Micronics 216 manual Transducer Positioning, Mounting the Transducers

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TRANSDUCER POSITIONING

As the transducers for the Portaflow 216 are clamped to the outside surface of the pipe, the meter has no way of determining exactly what is happening to the liquid. The assumption therefore has to be made that the liquid is flowing uniformly along the pipe either under fully turbulent conditions or under laminar flow conditions. Further it is assumed that the flow velocity profile is uniform for 360° around the pipe axis.

Figure 8:- A uniform profile as compared to a distorted profile.

“A”“B”

The difference between (a) and (b) is that the Mean Velocity of the flow across the pipe is different and because the Portaflow 216 expects a uniform flow as in (a), the distorted flow as in (b) will give measurement errors which cannot be predicted or be compensated.

Flow profile distortions result from upstream disturbances such as bends, tees, valves, pumps and other similar obstructions. To ensure a uniform profile the transducers must be mounted far enough away from any cause of distortion such that it no longer has an effect.

Figure 9:- Sensor Mounting

CORRECT INCORRECT

FLOWFLOW

> 20

< 20 D

10

20

5 20

FLOWFLOW

The minimum length of upstream straight pipe is 20 Diameters and 10 Diameters downstream that ensures accurate results will be achieved.

Flow measurements can be made on shorter lengths of straight pipe down to 10 Diameters upstream and 5 Diameters downstream, but when the transducers are sighted this close to any obstruction errors can be considerable.

It is not possible to predict the amount of error as this depends entirely upon the type of obstruction and the configuration of the pipe work and flow profile.

The message therefore is clear: Do not expect to obtain accurate results if the transducers are positioned closer than allowed to any obstruction that distorts the uniformity of the flow profile.

MOUNTING THE TRANSDUCERS

It will be impossible to achieve the accuracy of measurement specified for the Portaflow 216 if the transducers are not clamped to the pipe correctly and if the data - I.D. O.D., Pipe Material - are not accurate.

Apart from the correct positioning and alignment of the transducers, of equal importance is the condition of the pipe surface in the area under each of the transducers.

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Contents Portaflow Fast Track Set up Procedure Inverted view of grease applied to sensor block Connectors Pulse Cable ConnectionsBattery Circuit KeypadTransducers Switch 0n… Option number for the software Main MenuMain Menu Quick Start Enter MillimetresAttach Sensors Select Enter and the display will now showXXX Error Messages Appear HereMain Menu View/Edit Site Data VIEW/EDIT Site DataSite Number Dimension UnitsList Sites Site NameRead Flow Main Menu Select Sensor modeSensor Mode Sensor SETDisplay backlight Main Menu Set Up Instrument Pulse Output KeyEnabled Application OptionsMain Menu Read Flow Delete KeyOptions Key Damping sec Reset + Total/- TotalTotal Calibration FactorError Messages Status MessagesW8 mA Load to High Temperature range is -20C to +125CW6 mA OUT Overange Other MessagesReflex mode Enter a lining thickness firstTransducer Positioning Mounting the TransducersPropagation Velocity or Sound Speed CorrectincorrectLiquid Conditions Reynolds NumberApplication Temperature To calculate Re use the following formulaMaximum Flow Red connector upstream Blue connector downstreamGull wing and spring attachment Peizo electric crystal Supply Voltage Battery PackEnclosure OutputsWarranty Liquid Sound Speeds H2OSubstance Form Index Specific Gravity Sound Speed ∆ v/ºC C2H3N CH3CO2O C2H6O C2H7NO C4H9NOCH2I2 C2H5ICH4 CH4O C6H5FC3H8O C3H8O C7H9N C7H9N CH4O C7H8C7H8O C4H9NO C6H5NO2 CH3NO2 C9H2O KNO3C3H8O C2H6O H2SO4 CF4 C4H9NOH2O CH4O Instrument differences Charging Controller ICCharging Voltage SoftwareQuicker full charge Examples