B.E./B.Tech. Degree Examination, April/May 2008

B.E./B.Tech. Degree Examination, April/May 2008

Fifth Semester- Mechanical Engineering (Regulation 2004) 

ME 1305 - APPLIED HYDRAULICS AND PNEUMATICS

Time: Three hours

Answer ALL questions. 

Maximum: 100 marks

Part A - (10 × 2 = 20 marks) 

1. List any four advantages of using the fluid power system.

Ans. Refer Chapter 7, Q. No. 1, Two Marks Q&A, Page No. 1.23.

2. What is Viscosity Index? What do you infer from V.I. number of an oil? 

Ans. Refer Chapter 12, Q. No. 2, Two Marks Q&A, Page No. 2.22.

3. Name any four hydraulic fluids that are commonly used.

Ans. Refer Chapter 23, Q. No. 2, Two Marks Q&A, Page No. 2.24.

4. What is pump cavitation? How can you avoid it?

Ans. Refer Chapter 4, Q. No. 35, Two Marks Q&A, Page No. 4.39.

5. Draw the ANSI symbol for (a) Pilot operated check valve, (b) Shuttle valve. 

Ans. Refer Chapter 6, Q. Nos. 17 & 16, Two Marks Q&A, Page No. 6.49.

6. What is the use of a temperature switch?

Ans. Refer Chapter 7, Q. No. 7, Two Marks Q&A, Page No. 7.16.

7. How can you specify an air compressor?

Ans. Refer Chapter 11, Q. No. 8, Two Marks Q&A, Page No. 11.21. 

8. What is meant by an air-over-oil system?

Ans. Refer Chapter 9, Q. No. 16, Two Marks Q&A, Page No. 9.35. 

9. Define the terms 'Lap' and 'Nut with respect to servo valves. 

Ans. Refer Chapter 6, Q. No. 38, Two Marks Q&A, Page No. 6.52. 

10. State 'Coanda effect'.

Ans. Refer Chapter 15, Q. No. 5, Two Marks Q&A, Page No. 15.28. 

Part B - (5 × 16 = 80 marks)

11. (a) (i) List out the advantages and disadvantages of hydraulic power system. 

Ans. Refer Chapter 1, Sections 1.75-1.76, Page No.1.14.

(ii) What are the functions of a fluid in any fluid power systems? 

Ans. Refer Chapter 2, Section 2.1.1, Page No.2.1."

(iii) What are the required properties of a good hydraulic fluid? 

Ans. Refer Chapter 2, Section 2.5, Page No.2.12.

 [OR]

(b) Write short notes on the following:

(i) Laminar and turbulent flow.

(ii) Energy losses in valves and fittings.

(iii) Darcy's equation.

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

(ii) Refer Chapter 3, Section 3.15, Page No.3.17.

(iii) Refer Chapter 3, Section 3.14, Page No.3.14.

12. (a) (i) How much hydraulic power would a pump produce when operating at 125 bars and delivering 1.25 litres per second of oil? What power rated electric motor would be selected to drive this pump if its overall efficiency is 88%.

Ans. Refer Chapter 4, Example 4.5, Page No.4.39.

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

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

 [OR]

(b) (i) Explain with neat sketch, the principle and operation of telescopic cylinder.

Ans. Refer Chapter 5, Section 5.6, Page No.5.8.

(ii) With respect to hydraulic motors, define the following terms:

(1) Volumetric efficiency.

(2) Mechanical efficiency.

(3) Overall efficiency.

Ans. Refer Chapter 5, Section 5.15, Page No.5.20.

13. (a) (i) Explain the sequencing of two double-acting cylinders with a neat circuit. 

Ans. Refer Chapter 8, Section 8.10, Page No.8.13.

(ii) With a neat sketch describe the construction and operation of a pressure compensated flow control valve.

Ans. Refer Chapter 6, Section 6.22, Page No.6.27.

[OR]

(b) (i) With a neat sketch, explain how two hydraulic cylinders motion can be synchronized.

Ans. Refer Chapter 8, Section 8.10, Page No.8.13.

(ii) Make a circuit, showing an intensifier in a punching press application. 

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

14. (a) (i) 4 rotary vane air motor has a displacement volume of & cm3 and operates at 1750 rpm using 700 kW gauge pressure air. Calculate the standard m3/min rate of consumption and kW power output of the motor. Assume the temperature remains constant.

Ans. Refer Q.No.14(a), Solved Anna University Question Papers, Apr/May 2015. 

(ii) Explain the function of an air pressure regulator with neat sketch. 

Ans. Refer Chapter 11, Section 11.8, Page No.11.12.

 [OR]

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

Ans. Refer Chapter 13, Example 13.3, Page No.13.32.

15. (a) (i) Draw and explain the working of proportional pressure reducing valve. Ans. Refer Chapter 6, Section 6.26.4, Page No.6.39.

(ii) What is meant by ladder programming?

Ans. Refer Chapter 15, Section 15.10.1, Page No.15.22.

(iii) Draw the basic standard symbols that are used in ladder diagram? Also show rungs in a ladder diagram.

Ans. Refer Chapter 14, Section 14.3, Page No. 14.6.

[OR]

(b) (i) Describe various selection criteria for pneumatic components. 

Ans. Refer Chapter 16, Section 16.12, Page No.16.13.

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

Ans. Refer Chapter 17, Section 17.44, Page No.17.6.