Chamber vs. Nozzle (External) Vacuum Sealers: Which Do You Need?

How the two types work

Chamber vacuum sealers

In a chamber vacuum sealer, the whole bag goes into a closed chamber. The open end of the bag lies across the seal bar. When the lid closes, the pump evacuates the chamber, so the air leaves the bag and the space around it at the same time. Then the seal bar presses the bag closed and heats it, the seal cools, and air flows back into the chamber. The outside pressure presses the bag tightly around the product.

Because the pressure inside and outside the bag drops together, liquids stay in the bag. That is the main reason restaurants, butchers and food producers use chamber machines. Chamber sealers also work with smooth vacuum pouches, which are widely available in many sizes.

Nozzle (external) vacuum sealers

A nozzle vacuum sealer, also called an external or retractable nozzle sealer, has no chamber. The operator slides the open end of the bag over a nozzle. The nozzle draws the air out of the bag, retracts, and the jaws seal the bag. Many models can also flush the bag with nitrogen or another inert gas before sealing.

Because there is no chamber, the bag size is limited only by the seal length. That makes nozzle machines the standard choice for large parts, long products and bulk bags, and for foil, mil-spec and ESD bags in electronics, medical and aerospace packaging.

Chamber vs. nozzle at a glance

When a chamber sealer is the right choice

Choose a chamber machine when you pack food, especially moist products, marinades, soups or sauces. Restaurants use them for sous-vide bags and portioned prep, butchers for fresh cuts and roasts, and cheese and coffee producers for retail packs and storage.

Chamber machines range from compact tabletop units to double chamber production machines. The Turbovac TS40 is a typical tabletop model: a 16.5″ seal bar, products up to 7″ high and Busch pumps of 20 or 25 m³/h. For liquids, the Omcan 48246 Trento holds the bag upright in a vertical chamber. For production, double chamber machines such as the Omcan 43632 let the operator load one chamber while the other runs.

Chamber sealers are also used outside food. The AmeriVacS AVC-20 creates vacuum with compressed air instead of an electric pump motor, so there is no oil in the machine. AmeriVacS describes it as clean room compatible.

When a nozzle sealer is the right choice

Choose a nozzle machine when your bags are too large or too long for a chamber, when you pack dry or solid products, or when you work with foil, mil-spec or ESD bags. Typical jobs are dry packaging of electronic components in moisture-barrier bags, packing medical devices, protecting aerospace parts for storage, and vacuum packing bulk goods such as coffee, nuts or textiles.

The AmeriVacS AVN vacuums, flushes with inert gas and seals in one foot-pedal cycle, in seal lengths from 20″ to 50″. Vacuum and gas can each be switched off, so it also works as an impulse sealer. The AmeriVacS CAVS has a built-in compressor and runs on a standard outlet. AIE's VA Series uses twin retractable nozzles, and the VAD and GSD Series add a double seal for thick bags.

How to size the machine

Seal length

Measure the widest bag you use and add room at both ends. On a chamber machine, the seal bar sets the maximum bag width; on a nozzle machine, the seal length does.

Chamber height

For chamber machines, check the usable height. A roast or a stack of portions needs more height than flat sliced products. Omcan's floor models list the height at the rim and under the dome cover separately.

Pump capacity and output

Chamber pumps are rated in m³/h. A larger pump evacuates the chamber faster, which shortens each cycle when you pack many bags in a row. A second seal bar or a second chamber raises output further.

Vacuum only or gas flush?

Vacuum removes air and with it most of the oxygen and moisture in the bag. Gas flush goes one step further: after the vacuum step, the bag is filled with an inert gas, usually nitrogen, and then sealed. This lowers the oxygen left in the pack and keeps soft or fragile products from being pressed flat. Electronics manufacturers often use nitrogen flush for moisture-sensitive components; food producers use it for products such as baked goods and snacks.

Gas flush needs a gas supply on site, and the machine must be equipped for it. If you are unsure whether you need it, a machine where the gas function can be switched off, such as the AmeriVacS AVN, keeps both options open.

Power, compressed air and space

Most tabletop chamber sealers plug into a standard 120 V outlet. Larger floor and double chamber machines may need 220 V single-phase or 3-phase power and are installed by an electrician. Many nozzle sealers use shop air: AmeriVacS lists 6 CFM at 110 PSI for the AVS and AVN-20 to 35. If you have no compressed air, choose a self-contained model.

Plan the workspace too. Nozzle sealers need room in front of the machine to hold long bags flat. Floor models need floor space and room to open the lid.

Bags and running costs

Both types use smooth bags, which are generally less expensive than the embossed bags needed by small household-style suction sealers. Plan for bags in the sizes you use most, seal bar tape and, on oil-lubricated pumps, pump oil. On nozzle sealers, the heating element and its cover wear with use. Ask for the consumables list of your model with your quote.

Common mistakes

The most common mistake is buying a chamber that is too small for the largest product. The second is choosing a nozzle sealer for liquids. The third is overlooking utilities: a nozzle sealer without enough compressed air will not reach its rated vacuum, and a 3-phase floor model cannot run on a kitchen outlet. Check bag size, product type and utilities before you compare prices.

Recommended Equipment

For food and liquids: the Turbovac TS40 and the Omcan 48246 Trento, or browse all chamber vacuum sealers.

For large bags, foil and ESD bags: the AmeriVacS AVN, the self-contained AmeriVacS CAVS and the AIE VA Series, or browse all nozzle vacuum sealers.

Not sure yet? The Vacuum Sealer Selector suggests a machine type from your bag size and product.