Water is flowing through a series of four tanks and getting heated as shown in figure. It is desired to design a cascade control scheme for controlling the temperature of water leaving the tank 4 as there is a disturbance in the temperature of a second stream entering the tank 2. Select the best place to take the secondary measurement for the second loop?

Related Mcqs:

1. Water is entering a storage tank at a temperature T0 and flow rate Q0 and leaving at a flow rate Q and temperature T. There are negligible heat losses in the tank. The area of cross-section of the tank is A0. The model that describes the dynamic variation of temperature of water in the tank with time is given as________________?

   A. Q0(T0 – T) = Ac . h (dT/dt)
   B. Q0T0 – QT = Ac . h (dT/dt)
   C. Q(T0 – T) = Ac . h (dT/dt)
   D. Q(T0 – T) = Ac . (dTH/dt)

2. Cascade control means _______________?

   A. Feed forward control
   B. More than one feed-back loop
   C. On-off control
   D. One feed-back loop

3. Temperature control of an exothermic chemical reaction taking place in a CSTR is done with the help of cooling water flowing in a jacket around the reactor. The types of valve and controller action to be recommended are________________?

   A. Air to open valve with the controller direct acting
   B. Air to close valve with the controller indirect acting
   C. Air to open valve with the controller indirect acting
   D. Air to close valve with the controller direct acting

4. Normal mercury thermometer can be used to measure a temperature of about 300°C. However, its maximum temperature measurement range can be increased upto about 500°C by__________________?

   A. Filling nitrogen under pressure in the stem
   B. Increasing the diameter of the tube
   C. Using steel tube in place of glass tube
   D. Accounting for the tube expansion

5. Temperature of molten pig iron (1450°C) and molten slag (1500°C) flowing out of a blast furnace is measured by a/an_______________?

   A. Chromel-alumel thermocouple
   B. Optical pyrometer
   C. Radiation pyrometer
   D. Either B. or C.

6. Which of the following does not figure in the list of seven substances selected for international temperature scale ?

   A. Ice (F.P) and steam (B.P)
   B. Oxygen and sulphur (B.P)
   C. Antimony and silver (F.P)
   D. Zinc (B.P) and mercury (F.P)

7. Platinum resistance thermometer is the international standard for temperature measurement between __________________?

   A. Triple point of hydrogen and freezing point of antimony
   B. 13.81°K to 903.9°K
   C. Both A. and B.
   D. Neither A. nor B.

8. Helium gas constant volume thermometer is suitable for the measurement of a temperature of ______________ °C?

   A. < 100
   B. < 0
   C. > 0
   D. > 800

9. Measurement of sub-zero Celsius temperature in industry is done most commonly by __________________?

   A. Thermocouples
   B. Resistance thermometers
   C. Gas thermometers
   D. Bi-metallic thermometers

10. Accurate temperature measurement performance of a radiation pyrometer cannot be affected, if the ?

    A. Enhancement or attenuation of radiation occurs in the sighting path
    B. Object and surrounding are at almost the same temperature
    C. Object has varying emissivity
    D. Object is transparent