Before Start - ITT FLYGT 4901 Instalación, Servicio Y Mantenimiento

Before start

The ball rests on the inner membrane. The oil is in the
oil chamber, the outer membrane is up and the inner is
down.
When the pump starts:
The valve is open when the pump starts. The flow from
the pump is led through the valve and the pump sump
is being flushed. An underpressure induced by the flow
occurs in the valve body. This underpressure begins in-
verting the outer and inner membranes and lifts the
ball. See figure 1.
After approximately 20 seconds, the oil flows from the
oil casing to the space between the inner membrane
and valve body bottom via the regulating valve, forcing
the inner membrane to invert and thus pushing the ball
into the jetstream. The ball then obstructs the flow
through the valve and the pump begins pumping the liq-
uid out of the sump. See figure 2.
FUNCTION
When the valve is closed, the underpressure is instan-
taneously changed to overpressure, which forces the
membranes and the oil back to their initial positions.
See figure 3.
Figure 1.
Before first start:
During the running-in period there is some risk that
the valve will become clogged with solid particles
and sludge stirred up from the sediment on the
bottom. In order to prevent this, it is recommended
that the sump should be emptied and cleaned be-
fore the flush valve is put to use.
Figure 2.
7
Figure 3.