Sensia 3300 EFM, Installation, Operation & Maintenance Manual

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Measuring Liquid via a Differential Pressure Meter
Best Practices
The Scanner 3300 calculates liquid flow through outputs from a MVT connected to a differential pressure meter. To en-
sure measurement accuracy, ensure that the meter run complies with the following AGA 3 and ISO 5167 guidelines, as
applicable:
• Do not place unit near vents or bleed holes that discharge corrosive vapors or gases.
• Consider the orientation of the meter run when determining the best position for mounting the Scanner.
– If the MVT is mounted to a horizontal pipeline, make sure process connections are horizontal with the pipeline,
or sloped downwards towards the Scanner. Mount the MVT below the pressure taps at the pipe. Use the side
(upper) ports as process connections and the bottom ports for draining and filling the differential pressure
housings.
– If the MVT is mounted to a vertical pipeline, install the sensor below the differential pressure source
connections. Slope all tubing downward at least 1 in./LF to avoid gas entrapment.
• Mount the MVT as near level as possible such that the operator has a clear view of the LCD, and can access the
keypad easily when the enclosure cover is removed. The location should be as free from vibration as possible.
• Make sure the high port of the sensor (marked “H”) is connected to the upstream side of the meter run.
• Pipe diameters (D) should be between 2 in. (50 mm) and 39 in. (1000 mm) per ISO 5167; or greater than 2 in. (50
mm) per AGA 3.
• Pipe Reynolds numbers must be above 5000. Avoid high-viscosity liquids (greater than 15 cP).
• d (orifice diameter) must be greater than or equal to 0.45 in. (11.5 mm).
• Orifice β (diameter ratio) must be greater than or equal to 0.1 and less than or equal to 0.75.
• Gauge lines should be of uniform internal diameter and constructed of material compatible with the fluid being
measured. For most applications, the bore should be no smaller than 1/4 in. (6 mm) and preferably, 3/8 in. (10
mm) in diameter. The internal diameter should not exceed 1 in. (25 mm). If high-temperature fluids are likely to be
encountered, make sure the measuring tube used is rated for the anticipated temperature range.
• If there is possibility of freezing, the gauge lines can be filled with a suitable seal liquid. The seal liquid should be
somewhat denser than the process fluid, should not dissolve in it, should have a sufficiently low freezing point, and
should be non-toxic. Alternatively, heat tracing can be used.
• Gauge line length should be minimized to help prevent pulsation-induced errors.
• Gauge lines should slope upward to the meter at a minimum of 1 in./ft.
• If gauge lines must slope in more than one direction, do not allow more than one bend and install a gas trap.
• Gauge lines should be supported to prevent sag and vibration.
• Where pulsation is anticipated, full-port manifold valves with a nominal internal diameter consistent with the gauge
lines are recommended.
If the MVT is mounted to a cone meter, consider the following guidelines in addition to the best practices listed above.
• Position the cone meter so that there are 0 to 5 diameters of straight pipe upstream of the meter and 0 to 3 diameters
of straight pipe downstream of the meter.
• Install the meter so that the static pressure tap is upstream of the differential pressure tap. The high side of the MVT
transducer must also be situated upstream.
• Install shutoff valves directly on the pressure taps. Choose a shutoff valve that is rated for the ambient temperatures
of the location and the operating pressure of the pipe in which it will be installed, and for use with dangerous or
corrosive fluids or gases, if applicable. The valves must not affect the transmission of the differential pressure signal.
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Section 2 Scanner 3300 EFM