Sensors

Question 1

Bourdon Tube

Answer 1

Pressure is measured as the amount of straightening of the bourdon tube

Question 2

Diaphragm

Answer 2

Pressure is measured as the amount of deformation of a flexible membrane

Question 3

Piezo electric pressure transducer

Answer 3

When a force is applied to the crystal an electrostatic charge is formed on the surface of the crystal, the charge is proportional to the force the range is up to 5000 bar used for rapidly varying high pressures

Question 4

Strain gauge

Answer 4

Measures the elastic deformation of a material due to the pressure acting on it. When the stress acts on the material it elongates and resistance is proportional to length the change in pressure give a change in resistance which can be measured. Range up to 700 bar maximum temp of 150 degrees.

Question 5

LVDT

Answer 5

Linear variable differential transformer, transformer measures linear displacement the core moves so changed the induced voltage in secondary coil to change operating pressures of 400 bar

Question 6

Bi metallic strip

Answer 6

Two different metals bonded together since the expansion of each material is different then when heat is applied the strip will bend can be connected to a local gauge

Question 7

Radiation thermometer

Answer 7

Electromagnetic radiation emitted from a material changes with the temperature of the material the wavelength of the radiation changes. For accurate readings the emmisivity of the material must be known range -30 to 3300

Question 8

Thermocouple

Answer 8

To dissimilar metals joined at the ends and each end is at a different temperature then a current will flow due to different emfs generated at each end. Range -200 to 1000 degrees

Question 9

RTD

Answer 9

Resistance thermometric device resistance of the wire changes due to the temperature range of about 0-200 degrees

Question 10

Ultrasonic level measurement

Answer 10

Ultra sound wave is released and the time taken for the signal to return therefore the distance travelled and the level of the tank can then be calculated

Question 11

Interface detection

Answer 11

A device that changed due to what liquid the detector is in proximity to

Question 12

Volume meter

Answer 12

Measure the volume of fluid passing a given point operate by filling and emptying chambers of known volume

Question 13

Variable area flow meter

Answer 13

The variable area is an indication of the quantity of fluid passing by producing a constant pressure difference

Question 14

Differential pressure

Answer 14

Difference in pressure across a restriction in the pipe and flow is proportional to the square root of the pressure difference

Question 15

Turbine meter

Answer 15

The moving fluid rotates a cane which produces a rotation proportional to fluid velocity

Question 16

Ultrasonic flowmeter

Answer 16

Has an ultra sound transmitter and receiver and works by the phase shift between the signals due to the flowing liquid