ANAND INSTITUTE OF HIGHER TECHNOLOGY

ELECTRONICS AND INSTRUMENTATION DEPARTMENT

EI2303INDUSTRIAL INSTRUMENTATION II

STAFF NAME : JANSIRANI T. SUBJECT CODE:EI2303

DESIGNATION: LECTURER CLASS : III YEAR/V SEM

QUESTION BANK

UNIT I–VARIABLE HEAD TYPE FLOW METERSPART A

1. List some of the sealing fluids used in orifice tappings. (APR / MAY 2005, MAY / JUN 2007)

Chloro naphthalene, dibutul phthalate chlorinated oils.

2. Write the expression for the velocity of air in pitot tube. (APR / MAY 2005)Velocity of air can be calculated by taking the square root of the

difference between the total pressure and the static pressure and multiplying that by the C/D ration.

Velocity Vp= C/D (Pk-PS)1/2

Where,Vp – Velocity

C- Dimensional constantD-DensityPT-Total PressurePS-Static pressure

3. Name the types of Orifice plate. ( MAY / JUN 2006)There are two standard types,

Thin orifice plate. Sharp square edge orifice plate.

Some other sub divisions are,

Concentric orifice plate Eccentric orifice plate

Segmental orifice plate Quadrant edge orifice plate

4. Define stagnation point in pitot tube. (APR / MAY 2004, MAY / JUN 2006)When a solid body is kept centrally and stationary in a pipe line with a fluid

streaming down, the velocity of the fluid starts diminishing due to the presence of the body till it is reduced to zero directly in front of the body. This point is known as the stagnation point.

5. List the advantages of venture flow meter. (MAY / JUN 2007) It causes low permanent loss. It is widely used fir high flow rates. It is available in very large pipe sixes. It has well known characteristics. It can be used at low and high beta ratio.

6. Define discharge coefficient. (NOV/ DEC 2007)Discharge coefficient is defined as the ratio between actual volumetric flow rate

and ideal flow rate.Cd = qact/ qideal

Where,qact - - actual volumetric flowrateqideal – ideal volumetric flowrate

7. What is laminar flow? (APR / MAY 2008)When the velocities of fluids moving through uniform conduits are at low

velocities, the motion of individual particles are usually along lines which are parallel to the conduit walls.

The velocity of particles is greatest at the centre and theoretically zero at the wall of the conduit. Plots of individual loci are called Streamlines and the flow is Laminar.

8. How do you classify the flow meters? (MAY / JUN 2009)Flow meter is a device that measures the rate of flow or quantity of a moving fluid

in an open or closed conduit. Flow measuring devices are generally classified into four groups. They are,

Mechanical type flow meter Inferential type flow meter Electrical type flow meter Other type flow meter –Purge flow regulators, Flow meter for solid flow

measurement, cross-correlation flow meter, Vortex shedding flow meter, flow switches

9. What is vena contracta point? (NOV / DEC 2009)In the fixed restriction variable head type flow meters, the ideal volumetric flow

rate is Q = AV

For actual flow conditions with frictional losses present, a correction to the flow rate formula is necessary. Besides, the minimum area of the flow channel not occurs at the restriction but at some point slightly downstream, known as the Vena contracta point.

10. State Bernoulli’s theorem.Bernoulli’s theorem states that in a flowing stream, the sum of the pressure head,

the velocity head and the elevation head at one point is equal to their sum at another point in the direction of flow plus the loss due to friction between two points.

11. Define Velocity head and Pressure head.Velocity Head:

Velocity head is defined as the vertical distance through which a liquid would fall to attain a given velocity.

Pressure Head:

Pressure head is the vertical distance which a column of the flowing liquid would rise in an open ended tube as a result of the static pressure.

12. Define the term velocity approach factor in fluid flow measurement. (MAY / JUN 2009)

The velocity approach factor means taking the square root of the difference between the total pressure (PT) and the static pressure (Ps) and multiplying that by the ratio C/D.

