How to select primary element Differential Pressure flow measurement?


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Advantages and Limitations of different types primary element (Differential Pressure Flow Measurement)

Square Edge Concentric Orifice Plate

Recommended Service - Clean Liquid,Gases,Steam

Advantages - Easy to install
Low cost
Easy to replace

Limitation - Relaxation piping requirement
High head loss
Accuracy affected by installation and orifice condition

Conical / Quadrant edge concentric orifice plate

Recommended Service - Viscous Liquid

Advantages - Easy to install
Low cost
Easy to replace

Limitation - Relaxation piping requirement
High head loss
Accuracy affected by installation and orifice condition

Eccentric / Segemental Orifice plate

Recommended Service - Liquids and gases containing secondary fluid phases

Advantages - Easy to install
Low cost
Easy to replace

Limitation - Relaxation piping requirement
High head loss
Accuracy affected by installation and orifice condition
Higher uncertainties of discharge coefficient data.

Integral Orifice

Recommended Service - Clean Liquids,Gases,Steam

Advantages - Easy to install
No lead lines
Low cost

Limitations - Relaxation piping requirements
Proprietary design requires calibration
High head loss
More prone to clogging than standard orifice plate

Venturi / Flowtube

Recommended Service - Clean and dirty liquids,Gases,Steam,Slurries

Advantages - Low head loss
2 to 9 times less relaxation piping than orifice
Higher flow capacity than orifice for same differential pressure
Accuracy less affected by wear and installation condition than orifice

Limitation - High Initial Cost

Nozzle

Recommended Service - Clean Liquids,Gases,Steam

Advantages - Higher Flow capacity than orifice for the same differential pressure
Accuracy less affected by wear and installation condition than orifice
Good for high temperature and high velocity application
Mass transfer standard for gases

Limitation - Harder to replace than orifice
High head loss

Segmental Wedge

Recommended Service -Dirty Liquid,Gases,Steam,Slurries,Viscous Liquid

Advantages - No lead lines
Minimal clogging potential
40% less head loss than orifice
Minimal relaxation piping

Limitation - Proprietary design needs calibration
High initial cost
Requires remote seal differential pressure transmitter,harder to zero

Venturi Cone

Recommended Service - Clean and dirty liquids,gases,Steam,Viscous liquids

Advantages - Minimal relaxation piping
Low flow capability

Limitation - Proprietary design