
Ensurethataliquidsystemhasnoairorvapour
entrained
Ensurethattheflowvariationsduringtestingareata
minimum,usuallybetterthan±1%variation
Ensuretherearenoprotrudinggasketsupstreamofthe
meter(forturbinemetersetc.)
Measurethepipingtoensurethatdimensionsand
finisharewithinstandardlimits
Ensurethatthemeasurementequipmentisinstalledin
accordancewithstandardsortothemanufacturer’s
recommendations

ThisishowLitreMetercalibrateflowmetersin
thefactory:

CALIBRATION
MostLitreMeterflowmetersarecalibrated
usingagravimetricmethod.Aflowrateis
establishedthroughtheflowmeterwiththe
outputflowreturningtothemainreservoir.At
thecommencementoftest,theoutputflowis
divertedintoaweightank.Whensufficient
volumeoffluidhasbeencollectedinrespectof
thatflowrate,theoutputflowisdivertedto
themainreservoironcemore.Thetimefor
thevolumeoffluidtobecollectedisrecorded,
togetherwiththenumberofpulsesproduced
bythetransmitter.Thedensityofthefluidis
determinedattimeofcalibration.Volume
dividedbytimeequalsflowrate.Thenumber
ofpulsesdividedbyvolumeequalsthepulses
perlitreMeterFactor.Thecalibration
certificateispreparedfromatableofthese
values.Ifon‐sitecalibrationisrequiredanda
knownvolumeoffluidflowcanbeestablished,
thenthesamecalculationsapplytoreproduce
thecalibrationcertificate.


Document No LM0670 Issue A Rev 2 November 2017 Page 13 of 15
Avoidpulsatingflowandcavitationtohavemeaningfulresults

Prepare a weigh tank . Thetankshouldofsufficientsizetocontainavolumeoffluidrunningatthe
requiredrangeofflowsforaminuteorso.Forexample,ifthemeterhasaflowrangefrom1to30litresper
minutethena30litretankwouldbeappropriate.Asthetankmaybedifficulttoemptycompletelyhavingita
littlelargerisadvisable;careshouldbetakenthatitisdeepenoughorsoshapedthatsplashingoutsideofthe
tankdoesn’toccur.Thetankneedstobeweighedbeforeandafterthetesttosufficientaccuracy.Forlower
flowratesthereisnotnecessarilyarequirementtomeasure30litreseachtime.Thiswilldependonother
factorssuchasweighscaleresolution,accuracyofweighscale,accuracyofflowmeterandaccuracyofdensity
determination.Thismethodisnormallyusedforwaterwherethedensityiswellknownasitmeasuresmass
butwillbeappliedtovolumetricflowmeters.AsguidanceLitreMeterrecommendsaweighscalewitha
resolution10,000timessmallerthanthemaximumweightandadensitometeraccuratetothe±0.001g/cm³(if
waterisn’tused).Insomeinstances,avolumetrictankcouldbeusedwherethevolumeisaccuratelyknown.


Prepare start and end of test. Therearetwooptions:

Flying start and finish
Thismethodisverywidelyusedwhenflowratemetersmustbecalibratedwithwater.Itisperhapsless
appropriateforthecalibrationofvolumetricmeters,orformeterswhicharebeingcalibratedwithoilsorfuels.
Themassflowrateiscalculatedbydividingthemasscollectedinthetankbythediversiontime,andthiscan
beconvertedtoavolumetricflowratebydividingitbythedensityattheappropriatetemperature.Adiversion
iscausedbyswitchingthestreamoffluidintoaweightankatthestartofthetestandreversingtheswitchat
theendofthetest.Accuracyofcalibrationisobtainedbyensuringthetimingerroratthestartandendis
minimisedbybothgoodtechniqueandbyrelativelylongtestperiods(atleast60seconds,forexample)and
repeatable,quickdiversion.