Vp= C/D (Pk-Ps)1/2

13. What is the basic principle of obstruction meters?When a fixed area flow restriction of some kind is placed in a pipe carrying the fluid whose rate of flow is to be measured, the flow restriction causes a pressure drop which varies with the flow rate. This pressure drop is measured using a differential pressure drop becomes a measure of flow rate.

14. What are the advantages of orifice over venturimeter? (APR/MAY 2010) Orifice can be used in awide range of pipe sizes.(3.175 mm to 1828.8 mm) but

the venturimeter not useful below 76.2 mm pipe size. Orifice are well known characteristics and easy to inspect but the venture

meter are more difficult to inspect due to its construction.

Cost of orifice is low and venturimeter cost is high. Orifice can be installed between existing pipes flanges and venture meter

required lot of space.

15. Write down any two applications of pitot tube.(APR/MAY 2010) A Pitot tube can measure the fluid flow velocity by converting the kinetic

energy in the fluid flow into potential energy. If average duct velocities, or mass or volumetric flow rates are required, it is

necessary to perform a Pitot traverse of the duct. Modern aircraft use a pitot tube as their primary tool to measure their speed. The pitot tube are used in air application as ventilation and HVAC systems.

16. What are the advantages of using venturi tube as a restriction element?(NOV/DEC 2010)venturi tube as a restriction element because,

It causes low permanent pressure loss when compared with orifice plate. It can be used at low and high β ratios. It is more accurate over wide flow ranges than orifice and flow nozzles.the

accuracy range is from ±1/4 to±3%. It can be used to handle slurries and dirty liquids but the annubar tubes are

unsutable for dirty liquids. The orifice plates tend to clog, thus reducing use in slurries but the venturi is

used to handle slurries.

17. What is Dall tube?(NOV/DEC 2010)The Dall tube is amodified form of venturi tube. It is one of the type of flow meter

used for mesuring the flow rate of water, sewage, air and steam. It is used where the velocity of flow throgh the pipe having specified head loss.Thedall tube is made of gun metal. For 450 mm and larger sizes, high grade cast iron is used.It is also made by lithium coating in order to avoid corrosion of pipe by the fluids.

Types of Dall tube Linear type Dall tube Contour Dall tube FabricatedDall tube Sewage Dall tube

18. What are the advantages of venturitube over orifice plate? (NOV.DEC.2012)

More accuracy

19. What is pitot tube? (NOV.DEC.2012)

An obstruction type primary element used mainly for fluid velocity measurement is the pitot tybe.

PART B

1. Explain the operation of Orifice plate (8) (APR/MAY 2004)

2. Explain the operation of Venturi tube with neat sketch. (8) (APR/MAY 2004)

3. Write a short note about Flow Nozzle. (8) (AR/MAY 2005, APR/MAY2008)

4. Write a short note about Pitot tube with neat necessary equations.(8)(AR/MAY 2005, APR/MAY2008)

5. Discuss the installation and tappings in Orifice flow meter. (16) (APR/MAY2005)

6. Discuss the principle of operation, merits, demerits of any two types of variable type flow meters with necessary sketches and equations.(16) (NOV/DEC 2005)

7. Discuss in details the installation and piping arrangement of different fluids in head flow meters.(16)(NOV/DEC2005, MAY/JUN2009,APR/MAY 2010)

8. Explain the principle of operation of any two types of head flow meters with neat sketch. (8)(MAY/JUN2006)

9. Discuss the piping arrangements of different fluids in head flow meters.(8)(MAY/JUN2006)

10. Explain the principle of operation of pitot tube with neat sketch. (6)(MAY/JUN2006)

11. Discuss the installation of head flow meters. (10)(MAY/JUN2006)

12. Explain the principle, types, machining and mounting methods of the orifice with necessary sketches and equations.(16)(MAY/JUN2007)

13. Explain how the fluid velocity is measured using pitot tube and derive the expression for the velocity coefficient.(16)(MAY/JUN2007)

