15
box. Excess pressure from an external
source can be very destructive to packing.
More pressure is required, however, for
abrasive slurries than for clear liquids.
Examination of the leakage will indicate
whether to increase or decrease external
pressure. If slurry is present in the leakage,
increase the pressure until only clear liquid
drips from the box. If the drippage is corrosive
or harmful to personnel, it should be collected
and piped away.
A common error is to open the external piping
valve wide and then control the drippage by
tightening the packing gland. A combination
of both adjustments is essential to arrive at
the optimum condition. The life of packing
and sleeve depends on careful control more
than any other factor.
FIGURE 9 – CONTROLLED PRESSURE
SYSTEM
FLOWMETER
PRESSURE
REDUCING
VALVE
PRESSURE
GAUGE
STUFFING BOX
