Fiber optic temperature sensor for temperature monitoring during microwave oven heating process

Microwave oven/microwave is, as the name suggests, a modern cooking appliance that uses microwaves to heat food. Microwaves are a type of electromagnetic wave. A microwave oven consists of a power supply, a magnetron, control circuits, and a cooking chamber, etc. The power supply provides approximately 4000 volts of high voltage to the magnetron. Under the stimulation of the power supply, the magnetron continuously generates microwaves, which then pass through a waveguide system and are coupled into the cooking chamber. Near the inlet of the cooking chamber, there is a rotatable stirrer because the stirrer is a fan-shaped metal that reflects microwaves in all directions when it rotates, thus evenly distributing the microwave energy throughout the cooking chamber and heating the food. The power range of a microwave oven is generally 500 to 1000 watts.

A microwave oven is a cooking appliance that uses food to absorb microwave energy in the microwave field to heat itself. In the microwave generator of the microwave oven that produces microwaves, a microwave electric field is established in the oven chamber, and certain measures are taken to make this microwave electric field as uniformly distributed as possible in the oven chamber. Put the food in this microwave electric field, and the control center controls the cooking time and the intensity of the microwave electric field to carry out various cooking processes.

In simple terms, microwaves are a high-frequency electromagnetic wave. They themselves do not generate heat. Microwaves exist everywhere in the universe and nature, but since they are dispersed and not concentrated, they cannot heat food. The microwave oven utilizes its internal magnetron to convert electrical energy into microwaves and penetrate the food at a 2450 MHz oscillation frequency. When microwaves are absorbed by the food, the polar molecules (such as water, fat, protein, sugar, etc.) within the food are attracted and vibrate at a speed of 2.45 billion times per second, which is the macroscopic manifestation of heating the food. The principle of microwave heating is simply: When microwaves are radiated onto the food, food always contains a certain amount of water, and water is composed of polar molecules (the positive and negative charge centers of the molecule do not coincide even in the absence of an external electric field). The orientation of these polar molecules will change with the microwave field. Due to the movement of the polar molecules of water in the food and the interaction between adjacent molecules, a phenomenon similar to friction occurs, causing the water temperature to rise, and thus the temperature of the food also rises. Food heated by microwave is heated uniformly throughout the object and heats up quickly. It heats to a depth of 5 cm into the food at a frequency of 24.5 billion times per second, accelerating the movement of molecules.

Three taboos when using a microwave oven to heat food:

1. Do not heat meat to half-cooked and then heat it again in the microwave oven: Because bacteria will still grow in partially cooked food, when heated again in the microwave oven with a short time, it is impossible to kill all the bacteria, and the bacteria will still multiply, which will endanger human health. Frozen meat food must be thawed in the microwave oven first, and then heated to cooked food.

2. Do not freeze meat that has been thawed in the microwave oven again: Because the meat has been heated outside the microwave oven, it has actually been heated to a low temperature layer. At this temperature, bacteria can multiply. Although it can stop multiplying when frozen again, it cannot kill the live bacteria. Therefore, if the meat that has been thawed in the microwave oven is put back in the refrigerator for freezing, it must be heated to fully cooked.

3. Do not fry food: Because fried food contains a high amount of oil, and high-temperature oil can cause splashing, which can lead to a fire. If accidentally causing a fire inside the oven, do not open the door but first turn off the power and wait for the fire to go out before opening the door to cool down.

Three don'ts when using a microwave oven to heat food:

1. Do not use ordinary plastic containers: Use specially designed microwave oven utensils to hold food and heat it in the microwave oven. One is that hot food will deform the plastic container, and the other is that ordinary plastic will release toxic substances, contaminating the food and endangering human health. 2. Do not use metal containers: Because containers made of iron, aluminum, stainless steel, enamel, etc. that are placed in the microwave oven will generate electric sparks and reflect microwaves when heated by the microwave oven. This will not only damage the oven but also make the food undercooked.

3. Do not use sealed containers: When heating liquids, use wide-mouth containers. Because in a sealed container, the heat generated by the heating of the food is not easily dissipated, causing excessive pressure inside the container and potentially leading to a rupture accident. Even when cooking shell-containing foods, it is necessary to pierce the shell with a needle or chopsticks in advance to prevent cracking, splashing and dirtying the oven walls, or causing injuries from splashing.

Finally, let's introduce a fiber optic sensor applied during the heating process of the microwave oven for temperature monitoring. That is the fiber optic temperature sensor - FOT-L-SD and the fiber optic temperature sensor - FOT-L-BA, which are imported by Gongcai Network from abroad. FOT-L-SD and FOT-L-BA are a type of fiber optic temperature sensor that is very suitable for measuring temperature in extreme environments, including low temperatures, nuclear environments, microwaves and high-intensity RF, etc. FOT-L integrates all the excellent characteristics you expect from an ideal sensor body. Therefore, even in extreme temperatures and unfavorable environments, these sensors can still provide high-precision and reliable temperature measurement.

The main features of both FOT-L temperature sensors are that they are completely unaffected by EMI and RFI. At the same time, they are small in size, have built-in safety devices for dangerous environments, are resistant to high temperatures, corrosion-resistant, and have high accuracy. Based on fiber optic technology, the sensors are essentially unaffected by EMI and RFI. The light sensor is not active in the electronic field, so it will not emit or be affected by any type of electromagnetic radiation, whether it is microwaves, RF or NMR.