14. Briefly explain the principle of operation of the pitot tube an derive the relevant equation for pitot static tube for air speed measurement.(16)(NOV/DEC2007)

15. Explain the principle of operation of Venturi tube with neat sketch and discuss the merits and demerits. (16)(NOV/DEC2007, NOV/DEC2009)

16. Describe the construction and working principle of dall tube and describe its advantages and disadvantages.(16)(APR/MAY2008)

17. Distinguish between variable head and variable area flow meters. Explain the working principle of any one type of variable head flow meter with neat sketch. (16)(MAY/JUN2009)

18. Write short note about Pitot tube. (8)(NOV/DEC2009)

19. Write short note about Dall tube. (8)(NOV/DEC2009)

20. With neat diagram, explain any two types of variable type head meters used in flow measurement. (APR/MAY 2010)

21. Describe construction and working of venturi tube with neat sketck. Also derive the Bernoulli equation. (NOV/DEC 2012)

22. Describe how head flow meters are installed and various precautiond to be carried out while installation. (NOV/DEC 2012)

UNIT II

QUANTITY METERS, AREA FLOW METERS AND MASS FLOW METERS

PART A

1. Give the classes of positive displacement type flow meters.(APR / MAY 2005)2. Mention some positive dispalcement type flow meters.(NOV/DEC 2010)

Positive dispalcement type flow meters are generally used for accurate measurement of steady flow.Positive displacement type flow meters are classified as follows,

Nutating disc type Oscillating piston type Sliding vane, retracting vane type Lobed impeller type Oval shaped gear type Reciprocating piston type Fluted rotor type Bellow gas meter

3. Name any two flow meters to measure mass flow meter.(APR / MAY 2005) Angular Momentum Mass flow meter (or) turbo Mass flow meter Coriolis Mass flow meter liquid bridge mass flow meter

4. List the advantages of rotameter. (NOV / DEC 2005, MAY / Jun 2006, MAY/JUN 2009)

Good rangeability Good for measuring small flows Easily equipped with alarm switches Handles wide variety of corrosive Can be used in some light slurry services

5. To measure the mass flow rates of foams, slurries and mixture which type of mass flow meter can be used.Coriolis Mass flow meter can be used to measure the, mass flow rates of foams, slurries

and mixture.6. Name few variable area flow meter. (MAY / JUN 2007)

Rotamater Cylinder and piston type flow meters

7. Differentiate the device Weir from rotameter. (MAY / JUN 2007)Weirs are used to measure flow rate in open channels such as water works

includes irrigation, waste and sewage system but the rotameters are used to measure flow rate in closed channels. Weir is an obstruction in a flowing stream over which the liquid is made to pass but the rotameter consists of a vertical tapered tube with a float which is free to move up and down within the tube

8. List the applications of coriolis flow meter. (NOV/DEC2007)

It can measure the flow rate of special materials such as sticky, thick, viscous fluids, oils and sand mixtures, butter, liquids containing gases etc.

Coriolis mass flow meter can detect the flow of all liquids, including Newtonian and non Newtonian, as well as that of moderately dense gases.

Self-draining designs are available for sanitary applications that meet clean-in-place requirements.

Flow measurement in food processing industries.

9. What is meant by coanda effect? (NOV/DEC 2007)Coanda effect or wall-attachment effect, the tendency of a moving fluid, either liquid or

gas, to attach itself to a surface and flow along it. As a fluid moves across a surface a certain amount of friction (called "skin friction") occurs between the fluid and the surface, which tends to slow the moving fluid. This resistance to the flow of the fluid pulls the fluid towards the surface, causing it stick to the surface.

10. What is the disadvantage of turbine mass flow meter? (MAY/JUN 2009)

It use is limited for slurry applications It faces problems caused by non lubricating fluids Its cost is high

11. List the factors to be considered while selecting a positive displacement meter for liquid measurement. (NOV/DEC 2009)

Accuracy (in %)     Temperature range (in degree C)

12. What is “Hoverflo”? (NOV/DEC 2009)

The Hoverflois a flow meter, it accurately measure theflow of highly corrosive, aggressive andnon lubricating liquids and chemicals.The flowmeter has two turbines connected by a central shaft. The liquidflows through both turbines, spinning the shaft whilst it hovers. The lowerturbine has magnets sealed in the rim which are detected by the sensor togenerate pulses. The frequency of the pulses is proportional to your flowrate.

