How Does a Vacuum Sealer Work?
A vacuum sealer removes the air from a bag or container and seals it closed. This is done using a combination of suction and heat. The suction removes the air from the bag, and the heat is used to seal the bag closed.
That is the basic description of how a vacuum sealer works, but for a more in-depth look, we need to determine the type of vacuum sealer used. All vacuum sealers are supposed to remove oxygen from a container to help reduce spoilage, but how they do it can differ. This post will explain how different vacuum sealers work and which may be best for you. If you're considering vacuum packaging for a business, check out a previous article titled how to choose a vacuum sealer for your business. We explain in more detail the differences and benefits of each type of vacuum sealer.
Types of Vacuum Sealers
Before understanding how a vacuum sealer works, let's briefly explain the types of vacuum sealers available, and then we will dive into how each one works.
Edge Vacuum Sealers - Possibly the vacuum sealer most people are familiar with because of popular home-use brands like Foodsaver and Seal-a-Meal. They are distinguishable by the lid that closes over the open end of the vacuum bag once it is lined up properly in the vacuum sealer. Edge sealers most often feature a built-in compressor which is important when we discuss how the sealer works. They also almost always require channeled vacuum bags. The channeled bags allow more airflow out of the bag than a smooth vacuum bag.
Nozzle Vacuum Sealers – Feature a nozzle to be inserted into the vacuum packaging container for air removal. Most nozzle-style sealers have a retractable nozzle for when the vacuum cycle is complete. These machines are popular for commercial use and feature a built-in vacuum pump or an external air compressor to create a vacuum. If desired, they can also integrate a gas flush cycle for a different style of modified atmosphere packaging. Because of the suction through the nozzle, products with excessive liquids are not recommended through a nozzle vacuum sealer.
Chamber Vacuum Sealers - Creates a vacuum within the chamber to push air out of the bag. Chamber vacuum sealers are larger than edge sealers and often found in commercial settings due to the cost. Digital control settings allow users to set the desired vacuum amount for air removal. Chamber sealers are an excellent option for products with excessive or all liquids.
How Does an Edge Vacuum Sealer Work?
Before explaining how an edge vacuum sealer works, let’s review the basic process of using the sealer.
- Users fill a bag full of what they want to vacuum package
- The sealer lid is opened, and the open end of the bag is placed on the sealer
- Once lined up, the sealer lid is closed and pressed down
- The vacuum begins to remove air from the bag
- Once the vacuum is complete, the sealer closes and mends the bag to form a seal
- A light or indicator will show when the process is complete
- Upon Completion, a button can be pressed to release the vacuum and open the lid.
Edge vacuum sealers such as Foodsaver and Seal-a-Meal use a liquid reservoir with gaskets to form an airtight closure. Once the lid is closed, the vacuum can begin air removal from the bag.
Below is an image of the reservoir for an edge sealer. The gaskets around the reservoir helps to form an airtight seal once the lid is closed.
The small hole pictured below is how air is removed from the bag once the lid is closed.
The internal vacuum pump is the workhorse of the edge sealer. It has a tube running to the hole in the sealer for air removal.
After air removal, the sealing wire heats and begins to melt and mend the ends of the bag together to form a seal. Tape is over and under the metal wire to protect it.
Because the sealing area has created a vacuum, a button should be pressed to release the vacuum to open the sealer lid.
Edge vacuum sealers have a lot of great features. The liquid reservoir is excellent for catching any potential juices that may exit the bag during the vacuuming process. They are small, lightweight, and optimal for home use. Most are easy to clean and can be put up when not in use.
When things go wrong, two primary parts can be the cause. It is typical for sealing wires to burn out over time, similar to a filament in a lightbulb. The tape over the sealing wire is the first line of defense. Replacing it when it becomes worn will help increase the life of the wire. Another problem with an edge vacuum sealer is the vacuum pump going out. This will often cause enough reason to buy a new sealer rather than replace the pump. When using an edge sealer, it is important to use channeled or textured vacuum bags. They allow air to flow out of them, and smooth bags will not work with this vacuum sealer.
How Does a Nozzle Vacuum Sealer Work?
