flow meter operation & maintenance - … - flow meter.pdf3 area - velocity flow meter...
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MWEA Collection System Seminar September 11, 2014
FLOW METER OPERATION & MAINTENANCE
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Operations & Maintenance
• Permanent Meters
• Billing meters
• Meters used for Temporary Studies
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Area - Velocity Flow Meter
• Continuity Equation Q = A x V
• Q = the volumetric flow rate
• A = the cross sectional area of the flow
• V = the mean velocity
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Area Velocity Flow Meters
Area Velocity (Continuous Wave Doppler)
Flow Meters
Advantages
• Easy installation & maintenance.
• Can measure flows down to 1 inch of level.
• No enclosure required.
• Relatively low cost.
Disadvantages
• Accuracy of +5% in normal field conditions.
• Maintenance required (Sensor subject to fouling and grease).
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Doppler - Area Velocity Meter Probe
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Pressure - Depth sensor
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Doppler - Area Velocity Meter Probe
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Atmospheric Pressure
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Pressure Sensors
• Atmospheric vent tube
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DESICCANT - ATMOSPHERIC REFERENCE
• Blue is good!!
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DESICCANT
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It’s time to replace the desiccant
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Pressure Sensors are expensive
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Pressure - Depth sensor
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Communicate with Maintenance staff
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Site Selection - ?
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Range Gated Doppler Flow Meter
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ADFM
• Ultrasonic level sensor
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ADFM Velocity Profile
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Full Pipe Flow Meter (ADFM)
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ADFM Flow Meter
• AC or DC powered
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Radar Flow Meter
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Radar Flow Meter
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Radar Flow Meter
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Radar Flow Meter
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Radar Flow Meters
Advantages • Non-contact level and
velocity sensors.
• Will work in large & small pipes.
• Easy installation & maintenance.
• No enclosure required.
• Relatively low cost.
Disadvantages • Accuracy of +5-% in
normal field conditions.
• Surface velocity only.
• Requires trained technician for repair and calibration.
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LASER - FLOW METER
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LASER FLOW METER
• No contact with the flow
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LASER FLOW METER
• Multiple velocity reads
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LASER FLOW METER
• No contact with the flow
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Laser Flow Meters
Advantages • Non-contact level and
velocity sensors.
• Multipoint profile, (15 -measurements 5 horizontal and 3 vertical
• Depth measurements (5%, 8% and 11% of depth)
• No enclosure required.
• Relatively low cost.
Disadvantages • Accuracy of +5-% in
normal field conditions.
• Maximum depth penetration is 6”
• Therefore the meter is seeing peak velocity and is unable to see the full profile of the flow
• Requires trained technician for repair and calibration.
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Magnetic Flow Meter
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Magnetic Field
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Magnetic Flow Meter Probe
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Magnetic Flow Meter Probe
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Battery Powered Meters
• You get what you pay for
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TRANSIT-TIME FLOW METER
• Multi-Path Meter
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Transit-Time Flow Meter
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Transit-Time Flow Meter
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Transit Time Flow Meters
Transit-Time Flow Meters
Advantages • High degree of accuracy
(+2 to 5%) – Open Channel. (+0.5%) Full pipe application.
• Good for large pipes.
• Wide flow range.
• Ability to handle poor hydraulics.
Disadvantages • Relatively high cost.
• Air entrainment can cause issues.
• Requires a skilled technician and specialized equipment.
• Above ground enclosure required.
Transit Time Flow Meters
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• Cable Repair
– Don’t step on the cables. You can nick the cable jacket and this may allow moisture to cause short circuits.
– Most cables can not be repaired.
– If the cable or probe are damaged, it is very costly to replace.
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Magnetic (MAG) Flow Meter
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Magnetic Flow Meters
Magnetic Flow Meters
Advantages • High degree of accuracy
(+0.5%) and consistent over full flow range when calibrated properly.
• No obstructions to flow.
• No moving parts.
• Wide flow range.
• Fixed area measurement
Disadvantages • Requires a FULL pipe
• Relatively high construction cost.
• Power supply is required.
• Repairs require skilled technician and specialized equipment.
• Electronic components vulnerable to lightning damage.
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Verify Your Information
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Pull out the maintenance file and check the settings
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Check all of the settings
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Parshall Flumes
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Ultrasonic Down Looker
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Parshall Flumes
Advantages • High degree of accuracy
(+2%) and consistent over full flow range when calibrated properly.
• No moving parts.
• Wide flow range.
• Sediment control.
Disadvantages • Relatively high
construction cost.
• Level measurement required.
• Possible construction flaws.
Parshall Flumes
Parshall Flume with Foam
Parshall Flume with Solids
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The Data Looks Good ???
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Verify the As-Built Information
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Velocity Profiling
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Portable Velocity Meter
• Send it back to the factory once per year to be re-certified
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Velocity Profile
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Why isn't there any velocity reads?
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Flow Lab Verification
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Flow Lab Verification
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