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As the manufacturer of the designs shown below, we have extensive calculation methods at our disposal to optimise the design for every application. Our modern manufacturing processes guarantee perfect operation, a long service life and a high level of safety.
Axial expansion joints are designed to compensate for axial movements. However, angular and lateral movements can also be absorbed by a suitable design.
Angular expansion joints are designed to absorb angular movements and are generally fitted with joints that absorb the axial reaction forces. Due to these tensions, however, they are not suitable as individual elements to compensate for combinations of movements. In pipeline construction, they are preferably used to form joint systems that can easily absorb large movements in any plane.
Lateral expansion joints are used to compensate for lateral movements (axial misalignment). They have braces that absorb axial reaction forces and are therefore not suitable for other types of movement. These expansion joints are available in both articulated and tie-rod versions.
All expansion joint types can be manufactured with the various bellows profiles.
The Rattay Group offers 4 different shaft profiles for expansion joint bellows, depending on the application. After selecting the most suitable type of shaft for the application, our engineering department designs the bellows. The best compromise between compressive strength and flexibility is sought, while always optimising material costs.
This is the most commonly used shaft type in the expansion joint bellows sector. This type of shaft is perfectly suited when flexibility requirements are paramount and the operating pressure is moderate.
The U-profile with reinforcement rings is an alternative to toroidal bellows. Bellows with a reinforced U-profile are particularly suitable for lateral and angular movements.
This is the ideal profile for very high pressure applications that require the absorption of axial movement, such as tubular heat exchangers. Its resistance results from the absence of bending stresses in the side walls of the bellows, which are generally the limiting factor for the conventional U-profile.
The use of special forged parts, which also serve as hydroforming tools, reinforcements and end pieces, is a more cost-effective solution than conventional reinforced expansion joints.
In addition, the low height of the shafts significantly reduces the pressure on the tube plates of the heat exchanger, especially compared to flanged and flooded bellows.
The Omega ZH bellow was specially developed by SFZ for the LNG (liquefied natural gas) market.
It is particularly suitable for the stringent requirements in shipping, especially in cryogenic temperatures, hogging, sagging, fatigue and pressure.
Tradition and family values such as loyalty and reliability have always played a major role at RATTAY.
