The rubber expansion joint consists of three basic parts, the Tube, the Body and the Cover. See figure 4.
2.1 tube
Depending on operating conditions, the inner tube usually consists of a protective coating and a leak-proof liner made of synthetic or natural rubber. The pipe is seamless and extends through the hole in the joint to the outer edge of the flange. It aims to eliminate the possibility of material penetration and fabric weakening in the "main body". The design of the pipe can be used in a wide range of service conditions, such as chemical corrosive media, oil, sewage, gas and media with impurities, etc. Medium will determine the rubber body type, often used are: fluorine rubber, fluorine rubber ®), FEP fluorocarbon, Hypalon ®, neoprene and FDA approval of materials, such as white neoprene or white EPDM is also available.
2.2 the main body
The main body is usually a reinforced combination of metal and braid, which is supported by a flexible member between the inner tube and the outer covering. The woven fabric is high quality synthetic fiber such as polyester, nylon, aramid etc. Temperature and pressure requirements should be considered to maintain good adhesion and flexibility. The metal reinforcement is a solid steel ring embedded in the main body of the expansion joint. Size and stability required for pressure or vacuum requirements. They are made of high strength materials and are round or rectangular.
2.3 outer covering layer
The outer covering is a uniform rubber layer glued to the outside of the expansion joint. The main function is to protect the rubber expansion joints from external damage, to resist the chemical, oil, sunlight, acid, smoke and ozone erosion. The outer cladding takes into account the environmental conditions used by the expansion joints.