EXTERNAL POLY PUMP

The POLY dosing pump unit (EPP) consists of several functional parts. The base
is a welded supporting frame which the individual parts are attached to. EPP
supplies material for spraying at the defined pressure and temperature according
to the input parameters of the recipe.
Low-pressure polyol supply line (with the pressure of 2 - 8 bar) is connected to
EPP input. It leads to Mann & Hummel (A06) filter. Material is fed via
BARMAG high-pressure gear pump (P01) via manifold (A04) fitted with
manometers (PI01, PI02), pressure transducers (PR01, PR02) and HAWE safety
valve (V11). This pump is driven by SEW motor (MOT 01) via SYNTEX35-
ROTEX GS 38/45 (C01) clutch. The material then flows (at the pressure of 40 -
100 bar) through a flow-meter (QR01), heat exchanger (HE03), high-pressure
filter (A07) and checkpoint. Material pressure (PR03) and temperature (TE02)
are monitored here. Material then continues via stream distributor to the head
and then returns to EPP via the stream distributor.
Another checkpoint is on EPP return line. It monitors the material temperature
(TE03). This is followed by three pneumatic valves VSCDN4 (V30, V31, V32)
and pressure adjustment valve (V21) that sets the pressure value during HPR.
Valve V31 is closed in normal operation. It opens only during flow calibration
while valve V32 closes. V32 is closed also during spraying.
When valve V30 closes, material flows to high-pressure circulation based on
setting of the reducing valve V21.
EPP is in continuous operation (during operation of the entire line), because
material must keep circulating.