Hydraulics & Pneumatics - Dec 2014

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) State Pascal's law. Explain with neat sketch, the basic hydraulic power system(6 marks) 1 (b) Explain the construction and working of Balanced Vane Pump.(8 marks) 1 (C) A Vane has a rotor of diameter 50 mm, a cam ring of diameter 80 mm and the vane of width 40 mm. Compute the volumetric displacement if the eccentricity is 10 mm.(6 marks) 2 (a) With sketch briefly explain linear hydraulic actuators(6 marks) 2 (b) Explain with neat sketch the operation of Swash Plate Piston motor in hydraulic system(5 marks) 2 (c) A hydraulic motor has a volumetric displacement of 123 cm³ operating at a pressure of 60 bar and speed 1800 RPM. If the actual flow rate consumed by the motor is 0.004 m³/sec and the actual torque delivered by the motor is 100 Nm. Find: i) Volumetric efficiency, ii) Mechanical efficiency, iii) Overall efficiency(9 marks) 3 (a) Explain with a neat sketch the working of four way, two position directional control valve with symbolic representation(6 marks) 3 (b) Explain with a neat sketch construction and operation of simple pressure relief valve(7 marks) 3 (c) Explain briefly with neat sketch working of pressure compensated flow control valve.(7 marks) 4 (a) Explain with a neat circuit diagram the working of a regenerative circuit(8 marks) 4 (b) Explain with a neat circuit working of a sequencing circuit in a drilling machine(8 marks) 4 (c) What are hydraulic accumulators? Classify the accumulators used in hydraulic system.(4 marks) 5 (a) Explain any five desirable properties of a hydraulic fluid(10 marks) 5 (b) What are the functions of reservoir system? Explain briefly with neat sketch construction of reservoir system(10 marks) 6 (a) Explain the characteristics of compressed air(6 marks) 6 (b) Define pneumatic system. Give the difference between hydraulic and pneumatic system(6 marks) 6 (c) Explain end position cushioning in pneumatic cylinder with diagram(8 marks) 7 (a) Explain with a neat sketch control of extension of a double acting cylinder using logic gates.(10 marks) 7 (b) Explain with a neat sketch construction and operation of a typical quick exhaust valve to increase the actuation speed of a cylinder in a pneumatic system.(10 marks) 8 (a) Explain with a neat diagram coordinated sequence motion of two cylinders(10 marks) 8 (b) Write a short note on air dryer and air filter.(10 marks)