Coriolis Mass Flow Meter Working Principle
The operation of a Coriolis flow meter is based on the mechanics of motion. The Coriolis force happens when a mass moves in a rotating inertial frame. The rotation is created by vibrating two opposing tubes on the flow meter. When a fluid flows through the opposed vibrating tubes, the tubes twist due to the Coriolis force. The twisting alternates with the vibration and creates two phase-shifted sinusoidal wave forms on coils mounted to the tubes. The amount of shift is proportional to the mass flow rate. In addition, the frequency of vibration is proportional to the fluid density. The signal shift and the frequency of vibration can be precisely measured, which makes the Coriolis meter one of the most accurate types of flow meters.
As this principle measures mass flow independent of what is within the tube, it can be directly applied to any fluid flowing through it – LIQUID or GAS – whereas thermal mass flow meters are dependent of the physical properties of the fluid. Furthermore, in parallel with the phase shift in frequency between inlet and outlet, it is also possible to measure the actual change in natural frequency. This change in frequency is in direct proportion to the density of the fluid – and a further signal output can be derived. Having measured both the mass flow rate and the density it is possible to derive the volume flow rate.
Coriolis meter main Features
- A Coriolis meter can be applied for variety of applications ranging from adhesives and coatings to liquid nitrogen.
- Typical rangeability of curved tube designed Coriolis meters vary from 100:1 to 200:1 whereas for straight-tube meters its rangeability is limited i.e. about 30:1 to 50:1. Besides, accuracy of straight tube meters is low.
- In case of Coriolis meters, no compensation is needed for temperature and pressure variations. Also mass measurement is insensitive to changes in viscosity and density.
- They are particularly helpful for handling liquids whose viscosity changes according to velocity while temperature and pressure remains constant.
- These are called universal meters, since they are capable enough to measure nearly all liquids, slurries and gases. They can measure all liquid flows such as Newtonian, non-Newtonian and moderately dense gases as well.
- They can be employed to measure liquid density also.
- No Reynolds number restrictions are allied with Coriolis flow meters.
- They are also not affected by deformations in velocity profile
Coriolis meter Technical specification
Sizes :-
1 / 25 to 10 in. (1 to 250 mm)
Fluids Liquids:-
slurries, gases (compressed, low-pressure, etc.), liquefied gases; not gas-liquid mixtures
Flow Range :-
0 to 63,000 lb /min (0 to 28,300 kg/min)
Operating Pressure :-
Depends on tube size and flange rating: 1400 PSIG (100 bar) typical standard rating;5000 PSIG (345 bars) typical high-pressure rating.
Operating Temperature: –
Depends on design: − 60 to 400 ° F ( − 50 to 200 ° C) typical standard; 32 to 800 ° F(0 to 426 ° C) high-temperature, special versions also used for cryogenic applications.
Measured Variables :
Mass flow, volume flow, density and temperature
Pressure Drop :-
Function of flow, viscosity, and design, varying from very low (<0.1 PSIG, 10 mbar) to moderately high (22 PSIG approximately 1.5 bar)
Price :-
Depends on size and design: 1 / 25 in. (1 mm), $5000; typical 1-in. (25-mm) meter, $7000; 6-in. (150-mm), $27,500.
Coriolis flow meter advantages and disadvantages
Advantage of Coriolis flow meter :-
- Coriolis flow meter is capable of measuring a wide range of fluids that are often incompatible with other flow measurement devices. The operation of the flow meter is independent of Reynolds number; therefore, extremely vicious fluids can also be measured. A Coriolis flow meter can measure the flow rate of Newtonian fluids, all types’ non-Newtonian fluids, and slurries. Compressed gases and cryogenic liquids can also be measured by some designs.
- Coriolis flow meters provide a direct mass flow measurement without the addition of external measurement instruments. While the volumetric flow rate of the fluid will vary with changes in density, the mass flow rate of fluid is independent of density changes.
- Coriolis flow meters have outstanding accuracy. The base accuracy is commonly on the order of 0.2%. In addition, the flow meters are linear over their entire flow range.
