Reference Manual

10B −3
Figure 10B-1. Chip Feeding
E1214
speed drive on the chip meter drive. It is important
to keep the chip meter full in order to maintain a
steady feed rate. A vibrator is provided on the chip
hopper for intermittent use, as required, to ensure
a steady feed of chips to the chip meter.
Chips leaving the chip meter drop into a second
feeder, called a low pressure feeder. It is simply a
continuously rotating, tapered star feeder, which
forms a seal between atmospheric pressure and
15-18 psig of the next stage. Its primary function is
to prevent steam leakage and to deliver chips to
the steaming vessel. Steam is injected into the
ends of the rotor housing in order to blow sawdust
and chip fines out. The pressure remains in the
empty pocket after the chips have dropped out
and is relieved through a pipe connected to the top
of the chip hopper. To ensure a steady feed, the
low pressure feeder is designed so that one
pocket is being filled with chips, one pocket is
discharging chips, and one pocket is relieving
steam to the chip hopper.
Valve: TV-2A Chip bin temperature
This valve provides an alternate source of low
pressure steam to the steaming vessel where the
wood chips are pre-steamed at atmospheric
pressure.
D Typical process conditions:
— Fluid: Steam
— T = 325 – 400_F
— P = 60 – 80 psig