Choosing the right lab oven can seem like a daunting task, given the wide range of different ovens available on the market and the technical complexities of how they operate.
In this article, we help you to make sense of this maze of information by breaking down the main oven types, their advantages and disadvantages, and their typical applications.
We also discuss in detail the key factors you should consider when buying a lab oven, helping you to make a well-informed choice.Finally, we guide you through where you can find all the important technical information you need on the LabOvens.net product pages.
Types of oven and typical applications
Before we dive into the technical details to consider when buying a lab oven, let’s survey the main types of ovens and the typical applications they are used for.
Natural (gravity) convection oven
Natural convection ovens rely on gravity-driven convection within the oven chamber, which is caused by temperature and density differences in the heated air.
As the air currents involved in this convection tend to be slow, natural convection ovens are a good choice for heating samples that would be easily disturbed by air movement or may be sensitive to airborne contaminants.
However, the slow airflow also means that heat may be less evenly distributed around the chamber compared with forced convection ovens. This reduces the stability and uniformity of the heating in the oven.
- Drying (e.g., powders or lightweight materials that would be disturbed by a strong airflow)
- Baking (heating delicate samples without dehumidifying them)
- Any other heating application in which the samples would be sensitive to air movement
Forced (mechanical) convection oven
Forced convection ovens use a motorized fan to blow heated air through a baffle that distributes the heat evenly throughout the oven chamber.
They are suitable for a wide range of applications that require stable and uniform temperatures across all of the samples being heated. In particular, they are well-suited to evenly heating large numbers of samples simultaneously, or for heating samples with a high moisture content.
- Drying (e.g., glassware, electronics, pharmaceutical preparations)
- Baking (suitable for a wide range of non-delicate samples)
- Curing (hardening polymers to make glues, epoxies, and other compounds)
- Vulcanizing (rubber)
- Electronic burn-in
- Quality testing
In addition, forced convection ovens are sometimes used for studies of drug metabolism and protein function, or for heated storage of pills or drugs. However, given their tighter control of temperature, incubators are generally more suitable for these tasks.
Cleanroom ovens are used for heating applications that require the heated air to be free of contaminants, such as airborne particles, microbes, or aerosols. These ovens use a filter to remove particulate matter from the air before it is drawn into the oven chamber.
When choosing a cleanroom oven, make sure that the filter fitted to the oven is of a sufficient standard for your needs. Filters are rated by the average percentage of particulate matter they are able to retain:
Efficient Particulate Air (EPA) filters
High-Efficiency Particulate Air (HEPA) filters
Ultra-Low Particulate Air (ULPA) filters
- Sterilizing (e.g., medical equipment)
- Curing epoxy in a clean environment
Vacuum ovens are used for samples that require heating in an air-free or inert environment, such as oxidation-sensitive samples.
Air and moisture in the oven chamber is removed by a vacuum pump, while heating is achieved via conduction from the walls to the shelves on which the samples are placed.
Vacuum ovens are an excellent choice for desiccation, as the vacuum lowers the standard boiling point of liquids, allowing for quicker drying.
- Desiccating (to remove moisture from samples)
- Determining moisture content of samples
- Oxygen-free heating (for samples sensitive to oxidation, corrosion, or scaling)
Removing residual alcohol from concentrated THC or CBD after ethanol extraction of cannabis has been a major new application for vacuum ovens in recent years. Solvents such as alcohol evaporate at a lower temperature in a vacuum, avoiding the need to use high temperatures that could thermally decompose the cannabinoids.
Key factors to consider
No matter which type of oven you need, there are a range of key factors to consider before making your purchase.
Below, we explain why these factors are important, and include the key terminology to look out for when weighing up the technical specifications of different ovens (see the final section below on where to find these specifications on the LabOvens.net product pages).
Temperature and airflow
The temperature range (℃) and maximum temperature (℃) of the oven depends on what you want to use the oven for and the kind of samples you will be placing in it.
How hot does the oven need to be to achieve good results for your target application(s)? Consider all of the possible applications that you might need to use the oven for.
Lab ovens can range in temperature from ambient (room) temperature to over 300℃, depending on the model. Selecting an oven with a slightly higher maximum temperature than needed could help to ensure the robust performance of the oven over its working lifetime.
Temperature uniformity and stability
In addition to the temperature range, the uniformity and stability of the oven temperature are key variables to keep in mind. The temperature uniformity (℃) specifies how even the heating is throughout the oven chamber, while the temperature stability (℃) determines how much the temperature typically deviates from the requested target temperature.
Some applications require very precise heating of all of the samples within the oven chamber, while for other applications, these considerations are less critical. Because of the active distribution of heated air, mechanical convection ovens offer greater temperature uniformity and stability than gravity convection ovens.
Heat-up and recovery time
In addition, mechanical convection ovens typically offer a faster heat-up / ramp-up time (min) (also known as the heating rate). This is the time taken to reach a set target temperature from ambient room temperature.
A related consideration is the heat recovery time (min), which is how long it takes the oven to reheat after the door has been opened.
Heating times such as these might be important if you need to process samples quickly or expect to be opening the door often to adjust or exchange samples.
