Screening Technologies-An Overview...(Electromagnetic, Doppler Ultrasonic) Non-Contacting Sensor...
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Flow Measurement Presented to: Iowa WEA Operator Training Presented by: Chris Johnson-Gurney and Associates Marshalltown, Iowa September 10, 2015
Transcript of Screening Technologies-An Overview...(Electromagnetic, Doppler Ultrasonic) Non-Contacting Sensor...
Flow MeasurementPresented to: Iowa WEA Operator Training
Presented by: Chris Johnson-Gurney and AssociatesMarshalltown, Iowa
September 10, 2015
Overview
◦ Theory/Computations
◦ Reasons for Measurement
◦ Accuracy vs. Repeatability
◦Methods
◦ Data Collection/Management
Take-Away
◦ “Almost Everything in Flow Measurement is a Compromise”
Theory
◦ How to Compute
◦ Flow = Velocity x Area (Continuity Equation)◦Q = vA
Reasons
◦ Why measure flow?
Operation: Provide information to make process decisions or control another process.
Identify problems (i.e. I&I) (Pre and Post Monitoring)
Regulatory Compliance/Billing
Accuracy vs. Repeatability
Methods
◦ Depth of flow at a known point (pipe, weir, flume, etc.)
◦ Pump-Hours Hours of Pump Run Time x Pumped Flow Rate
Need to know wet well size, control elevations, and time to pump “off” level
Methods
◦ Depth of flow at a known point (pipe, weir, flume, etc.)
◦ Pump-Hours Hours of Pump Run Time x Pumped Flow Rate
Need to know wet well size, control elevations, and time to pump “off” level
Methods (cont’d)
◦ Automatic
Full Pipe
Open Channel
Methods (cont’d)
◦ Automatic
Full Pipe
◦ Magnetic Spool
◦ Insertion Magnetic
◦ Clamp On
Methods (cont’d)
◦Magnetic Spool Advantages◦ Proven Technology◦ Relatively Inexpensive for smaller pipe
diameters
Disadvantages◦ Electrodes Fouled◦ Less Accuracy at Lower Flows
Methods (cont’d)
◦ Insertion Magnetic Advantages◦ Relatively inexpensive over a wide range of
pipe diameters◦ Easy installation/removal for maintenance
Disadvantages◦ Debris hang up in wastewater application◦ Can be less accurate if pipe not profiled
Methods (cont’d)
◦ Clamp On Advantages◦ Relatively inexpensive over a wide range of
pipe diameters◦ Easy installation◦ Can be excellent solution if applied properly
Disadvantages◦ Misapplications have given bad reputation
Methods (cont’d)
◦Open Channel Level with a Primary Device (weir, flume, etc.)◦ Transducer to measure level and
transmitter to compute flow.
Methods (cont’d)
◦ Level with a Primary Device (weir, flume, etc.)◦ Advantages Probably most accurate Can manually measure if electronics fail
◦ Disadvantages Structures can be expensive
Methods (cont’d)
◦ Submerged Sensor (Electromagnetic, Doppler Ultrasonic)
◦ Non-Contacting Sensor (Radar or Laser velocity measurement, ultrasonic level
Methods (cont’d)
◦ Submerged Sensor Advantages◦ Relatively inexpensive◦ Can fit in existing structures, manholes
Disadvantages◦ Debris, grease, etc can foul sensor◦ Access (Manhole/Confined Space Entry)
Methods (cont’d)
◦ Non –Contacting SensorMeasures Level by Ultrasonic and Velocity by Radar
Methods (cont’d)
◦ Non-Contacting Sensor Advantages◦ Non contacting with wastewater flow◦ No confined space entry◦ Retrofit to existing structures◦ Can be removed from grade level
Disadvantages◦ More expensive◦ Additional features required to measure
surcharge flow
Data Collection/Management
Data Collection/Management
Data Collection/Management
◦ Laptop to Data Logger
◦Web Based Data Collection
Considerations
◦ Accuracy vs. Repeatability
◦ Price
◦ Structures
◦ Company Experience
Troubleshooting
◦ Have as much information as possible.
Questions????????
Contact information:Gurney and Associates
4428 South 108th StreetOmaha, NE 68137(402) 551-7995
