industrial instrumentation 2009

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INDUSTRIAL INSTRUMENTATION-II ( SEMESTER - 6 )

6869 (15/06)

CS/B.TECH (ICE)/SEM-6/IC-603/09

1. ………………………………Signature of Invigilator

2. ………………………………Signature of the Officer-in-Charge

Reg. No.

Roll No. of theCandidate

– – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –CS/B.TECH (ICE)/SEM-6/IC-603/09

ENGINEERING & MANAGEMENT EXAMINATIONS, JUNE – 2009INDUSTRIAL INSTRUMENTATION-II ( SEMESTER - 6 )

Time : 3 Hours ] [ Full Marks : 70

INSTRUCTIONS TO THE CANDIDATES :1. This Booklet is a Question-cum-Answer Booklet. The Booklet consists of 32 pages. The questions of this

concerned subject commence from Page No. 3.2. a) In Group – A, Questions are of Multiple Choice type. You have to write the correct choice in the

box provided against each question.b) For Groups – B & C you have to answer the questions in the space provided marked ‘Answer

Sheet’. Questions of Group – B are Short answer type. Questions of Group – C are Long answertype. Write on both sides of the paper.

3. Fill in your Roll No. in the box provided as in your Admit Card before answering the questions.4. Read the instructions given inside carefully before answering.5. You should not forget to write the corresponding question numbers while answering.6. Do not write your name or put any special mark in the booklet that may disclose your identity, which will

render you liable to disqualification. Any candidate found copying will be subject to Disciplinary Actionunder the relevant rules.

7. Use of Mobile Phone and Programmable Calculator is totally prohibited in the examination hall.8. You should return the booklet to the invigilator at the end of the examination and should not take any

page of this booklet with you outside the examination hall, which will lead to disqualification.9. Rough work, if necessary is to be done in this booklet only and cross it through.

No additional sheets are to be used and no loose paper will be provided

FOR OFFICE USE / EVALUATION ONLYMarks Obtained

Group – A Group – B Group – CQuestionNumber

TotalMarks

Examiner'sSignature

MarksObtained

…………………………………………………………Head-Examiner/Co-Ordinator/Scrutineer



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ENGINEERING & MANAGEMENT EXAMINATIONS, JUNE – 2009

INDUSTRIAL INSTRUMENTATION-IISEMESTER - 6

Time : 3 Hours ] [ Full Marks : 70

GROUP – A

( Multiple Choice Type Questions )

1. Choose the correct alternatives for any ten of the following : 10 × 1 = 10

i) In a Rotameter, used for measuring flow rate of a fluid, P a : pressure above the

float, P b : pressure below the float, A : area of float, V : volume of the float,

d 1 : density of float material, d 2 : density of the fluid, g : acceleration due to

gravity.

Which of the following equations describes the equilibrium of the float ?

a) ( ) P b – P a A = Vg ( ) d 2 – d 1

b) ( ) P b + P a A = Vg ( ) d 2 + d 1

c) ( ) P a – P b A = Vg ( ) d 2 – d 1

d) ( ) P b – P a A = Vg ( ) d 2 + d 1 .

ii) Hydrostatic pressure level indicator is a

a) direct method of liquid level measurement

b) indirect method of liquid level measurement

c) none of these

d) all of these.

iii) The type excitation to produce magnetic field used in the electromagnetic

flowmeter is

a) A.C. b) D.C.

c) pulsating D.C. d) A.C. and D.C.



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iv) In a vortex flowmeter, fluid velocity is

a) directly proportional to vortex frequency

b) inversely proportional to frequency

c) squre root of vortex frequency

d) none of these.

v) To avoid ground loop, we can use

a) single point ground b) ground bus

c) ground plane d) any of these, which is appropriate.

vi) Laser-based level measurement depends on

a) the accurate detection of the time it takes for a light pulse to travel to theprocess material surface and back

b) the velocity of light

c) X-ray radiation

d) all of these.

vii) What is the height of liquid column in a closed tank ?

The hydrostatic pressure is given as 3000 kg/m 2 and the external pressure on

liquid in the tank is 450 kg/m. Assume density of water as 1000 kg/m 3 .

a) 2·55 m b) 2·65 m

c) 2·85 m d) None of these.

viii) A flowmeter whose output is independent of fluid density is

a) Turbine flowmeter b) Electromagnetic flowmeter

c) Venturimeter d) Orifice meter.

ix) A Pitot tube is used for measuring velocity of a gas, flowing in a duct. The

velocity is proportional to

a) square root of the total pressure measured by the tube

b) the total pressure measured by the tube

c) difference between the total pressure and static pressure

d) square root of the difference between the total pressure and staticpressure.



