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The global packaging industry reached a value of $770.5 billion in 2020. Some items need stored or shipped in special sealed packaging for various reasons. Hermetically sealed containers are an essential part of product logistics spanning industries from food to medicine.
There is no question that packaging, preserving, and protecting certain products is essential for many products. But what is hermetic sealing, what is it used for, and how are the seals made? Keep reading as we answer these questions and more.
What Is Hermetic Sealing?
Hermetic is a Greek word meaning “like the Greek god Hermes.” It was the alchemists of long ago that invented the process of making airtight glass containers that they used for distillation.
Hermetic seals are not only used in the food industry. Manufacturers, across many industries, use airtight seals for preserving any product that exposure to the air or moisture is a problem.
It is important to realize that hermetic seals are “airtight seals” meaning that no gas can escape or penetrate the seal. This also means that they protect against liquid and particle contamination as well. Used in this way, the technology protects against any leakage in or out of the containment of the product.
What is Hermetic Sealing Used For?
Packaging that stops the flow of gases is essential for food preservation such as vacuum sealing and canning. A major trend in the food industry is the increased demand for fresh products without additives and preservatives. In order to keep the shelf life of products long enough, food manufacturers rely on superior airtight packaging.
Hermetic seals are not only used in the food industry. Airtight seals are used in many industries for preserving any product that exposure to the air or moisture is a problem.
The science of food preservation is as old as the hills. We have been salting, drying, and fermenting food since ancient times.
The history of canning goes back to the turn of the 18th century in France. Napoleon Bonaparte wanted a way to preserve food for his constantly traveling soldiers. The first canning was heat-treated jars with wax seals.
In 1810, Peter Durand of England invented the process of “true canning” where the food is enclosed in tin cans. It wasn’t until 1912 that American Thomas Kensett founded the first U.S. canning factory. These days canned goods are in almost every kitchen with shelf lives of many years.
Big pharma is one of the biggest industries using hermetic sealed plastic bottles. Medications are particularly vulnerable to exposure to the air and moisture.
An airtight seal is needed for vacuum packing. Vacuum packing is a way of protecting the container’s contents and also minimizing the surface area needed for packaging and shipping.
Electrical components and wires must be protected from the elements to prevent corrosion. Many electrical and electronic devices wouldn’t even work properly or at all without hermetic seals.
Manufacturers and suppliers, like Douglas Electrical, use vacuum technology and epoxy to make airtight cables, connections, and enclosures. The manufacturing of coaxial connectors, RF semiconductors, and relays or a few examples of hermetic sealing applications in the electronic component industry.
How Is the Seal Made?
The process for airtight sealing is different depending on the materials being used and the products contained in the package. Cheap one-use packaging is the domain of plastics. Heavy objects may need more durable material such as metal or porcelain and electrical applications may require material considerations like the flexibility of rubber.
Hermetic sealing of glass containers allows the contents visibility or light exposure. Metal-to-glass seals can also withstand high temperatures making them ideal for some applications. Metal-to-glass seals can withstand temperatures of 250°C (compression) and 450°C (matched).
Often times, a hermetic seal is created by welding pieces of metal together. If wielded properly, metal on metal seals are strong and durable making them good for containers that are susceptible to drops and other abuse during shipping or use. Aluminum canned goods are a good example of this principle in practice.
Metal foils are commonly used to seal containers such as pill bottles and chemicals like bleach. Metal seals are also used in sustainable architecture and in more efficient HVAC systems.
Plastic and Epoxy Seals
The cheapest and most often used process is the plastic container sealed with epoxy. The quality and effectiveness of epoxy seals largely depend on the thermal expansion of the substrate and epoxy.
Epoxy seals are great for electrical devices as the epoxy bonds with brass, copper, or another epoxy. The flexibility in the use of epoxy seals has made their use in electrical and electronic devices commonplace. Without a hermetic seal, many of our day-to-day devices could not function or need replacing more often.
The biggest disadvantage of this type of seal is it can not withstand extreme heat. When the seal needs to withstand extreme heat manufacturers use glass, metal, or both.
Seal of Approval
Our modern lifestyle is propped up by technologies that most of us take for granted. Hermetic seals are one of those vital technologies that make our very lifestyles and modern society possible. From preserving food to functioning devices hermetic seals make it all possible.
Now, you can talk about the importance of waterproofing and airtight seals in manufacturing. When the question “what is hermetic sealing?” comes up you have the answer. For more articles on how we are constructing the world, keep reading or blog.