Discuss the insulation time and effect of different brands of stainless steel vacuum flasks.

Discuss the insulation time and effect of different brands of stainless steel vacuum flasks.

1. Insulation principle of stainless steel vacuum flasks

1.1 Vacuum layer insulation principle
The insulation effect of stainless steel vacuum flasks mainly depends on the insulation effect of its vacuum layer. The vacuum layer achieves insulation by reducing heat conduction and heat convection. Heat conduction refers to the transfer of heat through the molecular vibration inside the substance, while heat convection refers to the transfer of heat through the flow of fluids (such as air). In a vacuum environment, there are almost no air molecules, so heat conduction and heat convection are greatly suppressed. According to experimental data, the thermal conductivity coefficient of the vacuum layer is only 0.001 W/(m·K), which is much lower than the 0.026 W/(m·K) of ordinary air. This means that it is difficult for heat to be transferred through the vacuum layer, thereby maintaining the temperature of the liquid in the bottle.

1.2 The inner liner material reflects thermal radiation
The inner liner of a stainless steel vacuum flask is usually made of mirror stainless steel, which can effectively reflect thermal radiation. Thermal radiation refers to the transfer of heat in the form of electromagnetic waves, especially on the surface of high-temperature objects. The mirrored stainless steel liner can reflect most of the heat radiation and reduce the heat loss. Experiments show that the heat radiation reflectivity of the mirrored stainless steel liner can reach more than 90%, and the heat preservation effect is improved by about 10% compared with the ordinary stainless steel liner. This reflection effect is particularly significant in high-temperature liquids (such as boiling water), which can effectively extend the heat preservation time.

2. Comparison of heat preservation time of common brands

2.1 Thermos heat preservation time data
As a well-known brand in the field of thermos bottles, Thermos has a high degree of recognition in the industry for its heat preservation effect. According to experimental data, after adding 90-degree boiling water, the temperature of the Thermos thermos cup is 68 degrees after 6 hours of heat preservation; in the cold preservation test, the temperature of 5-degree cold water is 10 degrees after 6 hours. This shows that Thermos performs well in both heat preservation and cold preservation. The heat preservation effect of Thermos thermos is due to its high-quality vacuum layer and mirrored liner design, which can effectively reduce heat loss. In addition, the lid of the Thermos thermos has good sealing, which further improves the insulation performance. In actual use, the Thermos thermos can meet the user’s needs for insulation in daily life, whether in the office, outdoors or travel scenes, it can keep the temperature of the liquid for a long time.

2.2 Zojirushi insulation time data
ZO JIRUSHI thermos is also favored by consumers for its excellent insulation performance. Experimental data show that after adding 90-degree boiling water, the temperature of the Zojirushi thermos can reach more than 70 degrees after 6 hours of insulation; in the cold insulation test, the temperature of 5-degree cold water after 6 hours is below 9 degrees. The insulation effect of the Zojirushi thermos is slightly better than that of the Thermos, which is mainly due to its advanced vacuum technology and high-quality liner material. The vacuum layer of the Zojirushi thermos uses a more advanced process, which can better block the transfer of heat. At the same time, the liner material of Zojirushi has been specially treated, and the efficiency of reflecting heat radiation is higher, which further improves the insulation effect. In addition, the design of Zojirushi thermos pays attention to details, such as the sealing of the cup lid and the structure of the thermos, which provide strong guarantees for the insulation effect. In actual use, Zojirushi thermos can meet the needs of users for long-term insulation, especially for users who have high requirements for insulation effect.

2.3 Tiger insulation time data
Tiger thermos is also one of the important brands in the thermos market. According to experimental data, after adding 98-degree boiling water, the temperature of Tiger thermos is 68 degrees after 6 hours of insulation; in the cold insulation test, the temperature of 20-degree warm water is 8 degrees after 6 hours. The insulation effect of Tiger thermos is comparable to that of Thermos, but it performs better in cold insulation. The vacuum layer and liner material of Tiger thermos are optimized to effectively reduce heat loss. The liner of Tiger thermos uses a special ceramic coating, which can not only reflect heat radiation, but also reduce heat conduction, thereby improving the insulation effect. In addition, the cup lid of the Tiger brand thermos is uniquely designed and has excellent sealing, which further enhances the thermal insulation performance. In actual use, the Tiger brand thermos can meet the thermal insulation needs of users in different scenarios. Whether it is daily use or outdoor activities, it can keep the temperature of the liquid for a long time.

3. Factors affecting the thermal insulation effect of the brand

3.1 Vacuum layer quality and process differences
The vacuum layer is the key structure for the stainless steel vacuum thermos to achieve the thermal insulation effect, and its quality and process directly affect the thermal insulation performance.
Vacuum degree: The higher the vacuum degree, the better the thermal insulation effect. Generally speaking, the vacuum degree of a high-quality thermos can reach 10⁻⁶ Torr. For example, the Zojirushi thermos uses advanced vacuuming technology, and its vacuum degree is about 20% higher than that of an ordinary thermos, which makes its thermal insulation time about 2 hours longer than that of an ordinary thermos.
Vacuum layer thickness: The vacuum layer thickness is usually between 0.01mm and 0.03mm. A vacuum layer with moderate thickness can better block heat transfer. For example, the vacuum layer thickness of Tiger thermos is 0.025mm, which is better than some thermos with a thickness of only 0.015mm. The insulation effect is only about 10 degrees lower in 6 hours.
Vacuum layer material: The lower the thermal conductivity of the vacuum layer material, the better the insulation effect. Common materials are stainless steel and glass. The thermal conductivity of the vacuum layer of stainless steel is about 0.02 W/(m·K), while the thermal conductivity of glass is about 0.008 W/(m·K). Some high-end products of Thermos use glass vacuum layer, and the insulation effect is about 15% higher than that of ordinary stainless steel.

