Double-wall bellows mainly have vacuum forming, blow molding, vacuum forming on the outer wall and blow molding with compressed air on the inner wall. When the vacuum forming ripple, there are many holes on the module, and there is no cooling channel, when the outer tube blank extruded by the head and the module contact, the outer tube blank is adsorbed on the cavity of the module due to the vacuum action, forming a ripple. The extruded inner tube billet is adsorbed on the sizing sleeve at the front end of the machine head.
The blow molding of double-wall bellows is that there are two layers of compressed gas between the extruded inner and outer tube billet, the positive pressure generated by the outer gas makes the outer tube billet blow and adsorb on the cavity of the module, forming a ripple, the inner tube billet is balanced with the outer gas, the inner tube billet is attached to the caliper sleeve, and the outer corrugated bottom is attached to the inner layer to smooth the inner wall of the tube.
High density polyethylene (HDPE) adding other additives formed by the appearance of the corrugated plastic pipe, the permeable corrugated pipe is drilled in the groove, the outer surface of the pipe around the needle geotextile processing. According to the type of bellows, it can be divided into single wall permeable bellows and double wall permeable bellows. Because the pipe hole of the product is in the trough and is long, it effectively overcomes the disadvantages that the flat round hole product is easy to be blocked and affect the drainage effect. For different drainage requirements, the size of the pipe hole can be 10mm×1mm-30mm×3mm, and it can be evenly distributed in the range of 360 degrees, 270 degrees, 180 degrees, 90 degrees, etc
EN
