Patent ID: 7172406

Claim:
An installation for blow-molding or stretch-blow-molding containers, particularly bottles, from parisons made of thermoplastic polymer such as PET, this installation comprising: on the one hand, at least one blowing mold comprising two mold portions that can be brought together so that they touch via respective contact faces and then define at least part of a molding cavity opening onto one face of the mold via a neck passage able to receive the neck of the parison which is able to rest, via an annular flange, against said face of the mold, and, on the other hand, blowing means including a blowing nozzle of the bell type able to be brought to bear frontally in a sealed manner against said face of the mold, sitting over the neck of the parison, said two mold portions being able to move apart during the blowing under the effect of the pressure of the blowing fluid with the formation of a gap between the aforesaid contact faces of the two mold portions, wherein leakage means of relatively large cross section, when considered by comparison with the cross section offered to the fluid by the aforesaid gap, are provided from at least one contact face of at least one mold portion and extending beyond the seating for the bell of the blowing nozzle, whereby the high-pressure blowing fluid that can enter the gap is removed at least for the most part by said leakage means and only a small proportion at most of said fluid can, at a relatively low pressure, get as far as the molding cavity.