Hydraulics & Pneumatics - Jun 2015

Mechanical Engg. (Semester 7)

TOTAL MARKS: 100
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks. 1 (a) What are the advantages, limitations and applications of hydraulic systems?(6 marks) 1 (b) With a neat sketch, explain construction and working of unbalanced type gear pump and derive expression for volumetric displacement of the pump.(9 marks) 1 (c) Define the terms volumetric displacement, theoretical flow rate, volumetric efficiency and mechanical efficiency.(5 marks) 2 (a) Distinguish clearly between 1^st class, 2^nd class and 3^rd class leaver system used in hydraulic system.(9 marks) 2 (b) With a neat sketch, explain the working of axial piston motor.(5 marks) 2 (c) A hydraulic motor has 82cm² (0.082L) volumetric displacements. If it has pressure rating of 70 bar and it receives oil from 0.0006m3/sec (0.60LPS) theoretical flow rate pump. Find the motor i) Speed ii) Theoretical torque iii) Theoretical power.(6 marks) 3 (a) With a neat sketch, explain the three of centre flow chart configuration for Three positions, Four way valves.(9 marks) 3 (b) With a schematic diagram, explain the working of simple pressure relief valve.(5 marks) 3 (c) Explain the working of sequence valve with an example.(6 marks) 4 (a) Explain with suitable circuit how Automatic cylinder reciprocates with two sequence valves.(10 marks) 4 (b) Explain with Hydraulic circuit, how speed control can be achieved in Hydraulic motor.(6 marks) 4 (c) Explain spring loaded type accumulator used in Hydraulic system.(4 marks) 5 (a) Give three important functions of Baffle plate used in reservoir.(7 marks) 5 (b) Define the terms Beta ratio and Beta efficiency of filters.(7 marks) 5 (c) Name five things that can cause a noisy pump.(6 marks) 6 (a) Explain the characteristics of compressed air.(5 marks) 6 (b) Sketch and explain the working of rod-less cylinder.(5 marks) 6 (c) Explain briefly the end position cushioning of pneumatic cylinder.(10 marks) 7 (a) Write a note on direct and indirect actuation of pneumatic cylinder.(10 marks) 7 (b) Explain the logic OR function with shuttle valve and the double acting clinder.(10 marks) 8 (a) Explain the Motion control diagram for a 2-cylinder circuit.(8 marks) 8 (b) Write a note on relays used in electro-pneumatic control.(6 marks) 8 (c) Sketch and explain the non receiving type pressure regulator.(6 marks)