13. What are the intermediate measuring parameters in mass flow meter? (APR/MAY 2004)

   Depending on the type of movement an inertial torque a  coriolis force (or) a gyroscopic effect is developed / produced which can be measured and

which is proportional to the mass flow rate

14. What do you mean by priori? (APR/MAY 2008)15. What are the significant sources of error in the mass flow meter? (APR/MAY 2008)16. What are the different types of thermal flow meters?(NOV/DEC 2010)

Thermal Flow meters can be divided into two categories:1. Heat transfer flow meters.2. Hot wire probes or heated thermopile flow meters.

Heat transfer flow metersFlow meters that measure the rise in temperature of the fluid after a known

amount of heat has been added to it.They can be called heat transfer flow meters.Hot wire probes or heated thermopile flow meters

Flow meters that measure the effect of the flowing fluid on a hot body. They can be called hot wire probes or heated thermopile flow meters

Both type of flow meters can be used to measure the flow rates in terms of mass, especially on gas service.

17. Define the term Mass flow rate.(APR/MAY2011)18. List the instruments used for the measurement of volume flow rate.APR/MAY2011)

The quantity meter operating on a volumetric basis is found in several types.19. What is coriolis effect? (NOV/DEC 2012)

It is a vibration creation in a parallel pipeline during which the fluid flows continuosly.

20. State the principle of Nutating disc. (NOV/DEC 2012)

It is a positive displacement meter in which the moving assembly separates the fluid into increments depending on the input flowrate.

PART B

1. Explain the principle of operation of the turbine flow meter with neat sketch and discuss the merits and demerits. (16)(APR/MAY2005, MAY/JUN 2007, MAY/JUN 2009)

2. Explain with necessary equations and sketch the principle of operation of the rotameter.(16)(APR/MAY2005, MAY/JUN 2006)

3. Explain the principle of operation of different types of positive displacement mass flow meter with neat sketches.(16)(NOV/DEC2005, MAY/JUN2006, MAY/JUN 2007, NOV/DEC2009)

4. Write short notes about Calibration of flow meter. (8)(NOV/DEC2005, MAY/JUN2006)

5. Write short notes about Density measurement.(8)(NOV/DEC2005)

6. Write a short note on :i) Thermal mass flow meter. (8)(NOV/DEC2007, APR/MAY 2008,

MAY/JUN2009) ii) Helix type flow meter. (8)(NOV/DEC2007)

7. Explain the principle of operation of any one type of mass flow meter with neat diagram.(16)(NOV/DEC2007)

8. Explain the working principle of coriolis mass flow meter with neat diagram.(16)(APR/MAY 2008)

9. Write a short note on :i) Calibration of flow meter. (8)(APR/MAY 2008)ii) Outline the steps in calibrating a volumetric flow meter with a neat sketch.(8)

(MAY/JUN2009)

10. Vortex shedding flow meter. (8)(NOV/DEC2009)11. Describe with neat sketch, the construction and working of inferential flowmeter

and reciprocating pumps. Also state its advantages and disadvantages. (NOV/DEC 2012)

12. Discuss the working principle theory and installation of thermal type mass flowmeter. (NOV/DEC 2012)

UNIT III- ELECTRICAL TYPE FLOW METER

PART A

1. Give the category of liquid for which the electromagnetic flow meter can be used.(APR/MAY 2004)

The category of liquid for which the electromagnetic flow meter can be used are Corrosive acids, acid slurries, paper pulp, detergents, beer etc., 

2. Write the expression for vortex frequency in a vortex flow meter. (APR/MAY 2004, NOV/DEC2005)

Vortex frequency f = NsV/wWhere, Ns- Constant called theStrouhal number

V- Velocity of the fluidw- Width of the shedding facing the flow

3. Give the types of excitation used in electromagnetic flow meters. (APR/MAY 2005) DC excitation 50Hz Ac excitation Pulsed DC excitation

4. Explain the principle of anemometer.(APR/MAY 2005)

The basic system consists of an electrically heated wire suitably mounted in the flowing fluids. Due to the change in the velocity of flowing fluid, the heat lost by the hot wire will also change.A relation between this loss of heat and the fluid flow can be derived.

