Temperature Measurement

Question 1

ITS 90 Purpose (International Temperature Scale)

Answer 1

Is an equipment calibration standard for making measurements on the Kelvin and Celsius temperatures scales

Question 2

Why temperature is measured

Answer 2

Control
Safety/Data
Production

Question 3

Tags starting with T

Answer 3

Temperature Transmitter TT-100
Temperature Indicating Transmitter TIT-100
Temperature Controller TC-100
Temperature Indicator Controller TIC-100
Temperature Recorder TR-100
Temperature Element TE-100
Thermo well TW-100

Question 4

Physical attributes of substances that could be used to measure temperature

Answer 4

Metal expands when heated
Gas/Liquid expands when heated (pressure change)
Substances melt at certain temperature
Thermocouple
RTDs
Infrared Radiation

Question 5

Seebeck Effect - Dissimilar metals bonded together create mV

Answer 5

Thermocouple

Question 6

Resistance of pure metal changes proportional to temperature change

Answer 6

RTDs

Question 7

black-body radiation emitted as a function of an object temperature

Answer 7

Infrared Radiation

Question 8

Most popular thermocouple

Answer 8

K type

Question 9

why are certain metals used more for thermocouples

Answer 9

a number of standard types are used because they possess predictable output voltages and large temperature gradients

Question 10

ASTM negative wire is always

Answer 10

red

Question 11

Can we measure voltage from a thermocouple?

Answer 11

A thermocouple creates an output voltage based on the temperature difference between its cold (reference) junction and its hot junction

Question 12

Resistance Temperature Detector

Answer 12

RTD

Question 13

temperature transducer that provides temperature information as the change in resistance of a metal wire element often platinum

Answer 13

RTD

Question 14

RTD Materials

Answer 14

Platinum - most common
copper
nickel
tungsten
balco (nickel/iron alloy)

Question 15

RTD Advantages

Answer 15

Among the most accurate, reproducible, stable, and sensitive thermal elements available
Good sensitivity
Leads use conventional copper wire instead of more expensive extension wire

Question 16

RTD Limitations

Answer 16

Resistance output
Lower temperature range than thermocouples
Higher cost
more fragile construction
Subject to self heating
May be vibration sensitive
need a power source

Question 17

RTDs vs Thermocouples

Answer 17

RTDs generally used if temperature < 400 C
Thermocouples high as 3000 C
RTDs typically more linear than thermocouples