In reality, the heat retention duration of a vacuum insulated cup depends on the structure of the cup body and the thickness of the materials used.
Generally speaking, the thinner the material, the longer the heat retention time; however, thinner materials make the cup body more susceptible to dents and deformation, which can shorten its service life. Measures such as wrapping the outer layer of the inner liner with a thin metal film or copper plating can also enhance heat retention. Large-capacity cups with narrow openings tend to retain heat longer, whereas small-capacity cups with wide openings retain heat for a shorter period. The service life of a vacuum cup also depends on the cleanliness of the inner liner and the duration of the vacuuming process, with the structure of the vacuum furnace being the most critical factor.
The vacuum equipment used in the industry falls into two main categories comprising four specific types: vacuum exhaust stations (for "tipped" or "exhaust-tube" cups) and vacuum brazing furnaces. Vacuum brazing furnaces are further subdivided into single-chamber, multi-chamber, and high-pumping-speed multi-chamber models.
The single-chamber integral vacuum brazing furnace involves a long vacuuming cycle; if a manufacturer shortens this time to boost productivity, the cup's service life may be compromised-often limiting it to around eight years. Regarding vacuum cups produced via exhaust stations (tipped cups): the heating temperature during vacuuming is approximately 500°C. While the outer shell is less prone to deformation, the copper exhaust tube's welded joint is vulnerable to leaks caused by impact, requiring special protection during the semi-finished product processing stage.
The other major category is the vacuum brazing furnace method, which encompasses three distinct types. It may come as a surprise, but while the vacuum insulated cups we use daily look similar to standard insulated cups on the outside, their manufacturing process is far more complex and technically demanding. Consequently, vacuum insulated cups cost at least twice as much as standard insulated cups.
