Krones AG, Neutraubling, Germany, has patented a device and method for blow molding preforms, particularly PET preforms, into bottles. The invention simplifies the equipment and blowing process by eliminating an intermediate blowing stage or stages and utilizing proportional valves to control pressure.

“Normally, heated plastic preforms are formed into plastic containers by pressurizing with compressed air. In the prior art, usually several pressure stages are used to expand the plastic preforms,” the patent states. Typically, the process includes at least three inflation stages, each using a different air pressure. This necessitates a complex system of pressure reservoirs, as well as a relatively complicated procedure for forming the preforms, according to the patent.

The device includes a preform transport device and multiple forming stations. In a preferred embodiment, pressure reservoirs consisting of ring channels supply pressurized air to the preforms, with the pressure controlled by proportional valves.

Patent 10,155,335; issued Dec. 18