Principle Of Dry Heat Sterlization Using Hot Air Oven

The most common dry heat sterilization method in the laboratory is a hot air oven manufacturers India. Sterilization is the process of eradicating or destroying all microorganisms from a product or surface, including viruses, bacteria, and their spores, without affecting their quality or quantity. It is a dry heat-based physical method of sterilizing.

The nature of heat (dry or moist), temperature and time, number of microorganisms, nature of microorganisms, type of microorganism, and presence of organic material all influence sterilization by heat. Protein denaturation, oxidative destruction of key cell elements, and toxic consequences of high electrolyte levels are the mechanisms of action. It operates on the conduction principle, in which heat is absorbed by an item's outer surface and then transferred to the next layer.

The workings of a hot air oven

In electrical equipment, the principles of dry and hot air oven manufacturers India convection (the movement of heated air), conduction, and radiation are applied. Hot air convection systems are divided into two categories. Heated air expands and has a lower density than cooled air, so it rises and pushes the colder air away (, the cooler air descends). It creates temperature changes within the chamber, causing a delay in the turnover process.

b. Mechanical convection: A blower or fan is installed and actively forces heated air throughout the chamber. Bacterial endotoxins (or pyrogens) that are difficult to remove by conventional means are destroyed by dry heat. Because of this feature, it can be used to sterilize glass bottles that will be filled aseptically. Dry heat is more effective and kills by oxidation, protein denaturation, and toxic consequences of high electrolyte levels.

The Functions and Structure of a Hot Air Oven

It is divided into the sections below: o An insulated chamber with electric heaters that is encircled by an outer case o Shelves of a fan o Thermostat o Controls for door locking

A metallic cabinet with a heating filament and a wall-mounted fan. The thermostat, temperature control, and double-walled insulation hold the heat in and save energy (inner is a poor conductor, outer is metallic, an air-filled space between the layers). Electrically heated and equipped with a fan or blower to guarantee speedy and consistent heat distribution. Heating mechanism: Dry heat kills microorganisms by causing destructive oxidation of key cell elements, ii) protein denaturation, and iii) the toxic effect of high electrolyte levels.

The Benefits of Using a Hot Air Oven

Hot air oven manufacturers India Sterilization of items such as cigarettes that can withstand high temperatures without being burned. Glassware, powders, forceps, scissors, scalpels, glass syringes, and pharmaceutical items such as liquid paraffin, fats, grease, and dusting powder, to name a few, are among the items available.

The process for handling a hot air oven.

Wrap the items in cardboard, aluminum, or paper and place them in a container. Cotton wool must be inserted into the mouths of flasks, test tubes, and both ends of pipettes. Sterilization articles like Petri plates and pipettes can be arranged within metal canisters and then deposited. Place the articles at a suitable distance from one another to allow for free air circulation and uninterrupted ventilation. Close the door and turn the hot air oven on.

When the thermometer indicates that the oven hot air oven manufacturers India air has reached sterilizing temperature, the oven is heated for the specified amount of time (for example, 160°C for an hour). To avoid glassware breakage, allow a temperature drop to 40°C (about 2 hours) before removing sterilized goods.

Autoclaving's Benefits o There is no need for water, and there is no pressure build-up inside the oven, making it safer to operate with. o Smaller than an autoclave, but equally effective. o When compared to other methods, higher temperatures can be achieved. o This medication kills the bacterial endotoxin, which is something that not all treatments can do. o Only way of sterilizing oils and powders. An effective method of sterilization of heat-stable goods. o Sharps or instruments with a cutting edge are protected with this item (fewer problems with dulling of cutting edges). o It is non-toxic and has no negative effects on the environment.

Autoclaving's Drawbacks. o Some species, such as prion, are resistant to killing or inactivation. o High sterilizing temperatures can cause smokey glasses: the temperature holding period is 1 hour at 160°C, 30 minutes at 170°C, and 20 minutes at 180°C. o Because of the slow rate of heat penetration and microbial death, dry heat penetrates materials slowly and unevenly, making it time-consuming. o It necessitates a constant supply of electricity.

Because heating coils in the bottom of the machine enable hot air to rise inside the chamber by gravity convection, the static-air sterilizer is called an oven-type sterilizer. Dry-heat sterilizers are slower to heat, take longer to reach sterilizing temperatures, and have less consistent temperature control throughout the chamber than forced-air sterilizers.

A motor-driven blower pumps heated air around the chamber at a high velocity in a forced-air or mechanical convection sterilizer, allowing for faster energy transfer from the air to the instruments.


Microorganisms and bacterial spores are destroyed in hot air oven manufacturers India ovens by exposing them to extremely high temperatures for several hours. Conduction sterilizes goods by heating the item's exterior surfaces, absorbing the heat, and transporting it into the center.

Hot air ovens are often used to sterilize materials at 170 degrees Celsius for 30 minutes, 160 degrees Celsius for 60 minutes, and 150 degrees Celsius for 150 minutes.