Challenge
Our customer is a manufacturer of rolled steel products. They were experiencing reliability issues with the handling equipment that receives the steel slabs from the furnace, before feeding them into a rolling mill which turn these slabs into plate or coiled steel.
The slab, which weighs up to 5000kg, slides down a slope from the furnace reaching a speed approaching 6 m/s, before being brought to a controlled stop by a beam with 5 shock absorbers attached in parallel. Once stopped the shock absorbers were required to extend and push the slab back into a position on the conveyor before it continues onwards to be de-scaled and rolled.
The existing shock absorbers performed relatively well but had an extremely short operational life, lasting only 8-12 weeks before failing in service. The absorbers failed due to oil leakage and deterioration of the gas pressure which is required to push back the slab and reset the shock absorber for the next impact.
Our challenge was to replace the incumbent units with shock absorbers that would stand up to this tough application. Delivering an increased operational life to enable an increase in production and reduced maintenance and engineering costs.
Engagement
We spent time with our customer over several meetings to get all the necessary information regarding the application along with the required technical data to enable correct specification of the replacement shock absorbers.
Taking into consideration the mass of the falling slab and the impact speed, we specified the attributes required by the shock absorbers for the application. This was followed up by a simulation of the forces and deceleration experienced by the arresting solution to ensure that there would be no adverse effects to the supporting structure and mounting points.
Solution
To meet the extraordinary demands of the application, 5 custom built HI Shock Absorbers were designed and manufactured by ITT Enidine. They featured a custom orifice pattern, which was used to decelerate the steel slabs and match the specification of the application and relative forces. The solution was also very simple to install with minimal modification to the existing structure.
Benefits
The initial trial installed 5 sets and proved very successful. In application, the life or our Enidine shock absorbers was more than double the life of the original units.
The new solution brought immediate benefit to the customer. Delivering increased production volumes through a reduction in unplanned downtime. Also, a direct reduction in maintenance costs for repairs and replacement of the shock absorbers and the additional engineering work required to retain the integrity of the structure that catches the slabs.
