Rogue vibrations? A piping expansion joint can help

Are you experiencing issues with a pump that keeps failing? There are many reasons why a pump could be costing you money even when it’s properly sized, installed and aligned. Sometimes, it has nothing to do with the pump at all, but rogue vibrations coming from other machinery connected to the pump, or protecting the pump, are causing the problem. The often overlooked yet crucial component of the piping system – the piping expansion joint – could be the answer you’re looking for.

What is a piping expansion joint?

In piping systems, vibrations can travel down the pipes connected to other equipment. Without a well-placed and well-designed expansion joint, parts such as pump nozzles, valves and anchors could face excessive loading and vibrations. An expansion joint can be installed to help absorb such shock and vibration, reduce noise, and relieve stress on the anchor. It can even help with poor alignment.

Some expansion joints counterbalance thermal expansion, especially for high-temperature applications that can damage pipes and reduce their operating life. The expansion joint’s name comes from the fact that it enables the pipe to move in several ways, whether to compress or expand. In some cases, expansion joints are called compensation joints, which is more accurate given the fact that they usually compress to compensate for thermal and mechanical vibrations and/or movements in piping systems.

Some of the ways in which a piping expansion or compensation joint can move include axial extension/elongation, axial compression, lateral/transverse or angular (see Figure 1 below).

piping expansion joint


Figure 1: Axial extension and compression (in cm or inches), lateral or parallel movements (in cm or inches), and angular movements (in degrees), courtesy of Pumps and Systems.

Piping expansion joint materials

Piping expansion joints are either metallic or non-metallic to suit several applications.

Metallic: Expansion joints made from metal can also be used for high-temperature applications where pipes experience thermal expansion. When the temperature rises, the expansion joint compresses in response, which takes the strain off the anchor and pipe. However, metallic expansion joints often have a restricted life cycle. It’s important to know how many cycles a joint can adapt to the predicted movement to prevent metal fractures caused by fatigue.

Non-metallic: Non-metallic expansion joints such as those made from synthetic or natural rubber or other polymers are considered superior to metallic expansion joints. These consist of layers that contribute to the overall strength of the joint while maintaining flexibility. They are rarely affected by issues such as material fatigue, and have lower spring rates, which helps lower pipe and anchor loads for pipes made from PVC.

Non-metallic joints are often used for piping systems that experience thermal expansion. The materials used (such as rubber) help absorb shock and vibrations, whether from the pump, other equipment, or noise of transmission. They can handle more high-pressure applications, axial compression and lateral offset movement than metallic joints. They are also more suited for applications that process acids, solvents, and oils.

Another option for the vibration or misalignment issues that affect pump performance are braided stainless hoses with metallic or non-metallic liners. A braided hose is a type of flexible connector that can replace piping expansion joints for high pressure and temperature applications. They reduce load on pump nozzles by providing both lateral and angular movement.

As every part of the pump and pipe system is connected, a reliable piping system is crucial for pump performance. It keeps the pipes in good working condition, but also increases the lifespan of attached equipment, which reduces downtime and improves efficiencies over time.

If you’d like to know what type of piping expansion joint to use for your piping system, give us a call on 1-800-367-4180 (toll-free). We have experts on hand to help you choose, install, maintain, and monitor a variety of equipment. And to answer questions about things you’ve previously tried gone wrong.