Why does the thermos cup need to be vacuum tested repeatedly?

The insulation principle of the stainless steel thermos cup is to evacuate the air between the double-layer cup walls to form a vacuum state. Since the vacuum can block the transmission of temperature, it has a heat preservation effect. Let me explain a little more this time. In theory, the vacuum isolation temperature should have an absolute insulation effect. However, in fact, due to the structure of the water cup and the inability to achieve a complete vacuum state during production, the insulation time of the thermos cup is limited, which is also different. The types of thermos cups also have different insulation lengths.

So let’s go back to our title content. Why do thermos cups need to be vacuumed repeatedly before leaving the factory? Everyone knows that the purpose of vacuum testing is to ensure that every water cup is a thermos cup with intact performance when it leaves the factory, and to prevent uninsulated thermos cups from flowing to the market. So why do we have to do it repeatedly?

Repeatedly does not mean doing a water glass over and over again in the same period of time. That does not make any sense. Repeated testing refers to what must be done when a factory process may destroy or damage the vacuum state of the water cup. In theory, this testing standard needs to be strictly implemented by every water cup factory. Only in this way can all thermos cups on the market be guaranteed to be the same. It has a good thermal insulation effect, but in fact, considering the pressure of economic expenditure and cost, most factories will not perform repeated vacuum tests on water cups.

After the vacuuming is completed, a vacuum test will be done before the spraying process. The purpose is to screen out the ones that are not vacuumed and avoid increasing the spraying cost;

If the sprayed cup body is not assembled immediately and needs to be put into storage, it will need to be vacuumed again after the next time it is shipped out of the warehouse. Since most of the current water cup production is in automated or semi-automatic production, it is not ruled out that some water cups may have weak welds during the welding process. This phenomenon will cause problems to be detected during the first vacuum inspection, and the system may not be able to detect the problem after it has been stored for several days. The position of Tin Hau’s welding joints will cause vacuum leakage due to internal and external pressure, so vacuum inspection after delivery can screen out this type of water cups. At the same time, due to vibration during storage or transportation, the getter of a very small number of water cups will fall off. Although the getter falloff of many water cups will not affect the insulation performance of the water cup, there will still be some cases where the getter will fall off due to the falloff of the getter. Causes air leakage to break the vacuum. Most of the above problems can be sorted out through this inspection.

If the finished product still needs to be stored in the warehouse and stored for a long time before being shipped, the water cups that are about to be shipped still need to be vacuum tested again before shipment. This test can detect those that were not obvious before, such as vacuum. Welding and then completely sorting out the defective water cup such as leakage.

Some friends may ask after seeing this, since you have said this, it stands to reason that all thermos cups on the market should have good thermal insulation performance. Why do people still find that some thermos cups are not insulated when they buy water bottles? Excluding the reasons why some factories do not perform repeated vacuum tests, there are also vacuum breaks caused by water cups caused by long-distance transportation, and vacuum breaks caused by water cups falling during multiple transportation processes.

We have talked about many simple and convenient ways to test the insulation effect of water cups in previous articles. Friends who need to know more are welcome to read our previous articles.