Standing start and finish
Issimplerthanflyingstartbutthefollowingerrorscanoccur:
EnsurethattheMUTisfullpriortotesting;arushofaircanleadtolargeerrors.
Ifthestartsystemisrelativelyslowtheremaybeasignificantpartofthetestwhichisatavaryingflowrate–the
sameappliesfortheendportion.Timingmaybehardtocalculate.
Ifitisintendedtouseastanding‐start‐and‐finishmethodofcalibration,itisprobablybettertouseaweighscaleifthetest
fluidiswateroraviscousoil(above,say,5cSt),andtouseavolumetrictankwithlowviscosityhydrocarbons(below,say,5
cSt).
Installation
Ifnotalreadyinstalled;install
MUTintopiping.Tightenall
pipes/flangestoavoidleaks.
Selectappropriatepipeworkfor
eachmeterstyle;usemarkings
onmeterforflowdirectionand
orientation.Ensuremeteris
centredwithinpipework.
Ifnotalreadyconnected
electronically;connect
displaytometer.Ensuredisplay
issettoshoweither
totalor
flowrate
Alternativelypulsesoran
analoguesignalcanbe
measured
Beforecommencingtestmake
sureweightankisemptyor
nearlyempty.Closevalveand
tarescalestoshowzero.
Switchonpumpandcontrol
flow
Resettotalondisplay(ifonly
flowratedisplayisavailable,
notethevaluefortheduration
ofthetestandcalculatethe
averageattheendofthetest)
Commence the test
Eitherdiverttheflowor
commencetheflow.
Whenthetankhasreachedthe
specifiedweight(ortime)then
diverttheflowbackorstopthe
flow.Recordthe
weight/volume,emptytankas
necessary,resttheweighscale.
Repeatforeachflowrateas
required–factorycalibration
normallycoversfromminimum
flowratetomaximumflowrate
in8stepsbutiftheusageis
overadifferentorreduced
rangethanthatshouldbe
reflectedinthecalibrationflow
rates.Additionalconfidence
canbegainedbyrepeatingthe
testsateachflowrate.
Finishcalibration
AssessMUTperformance

Calculations
Compareeither:theactualflow
ratei.e.themassorvolume
dividedbythelengthofthetest
againstthedisplayedflowrate
Or:thetotalcollectedagainst
thedisplayedtotalorcalculated
total.
Createatableofresultsover
therangeofflowratesused.
Usingthemanufacturers
originalcalibrationcertificate
recalculateanydataintonew
‘points’.Thisassumesthataset
oflinearizationdatahasbeen
enteredoriginallyintothe
instrumentation.(Insome
cases,asinglemeterfactoris
used.Thetableofresultscan
beusedtoprovideanaverage
meterfactorovertherangeof
flowratestestedwhichwill
provideabetterseriesof
readingsoncemodified.)
Enterthenewdataintothe
instrumentation
Ideally,runthetestsagainto
checktheresultsoverafewof
theflowratesandconfirmthe
calculations.


Calculationexamplescanbe
foundonthenextpage:

