ME55 – APPLIED HYDRAULICS AND PNEUMATICS MODEL EXAMINATION

B.E./B.TECH.DEGREE MODEL EXAMINATIONS, OCT/NOV – 2011

REGULATIONS 2008

FIFTH SEMESTER

ME55 – APPLIED HYDRAULICS AND PNEUMATICS

MECHANICAL ENGINEERING

Time: Three Hours                                Date: 03.11.2011                               Maximum: 100 marks

ANSWER ALL QUESTIONS

PART – A (10 x 2 = 20 marks)

1.      Define Fluid power.

2.      Explain the term friction factor.

3.       What do you meant by non-positive displacement pump?

4.      What is cylinder cushion?

5.       Differentiate pressure control and pressure relief valve.

6.       Write the function of solenoid valve.

7.       What is the need for FRL unit?

8.       Name the various types of filters used in pneumatics.

9.       What is servo valve and how it is working?

10.   Define coanda effect.

PART – B (5 x 16 = 80 marks)

11.  (a) (i) Explain the hydraulic and pneumatic fluid power system                                    (12)
     (ii) Discuss the properties of hydraulic fluids.                                                             (4)
                                                             (OR)
(b) (i) How to calculate the frictional losses in the valves and fittings.                           (8)
     (ii) Define Reynolds Number                                                                                      (2)
     (iii) Differentiate between laminar and turbulent flow.                                              (6)

12.  (a) (i) Explain the working principle of external gear pump and determine its                             performance Measures                                                                                                    (10)

           (ii) Explain with a diagram the working of a telescopic cylinder                               (6)

(OR)

(b) (i) A pump has a displacement volume of 0.0819 *10-3 m3 it delivers 0.0758 m3 /min at 1000rpm at 67 bar if the prime mover input torque is 100 N- m  (1) What is the overall efficiency. (2) What is the theoretical torque required to operate the pump                (2+8)

(ii) Explain the factors which affect the selection of pumps and discuss in detail the          classification and performance features of different types of hydraulic pumps             (6)

13.  (a) (i) Explain the construction and working of pilot operated sequence valve.           (8)

    (ii) Make a circuit sketch, showing the use of an accumulator, as a hydraulic shock absorber.                                                                                                                      (8)

(OR)

(b) (i) Write and explain the working principle of pressure intensifier, with neat diagram.                                                                                                             

    (ii) Explain with a circuit how punching operation can be achieved.                           (8)

14.  (a) What is compressor? Explain the working principle of piston type compressor with

neat sketch.                                                                                                                      (16)

(OR)

(b) Design an electro hydraulic circuit for the following sequences A+B+A-B- where A & B stand for cylinder (+) indicates extension and (-) indicates retraction of cylinders. Incorporate provision for auto-manual selector and emergency stop.                           (16)

15.  (a) (i) Explain the construction and working principle of hydro mechanical servo valves with neat diagram.                                                                                                           (8)

     (ii) Enunciate various criteria for the selection of pneumatic components.               (8)

(OR)

(b) (i) List out various operating problems associated with pumps and valves and the

Corresponding possible causes and suitable remedy for each problem.                         (8)

      (ii) Explain the working principle of a PLC with neat block diagram.                     (8)