Installation Procedures Flashcards

When installing a vortex flow meter, what installation condition will prevent the meter from producing any output signal?

Answer: Reynolds number below the meter's minimum detectable threshold

Vortex meters require a minimum flow velocity (minimum Reynolds number) to generate detectable vortex shedding; below this threshold, output is zero.

During installation of a pressure gauge on a steam line, what accessory is installed to protect the bourdon tube from direct contact with high-temperature steam?

Answer: Siphon (pigtail) or condensate pot

A siphon or condensate pot fills with condensed water that acts as a thermal buffer, preventing live steam from entering the gauge's bourdon tube.

What grounding requirement is critical when installing a Coriolis mass flow meter to prevent measurement interference?

Answer: The meter flanges must be bonded to the process piping to equalize potential and prevent stray currents through the sensor

Equalizing potential between the meter and process pipe via bonding prevents stray electrical currents from flowing through the process fluid and disturbing the Coriolis drive or pick-up coils.

A technician installs a thermowell by threading it directly into a threaded process connection. What additional step must be verified before committing the installation to service?

Answer: Verify the thermowell wake frequency calculation (Strouhal number analysis) confirms no resonance with process flow-induced vibration

Flow-induced vibration can excite a thermowell at its natural frequency, leading to fatigue failure; ASME PTC 19.3 TW wake frequency analysis must confirm adequate safety margin.

When installing a differential pressure transmitter below the process taps on a liquid service, which configuration of impulse lines is correct?

Answer: Slope the lines downward from the taps to the transmitter so liquid drains toward the transmitter and fills the lines completely

On liquid service with below-tap transmitter mounting, lines sloped downward ensure liquid-filled impulse lines free of gas pockets that would create measurement errors.

What is the significance of specifying the 'wetted materials' of a pressure instrument during installation engineering?

Answer: Wetted materials must be compatible with the process fluid to prevent corrosion, contamination, and safety hazards

Incompatible wetted materials can corrode in service, contaminating the process, causing measurement drift, and potentially causing catastrophic seal failure.

During commissioning of a newly installed 4-20 mA loop, the technician reads 3.8 mA with the transmitter at zero-percent input. What is the most likely cause?

Answer: The transmitter zero is not trimmed, or there is excess resistance causing a voltage drop that reduces loop current

A reading below 4 mA at zero input typically indicates the transmitter zero is trimmed low or excess loop resistance is causing a voltage drop that the transmitter cannot overcome.