Copyright Goodheart-Willcox Co., Inc.
Chapter 18 Load-Sensing Pressure-Compensating (LSPC) Hydraulic Systems 449
of three coupler ports as shown in Figure 18-24. One port taps directly into
pump outlet pressure, one port allows for a return, and the third port requires
sending a signal pressure to the signal network. Figure  18-25 shows two
similar LSPC systems with one main difference in their designs. The signal
network in Figure 18-25A does not have power beyond. The signal network
in Figure 18-25B is equipped with power beyond and contains the necessary
shuttle valve and couplers for proper operation.
DCV Hydraulic Detent Kickout in LSPC Systems
As explained in Chapter 9, some manually operated DCVs have detented
levers that mechanically hold the spool in a fi xed position during opera-
tion. Once a high pressure is reached, the lever returns to neutral. The detent
kickout pressure is adjustable. The primary shuttle in this type of system has
the responsibility of choosing the higher working pressure from either the
extend or retract pressure and sending it to three locations: the secondary
shuttle valve, the detent kickout valve, and the pressure compensator valve.
Figure 18-24. Power beyond in an LSPC system requires at a minimum three different ports: a pump pressure
coupler, a return coupler, and a load-sensing coupler. Note that the power beyond return couplers are also known
as hydraulic motor return couplers.
DCV/SCV
couplers
Power beyond
pressure coupler
Load-sensing
coupler used for
power beyond
Power beyond
return coupler