A rubber expansion joint is a pipe expansion joint that is made from rubber. These are flexible connectors used within a pipeline, created using natural or synthetic elastomers and materials. Rubber pipe expansion joints also sometimes include metal reinforcement. Their purpose is to provide relief when there is a thermal expansion or to help deal with vibrations or movements.
Firstly, you will want to get everything prepared for installing your expansion joint. Follow these steps:
REMEMBER: Never install any rubber expansion joints next to a wafer type check or a butterfly valve. This could result in serious damage to the rubber flange bead from the lack of mating surface or connection from the bolt.
Check the application criteria.
You will need to check the anticipated operating conditions and compare these with the limits of the expansion joints. Never use a bellow where the conditions are more intense than they can withstand. This includes temperature, pressure, and vacuum.
Check the location.
Usually, the best place for an expansion joint would be close to the main anchor point. Following this, a pipe guide should also be installed to maintain the pipe alignment and stop undue displacement. This is only a very simple application to absorb expansion between fixed anchor points in a pipeline.
Check the expansion joint/bellow.
Take a look at the interior, exterior the flange faces for any signs of damage or cracks. The cover needs to be in top condition to prevent anything from penetrating the main carcass of the device.
The companion flanges that are to be connected to the expansion joint will also need to be checked along with the expansion joint flanges.
Check pipe alignment and support.
Piping should be aligned with no greater offset than 1/8”, and piping will need to be fully supported by hangers or anchors to ensure no weight is carried by the expansion joint.
For the installation process, follow the next steps:
Apply a lubricant before installation.
Your expansion joint could be coated with a graphite or glycerine solution to stop the joint sticking to the pipe flanges.
Insert expansion joints into the pipeline.
Take special care when pushing the joint into the application, as not to push the leading edge out of the groove. Never bolt it directly to another component without inserting a solid metal gasket.
Insert the bolts.
The bolts should be inserted via the arch side, so the heads are opposite to the arch, to make sure that the bolts do not impact the arch during compression.
Tighten the bolts.
Tighten each bolt gradually, alternating which one you are doing diagonally going around the flange. If this is not watertight after the first go, slightly tighten the nuts until it is fully sealed. You will not want any metal to metal contact with the rotating flange or pipe flange. Check this after a week and then have continuous checks periodically. The rubber may set after a period of compression, so this is very important.
Due to expansion joints needing periodic inspection, they should never be placed where they cannot be accessed for inspection. Expansion joints are often used within pipelines carrying hazardous material, such as liquids at elevated temperatures and pressures, so they must be operating smoothly.