Chapter 8
Visco
Twin_002 EN
Page 8-1
8.
Disturbances and their elimination
Disturbances on pumps and pump units can basically be of hydrodynamic, mechanical or electrical
nature.
8.1
Mechanical and hydrodynamic disturbances checklist
Type of disturbance
possible cause
Elimination
Pump does not start
Jam by foreign objects
Remove foreign objects
Deposits at shutdown
Immediately clean pump
Medium hardens (due to
temperature/chemical action)
Solids content too high
Check pump delivery conditions,
change project planning if
necessary
System pressure too high
Compare pump pressure rating
with system conditions, change
project planning if necessary
Delivery rate decreases or
is not reached any longer
Shut-off devices partly shut,
pipe line clogged
Open shut-off devices fully,
eliminate clogging
Screw spindles worn
replace
Trapped air in medium
Check suction line, medium supply
and seals
Seals defective
Replace seals
Pump does not suck
wrong direction of rotation
Correct direction of rotation,
observe directional arrow
Spindles mounted incorrectly
mount spindles correctly
Suction line clogged
clean
Pump or filter clogged
Clean pump / filter
Suction line draws air.
Seal line /
Increase filling level when sucking
from tank
Loud pump noise
Cavitation,
rotational speed too high or
suction pipe too narrow, clogged
Check project planning, chose
lower speed if necessary,
increase pipe line cross-section
8.2
Electric disturbances
Disturbances in the electric drive of the pumps or the pump unit can have numerous causes (power
supply, dimensioning of the drive, motor protection, etc.).
Eliminate disturbances in connection with the electric drive following the attached drive
manufacturer's operating and maintenance manual.
Manual ViscoTwin 104-xx 3A