417102233 Betriebsanleitung EMP III E00, E10
For metering in pipelines with underpressure, a pressure control valve
must be built into the metering pipe.
Fig. 6.3
NOTE
A pressure control valve or a metering valve is not an
absolutely hermetically sealing shutoff device.
To prevent the running out of the metering medium when the pump is
stopped, we also recommend the fitting of a solenoid valve which is
approved for use with the pump.
Injector valve (Metering valve)
The metering point should not be positioned below
the discharge container as this arrangement
creates a risk of the discharge container being
siphoned empty (see fig. 6.4).
If such an arrangement cannot be avoided for
configuration-technical reasons, absolutely an
appropriate pressure control valve is to be inserted
(see fig. 6.5).
Injector valve (Metering valve)
When using long metering lines or in the case of an inflexible pipe work,
a pulsation attenuator (fig. 6.6, pos. 1) should be installed in the pressure line
(directly behind the pressure valve of the metering pump) in order to avoid
pressure strokes.
The suction pipes must be kept as short as possible.
Long and twisted suction pipes may lead to air buildup in the system.
The max. suction height is 2 m and the max. flow velocity is 0.3 m/s!
(see also chapter
11.3 “Technical Specifications”).
Always lay the suction pipe so that it ascends to the suction valve of the
metering pump.
For system designs with a suction tube length of more than about 3
m and/or that must reach a suction height of > 2 m, an appropriate
lifting vessel must be installed to support the suction process. The
lifting vessel must be positioned above the pump.