All the steel cylinders that come through Knivsta are for the Swedish and Norwegian markets, and range in size from 2.5 liters up to 50 liters. Every week, the Knivsta facility processes around 1,600 cylinders, with thousands more stored outside awaiting processing. Exactly which cylinders enter the facility is determined by a complex inventory management system that ensures the right cylinders are inspected and processed to meet customers’ needs.
After being brought into the facility, a cylinder has its cap and valve removed in a process known as demounting. The cylinder then undergoes an internal inspection to identify possible cracks, rust, moisture or other foreign debris. Data is then entered in a maintenance log before the cylinder is placed on a ceiling-mounted conveyor belt that transports it slowly and steadily toward the next phase of its journey in Knivsta.
After a few minutes floating calmly through the air, the cylinder enters a decidedly harsher environment: the blasting chamber. Here the cylinder is blasted with an abrasive material under high pressure to remove any remaining paint, labels, or other residue. The cylinder emerges with a smooth, silver grey finish, at which point it is weighed before entering the inspection room.