Finally, the airflow pattern is another important factor to consider in terms of temperature uniformity in a mechanical convection oven.
Ovens providing horizontal airflow force air out of holes in the side of the chamber are best for heating samples arranged on horizontal trays or tiers.
In contrast, ovens with vertical airflow drive air upward from the bottom of the chamber, which is optimal for drying samples.
Size and capacity
The capacity or volume (L / cu. ft.) of the oven will define how many samples you can fit inside the oven chamber at one time. Smaller ovens can be sized at less than 2 cubic feet, while the largest models can offer more than 15 cubic feet.
In combination with the heat-up and recovery times at your target temperature, the capacity of the oven will determine the number of samples you can heat simultaneously and hence your overall workflow rate.
How many samples will you be processing and how fast will you need to process them? How many racks do you need the oven to have? Is the spacing between the racks enough for your samples?
One important point to note in terms of the capacity of the oven is that temperature control is harder in a larger oven. This means that it’s generally better to buy multiple smaller ovens to ensure temperature uniformity and stability, as well as to reduce heat-up and heat recovery times.
In addition to the dimensions of the interior oven chamber itself, you should consider the exterior dimensions (mm / inch) of the oven.
Where in your laboratory or workspace will the oven be situated? Will it be free-standing on the floor, or placed on a benchtop? Is there enough space in the lab, including to open doors?
Pay attention to the form factor of the oven and whether the oven comes fitted with wheels to allow it to be easily moved if needed.
Electrical requirements and energy efficiency
It’s also important to make sure that you have a power source that can meet the electrical requirements of the oven. Take note of the voltage (110 V or 220 V are the most common) and frequency required, in addition to the amperage of the oven. Larger ovens in particular may require a specialized power source to be installed by a qualified electrician.
To reduce running costs, you might also consider the energy efficiency of the oven. How many layers of insulation (or walls) does the oven have? The heat recovery time is generally a good index of the efficiency.
Control and ease of use
Features such as an interactive digital display for easy control and monitoring of the oven can be helpful, particularly if new or inexperienced users will be working with the oven on a regular basis.
Key control panel options to consider to improve the useability of the oven include: real-time performance reporting, timer and alarm functions, data logging, remote control capability, and security features, such as a lockable keypad.
A memory function can also be helpful so that settings for one or more commonly used heating protocols can be stored and re-run quickly and easily.
In addition, you should consider whether you require a viewing window to check the sample during heating without having to open the oven door, which disturbs the temperature in the chamber.
Safety and reliability
When you invest in an oven, it’s important to have confidence that it will perform reliably over many years of service. Therefore, make sure to check the warranty period offered by the manufacturer, and whether this warranty includes parts and/or labor.
In terms of safety, a pressure and/or temperature warning alarm is a key feature, and many ovens also include overheating sensors that will trigger an automatic shutdown of the oven if it is dangerously overheated.
A blow-out panel/door offers a final line of protection by rapidly lowering the pressure and temperature in the oven chamber in an emergency situation.
Maintenance and cleaning
The maintenance and cleaning of the oven can be a key consideration, especially if the oven will be in heavy use with little downtime. It’s important that the oven chamber is made of a corrosion-resistant material, such as stainless steel.
Chambers with rounded edges are especially helpful to allow easy cleaning and prevent contamination of samples by residues left on the chamber walls.
Finally, consider how moisture released from the oven will be removed from the room. Check the manufacturer’s specifications for details of the size and fittings for the exhaust port on the oven.
As well as the cost of purchasing the oven itself, you should factor in the running costs of the oven given its likely usage and power consumption. You should also budget for any oven accessories you need to buy, and for parts or labor not covered by the warranty.
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Where do I find key product specifications on LabOvens.net?
Now that you have a clear idea of the key factors to consider when buying an oven, we’ll explain where to find detailed information for each oven in the LabOvens.net product collection.
When you select a specific oven to view, the product page provides you with detailed information organized in three tabs (Overview, Key Attributes, and Manufacturer Specifications):
In addition to the Overview (left tab), which gives an overall description of the main features of the oven (left tab), you can view the Key Attributes (middle tab) of the oven:
- the maximum temperature within the oven chamber;
- the maximum capacity of the oven chamber;
- the air movement type used for heating;
- the electrical requirements for the oven;
- the warranty period offered.
You can also read through the more detailed Manufacturer Specifications (right tab).
Depending on the manufacturer, the specifications provided will vary. However, as discussed in this article, key information to consider might include:
- the interior and/or exterior dimensions of the oven, or its capacity / volume;
- the temperature range;
- the temperature uniformity and temperature stability;
- other relevant specifications, depending on your requirements (see the Key factors to consider section for guidance).
With the help of this article, we hope that you now have a good understanding of how to choose the right lab oven for your target application(s). By paying attention to the key factors outlined here, you can carefully assess the technical specifications of the different options and buy with confidence.Whether it’s a gravity convection, mechanical convection, cleanroom, or vacuum oven you’re looking for, we hope that the oven that you buy will continue to offer excellent performance to support your work for years to come!