54 SECTION 35 - HYDRAULIC SYSTEM
Anti-cavitation operation
Circuit relief valves with an anti-cavitation feature
are fitted in circuits where rapid extension of the cyl-
inder could create a void condition and permit the
transfer of oil from the high pressure side of a cylin-
der to the lower pressure (void) end of the cylinder.
When for example the boom is rapidly lowered and
the cylinder rod end circuit relief valve operates, oil
has been removed from the rod end of the cylinder
and a void created in the piston end. This oil is auto-
matically replenished by the anti-cavitation device in
the opposite circuit relief valve as follows:
The void creates a pressure lower in the cylinder
supply gallery and back pressure in the control valve
exhaust gallery acts on the outer face of the sleeve
poppet moving it to the right.
Exhaust oil is then directed into the cylinder supply
gallery to stop cavitation.
High pressure oil
Anti-cavitation oil supply to cylinder
Relief valve exhaust oil
1. Anti-cavitation system pressure relief valve
2. Cylinder rod
3. System pressure relief valve
4. Control valve exhaust gallery
5. Spool
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2
3
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5
F29542
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