6.5.5 Logic Control
The control system of the extruder was designed as simple as possible
for the operator. When everything is functioning normally, there is no
need of touching the basic settings and adjustments of the extruder. In a
normal state, the extruder works as one automatic part of the whole process.
The control system has been built up so that all manual extruder
operations needed (e.g. during maintenance and repair) can be carried
out directly from operation control board OS1.
Note! When manual control is used, all lockings are not necessarily
functioning to protect the operator or machines.
Interlocking of machines
The machines on the line just before the extruder (plate feeding conveyors
and plate feeder) and after it (cutter and stacker) affect the extruder
operation. Additionally, the concrete surface level in the feeder hopper
affects the extruder operation. Any malfunction occurring in these machines
stops also the extruder.
The extruder has an automatic detector for gaps between base molds.
The operation of the extruder (screws, vibrators, rollers and mixer) stops,
if a gap between the base molds is detected before the extruder. The
plate feeder conveyors work until the gap is closed.
In automatic operation, the screw drives, the vibrators and the mixer
work as one unit, assuming that also the plate feeder is in automatic operation
(OS3).
Planned operation
Normally the extruder has four operating stages:
- starting
- operating
- finishing
- cleaning
Note! Each work shift must carefully clean the extruder and also other
equipment!
Starting
The starting work steps are to be made before feeding concrete into the
feeder hopper. The extruder is kept in manual operation, and the base
molds coming from the plate feeder are driven through the extruder.The
plate feeder stops when a half of the first base mold has come out of the
extruder