Seal Head Fluid Paths for Foil Liner Wrinkle Prevention
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Solution Overview
Problem
Conduction and induction sealing processes for foil liners in containers often result in wrinkles or tears due to heat-induced expansion of the head space, which compromises the seal, especially in rigid containers like glass where expansion is not possible.
Innovation Solution
An apparatus with a seal head that includes fluid paths to pass fluid onto the foil liner, cooling it and creating over-pressure to counteract thermal expansion, thereby minimizing deformation and maintaining a secure seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conduction or induction sealing processes are used to heat the foil liner and sealing surface, then a secure bond is formed between the foil liner and container, but heat-induced expansion of the head space causes the foil liner to stretch, tear, or deform resulting in wrinkles that compromise the seal
Solution Approach 1:
The patent applies preliminary anti-action by introducing a cooling fluid through the seal head onto the foil liner during the sealing process. This cooling action counteracts the thermal expansion of the head space before it can cause the foil liner to stretch, tear, or deform. The cooling fluid creates over-pressure that pushes against the foil liner to maintain it in a taut state, preventing wrinkle formation while allowing the sealing process to create a secure bond.
Solution Approach 2:
The patent changes the temperature and pressure parameters during the sealing process by introducing a cooling fluid. The fluid is delivered at a temperature lower than the heated foil liner and at a pressure sufficient to create over-pressure in the head space. This parameter change allows the foil liner to remain cool and dimensionally stable while the sealing surface is heated, preventing deformation while maintaining seal integrity.
2Reliability
If heat is applied to create a bond between the foil liner and sealing surface, then sealing effectiveness is improved, but the head space pressure increases causing foil liner deformation and wrinkle formation
Solution Approach 1:
The cooling fluid is applied in advance and concurrently with the heating process to prevent the foil liner from deforming due to head space expansion. The fluid creates a counteracting force that maintains the foil liner's flat shape while the sealing process proceeds.
Solution Approach 2:
The cooling fluid acts as an intermediary substance between the heated foil liner and the expanding head space. It transfers cooling energy to the foil liner and creates over-pressure to counteract the thermal expansion forces, thereby maintaining the foil liner's shape during the sealing process.
3Adaptability or versatility
If vacuum panels are used in plastic containers to allow expansion and contraction, then head space expansion is accommodated, but rigid containers like glass cannot expand causing pressure to increase towards the foil liner
Solution Approach 1:
The cooling fluid serves as an intermediary that compensates for the rigid container's inability to expand. By delivering the fluid through the seal head onto the foil liner, the system creates over-pressure that counteracts the head space expansion forces, allowing rigid containers to accommodate thermal expansion without compromising the foil liner.
Solution Approach 2:
The patent uses pneumatic principles by introducing a fluid (typically gas) through the seal head to create over-pressure in the head space. This fluid pressure acts as a counterforce to the thermal expansion pressure, maintaining balance and preventing foil liner deformation in rigid containers that cannot expand like plastic containers with vacuum panels.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively prevents or minimizes wrinkles and tears in the foil liner during the sealing process, ensuring a reliable and hermetic seal by controlling pressure and temperature changes.
Implementation Method 1
heat and/or the heat from a hot-filled product within the container may cause the head space of the container to expand
Implementation Method 2
passing fluid through and out of the seal head and onto at least a portion of the foil liner
Implementation Method 3
an induction sealing process. In such a process, the foil liner and the sealing surface are heated as a result of an electromagnetic field that is generated by an induction coil
Implementation Method 4
the pressure in the head space can go is up towards the foil liner
Data Source
AI summary
An apparatus for sealing a foil liner to a container. The apparatus comprises a seal head that includes a body having a first end, a second end, and an axis extending through the first and second ends. The body further includes a sealing surface at the second end thereof facing away from the first end. The seal head further includes fluid path(s) for passing fluid through and out of the seal head and onto the foil liner. A method for sealing a foil liner to a container is also provided wherein a sealing surface of a seal head is aligned with a sealing surface of the container, wherein a peripheral edge of the foil liner is disposed between the sealing surfaces of the seal head and the container. Fluid is then passed through fluid path(s) in the seal head and out of the seal head and onto the foil liner.