On cases where the foil sits further than 4mm from the cap’s top surface, tunnel induction sealing head will allow you to seal it. Usually, this is the scenario with twist top spouts, flip top lids, sports drink caps, sipper caps or shaker caps.

When a coil shaped elongated coil generates high, rotating magnetic field, induction sealing occurs. The coil that carries a magnetic field is generated as well as, shift course several thousand times a second.

This magnetic field can pass through plastic or air. If it comes across metal, then it will work on producing current in the metal parallel to the coils that made the magnetic field.

A magnetic field produced from a “point” dissipates with the cube of its distance from that point. Generally, the magnetic field of an induction sealing machine ought to be within 5mm or ¼ inch from the sealing foil to have significant production speeds.

A number of cap variety do not match the standard flat top profile which presents a challenge to bring the magnetic field of the heat sealing equipment to within 5mm or ¼ inch from the sealing foil.

These types of specialty caps require an adaption from your standard flat coil sealing head to a tunnel sealing head. The Coils are designed to pass within the tunnel. The tunnel permits the protruding feature of the specialty caps to pass through the machine without moving the plane of the magnetic field farther away from the sealing foil within the bottle cap.

On the SealerOn webpage there is a youtube icon that will link you to videos showing SealerOn™ heat sealing or more accurately induction heat sealing using a tunnel sealing head.

Relying on the combination of cap and foil, the SealerOn™500 with a sealing tunnel installation has a speed capable of up to 10 meters per minute or 30 feet per minute.

The MeRo adjustable tunnel sealing machines are designed for faster induction sealing. These machines have the added and unique feature of having an adjustable width sealing head. This feature allows for higher concentrating and focussing of the induction field for increased sealing speed. A MeRo 2Kw unit is capable of sealing at sealing speed up to 30 Meters per Minute or 90 feet per minute depending on the cap and foil combination.

Less time required beneath the sealing head defines efficient cap sealing, which lead to higher production speed.

Flat profile sealing head allow an increased variety of cap sizes and permits the sealing head to be positioned at an angle over the product’s route to receive a sealing of cap diameters which are even wider than the coil winding pattern within the sealing head. Potentially a flat profile sealing head can seal caps from 30mm to 110mm wide. Not being able to seal specialty caps and lower speed throughput are the trade-offs for the flexibility of this profile.