WARNING!
The following measures are an advantage when
working with highly aggressive or hazardous feed
chemicals:
– Install a bleed valve with recirculation in the
storage tank.
– Install an additional shut-off valve on the dis‐
charge or suction ends.
CAUTION!
Warning of backflow
A back pressure valve or a spring-loaded injection
valve do not represent absolutely leak-tight closing
elements.
– For this purpose use a shut-off valve, a sole‐
noid valve or a vacuum breaker.
CAUTION!
Suction problems are possible
The valves may no longer close properly with feed
chemicals with a particle size of greater than 0.3
mm.
– Install a suitable filter in the suction line.
CAUTION!
Warning of the discharge line rupturing
With a closed discharge line (e.g. from a clogged
discharge line or by closing a valve), the pressure
that the metering pump generates can reach sev‐
eral times more than the permissible pressure of
the system or the metering pump. This could lead
to lines bursting resulting in dangerous conse‐
quences with aggressive or hazardous feed chemi‐
cals.
– Install a relief valve that limits the pressure of
the pump to the maximum permissible oper‐
ating pressure of the system.
CAUTION!
Uncontrolled flow of feed chemical
Feed chemical can press through a stopped
metering pump if there is back pressure.
– Use an injection valve or a vacuum breaker.
Installation
35