- The rangeability of flow meters is usually on the order of 20:1 or greater. Coriolis flow meters have been successfully applied at flow rates 100 times lower than their full scale flow rate.
- A Coriolis flow meter is capable of measuring mass flow rate, volumetric flow rate, fluid density and temperature — all from one instrument.
- The operation of the flow meter is independent flow characteristics such as turbulence and profile. Therefore, upstream and downstream straight run requirement and flow conditioning are not necessary. They can also be used in installations that have pulsating flow.
- Coriolis flow meters do not have internal obstructions witch can be damaged or plugged by slurries or other types of particulate matter in the flow stream. Entrained gas or slugs of gas in the liquid will not damage the flow meter. There are no moving parts witch will wear out require replacement. These design features reduces the need for routine maintenance.
- The flow meter can be configured to measure flow in either the forward or the reverse direction. In revere flow there will still be a time or phase difference between the flow detector, but the relative difference between the two detector signals will be reversed.
- Coriolis flow meter designs are available witch allow for use in sanitary applications, and for the measurement of shear sensitive fluids. Materials are available to permit the measurement of corrosive fluids.
Disadvantage of Coriolis flow meter :-
- Coriolis flow meters are not available for large pipelines. The largest Coriolis flow meter that is currently available has a maximum flow rating of 25,000 lb/min (11,340 kg/min), and is equipped with 6 in. (15 cm) flanges. When larger flow rates must be measured, two or more flow meters mounted in parallel are required.
- Some flow meter designs require extremely high fluid velocities in order to achieve a significant amount of time or phase difference between the flow detector signals. This can result in extremely high pressure drops across the flow meter.
- Coriolis flow meters are expensive. However, the cost of a Coriolis meter is often comparable to (or below) the cost of a volumetric meter plus densitometer used together to determine the mass flow rate.
- Coriolis flow meters have difficulty measuring the flow rate of low- pressure gas. Application with pressure less than 150 psig are marginal with the flow meter designs that are currently available. Low-pressure gases have low density, and their mass flow rate is usually very low. In order to generate enough mass flow rates to provide sufficient Coriolis force to be measured, the gas velocity must be extremely high. This in turn may lead to prohibitively high pressure drops across the meter.
Technical Specification of Coriolis flow meter
| Sl. No. | Parameter | Minimum Requirements |
| 1 | Line size | 1.5”/ 2”/3”/4” NB |
| 2 | Service | MS/SKO/HSD/ATF/ETHANOL/BIO DIESEL (Volumetric Flow) |
| 3 | Flow Min/ Operating/Max | For 2”/1.5” line : 30/300/ 500 LPM |
| For 3” Line : 200/1200/ 1500 LPM | ||
| For 4” Line : 200/2000/2400 LPM | ||
| 4 | Operating Pressure | 1 to 8 Kg/cm2 |
| 5 | Operating temp | Refer Site Data |
| 6 | Operating density | MS : 0.70-0.75 gm/cc SKO : 0.75-0.80 gm/cc HSD : 0.80-0.90 gm/cc |
| 7 | Viscosity @ 38 deg C | MS : 1.1 CST SKO : 1.2 CST HSD : 2.54 – 4.0 CST |
| 8 | Allowable Pressure Drop across MFM | Maximum 0.5 Kg/cm2 @ Maximum flow rate |
| 9 | Relative humidity limit | 95% non-condensing |
| 10 | Type | Microprocessor based Coriolis mass flow meter |
| 11 | Transmitter type | Remote / Integral |
| 12 | Sensor Tube | SS 316 / SS 904L or better |
| 13 | Wetted parts | SS 316 /SS 904L or better |
| 14 | Flow direction | Bi directional flow |
| 15 | Tube size (sensor) | To be sized by vendor |
| 16 | Transmitter Body Material | SS 304 / Die cast aluminum |
| 17 | Process connection | 1.5”/2”/3” / 4”RF, ANSI # 150 B16.5 (As per line size) |
| 18 | End connection Material | SS 316/ SS 316L |
| 19 | Mounting accessories | Required (As Applicable) |
| 20 | Accuracy | (For flow range 10%-100% of Maximum Flow rate) |
| i | Mass | +/- 0.05% |
| ii | Volume | +/- 0.05% |
| iii | Density | +/- 0.0002 gm/cc |
| 21 | Repeatability | Mass/ Volume : +/- 0.025% Density : +/- 0.0001 gm/cc |
| 22 | Batch Accuracy | ± 0.05% over full range |
| 23 | Minimum Data to be displayed on Local Display | · Mass/Volume flow rate (Selectable) · Mass/Volume totaliser (Selectable) · Online Temperature · Online Density
Other parameters at MFM/ Flow computer
other parameters |
| 24 | Electrical Connection | Suitable Cable entries with FLP double compression (Ni-Plated) Cable Gland to be provided as per design Engineering.
