Midland SPD-6, Operation, Parts & Service Manual

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Model SPD-6
Loop flushing shuttle spool
An integral loop flushing shuttle spool is used to separate
system A and system B pressures.
System delta pressure will cause the shuttle spool to shift,
allowing the low side system pressure to flow to the loop
flushing relief valve.
P003 490E
System
loop A
to Loop flushing
relief valve
System
loop B
P003 437
A
B
L2
W
Warning
Unintended vehicle or machine movement hazard.
Excessive motor loop flushing flow may result in the inability to build required system pressure in some
conditions. Maintain correct charge pressure under all conditions of operation to maintain pump control
performance in hydrostatic systems.
Loop flushing relief valve
The loop flushing relief valve is incorporated into all H1 motors. Use the loop flushing option in
installations that require fluid to be removed from the low pressure side of the system circuit due to
cooling requirements.
The loop flushing relief valve is also used to facilitate the
removal of contaminants from the loop. The loop
flushing valve is equipped with an orificed charge
pressure relief valve designed with a cracking pressure of
16 bar [232 psi]. Valves are available with several orifice
sizes to meet the flushing flow requirements of all system
operating conditions.
P003 491
P003 487
A
B
L2
40 [580]
30 [435]
20 [290]
10 [145]
10 15 20 30 05
10
[2.6]
20
[5.3]
30
[7.9]
40
[10.6]
50
[13.2]
60
[15.9]
70
[18.5]
P003 492E
0
Loop Flushing Relief Valve Size
Loop Flushing Flow l/min [US gal/min]
Lo
w S
yst
em P
ressur
e minus C
ase P
ressur
e
bar [psi]
Service Manual H1B 060/080/110/160/250 Bent Axis Motors
Operation
22
11024924 • Rev CB • February 2015