Schwing SP 750-18 - Bypass Check Valve

96
Maintenance
SP 500 / 750-15 / 750-18 / 1000 / 1250 Operation Manual
Bypass Check valve
The lter is equipped with an integral bypass check
valve with a 35 P.S.I. pressure-to-open rating.
When the lter is clogged with dirt, oil is having a hard
time making it through, the pressure di󰀨erence between
the lter inlet and the outlet rises. This pressure di󰀨er-
ence (commonly referred to as a pressure di󰀨erential)
is called delta P and is shown on the schematic as DP.
When the DP reaches 35 PSI, the check valve opens
and the oil returns to the tank unltered. If the lter did
not have the bypass check valve, it would simply break
apart when it was clogged.
All of the dirt ever trapped by the lter, plus the lter
itself, could go directly into the system.
The lter could also split open and leak to the ground,
draining the reservoir, and contaminating the environ-
ment.
Dirty Filter Indicator
Filter
Inlet
Outlet
Figure 3
Hydraulic Oil Filter