Industrial balancing repair of the fan assembly.

It was truly an honour to be elected in the revival of this failed, old and tired 60″ diameter double width Richardson fan assembly. This unit would be around 35 to 40 years old. We need to respect these old fan units for all the hard work they have done throughout the years. We must also respect the original manufacturers of this fan; they made them to last.

What our team needed to do was fabricate new larger diameter bolt-on hub discs for both impellers.

This creates more support on the impeller back plate and therefore stiffens the impeller when running at speed. We included a taper-lock hub and bush for ease of fitment and alignment on site and introduced adequate stiffeners to the back plate to add further strength. Sounds very simple but there were hours of designing, manufacturing and machining to get there.

Even though the majority of the work was in the manufacturing of the hub discs to ensure the impellers run concentrically. It’s the balancing procedure that would make the difference whether the assembly will run smoothly or not. Balancing a double width fan assembly is not as straightforward as it may seem. To achieve the best possible result, we cannot rely on balancing each impeller individually and assume it’s good enough to return to the client. Theory tells us that this method is sufficient, but, in practice, it does not work. The reason behind this is that the residual dynamic unbalance from each impeller, even though small, will fight against each other and generate a vibration. This is only because these impellers sit back to back on a common shaft.