cap sealing machine

What Shape Sealing Head is Best on an Induction Sealers?

Induction Sealers

To understand this question of the sealing head shape we must first understand how an induction seal is achieved.

The sealing head is the part of the machine that is placed over the path of the product cap/lid. Within the sealing head is usually long oval shaped coils of thick wire that carry high current that changes direction many thousands of times a second. This creates a magnetic field at right angles to the coil that also changes direction many thousands of times a second. The magnetic field can travel through air and plastic but it does get weaker as it travels away from the coils that generated the magnetic field. When the magnetic field comes across metal, it will act to generate current in the metal.

In the case of the heat sealing machine, it waits for a product that has a metal laminated foil in its cap. The magnetic field from the sealing head acts to generate current in the laminated foil and the laminated foil gets hot. Laminated to the foil is a layer that will melt or become “wet” with heat. When the product has completely passed from under the induction machine the foil will begin to cool and the layer that became “wet” will set to bond the laminated foil across the opening of the product.

From the above “theory” it can be understood that the sealing of a bottle or product using induction machines will depend on how long the product is under the magnetic field and how close it gets to that origins of the magnetic field.

There are two distinct shapes of sealing heads for cap sealers being Flat profile and Tunnel profile sealing heads.

The Flat profile sealing head is suitable for “Standard Flat Caps” . A “Flat Cap”, generally speaking, refers to a cap where the plane of the induction liner is within 4.0 mm of the plane of the Cap’s top surface.

The Tunnel profile sealing head is suitable for “Specialty Caps”. A Tunnel Induction Sealing Head lets you seal caps where the foil sits a distance greater than say 4 mm from the top surface of the cap; this is often the case with twist top spouts, flip top lids, sports drink caps, sipper caps or shaker caps.

The Tunnel sealing head concentrates the magnetic field to an area within the tunnel profile and hence provides stronger magnetic fields over a generally smaller width path for the products passing underneath. A Tunnel sealing head also allows the coils within the sealing head to have a path lower than the top of the product caps. This brings the magnetic field closer to the plane of the foil within “specialty caps”. The drawback to this Tunnel profile sealing head is that it is usually not very good for large caps and it does limit the range of cap sizes that can be efficiently sealed. There is a small exception to this rule with the MeRo™ brand induction sealer with an adjustable width tunnel profile. This machine can typically cater for a range of specialty caps with an adjustment of 30mm which would mean a typical cap diameter range of 30mm to 60mm could be very efficiently sealed.

Efficient cap sealing means that less time is needed under the sealing head and hence higher production speed is possible.

A Flat profile sealing head will allow for a greater range of cap sizes and even allows for that Sealing head to be placed at an angle across the product’s path to achieve sealing of cap diameters that are even wider than the coil winding pattern within the sealing head. It is quite possible to have a Flat profile sealing head that can seal caps from 30mm to 110mm wide. The trade-off for the versatility of this profile sealing head on a heat sealing head is lower speed throughput and an inability to seal specialty caps.

MeRo Flat Caps

Flat Caps

With Induction sealing it is important to identify if your range of plastic caps is considered “Flat Caps” or specialty caps.

A “Flat Cap”, generally speaking, refers to a cap where the plane of the induction liner is within 4.0 mm of the plane of the Cap’s top surface.

See the picture below:

With only Flat Caps, a Flat Sealing Head can be provided.
With A Flat Sealing Head it is possible to cater for a wide range of cap sizes.

The energy transfer for a Flat Sealing Head is not as efficient as a Tunnel sealing head but the versatility often makes up for the reduced speed throughput compromise of a Flat Sealing Head

Mero Flat Caps

MeRo Sealer Machine Introduction

MeRo Induction Sealer Machine Range

We believe there is no better value medium priced “High End” Induction Sealing Equipment. There are unique features to allow process validation and adjustable width sealing head tunnels are available.

MeRo Induction Sealer Machines feature:

An Air cooled system (Absolutely no need to water cool the induction head).
Compact construction for easy integration into the filling line.
High power efficiency thanks to the configuration of the power circuits and the use of IGBT modules.
Sinusoidal output waveform (Not Square or chopped).
Constant and Precise Output power due to the configuration of the regulation circuits.
Easy to use controls that display operating parameters and alarm signals.
Remote control Start-Stop interface.
Power variation monitor which can be set by the user to activate an alarm.
Manufactured in accordance with EN-60204-1 standards, Electromagnetic (EMC) compatibility in accordance with EN-5511 and EN50082-2 standards.
Motorized height adjustment
Set-Up Validation providing an Energy absorbed reading- A key advantage over Nearly Every other make

Depending on the range of product and cap, lid, closure shapes, different sealing heads can be supplied.

Options include:

Missing Foil Detection with Bottle Eject Mechanism or Signal
Bottle Accumulation Detection to avoid the situation where bottles are stalled under the active sealing head.
Pressurized Cabinet version to work in dangerous areas.
Fieldbus connection to the production process ASI/PROFIBUS/CAM OPEN/DEVICE NET
Integration of power regulation proportional to the speed of the conveyor via feedback from your existing conveyor’s speed controller. This is another key advantage that MeRo are able to offer over nearly other make.

Take a Closer Look

SealerOn™ Induction Machines – Take a Closer Look

What is Induction Sealing?

Induction sealing is a common packaging process to bond a foil seal across the opening of container, jar or bottle. Usually, the foil seal is placed into the cap or closure of the product to be sealed and then the cap or closure is placed over the filled product. The product then passes beneath an induction sealing machine and without ever touching the product the machine bonds the foil to the opening of the product.

How Induction Sealing Takes Place?

As soon as the container has been filled and capped – with a closure fitted with an induction liner – it travels beneath the induction sealing system. The non-contact heating system welds the liner to the container resulting in an air-tight and water-tight seal. Induction sealing machines or sealers, sometimes referred to as heat sealers, facilitate a product seal by emitting a high energy concentrated electromagnetic field. This field is created using high current thick windings (coils of wire), with voltage and current that switches back and forth at many thousands of times per second. The electromagnetic field passes through the air and the plastic of the containers cap to reach the Aluminum of the Induction Liner. The field then generates high frequency alternating currents on the surface of the foil which causes the foil to heat up.

Bonded to the Aluminum is a heat seal layer – usually a polymer layer that will melt with heat. When this heat sealing layer melts its bonds with the top surface opening of the container and as it cools it “sets” in place with the neck or rim of the container. The Food and Drug Administration regards induction sealing as a highly effective method of tamper evidence.

The SealerOn™ SealerOn400. This has been the Flagship of the SealerOn™ range and is being replaced by the SealerOn™ SealerOn500.

SealerOn™100 Induction Sealing Machine - Affordable Entry Level Induction Machine

SealerOn™ 3000 The SealerOn™ 3000 is typically rated for Flat Caps of Diameter 20 mm to 120 mm traveling on a conveyor at speeds up to 20 Meters (60 Ft) per minute.