An expansion joint rubber failure occurs when the temperature and pressure exceed the rating of the expansion joint. This is also known as “hard-boiling.” The rubber turns hard and becomes plastic. Fortunately, there are several types of replacement rubber available. Read on to learn more about the different types of rubber expansion joints.
Spherical joints
A Spherical expansion joint is a flexible, mechanical joint used to connect two adjacent surfaces. The flanges of this type of joint must be within certain dimensions. These dimensions are known as face-to-face dimensions. The rubber bead is the seal between these two surfaces, and any damage to it will lead to leakage.
Rebonded rubber
Rebonded expansion joint rubber is composed of high-quality rubber bonded to a resin. It is very resilient and can recover up to 90% of its original thickness. This material contains 97% post-industrial recycled content, is manufactured in the USA, and has excellent chemical and abrasion resistance. Rebonded expansion joint rubber can be cut to size on the job site or purchased in pre-cut pieces.
Metraloops
A Metraloop is a rubber expansion joint used in piping systems. This type of expansion joint can handle a wide range of movement and exerts low loads on the pipe. Its flanged ends prevent stress transfer to thin-walled threaded fittings. It is also available as a full-face joint and has integrated control rods.
711 Plus
The 711 Plus expansion joint is a new generation expansion joint designed for use with non-metallic piping. It features integral gusset plates built into the backing ring that eliminate the problem of cracking plastic flanges. It also offers a full face built-in rubber face, making it a great option for plastic piping applications. It is also able to withstand more movement than a Metrasphere, yet retains a lower spring rate than the 100HT.
UNISOURCE SERIES ED
UniSource ED expansion joint rubber is designed for use in duct systems with thin walls. The elastomeric rubber is thinner gauge than pressure piping and protects thin wall ducts from damage. These expansion joints feature integral rubber flanges. They are available in circular and rectangular styles. The rectangular style incorporates square corners and continuous rubber flanges on both ends. This design eliminates the need for splices in the body of the joint or near the corners. For increased axial movement, choose style “HA.” For increased strength, select Series ED expansion joints with metallic backing rings.
Style HA
When you need a flexible connection for piping in a specific area, a rubber expansion joint is the ideal solution. This expansion joint rubber material’s elasticity and ductility allows it to absorb pipe movements. Various configurations are available, including spherical and spool shaped connectors. In addition to its elastic properties, rubber expansion joints are ideal for isolating noise and vibration. This means you won’t experience pipe buckling from column loads or other unwanted dynamics.
Offset rubber expansion joints
Offset rubber expansion joints are an excellent choice for structural applications. They are able to withstand a range of pressures and are a cost-effective option. However, they do come with some disadvantages. One of these is that they require manual application. Furthermore, they are not always placed in the best position. Another disadvantage is that they must be applied in pairs. This means that two extra layers of material must be added to each sheet. These extra layers prevent delamination of the sheet.
Metraloops with control rods
When installing a Metraloops expansion joint, the most important thing to remember is the control rods. If they are not installed properly, the joint will fail due to excessive expansion. Fortunately, the control rods can be easily repositioned in the field without breaking the seal.