Chapter 4 Process Measurements and Instrumentations

What is the name of the sensor as shown in the picture.

• Differential pressure sensor

• Ultrasonic sensor

• Float sensor

• Bubble sensor

How does bubble sensor works in measuring the liquid level?

• The time required for an ultrasonic wave emitted by a transducer and reflected off the surface of the liquid to return to the transducer, thus determining the liquid level

• The differential pressure and density of the liquid, can obtain the liquid level

• The force required to keep the float in place is proportional to the liquid level.

• The pressure required to produce the continuous stream of bubbles can measure the liquid level.

What are the special features of level sensor?

I. Measurement can be accomplished without touching the liquid

II. There are no moving parts

III. Small and light

• I and II

• I, II and III

• II and III

• I and III

Which statement is correct about working principles of Resistance Temperature Devices (RTD) ?

I. Determine the temperature by measuring electrical resistance

II. Two different metals expand at different rates as they warm up.

III. The metal expand with temperature

IV. The electrical resistance of pure metals increases with increase in temperature.

• I, II and III

• I and II

• II and III

• I and IV

What are the conditions that may prevent the usage of orifice meter for flow rate measurement in pipeline?

I. Not enough available pressure drop e.g gravity flow

II. Fluid that far from their saturated vapor pressure

III. Flow of corrosive fluid

IV. Fluids with suspended solids

• I and II

• I, III and IV

• II and III

• III and IV

What is the name of the measurement?

• Strain Gauge Sensor

• Bellows-Type Sensor

• Bourdon Tube Sensor

• U-Tube Manometer

Which statement is correct about the working principle of Bourdon Tube Sensor?

I. When pressure is applied to the inside of the tube, the sealed end of the tube will tend to straighten out, which will cause a small amount of movement at the sealed end of the tube (expansion).

II. U-shaped tube half-full of liquid, one side of which is connected to the region of interest while the reference pressure (which might be the atmospheric pressure or a vacuum) is applied to the other.

III. This movement can be amplified directly by gears and a pointer to make a direct-reading pressure gauge

IV. The difference in liquid level represents the applied pressure

• I and II

• I and III

• II and III

• II and IV

What is the temperature range of thermocouple?

• -200 to 1400 °C

• 0 to 1400 °C

• 0 to 1000 °C

• 200 to 1400 °C

Which one is NOT the advantage of bellow-type sensor?

• Moderate cost

• Adaptability for absolute and differential pressure

• Limited availability of metals and work hardening of some of them

• Delivery of high force

Which one is NOT the disadvantage of Diaphragms Sensor?

• Lack good vibration and shock resistance

• Difficult to repair.

• Limited to relatively low pressures

• Cost is moderate.