Tube furnace and Muffle furnace as the two major "carry" in the field of heat treatment, frequently appear in the research and development front of the laboratory and the production line of the factory. Although the two are committed to providing a high temperature environment for materials and achieving various physical and chemical changes, they actually hide the universe in many dimensions such as design architecture, working mechanism, performance and application scenarios, and have differences that cannot be ignored. Accurate insight into these differences, whether it is the pursuit of academic breakthroughs in the scientific research workers, or the pursuit of economic benefits of the helm of the enterprise, can be targeted to select equipment, laying a solid foundation for the smooth promotion of the project. Next, let's take a full and deep look at the two devices and explore their mysteries.
1、appearance design and structural layout: different shapes, each has ingenuity
The first encounter between the tube furnace and the Muffle furnace, the visual impact is enough to make people perceive the difference between the two. Tubular furnace is like a long "time and space tunnel", the main body is in the shape of a thin tube, the furnace shell is mostly made of durable metal material, which not only has good heat dissipation performance, but also can effectively shield external electromagnetic interference. The inner core - quartz tube or ceramic tube, the texture of high temperature resistance, chemical stability, is the material to withstand high temperature experience of the "main battlefield". The material is accurately fed from one end of the tube, as if embarking on an exclusive journey, the whole process is in a relatively closed and quiet space, free from interference from external impurities. The heating element is spiral or ribbon, closely surrounding the reaction tube, like a loyal guard, to ensure that the heat is fully and evenly transferred to every inch of material in the tube.
On the contrary, the Muffle furnace is like a solid and heavy "energy treasure box", with regular shape and thick walls. The furnace cavity is spacious and open, providing sufficient "shelter" for materials. The furnace wall is carefully built by high-quality insulation materials and high temperature resistant bricks, and the heating resistance wire is cleverly hidden in the sandwich. After electricity is passed, the heat is transmitted through the layers of the furnace wall, gently and evenly diffused to the entire furnace chamber. The material is placed on a special shelf and crucible. The design of the shelf takes into account the load bearing and thermal conductivity to ensure that the material in different positions can be evenly heated. In contrast, the amount of material carried by the Muffle furnace at a single time is quite considerable, and the large Muffle furnace can even accommodate several cubic meters of samples at one time, which is extremely suitable for batch processing of large size and large quantities of materials, showing high efficiency.
2、the working principle: the subtle "door" between the same little differences
Both tube furnace and Muffle furnace rely on electric energy to drive, and convert electric energy into heat energy with the help of electric heating elements, so as to achieve high temperature "carving" of materials, but the specific working methods of the two are subtly different. The tubular furnace focuses on precision and customization. After starting the heating process, the electric heating wire around the reaction tube is activated instantaneously, the current passes through, the electric heating wire quickly heats up and becomes red, and the heat, like a smart spirit, permeates into the tube material evenly and efficiently through the tube wall. At the same time, the tube furnace's "black technology" - external gas pipeline and precision flow valve grand debut, with this system, operators can control the type of gas in the tube, flow rate and pressure, easily create a vacuum, inert gas surround, reducing atmosphere filled or specific mixture dense process environment.
Taking the sintering process of lithium battery electrode material as an example, the electrode material is extremely sensitive to oxygen, and the electrochemical performance of the material may be affected by a slight mistake. At this time, the tube furnace accurately introduces high-purity argon, which acts as a loyal shield to isolate oxygen and protect the chemical reaction of sensitive materials, ensuring that every detail of the reaction is accurate.
The working principle of Muffle furnace is slightly more "simple". At the beginning of electrification, the resistance wire in the interlayer of the furnace wall heats rapidly, and the heat is conducted by the furnace wall in a large area, and the temperature in the furnace cavity steadily rises. The temperature control system monitors temperature changes in real time, just like a rigorous butler, accurately adjusts the current size, maintains a constant temperature in the furnace, and meets the requirements of the material's established heat treatment time. Most conventional materials annealing, ashing treatment, Muffle furnace with this simple and efficient heating mode can be competent. Although its heating rate is slightly slower than the tube furnace, "slow work produces fine work", the spacious furnace chamber inside the Muffle furnace gives an excellent temperature uniformity, effectively avoiding the hidden danger of local overheating and uneven heating of the material, so that each material can enjoy a balanced heat "nourish".
3、temperature control accuracy and uniformity: each show their advantages
Temperature control is the "life door" of the heat treatment process, and the tube furnace and the Muffle furnace have their own advantages in this key dimension, showing completely different characteristics. Tubular furnaces rely on cutting-edge technology and sophisticated design to refine temperature control accuracy to near perfection. Thanks to the small diameter of the reaction tube and the fine heating layout, the temperature control error can be easily controlled within a very small range, and some high-end tube furnaces can even reach ±1 ° C.
Although the temperature control accuracy of Muffle furnace is not as fine as that of tubular furnace, conventional products are mostly maintained at ±5 ° C - ±10 ° C, but its spacious internal furnace chamber gives rise to excellent temperature uniformity. When large-scale material handling, even the samples in the corner position can be bathed in uniform heat, avoiding the dilemma of uneven product quality caused by temperature differences. Taking the batch ashing detection of geological ore samples as an example, a large number of ore samples are put into Muffle furnace at the same time, thanks to the temperature uniformity, the burning degree of each sample is consistent, and the test results are real and reliable, showing its practical value in the batch operation scenario.
4、Ability of atmosphere control
At the level of atmosphere creation and control, tube furnaces are called "experts" and have unique advantages that Muffle furnaces are difficult to match. With an external gas pipeline and precision flow valve, the tube furnace is like a magic master, which can adjust the atmosphere in the tube in real time and accurately according to the process requirements. Whether it requires an extremely vacuum environment to simulate the physical conditions of deep space; Or inert gas protection atmosphere, prevent material oxidation, nitriding; Or reductive atmosphere, help metal oxide reduction, tube furnace can be easily controlled, freely switched.
During the synthesis of ternary materials for lithium batteries, the precise control of oxygen content is a key link. The tube furnace accurately introduces the mixture of nitrogen and oxygen, closely monitors and adjusts the oxygen content, and helps the crystallization structure and electrochemical properties of the material to achieve the optimal state. In contrast, Muffle furnace, limited by the relatively closed box structure, the internal atmosphere is very difficult to replace, in most cases can only maintain the natural air atmosphere, even after improvement, it can only introduce a small amount of inert gases to a limited extent, it is difficult to meet the strict and changeable atmosphere control needs, in this field slightly inferior.
5、Conclusion
Tube furnace and Muffle furnace are just like two "masters" in the field of material heat treatment, each with unique skills and each good at winning. Tubular furnace with high precision temperature control, flexible atmosphere control, carved fine materials; Muffle furnace with large capacity, uniform heating, efficient processing of batch materials.