Like the edge sealer, before reviewing how it works, let’s go over the basic process of using the sealer.
- Users insert products into a vacuum bag
- The nozzle should be placed into the open ends of the bag and not touch the interior contents.
- The ends of the bag should be over the sealing wire and between the sealing bar.
- A foot pedal is pressed, and the sealing bar lowers to press down on the open ends of the bag.
- The nozzle removes air from the bag until the foot pedal is let off.
- Once the air removal stops, the nozzle retracts.
- The sealing wire heat and begins to seal the bag.
- Once the seal time is complete, a cool-down time is necessary for most bags allowing the seal time to cool down.
- Once finished, the seal bar is released, and the bag can be removed from the sealer.
Nozzle vacuum sealers are popular in a commercial setting and standard with an internal vacuum pump or external pump. Many nozzle vacuum sealers take longer for the seal and cool down time than air removal.
Below are some images and descriptions of how a nozzle vacuum sealer works. They have more moving parts than most edge sealers but are often much faster.
Once the nozzle is placed in the bag, and the foot pedal is pressed, the sealing bar clamps down on the bag.
Air removal begins through the nozzle with a vacuum or venturi pump if you have an external compressor, the bag pulls tight against the wrapped product.
The seal bar clamps down further, and the seal begins. When the seal is made, it is important to have no wrinkles in the bag. Impulses through terminals on each end het up the wire to mend the ends together.
Once the seal is made, the impulse heat stops, and the sealing bar remains closed, allowing time for a cool-down.
When the sealing bar releases, the bag can be removed. Air actuators engage and disengage throughout the process for the sealer to work correctly.
The speed of a nozzle sealer is often difficult to match. Bags can be free from oxygen in seconds or less with an external compressor and the proper PSI settings. Nozzle sealers are great for oversized, larger objects that need excessive air removal.
Nozzle sealers can have drawbacks as well. They are not the best option for packages with excessive liquids. Filters can be placed on a nozzle sealer to catch some liquids, but they are not made for primarily liquid products. They also have more moving parts than many edge and chamber sealers. The tape over the sealing wire should be replaced when torn to increase the life of the sealing wire.
How Does a Chamber Vacuum Sealer Work?
Chamber vacuum sealers create a vacuum within the chamber to remove air from the container. Let’s look at the basic operation of a chamber sealer.
- Insert products into a bag that will fit in the chamber.
- Hang the open end of the bag over the sealing edge.
- Close the lid and press the start.
- The lid will pull down, and air will exit the bag.
- Once the seal is complete, a cool-down is required.
- The vacuum is released from the chamber, and the lid can be opened.
Chamber vacuum sealers are great for commercial uses; more than one bag can be sealed and vacuumed in one cycle. Most chamber sealers have digital timers and settings for the amount of air removal and seal times. Chamber vacuum sealers can use an internal vacuum pump or external venturi pump, depending on the model and manufacturer.
The sealing area below will limit the number of packages placed in the sealer.
The digital controls or analog controls can be linked to the vacuum or venturi pump, and it engages creating a vacuum within the sealer.
Once the desired vacuum is reached, the seal is made the vacuum is released from the chamber. Then the lid can be opened for the bag removal.
Chamber vacuum sealers can seal multiple bags at once as long as the bags can fit inside the chamber and in the sealing area. They are perfect for fast-sealing liquids, grains, and other products. Some models can be used with an external compressor and pneumatic-operated lids for automatic vacuum packaging.
Like any product, chamber sealers can have drawbacks and parts to keep an eye on. Like the other sealers, the sealing area can get worn, the tape will need to be replaced, and the sealing wire will need to be over time. Entry-level chamber sealers can have an internal pump that may take excessive time to reach a complete vacuum. Over time, the buttons and digital readouts can wear and need to be replaced.
Ultimately, a vacuum sealer removes air from a package or container to increase shelf and storage life. The presence of excess oxygen can speed up spoilage and cause discolorations or freezer burn during storage. Our vacuum-packaged foods shelf life chart shows how long some products are expected to last with and without vacuum storage. It is a great way to see the benefits of choosing a suitable sealer once you understand how a vacuum sealer works.