Page 40 - PNEUMATIC AND HYDRAULIC
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2.9 Major Problems In Hydraulic System.
2.9.1 Cavitations
Definition;
“An unwanted condition that occurs in hydraulic pumps due to excess air in the
pump.”
How does cavitation occur;
When the suction is greater than the pressure levels, which causes air bubbles to
collapse at the outlet. This eroding of material is caused by local pressure peaks and
high temperatures. Motion energy (pressure energy) is required for an increase in flow
velocity of oil at a narrowing. Because of this, pressure drops at narrow point may
move into the vacuum range. Then bubbles are formed.
Affects:
i. pressure drops,
ii. noise,
iii. vibration,
iv. temperature rise.
2.10 Hydraulic fluids
A hydraulic oil or hydraulic fluid is the medium by which power is transferred in
hydraulic machinery. Common hydraulic fluids are based on:
i. Mineral based oil
ii. Water based oil
iii. Synthetic based oil.
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