In piping applications, rubber expansion joints are used to compensate for thermal growth, relieve piping stress and reduce vibration and noise caused by rotating equipment. These compliant products are available in a variety of sizes and materials, including EPDM, Nitrile and Hypalon.
Expansion Joint Styles
Senior Flexonics manufactures a wide range of rubber flexible joints that can be designed to meet customer specifications and applications. Standard stock units are built with a high-quality rubber tube and cover, nylon tire cord reinforcing and flanged collars that enclose the joint body. In addition, they feature a galvanized steel floating flange that rotates for easy installation and alignment of bolt holes.
Spherical Design Bellows
In addition to providing a more robust construction, the sphere design of these joints allows internal pressure to be distributed evenly across a larger area. This allows for a higher force capacity than hand fabricated arches and spools.
The sphere design also helps to prevent pulsation and pressure changes that might cause premature wear or failure. In addition, purge connections are available along with internal liners to reduce the bellows’ skin temperature in high-temperature applications such as catalytic cracker bellows.
Purging Connections
Purge connections are an essential component of these types of rubber expansion joint, as they help to flush out particulate matter and harmful solids that build up in the bellows. Additionally, they help to reduce the bellows’ internal heat and thus prolong the life of these expansion joints.
Pantographic Linkage
Another feature of these joints is a pantographic linkage, which is a scissors-like device that attaches to the spool or arch to positively distribute thermal movement equally between two bellows. This allows the joints to withstand a greater range of movements than a bellows with no linkage.
Control Rods
For piping systems that are not anchored, control rods are essential pieces of hardware added to the expansion joint during installation. They limit the amount of movement that the joint is exposed to during operation, especially if it is under large pressures or is being subjected to lateral offsets.
The use of control rods should not be construed as restraint, however. They are a safety precaution and must be installed and maintained properly to ensure they do not cause undue damage to the pipe or equipment that is being supported by the expansion joint.
Manual Manufacturing of Rubber Expansion Joints
Due to their manual production process, mandrel-built joints are labor and skill intensive. TANIQ has developed processes and equipment to automate the production of these joints, which results in significant production time reduction (up to 70% in some cases) as well as high product quality and consistency.
The automated production system enables one operator to produce a number of expansion joints at a time. In addition, the software that identifies the best path for the machine can be used to further optimize the production. Using smart point filtering and path optimizations, the operator can learn how to operate the machine within a week and execute only the few remaining manual operations.