5. What is the principle of ultrasonic flow meter? (NOV/DEC 2005,MSY/JUN 2006, APR/MAY2008)

Pressure waves released into a flowing fluid have their velocity and amplitude affected by the fluid velocity.In ultrasonic flow meters these changes of pressure waves of frequency greater than 20 KHz using specialized techniques.

Based on measurement of phase shift between the waves directed downstream and upstream alternately.

Based on the measurement of separation of frequency of oscillation directed downstream and upstream simultaneously.

6. Give any two application of electro-magnetic flow meter.(MAY/JUN 2006)

For high corrosive applications. For applications involving measurement of erosive slurries.

7. Give the merits of DC and AC excitation used in electromagnetic flowmeter.(MAY/JUN 2007)

DC: Miniaturing - Compact electromagnetic flow meters that uses pulsed Dc field. Zero settings are no longer required.

AC:

Polarization at the electrodes is avoided. High frequency excitation and amplification posses less problem.

8. Define Doppler Effect. (NOV/DEC2007, NOV/DEC2009)Doppler Effect is the shift in frequency and wavelength of waves which results

from a source moving with respect to the medium, a receiver moving with respect to the medium, or even a moving medium.

9. List the advantages of electromagnetic flow meter.(APR/MAY2008, NOV/DEC2009)

It can handle slurries,greasy materials and corrosive fluids. It has very low pressure drop. It can be used as bi-directional meter. It is available in several construction materials.

10. Give the principle Vortex shedding flow meter.(MAY/JUN 2009)

Vortex shedding which occurs when a gas or liquid flows around a non-stream lined object known as sluff body. When a fluid flows past an obstacle, boundary layers of slow moving fluid are formed along the outer surfaces of the obstacle and the flow is unable to follow contours of the obstacle on its downstream side. Thus the flow layers are separated from the surface of the object, and a low pressure area is formed behind the object which causes the separated layers to get detached from the main stream of the fluid and roll themselves into eddies or vortices in the low pressure area.

11. What are the commonly used methods of solid flow measurement?(MAY/JUN2009)The most common methods are,

Bucket conveyor method Curved plate and prefeed arrangement Nuclear method Leakage flow technique

12. List some application of nuclear method of solid flow measurement.This method can be used in

Chemical and fertilizer industries Paper industries for coal, copper, iron cores. Concentration associated industries for coal, copper etc Building material industries for sand, rock, cement, lime etc Food processing units for food, fruits, vegetables etc

13. How the flow rate is measured in target flow meter?The target flow meter measures flow by measuring the force on a target placed at

the center of the pipe at rights to the direction of fluid flow. The force produced will be proportional to the square of the flow.Q=K√F

Where, Q- Flow rateK-a known constant, F- force

14.  Write some factors to select the flow meter. First, by identifying the meters which are technically capable of performing

the required measurement and are available in acceptable materials of construction.

Second, by making the best choice from those available. A list should be made of the key parameters which the meter must be capable

of accommodating. In order to cover special features such as reverse flow, pulsating flow,

response time, and so on, it is necessary to study the individual meter specifications in detail and/ or obtain the manufacturer's comments and advice.

