EXTRACT Centrifuges generate high out of balance forces due to unequal settlement of
mass at various parts of its high speed revolving basket. Conventionally, a Pendulum
System is used. This however transmits significant dynamic forces to the structure/support.
Several leading institutes including Civil Engineering department, Roorkee and consultants
measured the vibrations and attempts were made to isolate these using conventionally
available rubber mountings. Resistoflex were contacted to re-design a suitable Vibration
Isolation System. A detailed combination of Steel Springs and Viscous Dampers were
designed to absorb the dynamic forces and isolate the Centrifuge. With an efficiency level
of 99% to ensure high isolation of forces to structure.
Since RCC inertia block was already cast, steel plates were welded to the reinforcement
and isolators were installed using out-rigger brackets.
In April'94, all the seven machines were re-installed. Two at ground floor and five on
elevated RCC and steel structures.
The machines were run at full speed with 4.5 Kg mass attached to the periphery of the
basket.
Vibration measurement were taken at various points and were found well-within the
designed Values. Subsequently machine was run at full load. New Vibration measurement
confirmed Centrifuges operation within the designed parameters.
In April '97 Vibration measurements were taken. In most cases transmitted Vibration were
the order of 0-20 micron. It was also revealed that maintenance of the machines was
drastically reduced after there re-installation on Spring Damper System.
