What is convection? This concept is commonly understood as the phenomenon of heat transfer in gases, granular media or liquids. This phenomenon exists in the mass of options and depends on the environment and forces, because of 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, one can propose a variant of the operation of conventional radiators. Heated air becomes lighter, thereby actively moving up. He is replaced by cold air. The cycle repeats, causing circulation. This type of convection leads to a uniform heating of the air in a given volume. If you install a fan in front of the radiator, we will get an example of forced convection. It will allow many times to distill air through the battery, mixing the warm and cold layers between each other. This will give a more uniform air temperature in the room. It is on this principle that the convection unit in the microwave oven works.
According to the device, microwave with convection can be of different types, but they always contain three basic elements: a heater in the form of a fan, a fan and a device responsible for temperature control. The convection block is usually located above the furnace chamber or on the rear wall. The heating element can be a tan or a quartz heater. In some models, the convection unit may not have its own heater, but instead it will use a tenhe of an ordinary grill.
Understanding the question of what convection is, it is worth considering how it works in microwave ovens. Using an asynchronous low-power motor, the impeller of the fan is driven. If the convection block is located on the back of the furnace, a 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 passive. If the oven uses a grill instead of a heater, the fan is replaced by a snail air compressor . Such devices use a low-voltage motor powered by a direct current. At the moment, a special mini-oven with convection deserved special popularity. This device allows you to get an excellent result when cooking.
On the control panel, there are usually relays engaged in controlling the motor and heating elements. The temperature in the kiln chamber is also set there. The temperature sensor is responsible for controlling the temperature, it is located outside the chamber on one of the walls. A complex system of signal transmission and control of the heating process ensures the maintenance of a constant temperature inside the furnace. All this allows you to achieve good results: the air warms evenly, facilitating the rapid and even preparation of products.
So, now you know what convection is.