Inertia Bases
inertia base and mount packages are used beneath mechanical equipment to improve
stability and to minimise the vibratory movement and noise transmission due to equipment
start-up, operation and run-down. They are designed and manufactured to meet with
individual requirements and are suitable for mechanical equipment such as pumps,
air handling units, chillers, booster sets, compressors, etc. They are supplied
to site ready for filling with concrete. We recommend that a concrete mix ratio
of 4 parts gravel : 2 parts sand : 1 part cement is used to give a concrete density
of 2,400 to 2,500 kg/m3. We request that our engineers are contacted for assistance
with this type of equipment. Inertia bases are designed to reduce noise and vibration
transmission between plant equipment and the building structure. They are
usually supported on helical steel spring mounts and are used to:- Provide stability
to a system. Lower the centre of mass. Reduce coupled mode problems. Minimise
the effect of external forces. Ensure an even load distribution. Add rigidity to
the plant / equipment. Reduce the effect of centre of mass estimates. Provide suitable
anti-vibration mount fixings. Reduce vibratory movement due to plant start-up and
run-down as the resonant frequency is passed. An inertia base is normally required
when vibrating plant is required to be isolated with high deflection mounts, typically
above 10mm deflection. If plant, such as a pump, is placed on springs without a
frame base, it will be unstable. An inertia base is a frame base into which concrete
is poured, which increases the mass of the base, consequently damping down the inertial
forces of the plant. The increased mass of the concrete in the base also lowers
the centre of gravity of the combined structure, decreasing the base dimensions
required to achieve stability. The height of the frame of the base must be at least
of the longest dimension between supporting mounts.
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