Document No LM0670 Issue A Rev 2 November 2017 Page 14 of 15
Data Collection
A B C D E F G H
1 Test # Approx flow rate
Weight
collected
Time for
test Density Calculated Volume
Displayed
Flow rate
Actual flow
rate
2 Litres/hour Kg Seconds gm/cm³ Litres Litres/hour
3
Col C Col F*3600
4
Col E Col D
5
6 1 1500 25.106 60.015 1.0015 25.068 1500 1503.73
7 2 1500 24.976 59.866 1.0015 24.939 1495 1499.66
8 3 1500 24.807 59.432 1.0015 24.770 1492 1500.39
9
10 4 1200 15.887 44.215 1.0015 15.863 1245 1291.59
11 5 1200 16.015 43.965 1.0015 15.991 1240 1309.40
12 6 1200 15.757 44.023 1.0015 15.733 1233 1286.61
13
14 7 Etc.
15 8 Etc.
Data Analysis
A B C D E F G H I
16
Data
Sets
Displayed
Flow rate
Actual flow
rate Difference
17
(Col G/Col
H)-1
18 Average of tests 1, 2 and 3 1495.667 1501.262 -0.37%
19 Average of tests 4, 5 and 6 1239.333 1295.863 -4.36%
20 Average of tests 7, 8 and 9
21 Etc. Etc.
Original Data
Revised Data, after calibration
A B C D E F G H I
22 Flow Rate Meter Factor New Flow Rate
Old Difference New
23 Run Litres per hour
Pulses
per litre Run Litres per hour
Pulses
per litre
was Pulses per
litre
24 # l/hr ppl # l/hr
ppl ppl
25 from original or last calibration certificate
Col G
x(1+Col H)
26 1 1686.06 851.815 1 1501.262 851.815 -0.37% 848.640
27 2 1237.26 850.707 2 1295.863 850.707 -4.36% 813.596
28 3 918.06 851.688 3 Etc.
29 4 603.90 857.140
30 5 484.314 868.801
31 6 363.030 879.710
32 7 244.398 890.983
33 8 127.716 918.669
34 9 53.412 941.109

Document No LM0670 Issue A Rev 2 November 2017 Page 15 of 15
Appendix
Fluidwell wiring – please also see separate wiring diagram
Refer to drawing depending on what has been supplied. The correct drawing is supplied with each order
and can be accessed via the website url. The url is given on the quick start instructions and the outside
of the flowmeter and instrument.
Integral Fluidwell Exi (F112, F118, F018 etc) display:
Connection of field wiring is simple.
1 – If the M20 gland thread is provided in the cover.
Remove the front of the display and feed the cable through the gland, up the stem and connect
to the terminals as shown in the other instructions.
2 – If the M20 thread is not provided, remove the front of the display and undo the nut holding
the instrument back box to the cover. Drill a 20mm clear hole in the desired position on the back
box - depending on field orientation. Feed the cable through the gland, up the stem and connect
to the terminals as shown in the display instructions.
Remote Fluidwell Exi (F112, F118, F018 etc) display:
Connection of field wiring is simple. Remove the quantity 4 M4 socket cap head screws retaining
the top cover to the cap. Remove the cover and pass through 2-wire customer field cabling. Use
a connector and attach it to the 2-wires of the field cabling. Ensure that the O-ring is in place on
the top cap surface. Lower the top cover onto the flowmeter top cap carefully over the O-ring
and reassemble using the M4 socket cap bolts. Draw down the gland provided by others and fit
to the thread provided in the top housing. Ensure field cabling is not straining the connector
within the cover; clamp the gland to the field cabling. The installation is now complete.
Exi display 4-20mA output option enables the unit to transmit a flow rate signal. This is optionally
available through the M20 gland on the side. It may be necessary to make the gland hole in the
instrument housing. This should be wired up as follows (Fluidwell display):
1. Remove the four counter-sunk screws on the display front.
2. Pull out the green 7-way adaptor plug.
3. Undo the M14 nut inside the display box and remove box.
4. There are four wires from the display. The two blue wires are the flowmeter signal. The
red and green wires (if fitted) are for the 4-20mA output. The terminals are also marked
(+) and (-). From the flowmeter body there are four wires. One pair is the active reed
switch, other pair not utilized (see Field Wiring section above). (See page 38 of the
display instructions for a wiring diagram of the display; Section 5 Configuration Example
3).
5. Reassemble the cover with the four cap bolts ensuring that the sealing O-rings are kept
in place.
6. Reassemble the display box onto the cover using the M14 nut.
7. Re-engage the 7-way adaptor plug and re-secure the instrument front with the four
counter-sunk screws. The flowmeter is now ready for operation.
To prove the flowmeter is functioning without being installed in the line, it is possible to
blow gently through the meter. You should be able to hear the rotor rotate and see the flow
display.
Ensure that any dangerous fluids that may be on the rotor assembly are removed
before this test.
Please do not use an airline as the rotor will be unknowingly damaged.