Doosan DA40 - The 5;2 way valve; The relief valve

SHOP MANUAL
SHOP MANUAL
LUBRICATION SYSTEM
Ch 4 Page 10 Ch 4 Page 11
LUBRICATION SYSTEM
A - Primary grease line A (port A)
B - Primary grease line B (port B)
P - From Pump
R
A
- Return line A to grease reservoir
R
B
- Return line B to grease reservoir
The relief valve
A relief valve is mounted in the grease line between
the plunger-pump and the 5/2 way valve . When the
grease pressure exceeds 250 bar during the pump-
ing phase, the relief valve will redirect the grease to
reservoir.
The maximum grease pressure will exceeded when:
• a malfunction of the grease pressure switch,
which is mounted in the system occurs;
• a malfunction in the cable of the grease pressure
switch occurs.
Relief valve
The 5/2 way valve
When the 5/2 way valve is at stationary (not ener-
gized), greasing will take place through primary
grease line A and the pressure in primary grease
line B will decrease and the grease will be lead back
to the reservoir through return line R
B
.
When the the 5/2 way valve is energized by the
control unit, the grease supply channel P will be con-
nected to primary grease line B and primary grease
line A will be connected to return line R
A
in the pump.
Greasing takes place through primary grease line B,
the pressure in primary grease line A will decrease
and the grease will be lead back to the reservoir
through line R
A.
Primary grease line ‘B’ outlet
Primary grease line ‘A’ outlet
5/2 Way valve
P
Figure 15
Figure 14
Figure 13