Rectangular Expansion Joint. Arcflex rectangularmetal expansion joints are designed to absorb movements in all three directions i.e. axial, lateral and angular. The rectangular bellows are mostly designed for very low pressure applications such as ducts, exhaust systems, ventilation systems etc.

In addition to our core product range containing a wide selection of circular expansion joints,also provides rectangular expansion joints.

Many design options
We design and manufacture rectangular expansion joints with single and multi-convolution bellows. These units can be made with no size limitation since they can be supplied in sections for transport and reassembly on-site.
Rectangular expansion joints can be designed to accept a combination of axial and lateral movement. When significant lateral movement is to be absorbed, a twin-bellows arrangement is usually required. Alternative corner arrangements can be supplied including single and double mitre and when necessary with rounded corners. Frames and bellows are available in a wide range of materials, sizes and configurations to suit individual customer requirements. These expansion joints are invariably used as customised solutions to expansion problems in rectangular ducting; they are purpose-designed and manufactured to match the customer’s unique requirements.

Variety of materials
The bellows can be manufactured in a variety of materials (the same as for round expansion joints), including austenitic stainless steels (300 series), duplex, aluminium, titanium, and high-nickel alloys such as Inconel, Incoloy, Hastelloy and Monel.

Insulation of rectangular expansion joints
To withstand conditions that have a high internal temperature (e.g.1000°C) and low external temperature (e.g. 90°C), a special flow liner can be fitted (for example made from 1.4845). The liner is made with expansion gaps to enable it to expand at the operating temperature without generating unacceptable buckling at the hot face of the liner. As part of the installation, the void in the flow liner is filled with an insulation bolster comprising high-temperature insulating materials. This reduces the temperature across the insulation to provide a lower “skin” temperature, for example 90°C.