我曾经听闻过一段关于宜兴龙窑的传说，那是一种独特的陶艺工艺，以其独特的烧制方式和产出的紫砂壶而著称。龙窑本身就像是古人描述中的龙，蜿蜒曲折，依山势而建，呈直焰式筒形穹状隧道。它通常长30到70米，高约12米，倾斜角度在8到20度之间，可以分为窑头、窑床和窑尾三部分。
在这座特殊的火炉中，每隔1.3米就会开一个小洞，这些洞被称作“鳞眼洞”，总共有50多个。这使得整个结构看起来像是一条巨大的蛇，从土砖构成拱形的内部延伸至外部。在燃烧室中，有单独的一根火膛以及通道内其他区域使用同样的系统。
Dragon Kiln's Burning Process
The burning process of the dragon kiln relies heavily on the skill and experience of the burners. They observe the temperature and color changes in both the flame and clay body to determine when it is time to open or close certain vents.
Advantages and Disadvantages
One advantage of using a natural slope for construction is that it follows the principle of natural upward movement for flames, thus reducing costs while maximizing heat retention. However, this method comes with high labor demands.
Once preheating has finished, workers dig into the first set of firing cones at the top of the kiln, with two burners standing on either side wall to add fuel. This process typically starts by heating up just above part of each piece until they turn pinkish red before moving on to other areas until all parts are fully heated.
As soon as pieces have been properly fired through one set of holes, their openings are sealed again with mud bricks covered in wet clay sealant. The same process continues until all sections have been fired evenly throughout.
According to archaeological findings from Tang Dynasty sites such as Yixing Renshou Dragon Kilns or Song Dynasty sites like Yixing Mountain Dragon Kilns, there were numerous dragon kilns found across various regions including Zhejiang Province's Longquan City and Guangdong Province's Chao'an County among others during Ming and Qing dynasties.
In terms of size variations based on production developments or product sizes themselves, dragon kilns ranged from 20-30 meters long during Tang-Song periods but gradually grew larger over time reaching lengths between 30-50 meters during Ming-Qing periods; even smaller ones started off around 10-15 meters long before growing longer too up to around 50-meter-long structures eventually developed.
These ancient ovens employed different slopes depending upon whether they were used primarily for producing ceramics (slopes ranging between 40-80 degrees) versus those used mainly for baking pottery (slopes increased further towards an angle range spanning between 1000-2300).
By Northern Song dynasty times however around mid-period marks began seeing utilization by local potters who made use specifically designated dragon kilns meant exclusively for crafting purple sand teapots—known today as yixing ware—these dragons stood approximately one meter tall while stretching out a length exceeding fifty meters roughly measuring at heights between2.6meters-to2.8meters compared against regular day-to-day ceramic-making models where standard height was significantly lower than these exceptional structures’ elevations; early versions included enclosed spaces inside ceramic bodies wherein sand particles would settle within cavities which would later be filled-in completely sealing them once full; thus enhancing overall quality control measures since then onwards marking significant advancements within craft technique evolution history!
Burnt-out materials utilized include pine branches along with hard wood varieties known as hardwoods combined together forming mixed combustible fuels following specific temperatures ranging anywhere from about1200oCto slightly higher levels measured precisely via chemical analysis testing methods revealing low water absorption rates along with moderate porosity percentages indicating excellent sintered strength characteristics observed amongst many samples discovered here—a testament showing that ancient craftsmen had already achieved rather impressive results given available resources at hand!