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