What is convection? By this concept it is customary to understand the phenomenon of heat transfer in gases, bulk media, or liquids. This phenomenon exists in a mass of options and depends on the environment and the forces due to which it arises. At the moment, we are interested in the air environment, since this phenomenon will be considered from the point of view of use in microwave ovens.
Understanding what convection is, it is worth saying that this phenomenon can be divided into two types: natural and forced. As an example of the first one, we can propose a variant of operation of conventional
heating radiators. Heated air becomes lighter, due to which it actively moves up. It is replaced by cold air. The cycle repeats, causing circulation. This type of convection leads to uniform heating of air in a given volume. If you install a fan in front of the radiator, then we get an example of forced convection. It will allow you to repeatedly distill air through the battery, mixing the warm and cold layers with each other. This will allow you to get a more uniform temperature in the room. It is by this principle that the convection unit in the microwave works.
According to the microwave device with convection, there can be different types, however, they always contain the three main elements: a heater in the form of a heater, a fan and a device responsible for temperature control. The convection unit is usually located above the oven chamber or on the rear wall.
The heating element may be a ten or a quartz heater. In some models, the convection unit may not have its own heater, and instead a conventional grill will be used.
Understanding the question of what convection is, it is worth considering how it works in microwave ovens. By means of an asynchronous low-power motor, the
fan impeller is driven. If the convection unit is located on the back of the oven, direct drive can be used. This means that the fan is located directly on the motor shaft. If the device is located above the furnace chamber, then a remote drive is used, for example, using a strap. If instead of a heater, a heating grill is used in the furnace, the fan is replaced by a "snail" type
supercharger . Such devices use a low voltage DC motor. At the moment, a mini-oven with convection has earned special popularity. Such a device allows you to get an excellent result when cooking.
The control panel usually contains relays engaged in controlling the engine and heating elements. The temperature in the furnace chamber is also set there. The temperature sensor is responsible for temperature control; it is located on one of the walls outside the camera. A sophisticated signaling and control system for the heating process maintains a constant temperature inside the furnace. All this allows you to achieve good results: the air warms up evenly, contributing to the rapid and uniform preparation of products.
So, now you know what convection is.