Direct-Sealed Cans
Description
The term "direct sealed can" describes a revolutionary development of the classic food can.In this case, an easy-peel membrane is sealed directly onto or into the can instead of the seaming of a separate metal end. This results in numerous advantages:
- maximum convenience for the consumer
- very low opening forces without tools (ideal for children and seniors)
- no risk of injury as there are no sharp edges (as with the standard or easy-open end) as well
- as good emptying properties as well as
- recloseability on using a plastic lid.
- cost minimization for the canmaker:
- enormous savings in material costs due to the omission of a lid ring
- simplified manufacturing process
- lower investment costs compared to peel-off or easy-open-end manufacturing lines
Direct-sealed food cans made of tinplate essentially consist of three components:
- the can body,
- a direct-sealed membrane on the top end of the can, and
- a metal bottom.
- optionally, a plastic snap-on lid may be applied
The can body is produced on a can line, in which - compared to the classical food can - instead of a seaming module for metal bottoms, a direct-sealing machine for membranes is used.
The metal bottom is produced on a separate end manufacturing line. The bottom is seamed on direct-sealed cans only after the filling process.
A fully automatic manufacturing line for direct-sealed cans consists of several individual machines which are linked together by means of conveyor belts. At the customer's request, Blema supplies a complete turnkey system.
Through a unique Blema development three-part food cans in all formats can now be embossed, with the embossing exactly matching the decoration of the can.
Variants
Direct-Sealing to Curl [RHO III]
The membrane is sealed to an outer roll formed on the top of the can.
Application examples: cocoa powder, coffee powder, instant tea, peanuts, snacks, (sweetened) condensed milk
Direct-Sealing onto Flattened Ledge [RHO V]
A deep bead is formed from the can wall, which is then flattened and forms the sealing surface for the membrane. This results in a similar appearance as in the case of the peel-off ring. The advantage of the technology is that here the membrane can be sealed into the can at any depth, thus creating a headspace separate from the product as a place for additional tools (spoons) or gimmicks (brochure, toys).
Application examples: milk powder, baby food, oatmeal flakes, peanuts
The technology is currently suitable for dry bulk goods as well as hot-filled goods (e.g., condensed milk) without subsequent autoclaving. A solution for sterile-resistant filling goods is currently under development.
Manufacturing of Direct-Sealed Cans
Can bodies for three-piece tinplate cans are manufactured on a fully automatic production line comprising the following individual machines:
Slitter
for the cutting of printed and / or lacquered blanks from sheets of tinplate
Transfer system
for the automatic feeding of blanks to the welding machine
Welding machine
for bending the blank into a tube and subseqent welding of the tube
Seam protection system
for applying a protective coating (powder coating or wet lacquer) to the inside and outside of the weld in order to avoid corrosion
Curing system
for heat-treating the protective weld coating
Combination machine
for final processing of the can body
The Blema-own, modular system GAMMA II allows for the individual combination of the following process steps in a machine for direct-sealed cans:
direct-sealing to top curl
- necking the can ends (one or both sides)
- flanging the lower can edge
- roll forming on the top edge of the can
- beading (to apply circumferential body beads, optionally)
direct-sealing to flattened ledge
- roll forming on the top edge of the can (to protect the open cut edge)
- flanging the lower can edge
- deep beading - forming of a single deep bead (on the can circumference)
- flattening the deep bead in order to create a sealing surface
- beading (to apply circumferential body beads, optionally)
Tester
for inline differential pressure testing of unilaterally seamed cans
Palletiser
for automatic collecting of cans on pallets (multi-ply with inlays and stretch wrap)
Technologies
NECKING | FLANGING | BEADING | FLATTENING | MEMBRANE SEALING |
---|---|---|---|---|
die necking | die flanging | rail beading | die flattening | hot contact sealing |
roll necking | roll flanging | roll beading | ||
curl forming | deep beading |
Machines for Direct-Sealed Cans
RHO III – Direct-Sealer for Metal Cans (Top Curl)
RHO V– Direct-Sealer for Metal Cans (Ledge)
direct-sealing machines for metal cans in turret design
products: 3-piece tinplate cans with sealed-on membrane