ProMinent Sigma 3 Basic Operating Instructions Manual page 35

CAUTION!
Warning of feed chemical spraying around
PTFE seals, which have already been used / com‐
pressed, can no longer reliably seal a hydraulic connec‐
tion.
– New, unused PTFE seals must always be used.
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. due to a clogged dis‐
charge line or by closing a valve), the pressure that the
metering pump generates can reach several times the
permissible pressure of the system or the metering
pump. This could lead to lines bursting resulting in dan‐
gerous consequences with aggressive or toxic feed
chemicals.
– Install a relief valve that limits the pressure of the
pump to the maximum permissible operating pres‐
sure of the system.
CAUTION!
Uncontrolled flow of feed chemical
Feed chemical may press through a stopped metering
pump if there is back pressure.
– Use an injection valve or a vacuum breaker.
CAUTION!
Uncontrolled flow of feed chemical
Feed chemical may press through the metering pump in
an uncontrolled manner in the event of excessive pri‐
ming pressure on the suction side of the metering pump.
– Do not exceed the maximum permissible priming
pressure for the metering pump or
– set up the installation properly.
Installation, hydraulic
35