Tunnel Sealing Head

Tunnel sealing heads are generally used in two situations, when the foil liner diameter is less than 53mm and for closures where there is a larger gap between the liner and the top of the closer.

Examples of this include child resistant caps and many dispensing caps. The tunnel sealing head was developed to address these concepts and is typically used in two situations. A tunnel sealing head allows us to most efficiently seal the package by directing the induction field from the top and sides of the container. Taller closures such as sports caps, push-pull, Yorkers and others place the foil relatively deep in the cap. So, the induction field is directed from the sides to efficiently seal the container.

  • 1 The strength of the electromagnetic field generated by your induction sealer dissipates exponentially with respect to the distance from the sealing head.
  • 2 The distance from the top of your cap to the foil inside the cap is not equal with all closure styles. Compare a flat continuous thread(CT) cap with a child resistant closure(CRC.) The foil in the flat CT cap is very near the top while the foil in the CRC maybe as much as 1/4" from the top of the cap!
  • 3 The physical size of the foil inner liner plays a role in determining which style of sealing head works best for your application. While it may seem a little counter-intuitive at first thought, it takes more energy to seal a smaller liner than it does a large one because as the liner increases in size, it also increases the amount of metal mass available to be heated.

KEY FEATURES Tunnel Sealing Head

  • Designed for containers where there is large distance between the top of the cap and the induction liner

  • Energy efficient design directs sealing energy from the top & sides to optimize induction field

  • Available in standard, wide & deep designs