Airflow Measuring Instruments and Their Applications - GHDonline
Airflow Measuring Instruments and Their Applications - GHDonline
Airflow Measuring Instruments and Their Applications - GHDonline
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Building Design <strong>and</strong> Engineering<br />
Approaches to Airborne Infection Control<br />
<strong>Airflow</strong> <strong>Measuring</strong><br />
<strong>Instruments</strong> <strong>and</strong> <strong>Their</strong><br />
<strong>Applications</strong><br />
Jack Price
Air Flow Measurements<br />
• Pressure Measurement<br />
– Pitot Travers<br />
• Hood Static Pressure<br />
– Hood entry loss factors<br />
– Hood entry coefficient<br />
• Heated Element<br />
Anemometers<br />
– Thermocouple<br />
– Thermister<br />
• Mechanical Devices<br />
– Rotating vane anemometer<br />
– Deflecting vane anemometer<br />
– Swinging vane anemometer<br />
– Bridled vane anemometer<br />
• Other Devices<br />
– Vortex shedding<br />
anemometers<br />
– Orifice meter<br />
– Venturi Meter<br />
– Canopy hoods<br />
CALIBRATION – CALIBRATION - CALIBRATION
Pitot Tube
Pitot Tube Traverse
Type 8500<br />
Thermocouple sensor
Thermister sensor
Venturi Meter<br />
20 x 10.080 Westfall Model 2300 Venturi Flowmeter<br />
96" Vinyl ester fiberglass<br />
universal venturi tube<br />
manufactured by Westfall<br />
Manufacturing Company
Orifice Meter
Design of Local Exhaust Hoods<br />
• Contaminant characteristics<br />
• Hood types canopy / slot / enclosing<br />
• Design factors<br />
- capture velocity - air distribution<br />
- flow rate - hot processes<br />
- flanges & baffles - hood losses<br />
- duct velocities - workers<br />
• Special Hoods<br />
• Push – Pull ventilation hoods
Single hood<br />
system with<br />
air cleaner<br />
<strong>and</strong> one fan<br />
exhaust
Friction loss<br />
in duct work
Duct Fittings
Exhaust Stacks & Re-entrainment
Distribution of Air Flow
Ventilation System Design Software
Fan Laws
Magnehelic<br />
gauge showing<br />
relationship<br />
between<br />
pressure drop<br />
<strong>and</strong> air flow rate
Questions ?
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