Checking Charge Pressure Of Nitrogen Gas In Accumulator (For Control Circuit) - Komatsu PC128UU-2 Operation & Maintenance Manual

MAINTENANCE PROCEDURE
CHECKING CHARGE PRESSURE OF NITROGEN GAS IN ACCUMULATOR
(FOR CONTROL CIRCUIT)
The accumulator is charged with high-pressure nitrogen gas, so mistaken operation may cause an explo-
sion, which will lead to serious injury or damage. When handling the accumulator, always do as follows.
The pressure in the hydraulic circuit cannot be completely removed. When removing the hydraulic
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equipment, do not stand in the direction that the oil spurts out when carrying out the operation. In
addition, loosen the bolts slowly when carrying out the operation.
Do not disassemble the accumulator.
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Do not bring it near flame or dispose of it in fire.
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Do not make holes in it or weld it.
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Do not hit it, roll it, or subject it to any impact.
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When disposing of the accumulator, the gas must be released. Please contact your Komatsu distribu-
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tor to have this work carried out.
FUNCTION OF ACCUMULATOR
The accumulator stores the pressure in the control circuit.
Even after the engine is stopped, the control circuit can be
operated, so the following actions are possible.
If the control lever is operated in the direction to lower the
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work equipment, it is possible for the work equipment to go
down under its own weight.
The pressure in the hydraulic circuit can be released.
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The accumulator is installed to the position shown in the dia-
gram on the right.
CHECKING FUNCTION OF ACCUMULATOR
Replace the accumulator every 2 years or every 4000 hours, whichever comes sooner.
Check the nitrogen gas charge pressure as follows.
1. Stop the machine on firm, level ground.
2. Set the work equipment to the maximum reach (arm fully
extended and bucket fully dumped) and hold the work
equipment at a position 1.5 m (4 ft 11 in) above the
ground.
NOTICE
Carry out the following procedure to lower the work equipment to the ground within 15 seconds of stop-
ping the engine.
When the engine stops, the pressure in the accumulator gradually goes down, so inspection can only be
carried out immediately after the engine is stopped.
4-62
WARNING
MAINTENANCE