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What I learned in week 9?, Patthiya Srimahaprom 61010789 - Coggle Diagram
What I learned in week 9?
Temperature Measurement
Thermowell
For a contact temperature measurement device
Principle
Thermal expansion techniques
Bimetallic
Bimetallic thermometer
Metal expand with increasing temperature
Accuracy: ±1% of span
Measurement range: -40 to 260 °C
Bimetallic Coils
Helical
Spiral
Liquid-in-glass
Types
Total immersion
Partial immersion
Accuracy depends on instrument quality, Temperature range, and types
Electrical techniques
Resistance temperature detectors (RTDs)
Electrical resistance of metal increases with increasing T
Two basic styles
Film type
Wire wound
Lead wires
3-wire RTDs
Used in industrial
4-wire RTDs
Used in laboratory
2-wire RTDs
Least accuracy
Accuracy better than thermocouples
Junction Semi-conductor sensors
Resistance decreases as the temperature increases
Thermocouples
Measuring a voltage
Two dissimilar metals
Types
Precious-metal thermocouples (Types S, R, and B)
Base-matal thermocouples (Types E, J, K, N, and T)
Components
Thermocouple wire
Extension/Compensation wire
Metal sheath
Thermowell
Plug / Connector / Accessories
Signal conditioning component / Readout
Optical and Radiation techniques
Pyrometer
The right wavelength
Metals select a shortest possible wavelength
Glass select a wavelength of 1.0, 2.2 or 3.9 micrometer
Plastic select a wavelength at which the transmission value is near zero
Chemical techniques
Use of the color changes is special color indicator
Crayon
Lacquer
Flow Measurement
Pressure-based flowmeter
Difference of pressure generated by acceleration
Venturi tube
Pipe purposefully narrowed to create a region of low P
Orifice plate
Metal plate with a hole in the middle
Tap locations
Flange taps
For orifice meter runs on large pipes
Vena contracta taps
For any given flow rate
Radius taps
For large pipe sizes
Corner taps
Used on small pipe diameters
For low flow rates
Integral orifice plate
Other types
Pitot tube
Annubar flow element
Target flow sensor
Flow nozzle
Segmental wedge
Pipe elbows
Patthiya Srimahaprom 61010789