Cable entry size shall be suitable for following cable type a. Power cable : 3Cx2.5 sq.mm Armoured Cu FRLS b. Signal cable : 2 pair x 1.5 sq.mm Armoured Cu FRLS (as applicable) c. Cat 6 cable |
| 25 | Power supply | 230 VAC, 50 Hz +/- 5% |
| 26 | Power consumption | Vendor to specify |
| 27 | Signal Input /Output | Ø Frequency Ø 4-20 mA / HART Ø Modbus TCP IP Following parameters shall be available as minimum over Modbus TCP/IP to TAS: · Mass and Volume flow rate · Mass and Volume totalizer · Online Temperature · Online Density · Meter-factor · Corrected Volume @ 15oC/29.5oC (Selectable) · Density@ 15oC/29.5oC (Selectable) · Critical Diagnostic data of MFM Ø Volume and Density conversion at 15oC/29.5oC are to be done using inbuilt ASTM table loaded in MFM/ Flow Computer. Ø Conversion using mathematical formula or ASTM table loaded in TAS shall not be accepted. |
| 28 | Reset counter and cumulative totalizer | The Flow Transmitter/Display Unit shall be equipped with minimum 8 Digits Cumulative Totalizer & 5 Digit Reset Counter with programmable decimal. |
| 29 | Surge Protection | The MFM shall be protected against surges, transients induced either by switching of heavy electrical loads or lightning. Compatible surge protectors recommended by OEM for signal and power supply, with necessary mounting accessories shall be included in the offer. The surge protector shall be designed and tested as per the requirements of BS EN 62305 /IEEEC62.41 /IEC 61643-21 |
| 30 | W&M Lock | Yes, Software and Hardware lock for sealing to be provided |
| 31 | Connectivity | Ø The frequency/ pulse output of the MFM to be connected to BCU for Mass/ Volume flow rate.The signal shall be linearly proportional to the volume / Mass flow rate which shall be read by the batch controller. Number of pulses generated for a unit Volume/Mass transferred, shall be user configurable. Ø Temperature Transmitter output to be connected to MFM/ Flow Computer for Temperature reading and compensation. Ø TCP IP output to be connected to TAS from MFM for remote display of all the above mentioned parameters in TAS including compensated Volume and Density at 15 Deg/ 29.5 Deg C. |
| 32 | Area classification | Zone 1, Group II A& B T3 |
| 33 | Housing Protection | Weather proof to IP65 or better & Explosion proof |
| 34 | Approval | · CCOE / PESO · CMRI/ ATEX · Type / Model approval from Indian Legal Metrology. · PTB/NMI – OIML R117 for Custody transfer |
| 35 | Calibration | Master MFMs shall be calibrated at FCRI Palakkad before dispatch. All other MFMs needs to be calibrated at respective OEM’s laboratory or at any NABL accredited Laboratory or at FCRI Palakkad before despatch in addition to proving and W&M stamping at site. |
Mass Flow Meter Inspection and Test Plan
This content provides you a sample mass flow meter inspection and test plan. This is a draft mass flow meter ITP and you need to modify it to meet your specifications.
