What Is an Autoclave, and How Does It Work?

January 08, 2019

You’ve probably heard the term “autoclave,” but what is an autoclave used for? If you’re relatively familiar with autoclaves, you probably only think about their use within one specific field. In fact, there are a surprising number of applications for autoclave technology and numerous options to make autoclaves work more efficiently.

how does an autoclave work?

What Is an Autoclave?

Autoclaves are large vessels that are pressurized and brought to high temperatures. They are usually cylindrical since the rounded shape is better able to safely withstand high pressures. Autoclaves are designed to hold items that are placed inside and then the lid is sealed. In fact, the words “auto” and “clave” mean automatic locking. Due to the pressures involved, safety valves are important to ensure that pressure of the steam inside is safely maintained. Autoclaves are commonly used for sterilizing equipment and tools, but they have a range of uses.

How Does an Autoclave Work?

After items or materials are placed inside an autoclave, the lid is sealed. Then most air is removed from the vessel. There are two options for how this is done. Gravity displacement units remove the air by pumping steam into the vessel. The steam displaces the air to create a vacuum. The other design, called a pre-vacuum, removes the air from the vessel using a vacuum pump.

After the air has been removed from the vessel, steam is pumped into the chamber at a high pressure. This causes the temperature to increase. After the target temperature is reached, the steam will continue to enter the vessel to maintain the desired temperature.

How Does an Autoclave Sterilize Instruments?

Medical tools and equipment are placed inside an autoclave. The lid is sealed, air is removed from the autoclave, and then steam is pumped into the vessel. Heat and pressure are maintained long enough to kill microorganisms and bacteria in order to sterilize medical tools.

lab hospital autoclave uses

How Hot Does an Autoclave Get?

Autoclaves are designed for many different purposes. For example, medical autoclaves generally reach a temperature of 121–140°C (250–284°F) for at least 3 minutes but for up to 15-20 minutes. The target temperature and the amount of time at that temperature is maintained depends on several factors.

These factors include the type of process desired, the type of items inside the autoclave, and how much room there is for the steam to freely move around the items inside the autoclave. Industrial autoclaves are often designed to maintain temperatures of up to 300°C but some specialty autoclaves can reach 400°C or more.

Autoclave Uses

Autoclaves date back to 1884 when they were invented by Charles Chamberland. Today they remain the technology of choice for sterilizing medical equipment. That is the function that most commonly comes to mind, but autoclaves have uses far beyond that.

Regardless of the application, the autoclave working principle remains the same, but the size of the autoclave needed, and target temperature and pressure depend upon how the autoclaves will be used.

Medical Equipment Sterilization

It is obviously important that any reused medical tools are properly cleaned to destroy bacteria and other contaminants. This includes surgical equipment, vessels, and any other items that will encounter bodily fluids or contamination from the air.

A hospital autoclave is not suitable for treating materials that can’t withstand high heat, but hospital autoclaves are used to sanitize a range of other equipment. A medical autoclave is used for surgical equipment but medical autoclaves are also used to sterilize the tools and equipment used by veterinarians, morticians, tattoo artists, dentists, and medical testing facilities.

Laboratory Equipment

Researchers need sterilized equipment for several processes. Specialty research-grade autoclaves are available for use in laboratory settings. Research-grade autoclaves are not approved for sterilizing items that will be used directly on humans, but lab autoclaves are designed to be more economical to operate than medical-grade autoclaves.

what is an autoclave used for?

Polymer Curing

Polymer composites are used in a range of industries. Autoclaves are used for polymer curing when it is important to ensure consistent hardening of the polymer material like when producing parts and components for the aerospace and shipbuilding industries.


Autoclaves are used in the vulcanization of rubber since the autoclaves provide the regulated heat and pressure necessary to produce consistent, high-quality products.

Synthetic Crystals

Crystals are used extensively by the electronics industry. Autoclaves provide the temperatures and pressures needed to produce high-quality synthetic quartz crystals.

Benefits of Using a Nitrogen Generator for Autoclave-Polymer Curing

Originally autoclaves used air, but nitrogen has become the preferred gas for many types of autoclave processes. There are a number of reasons for this. One of the main factors is the availability of nitrogen generators that are economical to have onsite.

Onsite nitrogen generators facilitate inexpensive production without requiring the delivery of pressurized tanks. By using nitrogen rather than the ambient air, more consistent results can be obtained without concerns about the presence of flammable oxygen.

The use of nitrogen becomes even more important for items produced at greater pressures and higher heat. At those levels of heat and pressure, many items can become highly flammable. The use of an inert gas like nitrogen becomes vital for safety reasons. Not only could a fire destroy the items within the autoclave, but the damage to the autoclave could also result in considerable expense and downtime while repairs are completed. Learn more about the benefits of a nitrogen generator for autoclave-polymer curing.

Onsite nitrogen generators have become more economical. For example, the GENERON® PSA nitrogen generator system can pay for itself in cost savings in as little as one year when compared to the price of purchasing tanks of nitrogen.

Nitrogen generators have the advantage of providing a continuous source of nitrogen, able to keep up with the needs of even large commercial polymer curing operations. There is no need for downtime to switch tanks or arrange for tank deliveries. Not only is the use of onsite nitrogen generation more cost-effective, but it reduces the environmental impact by eliminating the need for tank deliveries. With proper maintenance, nitrogen generators have an average lifespan of 10 years, making them excellent long-term investments. Contact GENERON to find out which PSA nitrogen generator system will work best for your company.

Want to learn more about the available options for nitrogen generators? Contact GENERON today for more product information.


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