15.List the limitations of an Ultrasonic flow meter.(MAY/JUN 2007)

16.List two precautions to be taken when using electromagnetic flow meter.(NOV/DEC2007)

17. What is Doppler effect? (NOV/DEC 2012)

18. Mention any two methods to measure flow in open channel. (NOV/DEC 2012)

PART B1. Explain the principle of operation of the electromagnetic flow meter with different

types of excitation and sketches.(16)(APR/MAY 2005, NOV/DEC 2005, MAY/JUN 2007, APR/MAY 2008, MAY/JUN 2009)

2. Write a short note on :i) Ultrasonic flow meters. (8)(APR/MAY2005)ii) Vortex flow meters. (8) (APR/MAY 2005, NOV/DEC 2007) & (NOV/DEC

2012)

3. Write a short note on :i) Solid flow rate measurement. (8) (NOV/DEC 2005, MAY/JUN 2006,

MAY/JUN 2007, MAY/JUN 2009) & (NOV/DEC 2012)ii) Selection guidelines for flow meter. (8)(NOV/DEC 2005, MAY/JUN 2006,

NOV/DEC 2007, MAY/JUN 2009)

4. Discuss the excitation schemes used in electromagnetic flow meters. (8)(MAY/JUN2006) & (NOV/DEC 2012) (16)

5. What are all the variations in a target flow meter? Explain the principle of operation of any one type with neat sketch.(8)(NOV/DEC2005, MAY/JUN 2006, MAY/JUN 2009, NOV/DEC2009) & (NOV/DEC 2012)

6. Explain the principle of operation of Ultrasonic Doppler flow meter with relevant equation.(16)(NOV/DEC 2007, NOV/DEC 2009)

7. Briefly explain any one types of ultrasonic flow meter with neat diagram. (16)(APR/MAY 2008)

UNIT IV - LEVEL MEASUREMENT

PART A

1. Give any two purge fluid used in air-purge level measurement system.(APR/MAY 2004, MAY/JUN2006)

The commonly purging fluids are Air Carbon or nitrogen

2. Write the principle used in ultrasonic method of level measurement. (APR/MAY 2005)

Ultrasonic level detectors use the principle of reflection of an acoustic wave from a liquid to vapour plane or vice versa. The interval of time from the instant of emission of an impulse to the instant of reflected impulse received is measured by any appropriate circuit. Time interval is proportional to liquid level.

3. What are all the methods of hydrostatic type of level measurement?(NOV/DEC2005)

Pressure gauge method Air bellows Air purge (or) bubbler system Liquid purge system Diaphragm box type Force balance type

4. When will you go for inductive type level measurement? (NOV/DEC2005)The permeability of the liquid whose level is to be measured is a variable one then

we go for inductive type level measurement.5. Will you use capacitive type level gauge for conductive liquids? Justify your

answer.(MAY/JUN2006)Yes, capacitive type level gauge are used for conductive liquids. If the liquid is

conductive the rod and the liquid form the plates of the capacitor, and the insulation between them is the dielectric.

6. Give the principle of the direct method of liquid level measurement.(MAY/JUN2007)

This is the simplest method of liquid level measurement. In this method, the level of liquid is measured by means of the following level indicators:i) Hook type level indicatorii) Sight glassiii) Float typeWhen the level of liquid in an open tank is measured directly on a scale, it is sometimes difficult to read the level accurately because of parallax error.

7. What do you mean by level switch.(MAY.JUN2007)When it is sufficient to detect the presence or absence of level at a particular

elevation, damped or absorption type level switches can be considered. These switches can be mounted outside or inside the tank, above or below the liquid level. These switches are limited to clean liquid insulations because coating can dampen the vibration.

8. Mention the advantages of air-purge system.(NOV/DEC2007)

Pressure gauge can be kept as far away as 500 ft from the tank with the help of piping.

This type of device is well suited for measuring the level of corrosive or abrasive liquids.

9. Is it possible to measure the level of liquid in the vessel by using DP cell?(APR.MAY2008)

Yes, we can measure the level of the liquid in the vessel by using DP cell.10. What are the limitations of float type level measurement system?(APR/MAY2008)

& (NOV/DEC 2012) They are normally limited to moderate pressures. They are tailored to tank geometry.