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x) An orifice plate is designed to generate DP of 250 mm w.c. at the maximum

flow rate of 100 lit/min. What is the flow rate when the DP across the orifice is

62·5 mm w.c. ?

a) 6·25 lit/min b) 25 lit/min

c) 50 lit/min d) 75 lit/min.

xi) In float type liquid level measurement, the density of the float

a) > liquid b) < liquid

c) = liquid d) none of these.

xii) The chassis of an instrument is connected to the earth ground to

a) get proper current in the load

b) get proper voltage across the load

c) eliminate leakage path

d) disconnect load from the circuit.

GROUP – B

( Short Answer Type Questions )

Answer any three of the following questions. 3 × 5 = 15

2. With the help of a neat sketch, explain how a torque tube-displacer assembly is used

for the continuous measurement of liquid level in a tank. 5

3. a) Prove that the scale of the rotameter tube is linearly related with volumetric flow

rate.

b) A rotameter designed to measure the flow rate of water is used to measure the

flow rate of brine ( specific gravity 1·15 ), without altering the scale. Would it be

more, or less ? Justify. 4 + 1

4. Draw and explain a scheme for level measurement of non-conducting type liquid with

bare capacitance probe in a conducting vessel. 2 + 3



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5. a) Describe with neat sketch the level measurement technique in open tank using

air purge / air bubbler system.

b) What modification will be done for pressurized tank ? 4 + 1

6. Explain stray capacitance effects. What are the precautions to be taken to prevent low

level signal sources from the influence of capacitive effects ? 2 + 3

GROUP – C

( Long Answer Type Questions )

Answer any three of the following questions. 3 × 15 = 45

7. a) Explain the principle of operation of Annubar.

b) A venturi tube of throat diameter 60 mm is placed in a water pipe of throat

diameter 100 mm to measure volumetric flow. The volumetric flow rate through

the tube is 80 × 10 – 3 m 3 /s. Water has a density of 1000 kg/m 3 and

viscosity of 10 – 3 Ns/m 2 .

i) Determine Reynolds number.

ii) Given the coefficient of discharge is 0·99, determine upstream and throat

differential pressures.

c) An orifice plate is situated in a water pipe of 50 mm diameter and has an orifice

of 30 mm diameter. For a Reynolds number of 1,00,000, the dischargecoefficient is 0·61. Calculate the nominal exit velocity V 2 at the orifice to give

this flow value and also the pressure differential. The value of density is

1000 kg/m 3 and the kinematic viscosity is 10 – 6 m 2 /s. 5 + 6 + 4

8. a) What is Coriolis acceleration ?

b) How is this concept used in dual tube Coriolis mass flowmeter for mass flow rate

measurement ?

c) Draw the signal processing block diagram of a Coriolis mass flowmeter.

d) Why is temperature measurement required for Coriolis mass flowmeter to

measure mass flow rate ?

e) What are the advantages and disadvantages of Coriolis mass flowmeter ?

2 + 4 + 4 + 2 + 3



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9. a) What is the basis of classification of hazardous area ? Give examples of class I,

class II and class III types of hazardous area.

b) What does IP65 signify ? What is its NEMA equivalent ?

c) What is meant by intrinsically safe barrier ? How does it provide safety ? What

types of barriers are used ? 4 + 3 + ( 2 + 3 + 3 )

10. a) What is Doppler Effect ? How is it used in flow measurement ?

b) Show that the Doppler shift frequency is proportional to velocity of fluid flow in a

pipe.

c) Show a signal processing block diagram associated to measure this Doppler shift

frequency.

d) A transit time ultrasonic flowmeter is used to measure velocity of a gas flowing in

a pipe. In such a case it was found that the zero flow transit time is 1·2 ms,

whereas when there was flow the differential transit time was 115 µs. The angle

between the line connecting the transmitter, receiver and the direction of fluid

flow is 30°. Find the velocity of the gas. By what will the transit time change for

± 2% change in the velocity of sound ? Velocity of sound in the gas is 500 m/s.

( 1 + 2 ) + 4 + 3 + 5

11. Write short notes on any three of the following : 3 × 5

a) Electromagnetic flowmeter

b) Anemometer

c) Radarlevel transmitter

d) Vortex flowmeter.

END

industrial instrumentation 2009

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