Copyright Goodheart-Willcox Co., Inc.
150 Hydraulic Systems for Mobile Equipment
If the series cylinders leak or get out of synchronization, it can be chal-
lenging to resynchronize the cylinders, also known as rephasing. Some planters
have rephasing orifi ces in the cylinders. The operator rephases the cylinders by
holding the DCV in the raise position until the cylinders are placed back in
synch. See Figure 6-37.
Some implements have the cylinders in parallel and use rephasing relief
valves. If one of the parallel cylinders reaches its end of travel and the operator
continues to hold the DCV in the raise position, the rephasing relief valve sup-
plies oil to the other cylinder that is continuing to extend. The rephasing valves
are commonly used in conjunction with a fl ow divider valve. The fl ow divider
valve is used to proportion oil to different sized implement cylinders that are
plumbed in parallel. See Figure 6-38. Proportional fl ow divider valves will be
explained in Chapter 8.
Figure 6-37. Rephasing orifices are commonly used in planter lift cylinders. They allow an operator to place the
cylinders back into synchronization by holding the DCV in the raise position until the cylinders are synchronized.
Figure 6-36. This table shows that the difference in areas between the master cylinder’s piston and rod must equal
the slave cylinder’s piston area.
°
Diameter (inches) Area (in2)
Master Cylinder Piston 3.25 8.292
Master Cylinder Rod 1.25 1.227
Difference in Master Cylinder Areas ° 7.065
Slave Cylinder Piston 3 7.065