Methods and apparatus for blow molding glass articles

Abstract

Methods and apparatus for forming glass articles such as bottles and the like utilize flows of pressurized cold cryogen vapor that are introduced into mold cavities which are being used to mold glass articles. The cold cryogen vapor hastens cooling and solidification of the articles so that the time during which the articles must be retained in their molds is significantly reduced. Reductions in mold retention times enable the apparatus to be operated at increased speeds, whereby its productivity is significantly increased. Productivity increases of 15 percent and often more can be achieved at relatively low expense. The use of cold cryogen vapor introduction into mold cavities is applicable to a variety of glass molding techniques including molding and blow molding. Cold cryogen vapor introduction can be used in staged molding procedures, for example in operations where a hollow blank or parison of glass is first press-formed in a roughing mold, and is then blow-molded in a finishing mold to assume its final form; in such a staged procedure, cold cryogen vapor introduction may be used in either or both of the roughing and finishing stages to expedite solidification and to permit increased productivity. In preferred practice the cold cryogen vapor is nitrogen gas that is released from a container of liquid nitrogen. Cold cryogen vapor may be mixed with flows of cooling and/or blowing gases for delivery with these gases into mold cavities. In preferred practice, cold cryogen vapor is delivered into the mold cavities without being mixed with other flows of cooling and/or blowing gases.