Expansion joints - from Nortesco

Purpose & Application:

Expansion joints are vital components in most industrial plants. They are installed as flexible connections in duct and pipe systems to prevent damage caused by variations in temperature, pressure or mechanical stress due to movement or vibration.

Application:

• Conventional power plants (oil, gas, coal-fired)
• Gas turbine and combined cycle systems
• Flue gas cleaning systems
• Diesel engine installations
• Petro-chemical plants
• Processing plants (steel works, cement works etc.)
• District heating systems
• Chemical plants
• Offshore installations

Please contact us to obtain further information or brochures on above products.

When selecting the right expansion joint for the application, a number of important factors must be considered (see Data Sheet/Inquiry Form): 

• operating conditions of the plant
• necessary chemical or thermal resistance levels
• requirements for pressure resistance, noise suppression etc.
• movements in the duct systems and other components

Operating conditions

If you consider the duct system of a power plant, you can see the many different demands that are to be met by the expansion joints. Rather simplified, the power plant may be subdivided into a "hot" and a "cold" area. On the hot side, the temperature load and the loading of the flue gas with fly ash is decisive. On the cold side, the expansion joint is, above all, affected by the formation of aggressive condensate, due to the temperature falling below the dew point.

Chemical or Thermal Resistance

The temperature as well as the medium has important influence on the choice of expansion joint type, the design, and the construction, and essentially the design is decided by the type of the medium.

The most important temperature values to consider are: operating temperature, excusion temperature, variations in temperature, design temperature and ambient temperature.

Special leakage requirements may be necessary, such as nekal tightness, flue gas tightness, defined leakage rate, drip-proof, leakproof, air or dust tightness.

Requirements for pressure resistance

The pressure has important influence on the choice of expansion joint type and the design. Fabric, rubber and metal expansion joints have different pressure capacities but pressure requirement should always be considered in relation to flexibility. Distinctions are made between positive pressure, negative pressure, variations of pressure (pulsations), pressure surges, and design or test pressure.

Movements

Axial compression and elongnation		Angular offset
Lateral offset		Torsion