FOIL SEALERS
Foil sealing offers many packaging advantages including leak protection, extended shelf life, tamper evidence and protection against pilferage.
When sealing aluminum foil to a container, there are two primary methods used in manufacturing facilities — conduction and induction sealing.
Conduction
A conduction sealing head uses electricity to power a heating element. Heat is transferred through the heated element to the metal conduction head. When the head is in contact with the container topped with aluminum foil, the combination of pressure and heat causes the foil to be hermetically sealed to the container.
Advantages:
- Simple design
- Lower initial cost
Disadvantages:
- Less forgiving on out of specification containers
- Limited sealing surface
- Longer start up and cool down times
- Potential operator hazard
Induction
Induction sealers have two main components; a power supply and sealing head(s). The power supply produces the necessary current for creating an electromagnetic field in the induction sealing head. As containers enter this field, the foil is heated. The sealing head has a soft rubber disc at the sealing surface, allowing it to conform to the top of the container and enhancing the integrity of the seal. The combination of pressure and heat results in a hermetic seal.
Advantages:
- Instant start up
- Energy savings
- Operator safety
- Reduced maintenance time and costs
- Wide range of closure designs
- Conforms to out of specification containers
Disadvantages:
- Higher up front costs
Induction Versus Conduction
Induction sealers offer instant start-up while conduction systems must warm up before working. Also with induction, an electromagnetic field creates the heat as opposed to the conduction "hot-plate" process. The induction process minimizes ambient heat, keeps the sealing head at a cool temperature, and improves operator safety. Induction also cuts clean-up time for product spillage because the product won't bake onto the sealing head. Maintenance is easier because there's no cool-down time. Induction relieves the headaches of maintaining a proper sealing temperature using elaborate temperature sensors and heater elements. New compact air-cooled sealing heads and advanced power supplies can generate as much power on high-speed lines as conduction systems. Another plus to packagers is energy savings: Induction sealing systems use less power than conduction sealing heads, which must maintain a constant high temperature.
One of the primary benefits of induction is that the sealing head is more forgiving of containers out of tolerance. Conduction relies on a hard metal plate making perfect contact with the container to be sealed. Induction technology utilizes a soft silicone pad which can mold to the contour of a container. The soft silicone rubber pad can also be used to seal the foil to a radius on the edge of the container.
These ultra-efficient induction sealing components operate at 1/10th of the power required by conduction sealers.
Induction is a well-proven sealing technology that requires virtually no maintenance and is ideal for the food, dairy, chemical, beverage, bottled water, pharmaceutical and personal care industries.