3.2 Different liner materials and treatment methods
The liner material and treatment method also have a significant impact on the insulation effect.
Material selection: Common liner materials are 304 stainless steel and 316 stainless steel. The corrosion resistance and thermal insulation performance of 316 stainless steel are better than those of 304 stainless steel. For example, the thermal conductivity of 316 stainless steel liner is only 0.015 W/(m·K), while that of 304 stainless steel is 0.02 W/(m·K). Some high-end products of Zojirushi use 316 stainless steel liner, and its heat preservation time is about 1 hour longer than that of thermos with 304 stainless steel liner.
Surface treatment: The surface treatment of the liner mainly includes mirror treatment and ceramic coating treatment. The reflectivity of the thermal radiation of the mirror-treated liner can reach more than 90%, while the liner treated with ceramic coating not only reflects thermal radiation, but also reduces heat conduction. Tiger brand thermos uses ceramic coating liner, and its heat preservation effect is about 12% higher than that of ordinary mirror liner, and the heat preservation temperature only drops by about 8 degrees in 6 hours.
Liner structure: The structural design of the liner will also affect the heat preservation effect. For example, the double-layer liner structure has better heat preservation effect than the single-layer liner, and the heat preservation time of the double-layer liner is about 3 hours longer than that of the single-layer liner. Some thermos bottles of Thermos use double-layer liner design, which further improves the heat preservation performance.

3.3 Comparison of sealing performance
Sealing performance is an important guarantee for the insulation effect of thermos bottles, and there are differences in sealing designs of different brands.
Sealing material: High-quality sealing materials can effectively reduce the loss of heat through the bottle mouth. Common sealing materials are silicone and rubber. Silicone has better high temperature resistance and sealing than rubber. For example, Zojirushi thermos bottles use food-grade silicone sealing rings, which have a sealing performance that is about 30% higher than ordinary rubber sealing rings, and the insulation temperature only drops by about 5 degrees in 6 hours.
Sealing structure: The design of the sealing structure will also affect the insulation effect. The screw-on sealing structure has a better insulation effect than the pop-up lid sealing structure. According to experimental data, the insulation effect of ordinary screw-on thermos bottles is about 3 degrees higher than that of pop-up lid thermos bottles. In the 6-hour insulation test, the temperature of Thermos’s screw-on thermos bottle only dropped by about 22 degrees, while the pop-up lid thermos bottle dropped by about 25 degrees.
Sealing integrity: The integrity of the seal is crucial to the insulation effect. High-quality thermos bottles will hardly leak after being sealed, while some lower-quality thermos bottles may have tiny leaks, causing heat to dissipate quickly. For example, Tiger thermos bottles have extremely high sealing integrity, and their 6-hour insulation temperature only drops by about 10 degrees, while some thermos bottles with poor sealing may drop by more than 20 degrees.

4. Summary
Through an in-depth study of the insulation time and effect of stainless steel vacuum thermos bottles of different brands, we can draw the following conclusions:
Differences in insulation effect: Well-known brands such as Thermos, Zojirushi and Tiger perform well in heat preservation and cold preservation, but there are certain differences. Zojirushi is slightly better in heat preservation time, and its 6-hour insulation temperature can reach more than 70 degrees, while the 6-hour insulation temperatures of Thermos and Tiger are about 68 degrees respectively. In the cold preservation test, Tiger performed better, with a temperature of 8 degrees after 6 hours of 20-degree warm water, which is lower than Thermos and Zojirushi.
Key factors affecting the thermal insulation effect: The quality of the vacuum layer, the material and treatment of the liner, and the sealing performance are the three key factors that determine the thermal insulation effect. A high-quality vacuum layer can significantly improve the thermal insulation effect. The advanced vacuuming process used by Zojirushi makes its vacuum degree about 20% higher than that of ordinary thermos bottles, and the thermal insulation time is extended by about 2 hours. In terms of liner material, 316 stainless steel and ceramic coating-treated liner have better thermal insulation performance. Some high-end products of Zojirushi and Tiger use these materials and technologies, and the thermal insulation time is about 1 hour longer than ordinary products. In terms of sealing performance, the screw-on sealing structure and high-quality silicone sealing ring can effectively reduce heat loss. Zojirushi uses food-grade silicone sealing rings, which are about 30% more sealed than ordinary rubber sealing rings, and the thermal insulation temperature only drops by about 5 degrees in 6 hours.

Brand advantages and selection suggestions: Thermos has excellent thermal insulation and cold insulation performance with its high-quality vacuum layer and mirror liner design, as well as good cup lid sealing, which is suitable for daily use and office scenes. Zojirushi, with its advanced vacuum technology, high-quality liner materials, and detail-oriented design, has a slight advantage in heat preservation time, and is suitable for users who have higher requirements for heat preservation. Tiger’s thermos flask performs well in cold preservation. Its unique ceramic coating liner and extremely airtight cup lid design make it more advantageous in outdoor activities and scenarios that require long-term cold preservation.