Why is a plansifter hung on rods?
A plansifter box can weigh tonnes and oscillates in a circle all the time. To pass as little vibration as possible to the building, the box is not fixed to the floor but hung on flexible sifter rods (suspension rods). The rods carry the box’s weight while letting it oscillate, acting as a flexible suspension system.
Why the material matters
Suspension rods flex and return millions of times, so they must be made of a composite with high fatigue strength: flexible but resistant to breaking. Rod diameter and length depend on the box weight and the sifter maker’s design; mixing rods of different diameters on one box spreads the load unevenly.
Inspection checklist
- Are there longitudinal or transverse cracks, fibre separation or whitening on the rod surface?
- Are the rod ends and connection points crushed or worn?
- Is the sifter box level, or is one corner lower than the others?
- Is there unusual noise or jolting during oscillation?
Replacing as a set, and safety
Damage on one rod shows the others have been exposed to the same fatigue, so replacing rods as a set is recommended. The suspension is a safety part: running on with a damaged rod can lead to serious risks such as the box falling. During replacement the box must be supported safely and the sifter maker’s instructions followed.
Send us the diameter and length of your current rods and the sifter model and we will supply the right rods.
