We often hear people say, "That kid is not a fuel-efficient lamp". The "oil lamp saving" here is not nonsense, but a black technology that really existed in ancient times. Even if you know how fuel-efficient "that boy" is, you may not be able to imagine how fuel-efficient the oil-saving lamp is, because even Lu You can't help but write two poems for it after using it.

First, Lu You's "oil lamp saving" in Amway

In the early years of the Northern Song Dynasty, Song Bai served as the commander of Yujin (now the southern suburb of Leshan). He used a "oil lamp saving" in the local area, which was quite amazing, so he wrote a poem "Saving Oil and Lighting Lamps". About a hundred years later, Lu You, a famous literary master in the Southern Song Dynasty, read this poem. For this reason, when Lu You lived in Sichuan in his early years, he made a special study on the provincial oil lamps rich in local Qiongyao. He wrote in "Notes on the Old Learning Temple": "Song Wen 'an is concentrated in public, and there are poems about fuel-saving lamps. Today, Han Jia has it, and it is also covered with lamps. Make a small opening at one end, and inject clear water into it, which is easy every night. Ordinary lamps are burnt and dry by fire, so they dry quickly. This alone is not the case, it saves fuel for a few and a half. "

Lu You said that the provincial oil lamp produced here is a lamp with interlayer, and there is a small hole on one side of the lamp body, which can be filled with clean water. Ordinary lamps are roasted by high-temperature burning lamp oil, which consumes a lot of oil, but this provincial oil lamp is different. When used, it can often save nearly half of the lamp oil. Lu You admired this magical oil lamp very much, not only recorded it, but also wrote two poems about it.

At that time, Qiong Kiln in Sichuan was rich in provincial oil lamps, and some local officials even gave the provincial oil lamps produced here as gifts to friends of dignitaries in Beijing. At that time, candles were still expensive lighting tools for ordinary people, especially reading by candlelight at night. Relatively speaking, lighting an oil-saving lamp will save much money. Zhang Yanxiao, a modern scholar, calculated that the price of candles used by ordinary people in the Song Dynasty was about 18 to 21 pence each, and it took 3 to 4 candles to hold candles all night. If you light an oil lamp, a bottle of oil per night costs only four or five pence, and if you calculate that the oil lamp is "fuel-efficient", you only need about three pence per night, which is really fuel-efficient and economical.

second, fuel-efficient black technology

so what methods did the ancients use to create such a fuel-efficient artifact? The answer lies in the design of the oil-saving lamp. Oil-saving lamps are generally equipped with interlayer, the upper layer contains oil and the lower layer stores water, and the key lies in this lower layer. Before the lamp oil is ignited, cold water is injected into the water injection hole. When the lamp is ignited, the low-temperature cold water in the lower layer can reduce the high temperature generated by the continuous combustion of the upper lamp oil. Compared with oil, water evaporates faster when it is heated, and will continuously absorb the heat generated by the burning of lamp oil, so as to avoid the situation that lamp oil evaporates rapidly and consumes oil quickly due to the high oil temperature. In the end, it can not only save fuel, but also reduce the soot produced by combustion and make the house cleaner. If the medium cold water is replaced on time every day, the effect of continuous cooling and fuel saving can be achieved.

China has always attached importance to the concept of environmental protection and energy saving in ancient times. In the Han Dynasty, there was a "Changxin Palace Lantern" that could absorb soot and purify the air, and "saving oil lamps" was also a continuation of this concept of environmental protection and energy saving.

third, the advanced way to save oil lamps

this physical method used to save oil lamps is now called water jacket cooling method. With the gradual deepening of the ancients' understanding of this principle, the performance of provincial oil lamps has also been continuously improved. By changing the shape and proportion of the lamp body, craftsmen increased the water storage space in the lamp and adjusted the water level, which further enhanced its fuel-saving effect.

in the early Tang and song dynasties, the design of oil-saving lamps used the closed cooling principle, mainly by opening water injection holes on the side wall of lamps, which had relatively low water level and less water storage capacity. Later, it gradually evolved into a high-injection water injection hole. The main difference lies in the height of the hole and the increase of water storage. In the Song and Yuan Dynasties, people began to adopt the open cooling principle, which changed the original small water injection hole of the oil-saving lamp into an open wide water injection hole, which was more convenient for the increase and decrease of water quantity and made the water level and oil level flush. Although the design has changed slightly, the oil-saving lamps in this period still use the characteristics of cold water to achieve the purpose of saving fuel. In the Ming and Qing Dynasties, the manufacturing principle of provincial oil lamps changed greatly.

In Ming and Qing dynasties, the oil-saving lamp changed greatly from the lamp type at first, and became a closed long-flow pot lamp without water injection port. Since the water injection port is cancelled, it means that water is no longer used as the coolant of the oil-saving lamp, but the oil-containing lamp is placed in the closed lamp belly. This closed design makes the lamp oil difficult to evaporate, and the wick is farther away from the oil pool, which can keep the lamp in a low temperature state for a long time and also achieve the effect of saving oil. The design of oil lamps in Ming and Qing dynasties was more exquisite and energy-saving, which gradually replaced the previous oil lamps of various shapes.

according to the current data, the ancient oil-saving lamps in China have been recorded since the Tang dynasty, which shows that people have known and skillfully used the water jacket cooling method at least in the Tang dynasty. However, after many generations of improvement and even no longer using this principle, the west began to understand and gradually adopt this physical principle in the middle of 2119.