11. What is hydrostep system?(NOV/DEC 2009)Traditional methods of measuring drum water level are costly, difficult to

maintain, and limited and differing accuracies. The hydro step system overcomes this disadvantage. The operation of hydra step depends on the difference in electrical resistivity of high purity water and steam at boiler pressure. The resistivity is measured at anumber of points arranged vertically at intervals in the pressure vessel and from this it can be said that high resistivity represent team and low resistivity represent water.

12. Mention the advantages of float type level measurement system.(NOV/DEC2009) It is possible to read the liquid levels in a tank from the ground level even if the

tank is kept below the ground level. Its cost is low and has reliable designs It operates over a large temperature range There is a choice of corrosion- resistant materials to make these.

13. Draw the setup of liquid level measurement for non-conducting liquids with equivalent circuit with a capacitive type Level sensor.(MAY/JUN2009)

14. ow is the measurement range limited in the float type system?(NOV/DEC2007)15. Why is purge method is so popular in industrial liquid level measurement?

(MAY/JUN2009)16. What is DPT?

PART B1. Discuss the principle of operation of various schemes of hydrostatic type level

measuring system with merits and limitations. (16)(APR/MAY 2005, MAY/JUN 2006, NOV/DEC 2007)

2. Explain how boiler drum level is measured using hydra step system. (8)(APR/MAY 2005) (NOV/DEC 2012) (16)

3. How liquid level is measured using float and displacer type sensor? (8)(APR/MAY 2005)

4. Discuss the principle of operation of various schemes of float type level measuring system. (16)(NOV/DEC 2005)

5. Discuss the principle of operation of electrical type of level measurement with neat sketches.(16)(NOV/DEC 2005, MAY/JUN 2009) & (NOV/DEC 2012)

6. Explain the principle of operation of displacer type level measuring schemes with neat sketch.(8)(MAY/JUN 2006, MAY/JUN 2009)

7. Explain the level measurement using nuclear radiation method.(8)(MAY/JUN 2006)

8. Explain briefly ultrasonic method of level measurements with diagram.(16)(NOV/DEC 2007, MAY/JUN 2009)

9. Describe the capacitance method of level measurement and mention its advantages and disadvantages. (16)(APR/MAY 2008)

10. Write a short note onLevel switches (8)(APR/MAY 2008)

11. Write a short note on Torque tube (8)(APR/MAY 2008)

12. Briefly explain the methods used to measure the level of a conducting liquid. (16)(NOV/DEC 2009)

13. Discuss the D/P method of level measurement. (8)(NOV/DEC 2009)

14. Explain the bubbler tube method of level measurement. (8)(NOV/DEC 2009)

UNIT V -MEASUREMENT OF HUMIDITY & MOISTURE

PART – A

1. Define absolute humidity and relative humidity. (APR / MAY 2005, MAY / JUN 2006,APR/MAY 2010)

Absolute Humidity:The weight of water vapor (Wv) in unit weight of the dry gas(Wg) is called as

Absolute humidity.H=Wv/ Wg

Relative Humidity:The ratio of moisture content of the gas to the maximum moisture the gas can

contain at that temperature.For, the ideal gas the relative humidity is the ratio of density of the vapour (ρH)

that at saturation (ρs).HR=ρH/ρs

2. Give few example for humidity sensitive material. (NOV / DEC 2005)Materials like lithium chloride, Phosphoric acid, calcium chloride, zinc chloride,

tin tetra chloride etc., are the examples of humidity sensitive material.

3. Define the term Dew point temperature. (MAY / JUN 2007, NOV / DEC 2007, NOV / DEC 2009, APR/MAY 2010)

By continuous cooling at constant pressure if the temperature of air is reduced, the water vapour in the air will start to condense at a particular temperature. The temperature at which the water vapour starts condensing is called as dew point temperature.

