A blow molding device for blow molding preforms into a predetermined shape. The blow molding device includes a batch-type mold provided with cavities, a heating furnace that heats preforms while the preforms are arranged in series, a transfer machine that simultaneously transfers the preforms as a batch to the cavities of the mold after the preforms are heated and sent out sequentially from the heating furnace, and a pressurized liquid feeder that feeds pressurized liquid to the preforms after the preforms are arranged in all of the cavities of the mold and the mold is closed.

A method for holding together, in its closed state, a blow mold of multipiece design of a blowing station for the blow molding of containers from preforms made of a thermoplastic material using a compressed air-operated mold clamp exerting a holding-together force. The mold clamp is pressurized with compressed air for the purpose of and for the duration of the generation of the holding-together force. The blowing station has a relief valve which can be controlled by control compressed air from a control compressed air line. The mold clamp is pressurized at least at times with control compressed air from the control compressed air line.