A rubber joint is a flexible connector fabricated of natural and synthetic elastomers, fluoroplastics and fabrics as well as metallic reinforcements used to absorb movements in a piping system while containing pressure and a medium running through it. It is the most cost-effective solution for piping systems that are subject to thermal growth, equipment movement and vibration or pressure pulsation.
The material selection and combination of elastomers is dependent on usage area and design conditions such as temperature, fluid and pressure. There are many natural and synthetic elastomers and special purpose fabrics available to create high performance expansion joints to meet challenging operating conditions.
Standard designs are constructed of EPDM rubber inner liner and cover with an embedded nylon cord reinforcement and wire reinforced flanged collars. They are floatable flanged for ease of installation and alignment.
Compared to metal joints, rubber flexible joints are light in weight and easily handled. They also equalize uneven flange surfaces to provide a gas tight seal without additional gaskets.
They are resistant to corrosive fluids, chemicals, abrasion and erosion. They have low friction and excellent acoustical impedance and absorb all forms of mechanical vibration, including lateral and axial.
There are two main styles of rubber joint, spool and spherical. Spool-type joints are cylindrical bodies with steel reinforcing rings. They have a full face flange and are designed to accommodate both single and multiple arches for longer lengths.
Spherical-type rubber joints are circular and are designed to distribute pressure evenly throughout the body. They do not require reinforcing steel and only fabric reinforcement, but they are more expensive than spool-type joints. They are often custom-manufactured for specific installations. They are available in carbon steel or zinc plated or hot dip galvanized carbon steel, stainless steel, duplex and other materials.
The flanges are drilled to match the pipework flanges. They can be used to compensate for minor misalignment, offset, or bending of pipes and are chemical and abrasion resistant. They can be installed on raised or flat flanges and are ideal for use in the oil, petrochemical, chemical, power generation, wastewater and water treatment industries.
Aside from being a cost-effective and environmentally friendly solution, rubber flexible joints are often the best choice for applications involving high vibration and sound dampening. They do not replace metal joints in all applications, but are widely recognized as the best solution in many cases.
They are a cost-effective solution for absorbing large directional movements in very short distances and can be installed on both raised and flat flanges. They are primarily used in chemical and petrochemical industries where they can reduce costs due to rework, downtime, labor and cleaning.
In addition, they can be used on both sloping and horizontal piping systems. They are also a good choice when there is no available space for metal joints.
These joints can be designed to withstand temperatures up to 110degC and pressures up to 15 bar under full vacuum, depending on the design. They can withstand continuous use for many years with proper maintenance.