文档介绍：Cover Story
THE RELATIONSHIP OF
VIBRATION TO PROBLEMS IN
FIGURE 1. As flow is reduced from a pump’s
Centrifugal BEP value, vibrations increase significantly,
more or less linearly, until the onset of
‘suction-recirculation flow.’ At lower flows
William D. Marscher, . than this, the vibration gets much higher, and
Mechanical Solutions, Inc. es erratic and uncertain, as shown by
Pumps the cross-hatched ared
specified prior to about 1985, it may be
Vibration analysis, when properly carried out, based only on avoidance of flashing and
not on recirculation onset, and should be
can help keep your pumps operating troublefree rechecked with the manufacturer.
ump reliability problems can be tion, and in the determination of ef- System design & installation
responsible for a large amount fective fix options. Suction design. The design of the
of the maintenance budget and pump suction has significant mechan-
Plost-opportunity cost at chemi- Design & selection influences ical ramifications. Both the mechani-
cal process plants. Typical reasons A pump should be selected that will cal connection of the suction flange
for pump failures can be diagnosed typically operate close to its BEP. Con- and the hydraulic design upstream of
early by applying the right kinds of trary to intuition, centrifugal pumps do the pump impeller are of key impor-
vibration testi