Method For Checking And Releasing Nitrogen Gas Charge Pressure In Accumula- Tor (For Control Circuit) - Komatsu PC490LC Installation And Instruction Manual

MAINTENANCE PROCEDURE
1.
Remove the cap for oil filler (F), and release the internal
pressure.
2.
Remove the bolts (4 pieces), and remove cover (1). The
cover (1) may be jumped out by spring (2). While pressing
down the cover, remove the bolts.
3.
Hold the top of rod (3), pull it up, and remove spring (2)
and strainer (4).
4.
Remove any dirt stuck to strainer (4), then wash it in flush-
ing oil. If strainer (4) is damaged, replace it with a new
one.
5.
Insert and set strainer (4) in projected portion (5) of the
tank.
6.
Install cover (1) so that the protruding part at the bottom of cover (1) holds spring (2), then fasten the cover
with the bolts.
7.
Install the cap of oil filler port.
For details, see"METHOD FOR INSTALLING HYDRAULIC TANK OIL FILLER CAP (3-150)".
METHOD FOR CHECKING AND RELEASING NITROGEN GAS CHARGE PRES-
SURE IN ACCUMULATOR (FOR CONTROL CIRCUIT)
The accumulator is charged with high-pressure nitrogen gas, so improper operation may cause an ex-
plosion, which will lead to serious injury or death. For handling, always observe the following.
• The pressure in the hydraulic circuit cannot be completely removed. When removing the hydraulic
equipment, do not stand in the direction that the oil spurts out when performing the operation. In
addition, loosen the bolts slowly when performing the work.
• Do not disassemble it.
• Do not bring open flame close to it or do not dispose of it in fire.
• Do not perform drilling, welding or flame-cutting.
• Do not hit or roll it, or subject it to any impact.
• When disposing of it, the gas must be released. Ask your Komatsu distributor to have this work per-
formed.
NOTICE
If the nitrogen gas charge pressure in the accumulator is low and operations are continued, it becomes
impossible to release the remaining pressure inside the hydraulic circuit if a failure occurs on the ma-
chine.
FUNCTION OF ACCUMULATOR
The accumulator has function of storing the pressure of the control circuit in it. Even after the engine is stopped,
the control circuit can be operated as long as the accumulator functions normally, so the following actions are
possible.
4-66
k k
WARNING
MAINTENANCE