Function; Before Start - ITT Flygt 4901 Instalación, Servicio Y Mantenimiento

FUnCtIon

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 inverting 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, forc-
ing 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
liquid out of the sump. See figure 2.
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Figure 1.
Figure 2.
Installation, Care and Maintenance Flygt 4901, Flush Valve
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.
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 sedi-
ment on the bottom. In order to prevent this, it is
recommended that the sump should be emptied
and cleaned before the flush valve is put to use.
(en)
Figure 3.
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