Preserving the freshness of canned food products is one of the most important things that packagers should take into account. Though there are other preservation methods like drying, salting, and canning, vacuum sealing is still the best option for most types of food. Different preservation methods offer different advantages depending on the food you want to preserve.
Vacuum can sealing machines are among the most widely used can seamers in the packaging industry to give food products their maximum shelf lives. But, do you know how they work? Keep reading to know more!
Table of Contents
What is a Vacuum Sealing Machine?
Vacuum sealing is a process of sealing a container through a vacuum chamber. Vacuum sealing machines remove the air from the containers before sealing them to keep the product fresh for long-term storage. The machine creates a vacuum inside the cans to prevent any compound from entering the containers to avoid food spoilage.
Types of Vacuum Sealing Machines
Vacuum sealing machines come in different models designed for home use and commercial applications. The major difference between these types is the absence/presence of a vacuum chamber unit. Some have built-in vacuum chambers and others don’t.
Chambered Vacuum Sealing Machines
Vacuum sealers with chamber units use vacuum pumps which are more powerful compared to the vacuum channels used by non-chambered vacuum sealers. In these machines, the entire container is placed inside the sealer.
When the chamber closes, the sealer sucks out all of the air inside it. Once all air has evacuated the container, the sealer seals the container tightly. Chambered vacuum sealers are ideal for sealing liquid like beer, powder, and solid products. Most vacuum can sealers are chambered.
Non-Chambered Vacuum Sealing Machines
Pouch or bag vacuum sealing machines tend to be non-chambered. This is the most common type of machine that most people are used to because the common consumer grade vacuum sealers that are used in the kitchens of homes are an ideal example of this design. In this arrangement, the sealer only processes the open edge of the pouch and the rest of its body is left out. That is why they are also referred to as external vacuum sealing machines.
Although chambered vacuum sealers have powerful vacuum pumps, these non-chambered ones have a suction system that has vacuum channels. This is the basic difference in design that determines their operation.
Working Principle of a Non-Chambered Sealer
The principle of operation is simple and effective with solid foods. It is usually done as follows:
- Preparation: The user puts the food item in a specially designed vacuum sealer bag. These bags are essential because they possess a textured or embossed inner surface, which forms small air channels, which enable air to be fully evacuated.
- Positioning: The open end of the bag is positioned over the sealing strip of the machine, which is found within a small trough or drip tray.
- Vacuuming: A small vacuum pump is activated after the lid is closed and locked. It draws the air out of the bag by means of the textured channels. The removal of air can be physically observed as the bag collapses around the food item.
- Sealing: The vacuum pump is switched off when a preset vacuum level is achieved and a heated sealing wire or bar is switched on instantly. It heats the plastic on either side of the bag and seals them together to form a strong, airtight seal.
- Finishing: The heating element switches off and the machine lets the pressure out, so the user can open the lid and take out the perfectly sealed bag.
Handheld Vacuum Sealers
The third type, which is the most portable and convenient, is the handheld vacuum sealer. They are small, usually rechargeable, wireless gadgets that can be held in the palm of your hand. They are the most basic type of vacuum sealing technology. Handheld sealers are different to countertop models that heat-seal bags. They are made to be used in special reusable bags or containers with a special air valve.
Principle of Operation of a Handheld Sealer
The procedure is centered on reusability and simplicity: The food is put in a proprietary bag or container with a small, circular, one-way air valve. The user holds the nozzle of the handheld device against the air valve on the container firmly. The small motor in the device removes the air through the valve with a press of a button. After the air is sucked, the user just pulls the device away. The container has a one-way valve that automatically seals the vacuum.
Key Characteristics:
- Advantages: They are very space-saving, transportable, and perfect to preserve fragile foods such as cheeses, deli meat, or salads without squashing them. The fact that the containers are reusable is also a major advantage.
- Limitations: The vacuum formed is usually not as strong as the countertop models and therefore not ideal in long-term freezer storage. Moreover, they can only be used with the manufacturer-specific valve-equipped bags or containers.
Handheld sealers are not a major packaging solution in an industrial or heavy commercial environment. They can however be handy auxiliary equipment in lab testing, making samples to be tested by senses or other very small scale activities where convenience is paramount.
Comprehensive Comparison of Vacuum Sealer Types
In summary, the choice of machine depends entirely on your product and production scale. For versatile, high-volume packaging, especially involving liquids or achieving the highest level of vacuum in cans, the Chambered Vacuum Sealing Machine is the definitive industrial choice.
Components of a Vacuum Sealing Machine
For you to understand how a vacuum sealing machine works, below are the major components of a vacuum can sealing machine.
#1 Seaming Head
While the vacuum sealer is sealing the can, the seaming head holds the lid and serves as support from the pressure exerted by the seaming rollers. They have customizable dimensions depending on the diameter of your cans.
#2 Seaming Rollers
The seaming rollers (1st and 2nd operation rolls) connect the can’s lid to its body to create a hermetic seal.
#3 Base Plate
This will spin with the can during the double seaming process. It supports the filled can’s body during the process.
#4 Vacuum Pump
A vacuum pump removes gas molecules inside of the sealed vacuum chamber to create a vacuum.
#5 Vacuum Chamber
This is where the vacuum can sealer performs the can sealing process..
#6 Control Panel
Every sealing machine comes with a control panel where you can set the parameters of the sealing process.
How Does a Vacuum Sealing Machine Work?
Now, let us proceed with knowing how vacuum can sealers work. Below is a short video you can check out for this:
According to Machine Automation
A vacuum sealer can either come in semi-automatic or fully-automatic design. The working principle of both is similar but there are some differences in how they are operated.
Automatic Vacuum Sealing Machines
Below is how automatic vacuum can sealers work:
- The operator feeds the machine with filled containers through the conveyor.
- The operator sets the sealing parameters through the control panel (usually integrated with a touch screen interface).
- The filled containers enter the vacuum chamber where the vacuum pump sucks out all of the air inside.
- The machine connects the lid to the can’s body.
Semi-Automatic Manual Vacuum Sealing Machines
Semi-automatic vacuum can sealers work the same way as automatic ones. The only difference is that the semi-automatic vacuum can sealers will need more help from the operator in the sealing process.
The operator needs to manually place each filled container into the machine and start the sealing process using a finger or footswitch. Once the current container is sealed, the operator will repeat the whole process for all remaining containers.
The Double Seaming Process
Once the vacuum sealer has removed all of the air inside the containers, the double seaming process follows.
1. Compression Stage
The machine compresses the can’s body towards the seaming head holding the lid.
2. First Roller Operation
The first seaming roller comes in and interlocks the can body’s flange with the lid’s curl to create a loose seam.
3. Second Roller Operation
Conclusion
Now that you know how vacuum sealing machines work, you might also want to build your own can sealing machine. Learning the fundamentals of packaging is always a good start if you want to enter the industry. This will ensure that whatever problem arises in your production line, you will be able to easily determine where the source of the problem is. We hope that you have learned a lot from this short guide. Or contact Levapack to customize your vacuum can packing line.
Related Post: Dry Canning vs. Vacuum Sealing in the Food Packaging Industry
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