3. AIR VESSEL
• An air vessel is a closed chamber containing compressed air in the top
portion and liquid in the bottom of the chamber.
• At the base of the vessel there is a opening where the liquid can flow
in and out of the vessel.
• Air vessel is fitted for the following reasons
(a) To obtain continuous supply of fluid at a uniform rate
(b) To save a considerable amount of work in overcoming the
frictional resistance in the suction and delivery pipe.
(c) To run the pump at a high speed without separation
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10. EFFECT OF ACCELERATION AND FRICTION IN
SUCTION AND DELIVERY PIPES DUE TO FRICTION
• The loss of head due to friction at the beginning of the suction stroke
and delivery stroke (i.e) θ = 00
hfs = 0
• The loss of head due to friction at the middle of the suction and
delivery stroke (i.e) θ = 900
hfs =
4𝑓𝑙 𝑠
2𝑔𝑑 𝑠
(
𝐴𝜔𝑟
𝑎 𝑠
)2
• The loss of head due to friction at the end of the suction and delivery
stroke (i.e) θ = 1800
hfs = 0
11. PRESSURE HEAD IN THE CYLINDER
• Pressure head in the cylinder at the beginning of the suction stroke
= 10.3-(hs+has)
• Pressure head in the cylinder at the middle of the suction stroke
= 10.3-(hs+hfs)
• Pressure head in the cylinder at the end of the suction stroke
= 10.3-(hs-has)
• Pressure head in the cylinder at the beginning of the delivery stroke
= 10.3+(hd+had)
• Pressure head in the cylinder at the middle of the delivery stroke
= 10.3+(hd+hfd)
• Pressure head in the cylinder at the end of the delivery stroke
= 10.3+(hd-had)
