Flow Measurement

Coriolis Flow Meter Installation: Best Practices for Accuracy

  • For the purpose of determining coriolis flow rate, a Coriolis mass flow meter, which is a subtype of flow meter that measures mass through the use of inertia and is commonly regarded as the type of flow meter that provides the most accurate readings, is utilised in many industrial settings.
  • Coriolis mass flow meters have been in use for a long time now. These meters are based on the concepts of the Coriolis effect.

How to install your Coriolis flow meter?

  • Coriolis meters do not have any restrictions placed on them with regard to the Reynolds number. 
  • In addition to this, they have no sensitivity to distortions in velocity profiles or swirl. 
  • As a consequence of this, there is no need for continuous lengths of relaxation piping either upstream or downstream of the meter in order to condition the flow.

Determine the best position for installation

Coriolis Flow Meter Installation: Best Practices for Accuracy 1
  • It is important to keep the flowmeter in a location that is not near any potential interference sources, such as a pump, as this could cause the pipe to vibrate. 
  • Care must be made to prevent the mutual influence caused by vibration resonance if the flowmeters are used in series along the same line. 
  • It is recommended that there be at least a 2-meter gap between each pair of sensors.
  • When installing the sensor, it is important to pay attention to the expansion and contraction of the process pipeline that occurs as a result of changes in temperature. 
  • It is highly advised that the sensor not be positioned in close proximity to an expansion joint of the process pipeline. In the event that this does not occur, the expansion and contraction of the pipeline will generate transverse stress, which will have an effect on the zero setting of the flowmeter as well as the accuracy of the measurement.
  • The flowmeter needs to be installed at a distance of at least 5 meters from any potential sources of electromagnetic interference in industrial settings, such as large power motors and transformers. 
  • The sensor needs to be positioned so that its measuring tube is constantly filled with fluid and pressure is maintained at the outlet; hence, it needs to be positioned in a position that is lower than the pipeline.
  • Upstream or downstream,  mass flow transmitter does not require a pipe that is perfectly straight. However, if more than one mass flow transmitter is installed in the same pipe, the distance between any two flowmeters must be greater than two meters. This distance must be maintained.

Arrangement Instructions

  • Installing the flow transmitter is necessary in order to ensure that the measuring tube will be completely full that the product being measured.
Coriolis Flow Meter Installation: Best Practices for Accuracy 2
  • The measurement tube should be positioned on the downside of the pipeline when the process medium is liquid or slurry (Picture), and on the top of the pipeline when the process medium is gas (Picture). 
  • When the process medium is a liquid, slurry, or gas, the measurement tube should be positioned next to the pipeline in a vertical installation (see Picture).

Installation at a challenging location for the measurement of liquids and gases

Coriolis Flow Meter Installation: Best Practices for Accuracy 3
  • The flowmeter must not be installed at the highest position of the tubing (A) if gas bubbles are predicted, or at the lowest point (B) if solid particles are expected.
  •  To avoid the flowmeter becoming empty, the meters should not be positioned in a drop-line near the open end (C).
  • Pipe reduction or extension should not be made directly before or after the flowmeter under any circumstances. 
  • Stay away from any control valves, orifices, or sound generators that are in close proximity to the sensor. 
  • Direct installation at the sensor side should be avoided wherever possible because this can lead to measurement inaccuracies. 
Coriolis Flow Meter Installation: Best Practices for Accuracy 4
  • If you are installing a flowmeter with a diameter of 6 inches or bigger, use the rubber connectors as a buffer to support the sensors.

Direction of the flow of material

Coriolis Flow Meter Installation: Best Practices for Accuracy 5
  • Installing the flowmeter in the appropriate direction is indicated by the arrow pointing in the direction of flow that is located in front of the flowmeter. Otherwise, the accuracy of the mass flow display on the transmitter may be compromised. 
  • When the medium of the process is a liquid or slurry, the flow direction is up-to-down; when the medium of the process is gas, the flow direction can either be down-to-up or up-to-down.
Coriolis Flow Meter Installation: Best Practices for Accuracy 6
  • If the process piping is correctly supporting the Coriolis meter, normal pipe vibration should not have an impact on the Coriolis meter’s performance in more recent Coriolis designs (Figure).
Coriolis Flow Meter Installation: Best Practices for Accuracy 7
  • The flow tube does not require any special supports or pads, but ordinary piping supports should be installed on either side of the meter. 
  • The particular meter design is likely to be sensitive to vibration if the installation instructions call for special hardware or supports, thus it is important to properly install the pulsation dampeners, flexible connectors, and mounting/clamping attachments advised by the manufacturer.
  • The manufacturer should be contacted if your application calls for mounting two Coriolis flow meters next to one another or in series, in order to avoid crosstalk between the two devices.
Coriolis Flow Meter Installation: Best Practices for Accuracy 8
  • Installing an air release upstream of the meter is advised if air bubbles are likely to be present in the process fluid. The following system design elements that cause the presence of air (and can frequently be removed at the design stage) are:
  • Allowing air escape through packing glands of pumps that create high suction vacuums (as can happen when pumping from underground storage).
Coriolis Flow Meter Installation: Best Practices for Accuracy 9
  • Stationary process fluid vaporisation in pipes exposed to the sun
  • High valve pressure decreases that result in flashing and vaporisation
  • Allowing the line to drain for whatever reason, including the absence of check valves
  • Use a single pipe to pump a variety of materials at various times.
  • Allowing for the development of foam in high-velocity fluids due to high turbulence.
  • It is advised to install any necessary strainers, filters, or air/vapor eliminators (upstream of the meter) in order to get rid of any unwanted secondary phases. An installation of an air eliminator is shown in Figure.
  •  Its purpose is to reduce the liquid’s speed so that the entrained air has more time to separate and be expelled through venting. 
  • The vent valve closes and opens, releasing the air, as a result of the rise and decrease in the liquid level in the eliminator caused by the buildup of free air (Figure).
  • To raise the backpressure on the meter and decrease the likelihood of cavitation or flashing, control valves should be positioned downstream of the meter.
  • Some Coriolis meters can be equipped with steam jackets when the process fluid needs to be maintained at a higher temperature. Electrical heating tape can be placed to the housing as an option. The manufacturer must install any jackets or heating tape.
  • A Coriolis meter can be used merely as a densitometer when flow-metering is not necessary. In this scenario, a small (1/2 in) meter is typically inserted in a by-pass line to reduce costs. Only clean services that won’t clog the meter’s narrow bore can use such a design. To ensure a flow through the meter, a restriction must also be added to the main piping (between the by-pass taps).

Sundareswaran Iyalunaidu

With over 24 years of dedicated experience, I am a seasoned professional specializing in the commissioning, maintenance, and installation of Electrical, Instrumentation and Control systems. My expertise extends across a spectrum of industries, including Power stations, Oil and Gas, Aluminium, Utilities, Steel and Continuous process industries. Tweet me @sundareshinfohe

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