-the invention of the refrigerator 1923
The invention of refrigerator made human beings have cool and fresh-keeping food. 1923, two Swedish engineers, Platen and Mendes, made the world's first refrigerator. Since then, refrigerators have entered thousands of households and become a common "home appliance companion" in people's daily life.
For thousands of years, human beings have been trying to keep themselves and food cool in hot weather. As early as BC 1000, people in China knew how to put ice cubes in the cellar in winter and keep them for use in summer. In the 8th century AD, the king of the kingdom of Baghdad filled his summer resort with foreign snow to cool down. But it was not until 1834 that the 68-year-old inventor Jacob Perkins applied for the invention patent of the compressor that people knew how to make artificial ice cubes. Perkins's machine works on the same principle as the household refrigerator we use today: it evaporates a compressed fluid to achieve refrigeration effect and then condenses it again. But Perkins used ether at first, but today he uses ammonia and freon.
The original appearance of the refrigerator is not pleasing. It is a simple "ice box" with slate lining, which can insulate heat, but because there is no independent ice storage compartment, meat and other foods are easy to change color when stored. As a result, some people began to develop mechanized refrigerators. /kloc-At the end of 0/9, some refrigerators used for commercial purposes were widely used: merchants used it to transport steaks around the world, used it to ice wine in restaurants in Paris, and even used it to build an ice rink. At the beginning of the 20th century, an engineer named willis carrier designed an "air conditioner" in a printing factory in Brooklyn, new york, which can not only reduce the temperature, but also control the temperature. Soon, his machines appeared in major shops and theaters. People further improved Carrier's system, and some smaller household refrigerators appeared during the First World War. However, this new invention has the defects of loud noise and easy leakage. In fact, it just installed a motor and a rotating belt in the old "ice box" shell, which made it look like an experiment.
1923, Swedish engineers Praten and Mendes made the world's first refrigerator, which used a motor to drive a compressor. Two years later, an American company bought out this technology patent and started mass production of refrigerators. Household refrigerators have since become popular all over the world. According to statistics, in the United States, the popularity of refrigerators is quite high, and the proportion of households without refrigerators is less than 1%.
From the first batch of refrigerators to today's "ubiquitous", the refrigerator itself has also undergone a huge "revolution". In the early days, refrigerators, electric compressors and food boxes were separated, and later they were combined into one. In refrigerators, the refrigerants used at first are toxic substances, such as ammonia or sulfuric acid, and then gradually developed into safer freon, which is still in use today. With the sharp increase in output, the price of refrigerators began to plummet. By 1944, about 85% of American families have refrigerators. Scientists are constantly innovating refrigerators, producing portable small refrigerators and developing new technologies such as sonic refrigeration to save energy. Because the volatilization of freon can easily lead to the reduction of ozone layer in the atmosphere, efficient fluorine-free refrigerators have appeared on the market at present.