Forming head seal

A hydraulic blow molding system for forming a preform and a plastic container from the preform during a one-step container molding process by injecting a liquid product into the preform, the system comprising:

• an injection core having exterior surfaces defining an interior shape of the preform;
• a preform mold assembly having interior surfaces cooperating to defining an exterior shape of the preform;
• a neck ring including radially inward facing surfaces defining a finish of the preform, the neck ring including a flange extending radially inward toward to the central axis, the flange contacting a top sealing surface of the finish of the preform and being coextensive with the top sealing surface;
• a forming head including an injection nozzle, the injection nozzle defining a central passageway terminating in an exit orifice, the central passageway defining a central axis therethrough;
• a source of liquid blow medium coupled to the central passageway of the forming head;
• a container mold assembly having interior surfaces cooperating to define a mold cavity in the shape of the plastic container and within which a body of the preform is received;
• and
• a sealing mechanism associated with the forming head, whereby the forming head is configured to apply a sealing force in an axial direction, the forming head engaging the neck ring and the sealing mechanism including a primary seal defined between an axial end face of the forming head and an upper axial face of the neck ring to form a seal whereby molding medium injected into the preform through the central passageway to form the container is prevented from passing between the neck ring and the forming head.

A hydraulic blow molding system for forming a preform and a plastic container from the preform during a one-step container molding process by injecting a liquid product into the preform, the system comprising:

• an injection core having exterior surfaces defining an interior shape of the preform;
• a preform mold assembly having interior surfaces cooperating to defining an exterior shape of the preform;
• a neck ring including radially inward facing surfaces defining a finish of the preform, the neck ring including a flange extending radially inward toward to the central axis, the flange contacting the top sealing surface of the finish of the preform;
• a forming head including an injection nozzle, the injection nozzle defining a central passageway terminating in an exit orifice, the central passageway defining a central axis therethrough;
• a source of liquid blow medium coupled to the central passageway of the forming head;
• a container mold assembly having interior surfaces cooperating to define a mold cavity in the shape of the plastic container and within which a body of the preform is received;
• a sealing mechanism associated with the forming head, whereby the forming head is configured to apply a sealing force in an axial direction, the forming head engaging the neck ring and the sealing mechanism including a primary seal defined between an axial end face of the forming head and an upper axial face of the neck ring to form a seal whereby molding medium injected into the preform through the central passageway to form the container is prevented from passing between the neck ring and the forming head, the sealing mechanism including a sealing member engaging a radial face of the flange, the radial face being generally parallel to the central axis.

A hydraulic blow molding system for forming a preform and a plastic container from the preform during a one-step container molding process by injecting a liquid product into the preform, the system comprising:

• an injection core having exterior surfaces defining an interior shape of the preform;
• a preform mold assembly having interior surfaces cooperating to defining an exterior shape of the preform;
• a neck ring including radially inward facing surfaces defining a finish of the preform;
• a forming head including an injection nozzle, the injection nozzle defining a central passageway terminating in an exit orifice, the central passageway defining a central axis therethrough;
• a seal pin being located in the central passageway and being axially moveable between an extended position and a retracted position along the central axis, in the extended position the seal pin engaging the injection nozzle and sealing off the exit orifice, in the retracted position the seal pin being disengaged from the injection nozzle and permitting the injection of blowing medium through the exit orifice and into the preform;
• a source of liquid blow medium coupled to the central passageway of the forming head;
• a container mold assembly having interior surfaces cooperating to define a mold cavity in the shape of the plastic container and within which a body of the preform is received;
• and
• a sealing mechanism associated with the forming head, whereby the forming head is configured to apply a sealing force in an axial direction, the forming head engaging the neck ring and the sealing mechanism including a primary seal defined between an axial end face of the forming head and an upper axial face of the neck ring to form a seal whereby molding medium injected into the preform through the central passageway to form the container is prevented from passing between the neck ring and the forming head.

A hydraulic blow molding method for forming a preform and a plastic container from the preform during a one-step container molding process by injecting a liquid product into the preform, the method comprising the steps of:

• forming a preform in a preform forming station by injecting a plastic material into a preform mold assembly having interior surfaces cooperating with an injection core and a neck ring to defining a shape of the preform;
• retaining the preform in the neck ring and transferring the preform to a container molding station;
• injecting a liquid end product into the preform to cause expansion of the preform to form a liquid filled container;
• the method characterized by
• compressively engaging an axial end face of the forming head with an upper axial surface of the neck ring forming a primary seal of a sealing mechanism located above the finish of the preform and in which a sealing force is applied in an axial direction of the preform;
• whereby the liquid end product injected into the preform to form the container is prevented from passing between the neck ring and the forming head.