21
The difference between pipeline systems of semi-automatic control and full-automatic control lies in
the part for water addition into the extrusion system. Water pipeline of the semi-automatic pipeline
system is shown in Fig.2-11.
1. Water inlet pipe 2. Water return pipe 3.Manometer I
4. Water pressure reducing valve 5. Manometer II 6.Water outlet
Fig.2-11 Water pipeline of the semi-automatic pipeline support
Water inlet pipe of the semi-automatic pipeline system is the same as that of the full-automatic
pipeline system equipped with a pressure reducing valve and a water discharge pipe that is
connected directly to the glass-tube flow meter installed on the body of principal machine. In
production, water addition to the conditioner and extrusion barrel was managed by manual control of
the shut-off valve under the glass-tube flow meter. Meanwhile, the flow rate can be indicated by the
floater inside the glass-tube flow meter. See Fig.2-12.
Fig.2-12 Glass-tube flow meter
The semi-automatic control system uses button-type panel control without touch screen. See
Fig.2-13.
The sole control performance of the control box of semi-automatic pipeline system is the control
of steam pipelines to conditioner and extrusion barrel. Referring to the instruments at mid-lower part
of Fig2-13, it regulates the opening of the constant-proportional control valve through controlling of
the output current 4
～
20mA. Meanwhile, this instrument indicates the flow rate of the steam through
receiving the current signal of the flow meter.
