The concept of double-walled bellows can be traced back to the 60-70s of the 20th century, and the rigid polyvinyl chloride (PVC-U) double-walled bellows has been launched in foreign markets, and began to be widely used in the drainage and sewage systems of developed countries in the 80s. In the early 80s, high-density polyethylene (HDPE) double-walled bellows were first developed in Germany. After years of development and improvement, HDPE double-walled bellows has developed from a single variety to a complete product series, and has been very mature in production technology and use technology. Due to its excellent performance and relatively economical cost, it has been greatly promoted and applied in developed countries such as Europe and the United States, replacing concrete pipes and cast iron pipes in large numbers. In China, the promotion and application of HDPE double-walled bellows is in an upward trend stage, and the product has been identified by the National Chemical Building Materials Testing Center, and all technical indicators have reached the use standard. In the 21st century, double-walled bellows technology continues to innovate, such as the development of third-generation products through molecular chain structure optimization and nano-enhancement technology, which increases the long-term ring stiffness retention rate to 95%, and the short-term impact resistance is increased by 40%, and the development is in the direction of intelligent pipe networks integrating intelligent monitoring, digital twins and other technologies.
