Vibration isolation
An isolator is chosen against the machine's running speed and the structure beneath it. Chosen by eye, it can make the problem worse.
Related
Every isolator has a natural frequency. Isolation only happens when the machine runs well above it; near it, the mount amplifies rather than isolates. That is why plant sitting on rubber pads sometimes transmits more than plant bolted to the slab, and why selection begins with the machine's speed and mass rather than a catalogue page.
What the work involves
- Isolator selection — springs, rubber or a combination, matched to running speed and load.
- Inertia bases — added mass where a machine needs help sitting still, particularly pumps.
- Flexible connections — on pipework and ductwork, so the machine is not bolted back to the building by its services.
- Isolated hangers — for suspended pipes, ducts and equipment.
- Restraints — to hold a machine in place without short-circuiting the isolation.
- Start-up and shutdown — considered, because a machine passes through its resonance each time.
Selection in practice
| Running speed | Sets the disturbing frequency; the isolator must sit well below it. |
|---|---|
| Static deflection | How far the isolator compresses under load — the practical measure of its softness. |
| Load distribution | Corner loads calculated so each mount deflects equally and the machine sits level. |
| Structure below | A stiff ground slab and a long-span floor need different solutions. |
| Environment | Temperature, oil, weather and fire exposure all rule out some materials. |
What we need
- Machine make, model, mass and running speed.
- Its position, and what lies directly below and beside it.
- The structure it will sit on.
- Service connections — pipes, ducts, conduit.
- The noise or vibration target in the affected space, if one has been set.
Tell us the room
Send dimensions and intended use. You get back an indicative acoustic treatment, a systems outline and a budget range.