Compensator

What Is a Compensator?

A compensator, also known as an expansion joint, is a flexible pipeline element that absorbs changes in length and volume in piping systems. Pipes expand and contract with changes in temperature and pressure, and they are also exposed to vibration and external movement. Without a flexible element, these forces are transferred to pipe supports, pumps, vessels and other equipment, causing stress, leaks and damage.

Compensators are a cost-effective way to balance pipelines. They absorb thermal expansion, dampen vibration and noise, and provide tolerance against movement caused by settlement, impact or earthquakes.

Working Principle

All materials expand as their temperature rises and contract as it falls. A compensator contains a flexible section, such as a rubber body or a metal bellows, that deforms elastically as the pipeline moves. In this way, axial, lateral or angular movement is taken up by the compensator instead of being transmitted to the rest of the system, and the pipeline can operate continuously and safely.

Compensator Types

The right type depends on the medium, temperature, pressure, vibration level and the direction of movement to be absorbed.

• Rubber compensators: excellent vibration and noise damping for water and HVAC lines at moderate temperatures.
• Standard axial (metal bellows) expansion joints: absorb axial movement caused by thermal expansion in steam, hot water and process lines.
• PTFE expansion joints: for chemically aggressive media.
• Lateral expansion joints: absorb movement perpendicular to the pipe axis.
• Dilatation compensators: for expansion gaps and building joints, including earthquake protection.
• Special expansion joints: designed for specific operating conditions on request.

Connection Types

Depending on the operating pressure and temperature of the pipeline, compensators are supplied with flanged, threaded or welded (SW/BW) connections.

Application Areas

• Heating, cooling and HVAC installations
• High-temperature process and steam lines
• Pump and compressor connections, to isolate vibration
• Systems in earthquake zones
• Any pipeline where thermal expansion is expected

Advantages

• Protects pipes, supports and equipment from thermal stress
• Absorbs vibration and reduces noise transmission
• Tolerates settlement, impact and seismic movement
• Economical compared with the protection it provides

Selection Tips

To choose the correct compensator, define the medium, operating pressure and temperature, nominal diameter, connection type and the amount and direction of movement to be absorbed. Luna Flow Control can help you select, or custom-build, the compensator best suited to your installation.