HELIFLU™ TZN Flowmeter Configurations The HELIFLU™ TZN Flowmeter can be installed either horizontally or vertically ( flow upwards). The diagram below represents a typical design of a flowmeter assembly and its related equipment. Pressure Drop Back Pressure For non LPG fluids, the numerical value of the minimum absolute back pressure should be estimated from the equation: Pback ≥2 x ΔP + 1.25 X Pí with: Pback : Back pressure ΔP : Meter pressure drop at max. flowrate ( + Flow conditioner) Pv : Vapor pressure at Max. temperature Pressure drop through the meter is proportional to the square of the flowrate. For a constant inlet, there is a maximum flowrate at which a turbine meter can be operated within acceptable error limits before performance deteriorates. This is due to cavitation effects. It will be noted that the lowest pressure occurs within the rotor and it is here that the cavitation may occur. This will be indicated by a sudden change in meter factor and is more likely to occur with a vapour pressure fluid with a low system operating pressure. By experience, on the Heliflu™ TZN Flowmeters, the vertical position of the meter with flowrate from the bottom to top, do not create significant meter factor change. When the flow range is too great for one meter or its prover, a bank of meters can be installed in parallel. Each meter in the bank shall operate within its minimum and maximum flow rates. 0 10 5 15 20 25 30 0 10 100 Delta P (PSI) Pressure drop across the HELIFLU™ TZN Flowmeters is approximately 3.6 PSI at maximum flowrate with a relative density of 1 (API gravity = 10) and a kinematic viscosity of 1 cSt. The pressure drop at any flowrate Q, for kinematic viscosity νand relative density d can be calculated from : with: P : Pressure drop (PSI) d : Relative density ν : Kinematic viscosity (cSt) Q : Flowrate (Bbl/h) Qmax : Maximum flowrate (Bbl/h) ΔP = x 3.6 x d x ν0.2 Q max Q ( )2 Coriolis mass flow meter PD meter HELIFLUTM meter Traditional turbine meter Meter run 10. D 5. D PT TT Block valve Valve to prover from prover Control Valve Check valve Strainer and/or Vapour eliminator Straightener Turbine meter Viscosity (cSt)
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