USN 1 P E

PESIT Bangalore South Campus Hosur road, 1km before Electronic City, Bengaluru -100

Department of Mechanical engineering

INTERNAL ASSESSMENT TEST – 1 SOLUTION Date : 17-08-2016 Max Marks: 50 Subject :Hydraulics and Pneumatics system Code :10ME73 Section: A, B&C Name of faculty : SS/ AK Time : 90 min

Note: Answer any five full Questions selecting atleast TWO questions from each part.

PART - A

1.Define Pascals law. Explain in detail multiplication of forces using pascals law.

2) State and explain the factors influencing the selection of a fluid. Ans)

3) A hydraulic cylinder is to compress a body down to a bale size in 10s. The operation requires a 3m stroke and a 40000 N force. If a 10 MPa pump has been selected, assuming the cylinder to be 100% efficient , find a) The required piston area. b) The necessary pump flow rate c) The hydraulic power delivered to the cylinder d) The output power delivered to the load. Ans)

4)Calculate the theoretical delivery of a gear pump. Module of the gear teeth is 6mm and width of gear teeth is 65 mm. Number of teeth on driver gear is 16 and pressure angle of the gear is 20. Pump speed is 1600 rpm. Outer diameter of gear is 108 mm and dedendum circle diameter is 81 mm. Volumetric efficiency is 88% at 7MPa. Also calculate the theoretical delivery from volumetric displacement and compare the two obtained values. Ans)

PART - B 5) With a neat sketch explain the working of vane pumps. Explain pressure-compensated vane pump and how does it work? Ans)

6. A hydraulic system operating at 105 Bars has following characteristics. Find i) Theoretical displacement of motor ii) Motor output torque

Pump Motor

Vd=100cm Vd=?

Volumetric efficiency=90% Volumetric efficiency=94%

Mechanical efficiency=90% Mechanical efficiency=92%

Speed=1000rpm Speed=600rpm

Ans)

7. Explain how direction control valves are classified. Ans)

8. Define volumetric efficiency, mechanical efficiency and overall efficiency of hydraulic motor. Why is the actual flow rate required by a hydraulic motor higher than the theoretical flow rate? Ans)

* * * * * * * * B.E/ 7 th sem (PESIT-BSC Internal)