4. What is dry and wet bulb psychrometer?(MAY / JUN 2009, NOV / DEC 2007, APR / MAY 2008)

Dry and wet bulb psychrometer is a device used to determine atmospheric humidity by the reading of two thermometers, the wet bulb and dry bulb thermometers. The wet bulb thermometer is kept wet by a moistened sleeve. It measures humidity by determining how much cooler the wet bulb thermometer is than the dry bulb thermometer and then calculates humidity by using appropriate graphs or tables.

5. What is Psychrometer?Psychrometer is an instrument used to measure Humidity. The general group of

humidity instruments which use two temperature measurement (Dry and wet bulb temperatures) and a chart to obtain the desired humidity values are called psychrometer.

6. What is dew cell? (APR / MAY 2008, NOV / DEC 2009) & (NOV/DEC 2012)Dew cell is an absolute humidity transducer based on a thermal system. The

principle of dew cell is that, the hygroscopic material absorbs humidity and starts dissociating. The dissociation will depend on the absorption of moisture and will be

measured by the change in the resistance between the two wires. The accuracy of this instrument is quite good and the response time is with in 3 to 5 min.

7. Why semiconductor thick film sensors are used for humidity measurement?Semiconductor thick film sensor for humidity measurements are based on:

i) Change in resistance that use RuO2 or special glass.ii)Change in capacitance that use glass ceramic, Al2O3.

iii)In the thin film processing technique, Ta2O5.

8. What is need for humidity measurement?Humidity affects human comforts and many industrial processes as in the case of

chemical industries, garments industries, food industries, leather industries, pharmatical industries, precision equipment manufacturing etc. So humidity measurement is important.

9. Define Moisture.Moisture is defined as the amount of water absorbed by a solid or a liquid. The

amount of free moisture present in any material is dependent upon its chemical and physical properties.

10. What are the advantages of thermal drying method? This method can be applied to solids, liquids and fibrous or granular material. This method does not require skilled operators. Initial investment and running costs are minimum. This method is not limited to either micro or macro samples.

11. What are the limitations of thermal drying method?The limitations of the method are that it does not give very accurate results, as it

cant differentiate between water and other volatile materials.12. List the properties of Non-Newtonian fluids based on which they are classified.

(APR / MAY 2005, MAY / JUN 2006)13. How does the psychrometer differ from a hygrometer? (MAY / JUN 2007)14. What do you mean the term consistency in viscosity measurement? (MAY / JUN

2009) & (NOV/DEC 2012)

PART – B

1. Explain the construction and principle of operation of dry bulb psychrometer with neat sketch.(APR/MAY2004, APR/MAY2005, NOV/DEC2005,APR/MAY 2010) & (NOV/DEC 2012)

2. Write short notes on solid flow measurement.(APR/MAY 2004)(8)

3. Explain how do you measure the moisture content of granular materials with neat sketch.(NOV/DEC2005,APR/MAY 2010)(8)

4. Explain the construction and working principle of the wire electrode type hygrometer.(MAY/JUN2006)(8)

5. Discuss he methods of measurement of humidity along with the necessary sketches and equations.(MAY/JUN 2007)(16)

6. Explain how the moisture is measured by infra red transmission technique with their merits and demerits. (MAY/JUN 2007)(16)

7. Describe the principle of operation of psychrometer type humidity measurements.(NOV/DEC2007)(16)

8. With aid block diagram briefly explain the measurement of moisture using distillation method.(NOV/DEC2007APR/MAY2008)(16)

9. Describe the construction and working principle of hygrometer for humidity measurement.(APR/MAY2008)(16)

10. Explain then principle of operation of humidity measurement. Explain the working principle of any one type of hygrometer with the neat sketch. (MAY/JUN2009)(16)

11. Discuss the principle of operation of different methods of moisture measurement.(MAY/JUN2009)(16)

12. Explain dry and wet bulb psychrometer with neat sketch.(NOV/DEC2009)(16)

13. What are the methods used in moisture measurement? Explain any one method.(NOV/DEC2009)(16)

14. Explain the commercial type dew point meter and rotameter type viscometer with a neat sketch. (NOV/DEC 2012) (16)