Use a horizontal band sealer when the filled bag lies flat and the contents stay put. Use a vertical band sealer when gravity would push product into the seal area: liquids, pastes, fine powders and loosely filled bags. The wrong orientation contaminates the seal and causes leaks.
The rule: where does the product go when the bag lies down?
Lay a filled bag on the bench. If the contents settle away from the open edge and the edge stays clean, a horizontal machine will work and is usually simpler to load. If product creeps toward the opening, or the bag will not stay flat, the seal area will be contaminated and a vertical machine is the correct answer.
Horizontal vs vertical
| Horizontal | Vertical | |
|---|---|---|
| Bag position | Lying flat on the conveyor | Standing, carried upright |
| Suits | Dry, stable, flat packs | Liquids, pastes, powders, loose fills |
| Seal contamination risk | Higher with mobile product | Lower — gravity works for you |
| Loading | Simple; bag laid on the belt | Bag guided upright into the belts |
| Height adjustment | Conveyor height to seal centre | Seal centre to bag height |
The adjustment that gets overlooked
On both orientations, the distance from the sealing centre to the conveyor decides which bag heights the machine can take. It is a published specification and it is the one that most often blocks a machine from running a customer's bag. Check it against your tallest and shortest filled bag before ordering.
Console and console-with-gas variants
Console models raise the whole assembly and add a stand, which helps when feeding from a filling machine rather than by hand. Where the pack needs modified atmosphere, an aerating variant flushes the bag before the seal closes it.
Band sealer variants are listed in the sealing range.
Figures in this article are drawn from the 137 machine series SilverSeal currently supplies, not from generic industry averages. Specifications vary by model — check the individual series page before specifying.
Frequently asked questions
Can a horizontal sealer run a bag with liquid?
Only if the liquid stays well below the open edge when the bag is flat. Otherwise the seal traps product and fails.
What decides the maximum bag height?
The distance from the sealing centre to the conveyor table, which is a published specification on each series.
Is a vertical sealer slower?
Not inherently. Belt speed is comparable; loading may be slightly slower because the bag has to be guided upright.
