Also known as mechanical convection ovens, forced air ovens are a type of laboratory oven. They are an indispensable piece of equipment in many industries and applications. These include chemical plants, laboratories, food processing environments, materials science, and heat processing industries as an essential element in creating food products.
If your laboratory or research centre is still home to a traditional hot air oven, now might be the time to consider switching to a forced air convection oven. We’ve turned up the heat and opened our forced air lab oven doors to explain how a forced air oven works, its benefits, and how it differs from a conventional oven.
Forced air oven meaning
A forced air oven or hot air oven is simply an oven with a fan. Most modern-day domestic and laboratory ovens are fan-assisted. They use force convective heat transfer, where fluid motion is generated by an external source (in this case, a built-in fan).
How does a forced air oven work?
Forced air ovens rely on the assistance of a blower fan to constantly circulate warm air around the oven chamber. Similar to a furnace, the hot air will travel through a duct system, creating a uniform temperature throughout the workspace and heating all areas of the item evenly.
Fresh air is drawn in from the rear or bottom of the oven and blown into the compartment past the heating elements onto the sample or product being tested. Often there is a port on the top of the oven — you can leave this open if there’s going to be a lot of moisture in the product to help speed up the drying process.
Forced air vs natural convection oven
Natural convection ovens rely on the natural rising of hot air to heat the interior of the oven. While the temperature remains fairly stable as air flows throughout the chamber, they cannot offer precise temperature uniformity.
On the other hand, they are a very economical choice as their overall cost is low and they don’t consume as much energy as forced air convection ovens. This is because they aren’t fitted with a motorised component.
You will need a forced air oven if your process requires higher accuracy and temperature uniformity, and where quality control of a particular item is critical to identify any flaws in the product.
What types of applications are forced air ovens used for?
Forced air convection ovens are used for a multitude of baking, curing, drying, and sterilisation processes across a variety of industries. Common uses include:
Aerospace – Curing of composite materials used in aircraft structures, testing of aerospace components, and preparation of spacecraft components for launch by removing moisture and other contaminants.
Agriculture – For the drying and processing of crops.
Automotive industry – Curing of paint, curing of composite materials, removing moisture or solvents from painted surfaces, etc.
Baking and curing materials – Ceramics, polymers, etc.
Biohazard waste – The ability of forced air ovens to reach a high-temperature range means almost any biohazardous material can be sterilised.
Biology research – Drying of biological samples such as bacteria, cells, and tissue to enable many types of biological analysis, such as DNA sequencing.
Chemistry research – Heating up and drying out chemical samples, such as crystals, precipitates, and powders.
Drying glassware and oxide carbonisation
Food production and quality analysis – The food industry rely on forced air convection ovens for baking, dehydrating, drying and cooking food products. They are also a vital component of quality control.
High-temperature testing – Enables laboratories to test hot solids and liquids without ever having to leave their workstations.
Medical research – Sterilisation of medical equipment and samples.
Pharmaceutical – Preparation of drug samples for testing. Drying, sterilising, and dehydrogenation of containers, glassware, and instruments used in drug manufacturing.
Samples with a high moisture content – The heat capabilities of a forced air oven will ensure total evaporation of the moisture.
What are the benefits of forced air ovens?
The efficiency and reliable results offered by forced air ovens is particular advantageous in settings where time and precision are critical, but their benefits don’t stop there.
Good test results wherever the sample is placed in the oven
Blowing hot air past the sample means there isn't any cool spots in the corners or around the product as it heats up that could compromise output quality. Since the fan inside evens out heating, you can expect your samples to dry uniformly, even on the inside.
Faster heating and drying time
Forced air convection ovens are ideal for production facilities that rely on processing samples quickly and effectively. This is because the items placed inside the chamber pick up heat faster because they’re always in contact with hot air, drying them out much quicker than a natural convection oven.
Efficient and cost-effective
Providing a constant temperature inside the chamber reduces the needs for regular temperature checks and adjustments. This means less labour costs associated with monitoring the oven, making them an affordable option for laboratories, researchers, and industries.
Kills bacteria, viruses, and other microorganisms
The hot air and uniform temperature that passes inside the chamber ensures the product is sterilised or dried evenly, reducing the risk of contamination or spoilage.
Along with being able to eliminate most disease-carrying pathogens, the heat can also penetrate deeply into thicker objects, giving an in-depth sterilisation effect, even for packaged items.
Rapid temperature recovery
The fast temperature recovery compared to basic drying ovens lets you use the heated items almost instantly, since they cool down quickly.
Factors to consider when choosing a forced air oven
Purchasing a forced air oven isn’t something your laboratory should take lightly. Analyse your process and consider the following factors, so you choose the one that best suits your needs.
Determine the minimum and maximum temperature you require.
Choose an oven with a maximum temperature that’s higher than you need. This helps ensure precision by keeping the temperature to a more median range, while giving you the flexibility to use the oven for different uses in the future.
Size of the air forced oven.
Our lab ovens come in a variety of dimensions. Ensure you measure the bench space available in your laboratory so the model you desire fits in the available space.
Energy efficiency
Look for a unit that is energy efficient, both for cost-effective use and to reduce your carbon footprint. A model that is easy to clean also helps reduce the risk of cross-contamination between materials.
Think about the features that are beneficial to you and your laboratory.
From an auto start function to fan speed controllers and over-temperature protection modules, pick out the features that are pivotal to your processes.
How often should I have my forced air lab oven calibrated?
In a non-forced air oven the temperature can vary a few degrees Celsius. In a good quality forced air oven, this will be under 0.5 degrees Celsius. Whenever temperature is critical to your process or part of a quality check, you should have your oven calibrated at regular intervals.
We have found ovens in the past with errors of more than 15 degrees Celsius. For non-critical work a single position calibration would be sufficient — however, we would recommend a survey of five positions at the top, middle, and bottom of the oven.
Why choose AML Instruments for your forced air lab oven?
Forced air ovens are complex instruments that rely on various mechanical and electrical systems to function correctly. Over time and with consistent use, these systems can deteriorate and lose accuracy.
Whether you run a commercial garage, or research institute, we understand how important it is for your forced air oven to operate correctly and efficiently. Not only do AML Instruments sell a range of laboratory ovens and furnaces, we also provide a full oven and furnace calibration service.
Contact us today for all your air forced oven needs.
