Quiz 6
1)

(a) Figure 1 below shows the arrangements of a circuit for a hydraulic system. The pump draws oil with a specific gravity of 0.90 from a reservoir and delivers it to the hydraulic cylinder. The cylinder has an inside diameter of 125 mm, and in 15 s the piston must travel
500 mm while exerting a force of 5000 kg. It is estimated that there are energy losses of
3.5 m in the suction pipe and 10.7m in the discharge pipe. Both pipe diameter is 50mm.
Calculate:
(i) The volume flow rate through the pump
[4 marks]
(ii) The pressure at the cylinder
[4 marks]
(iii) The power delivered to the oil by the pump if the pump has 70% efficiency
[9 marks]

Figure 1

2)
(a) Figure 2 shows water flowing from reservoir A to B. If the water surface elevation in reservoir B is 110 m, what must be the water elevation in reservoir A if a flow of 0.03 m3/s is to occur in the cast-iron pipe with gate valve fully open? (Assume ambient temperature)

[13 marks]
(b) Explain what is the purpose of the gate valve in the pipe system?
[4 marks]
(c) Draw the HGL and EGL for the pipe system.
[4 marks]
(d) Propose an improvement to reduce the losses in the pipe system. Justify your answer.
[4 marks]

Elevation = ?? m

A
Kent = 0.5
L = 150 m
Long radius Bend,
90° flanged

Gate
Valve

Elevation
= 110 m
L = 40 m

D = 60 cm

Figure 2

D = 60 cm

B
Kexit= 1.0