Page 161 - Fluid Power Engineering

Hydraulic Pumps 135

flow rate, Q , the increase in the oil power, ΔN, the pump outlet power, N ,
t out
and the driving torque, T , if the inlet pressure is 100 kPa.
t
4. The figure shown here explains the power transmission in a hydraulic power
system, as well as the causality relation of the system variables. Discuss it in detail.

5. Discuss the different types of power losses in displacement pumps.
6. Discuss the cavitation phenomenon in displacement pumps.
7. Give and discuss briefly the classification of hydraulic pumps.

8. Draw a schematic of a bent axis axial piston pump. Explain briefly its
function and give an expression for its geometric volume.
9. Deal with the pulsation of flow of axial piston pumps and the associated
pressure oscillation for a pump loaded by a loading orifice.
10. Draw a schematic of a swash plate axial piston pump. Explain briefly its
function and give an expression for its geometric volume.

11. Draw a schematic of a swash plate axial piston pump with inclined pistons.
Explain briefly its function and give an expression for its geometric volume.
12. Discuss briefly the need for variable displacement pumps.

13. Explain briefly the principal of operation of wobble plate pumps.
14. Classify and explain briefly the principal of operation of radial piston
pumps. Use the illustrations in Figs. 4.19, 4.20, and 4.21.
15. Draw a schematic of an external gear pump. Explain briefly its function
and give an expression for its geometric volume.
16. Discuss the speed limitations in gear pumps and derive the necessary
relations.

17. Discuss briefly the pulsation of flow in external gear pumps.
18. Deal with the problem of oil squeezing in external gear pumps.
19. Explain briefly the principal of operation of internal gear pumps and
discuss their flow and efficiency characteristics. (Use Figs. 4.26 and 4.27.)

20. Explain briefly the principal of operation of gerotors (Fig. 4.28) and screw
pumps (Fig. 4.29).