What happened to the soft rubber flat?
A slightly heated or pressurized medium will return to its original condition.
Rubber soft joint is a common rubber telescopic device". The inner pressure of the pipe or the equipment, because of the decrease of temperature or the venting of the vertical section, causes the internal negative pressure.
The two above are all correct, this is mainly to see where you are used, and if used in the settlement of the joint or expansion of the above, and then appear flat, then it is easy to burst the tube. It is important to note that metal bonding is recommended. Rubber joint is commonly used to shock, is not recommended when the expansion joints, expansion joints when used, if appear flat phenomenon, prone to pull off the situation (is flange off). The danger of exploding pipes everywhere. So it's not that rubber joints are bad, and it depends on where they are used.