| Mass Flow Meter Inspection and Test Plan Task | Vendor | TPI Inspection | Client |
|---|---|---|---|
| Mass Flow Meter Mill test reports | H | R | R |
| Mass Flow Meter Pressure test | H | W | R |
| Mass Flow Meter Performance test including calibration and hysteresis tests | H | W | R |
| Mass Flow Meter Insulation resistance test | H | W | R |
| Mass Flow Meter Final visual / Dimension Inspection | H | H | R |
| Mass Flow Meter Documentation review prior to release(Final activity of Technical Inspection) | H | H | R |
| Mass Flow Meter Pre-shipment Inspection | H | H | R |
H: Hold Point implies that relevant production activities shall not proceed until the continuation of work is permitted by Purchaser. (Notification req’d)
W: Witness point implies that Purchaser intends to witness the designated inspection feature. If Purchaser decides not to witness the relevant feature, production can proceed without permission of Purchaser. (Notification req’d)
S: Witness, but spot check basis. Initial operation will be witness point and subsequent operation will be witnessed at discretion of Purchaser considering the results of previous inspection. (Notification not req’d : Randam Inspection)
R: Review inspection & test records (Notification not req’d)
General Note :
1) Mass Flow Meter Witness/hold point by Code Inspector, when applied by Code /Local Regulation, is to comply with its requirements and to specify in Vendor’s ITP.
2) Type of Inspection by Mass Flow Meter Purchaser may be changed according to equipment criticality and vendor QC evaluation at job stage.
3) When requested in the requisition, detailed Mass Flow Meter ITP shall be submitted by Vendor.
4) Monitoring/Observation of Mass Flow Meter Vendor shop daily routine works (i.e.Storage of materials, Adherence to approved procedures, Testing tool calibration check, workmanship,cleanliness and etc.) shall be done by Purchaser during inspection visit.
5) 100% Mass Flow Meter inspection which is covered by the combination of witness / spot check / record review inspection & tests listed above and vendor’s original QC activity shall be confirmed by Purchaser’s inspector prior to shipment.
6) Unless otherwise specified in REQ., the Mass Flow Meter sampling Q’ty of ” S (Spot Witness Check) ” shall be as follows:
3 to 20→3Pcs(all if total 2 and less) , 21 to 50→5Pcs, 51 to 100→10Pcs,101 to 200→20Pcs, 201 to 300→30Pcs, 301 to 500→50Pcs
Minimum 25 pcs or more of the commodity shall be arranged for H/W/S inspection and test at one time inspector’s visit as much as practical.
7) Final Mass Flow Meter Visual Inspection/Documentation Review/Pre-Shipment Inspection may Pre be combined within one time visit.
Coriolis flow meter connections
Top five Coriolis flowmeter Manufacturer
| Coriolis Mass Flow meter Manufacturers / Vendors | Country | Website | Phone No. |
|---|---|---|---|
| ABB AG | GERMANY | www.abb.de | +49 62143810 |
| ABB LIMITED | UK | www.abb.com | +44 1925741111 |
| BOPP & REUTHER MESSTECHNIK GMBH | GERMANY | www.burmt.de | +49 6232657508 |
| DANIEL | UK | www.daniel.com | +44 1786433400 |
| EMERSON | UK | www.frco.com | +44 1162822822 |
| ENDRESS & HAUSER | GERMANY | www.endress.com | +49 71562090 |
| HONEYWELL | BELGIUM | www.honeywell.be | +32 27282386 |
| JORDAN KENT(ALDERLEY) | UK | +44 1454294556 | |
| KOBOLD MESSRING GMBH | GERMANY | www.kobold.com | +49 61922990 |
| KROHNE MESSTECHNIK GMBH & Co. KG | GERMANY | www.krohne.de | +49 2033010 |
| MECI S.A.S | FRANCE | www.meci.fr | +33 254039949 |
| OVAL CORPORATION | JAPAN | www.oval.co.jp | +81 333605121 |
| SIEMENS | GERMANY | www.powergeneration.siemens.com | +49 9131180 |
| SMITH METER (FMC) | GERMANY | www.fmcmeasurementsolutions.com | +49 41013040 |
| YOKOGAWA ELECTRIC CORP | U.A.E | +973 17358100 |
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