B.E./B.Tech. Degree Examination, April/May 2011

B.E./B.Tech. Degree Examination, April/May 2011

Fifth Semester - Mechanical Engineering - Regulation 2008 

ME 2305 - APPLIED HYDRAULICS AND PNEUMATICS

Time: Three hours

Answer ALL questions. 

Maximum: 100 marks

Part A - (10 × 2 = 20 marks)

1. Define fluid power.

Ans. Refer Chapter 1, Q. No. 1, Two Marks Q&A, Page No. 1.22.

2. Name two undesirable results when oil with a viscosity that is too high.

Ans. Refer Chapter 2, Q. No. 8, Two Marks Q&A, Page No. 2.22.

3. List the basic components required in hydraulic system.

Ans. Refer Chapter 1, Q. No. 16, Two Marks Q&A, Page No. 1.24.

4. Name four types of cylinder mountings.

Ans. Refer Chapter 5, Q. No. 18, Two Marks Q&A, Page No.:5.33.

5. List the three ways of applying flow control valves.

Ans. Refer Chapter 6, Q. No. 30, Two Marks Q&A, Page No. 6.51.

6. Name the basic type of accumulators used in hydraulic systems.

Ans. Refer Chapter 9, Q. No. 4, Two Marks Q&A, Page No. 9:34.

7. How do pneumatic actuators differ from hydraulic actuators?

Ans. Refer Chapter 12, Q. No. 10, Two Marks Q&A, Page No. 12.17.

8. State the difference between quick exhaust valve and flow control valve. 

Ans. Refer Chapter 12, Q. No. 8, Two Marks Q&A, Page No. 12.16.

9. What is meant by servo system?

Ans. Refer Chapter 6, Q. No. 34, Two Marks Q&A, Page No. 6.52.

10. What is ladder diagram?

Ans. Refer Chapter 14, Q. No. 13, Two Marks Q&A, Page No. 14.17.

Part B - (15 × 16 = 80 Marks)

11. (a) Compare the use of fluid power to a mechanical system by listing advantages and disadvantages.

Ans. Refer Chapter 1, Sections 1.5 & 1.6, Page No.1.5.

[OR]

(b) List and explain various hydraulic fluids.

Ans. Refer Chapter 2, Section 2.6, Page No.2.13.

12. (a) Classify the positive displacement pumps and describe the constructional features of screw pumps.

Ans. Refer Chapter 4, Sections 4.3 & 4.11, Page Nos.4.3 & 4.15.

[OR]

(b) What are the different types of fluid motors? Also explain the function of them.

Ans. Refer Chapter 12, Section 12.9, Page No.12.13.

13. (a) Explain the working of a pressure reducing valve with an example application. 

Ans. Refer Chapter 6, Section 6.16, Page No.6.22.

[OR]

(b) Explain the working of an intensifier with an example application.

Ans. Refer Chapter 9, Section 9.13.1, Page No.9.29.

14. (a) Compare pneumatic system with hydraulic system.

Ans. Refer Chapter 1, Section 1.9, Page No.1.19.

[OR]

(b) State the various types of air control valves. Also explain the working of quick exhaust valve.

Ans. Refer Chapter 12, Sections 12.2 & 12.6, Page Nos. 12.1 & 12.7.

15. (a) Describe the working of electro hydraulic servo valves with a block diagram. State at least two applications.

Ans. Refer Chapters 6 & 8, Sections 6.25 & 8.20, Page Nos. 14.6 & 8.34.

(b) (i) Write short notes on:

(1) Laminar and turbulent flow.

(2) Reynolds number.

Ans. 

(1) Refer Chapter 3, Section 3.6, Page No. 3.9.

(2) Refer Chapter 3, Section 3.7, Page No. 3.10.

(ii) Explain the working principle of hydraulic press with neat sketch.

Ans. Refer Chapter 3, Section 3.5.1, Page No.3.6.

12. (a) (i) Draw a single cylinder continuous reciprocating circuit using suitable components and also give the specifications.

Ans. Refer Chapter 8, Section 8.11, Page No. 8.15.

 (ii) How are the pumps classified? Explain with suitable sketch the working of unbalanced vane pump?

Ans. Refer Chapter 4, Sections 4.3 & 4.14, Page Nos. 4.3 & 4.18.

[OR]

 (b) (i) Explain the working principle of external gear pump and determine its performance measures.

Ans. Refer Chapter 4, Section 4.7, Page No.4.8.

(ii) What are the factors to be considered in the selection of a pump? 

Ans. Refer Chapter 4, Section 4.23, Page No. 4.34.

13. (a) (i) Describe an hydraulic circuit for synchronizing two cylinders.

Ans. Refer Chapter 8, Section 8.2, Page No. 8.16.

(ii) Explain the operation of a check valve with a neat sketch.

Ans. Refer Chapter 6, Section 6.7.3, Page No. 6.6.

[OR]

(b) (i) Explain with a suitable circuit how an accumulator can be used as

(1) An emergency power source.

(2) A leakage compensator.

Ans. (1) Refer Chapter 9, Section 9.10.3, Page No. 9.13.

(2) Refer Chapter 9, Section 9.10.1, Page No. 9.10.

 (ii) Highlight the advantages of regenerative circuit and explain it with a suitable application.

Ans. Refer Chapter 8, Section 8.5, Page No.8.6.

14. (a) (i) Discuss the construction of FRL unit.

Ans. Refer Chapter 11, Section 11.10, Page No. 11.5.

(ii) Explain the working principle of double acting cylinder with neat sketch. 

Ans. Refer Chapter 5, Section 5.4, Page No.5.4.

 [OR]

(b) Develop an electro pneumatic circuit by cascade method for the following sequence: A+ B+ B ̄ A ̄ where A and B stands for cylinders. + indicates extension and - indicates retraction of cylinders.

Ans. Refer Chapter 13, Example 13.3, Page No.13.22.

15. (a) (i) Explain the construction and operation of a two stage electro hydraulic servo valve.

Ans. Refer Chapter 6, Section 6.25.5, Page No. 6.34.

 (ii) What are the factors considered during the installation of pneumatic systems? 

Ans. Refer Chapter 17, Section 17.5, Page No.17.14.

[OR]

(b) (i) Explain the working principle of a PLC with neat sketch.

Ans. Refer Chapter 15, Section 15.9, Page No.15.21.

 (ii) List out any four operating problems associated with pumps and valves and the possible causes and suitable remedy for each problem.

Ans. Refer Chapter 17, Section 17.4, Page No. 17.5..