pfcs15-12 sae flow control

Description

FC – GENERAL INFORMATION
The Brand, full range pressure compensating variable flow control is designed so that the
orifice area varies as the lever is rotated. Fluid travels past the variable orifice, through
the compensator spool and then out the controlled flow port. Therefore the flow out of
the CF port is proportional to the orifice area which can vary from closed to open. The
sum of the controlled flow and the excess flow equals the inlet flow and as the controlled
flow increases the excess flow decreases. Both outlet flows are pressure compensated with
a spool that maintains a constant flow by adjusting for pressure. Hunting between the
compensated pump and our valve is dampened with a dashpot on the compensator spool.
Thus, the outlet flow is smooth and constant regardless of the pressure on the CF and EX
port. External seals on the rotary spool prevent contamination from getting between the
spool and the casting, thus preventing the spool from locking in one position. All FC’s
are built with stainless steel (416) rotary spools to help prevent the rotary spools from
locking up when they are in a corrosive environment. We also offer the FC with outlet
ports coming from the top of the casting.
ADJUSTABLE BALL SPRING RELIEFS – The adjustable ball spring relief (R) and the
adjustable high lift ball spring relief (B) allow the customer pressure compensated flow
up to the pressure setting on the relief. Once the pressure on the CF port increases above
the relief setting the relief valve opens and diverts flow to the EX port while maintaining
the pressure on the CF port. The EX port must be plumbed back to tank for both of these
reliefs. Both relief options are preset to 1500 psi (103 bar), standard, and field adjustable
from 750 to 3000 psi. (52 to 207 bar). Pressure settings between 250 and 750 psi (17 and
52 bar) can be achieved by using a different spring. The B option’s advantage over the
R option is that the cracking pressure at low and high flow is virtually the same. The B
option is also more stable when flow is traveling past the ball and spring. (See relief flow
charts on next page)
FREE REVERSE FLOW – The free reverse flow (55) option is designed primarily where
cylinders and motors are needed to go in reverse. Flow can go in reverse from either the
EX or the CF port to the inlet. Flow is not metered when it goes in reverse. The nonmetered flow travels past the poppet, down the center of the valve, past the compensator
spool and through the inlet. The steel poppet seat inside the free reverse flow check is
heat treated to assure a long life.