PET bottles can be produced in a one- or two-step process. 

PET bottles can be produced in a one- or two-step process. The Italian company Sipa offers its customer both technologies to accommodate specific plastic packaging needs. Compact brazed heate exchangers from Swep play an integral role in the processes.

Sipa’s process is divided into two parts: injection pressing and preform blowing. During the pressing stage, where the plastic powder is melted to form a preform, hydraulic oil is used to open and close the presses. The oil becomes hot and must be cooled. Because the bottles are used for beverages, hygiene standards appropriate for foods are essential. The manufacturing environment therefore is disinfected, which makes it aggressive towards steel heat exchangers.

According to the companies, Sipa selected compact brazed heat exchangers from Swep because the units combined high performance with the compactness required by the application. The exchangers have uncomplicated exteriors and simple connectors, making it easier to protect the unit with paint in the aggressive manufacturing environment. Prior to adopting the brazed exchanger technology, Sipa used shell-and-tube heat exchangers, but they were found too large for the application.

Now, the hydraulic oil from the pressing stage of the PET bottle process is cooled in a compact brazed heat exchanger. Sipa typically uses the B45 model, but the size of the heat exchanger required depends on the size of the bottle-producing unit and the quality of the cooling water provided for the system.