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9.1 General information on the operation
It must be ensured that
• discharge lines of safety valves end in a risk-free manner.
• no fluid can accumulate in the discharge lines.
• no more valves, shut-off cocks, etc. are installed in the discharge lines.
• the pressure chamber of the solenoid is always filled with hydraulic fluid.
Pressure peaks in the joint return line of more than one valve may cause unintended
spool movements and thus unintended switching processes. It is recommended to
use separate return lines.
9.2 Setting the valve to a low response pressure
When setting the valve, please ensure that the attached name plate is not
f
damaged or torn off.
You can set safety valves which have been provided with a hand wheel or rotary knob
to a lower response pressure without damaging the lead seal. To do this, the system
into which the safety valve is installed needs to be equipped with a pressure gauge
which indicates the pressure at port P or a pressure gauge has to be connected
temporarily to the additional M port, which is normally closed by a plug screw.
The response pressure of a safety valve may only be within the specified pressure
range due to the installed compression spring. The maximum flow indicated by the
component marking can only be utilized within this pressure range.
1.
Temporarily deactivate or remove any other pressure limiting devices which are
installed in the system and have an impact on channel P and seal any openings
which were caused by this.
2.
For systems without a pressure gauge installed in channel P, connect a pressure
gauge at the additional M port.
3.
Unload the valve spring as described in chapter 10.2.4 "Unloading the safety
valve", screw in the adjustment spindle again as far as possible but do not tighten
the lock nut yet after unloading the spring.
4.
Switch on the system and wait until the system pressure has built up.
Set the desired lower response pressure:
5.
Screw out the adjustment spindle so far that the pressure gauge indicates the
desired pressure. When you screw out the valve spindle, the safety valve opens
and limits the system pressure.
6.
Tighten the lock nut clockwise using a manual torque wrench with an accuracy of
± 10% and the tightening torque indicated in the table.
Table 12: Information on the lock nut
Valve type
Wrench size
Tightening torque
DB(W)...5X/...E
17
10 +5 Nm
RE25802-B/09.19, DB(W)...5X/...E, Bosch Rexroth AG
Operation
33/56
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