In addition to our core product range containing a wide selection of Circular Expansion Joints, Belman also provides Rectangular Expansion Joints.

Many design options
Belman 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.

Design range and scope of supply within Rectangular Expansion Joints

Rectangular expansion joints are customised solutions and are available in all dimensions, all sizes and all materials.

Large dimensions
If the Rectangular Expansion Joints are large, they can be delivered in sections to ease transit and installation. The Rectangular Expansion Joints can be supplied in segments of 2 or 4-sections with butt joints in the frames on the long sides of the unit. On installation the sections of the bellows and flow liner are fitted and welded into position by the installer. The Rectangular Expansion Joints are fitted with shipping bars temporarily welded to the flange edges to protect the Rectangular Expansion Joints, preventing damage during transit and assist with its handling into the final position at the jobsite.



Oval expansion joint
Rectangular expansion bellows
Rectangular expansion bellows
Rectagular bellow
Other Shapes


The shape of the pipe system and/or the shape of the counter flanges/mating flanges specifies the form of the Expansion Joint. Belman designs and manufactures the Oval Expansion Joints in all sizes, all materials and all designs.
Other Shapes


The shape of the pipe system and/or the shape of the counter flanges/mating flanges specifies the form of the Expansion Joint.
Belman designs and manufactures the Polygon Expansion Joints in all sizes, all materials and all designs.




Rectangular expansion joint 3D illustration

Variety of materials
The bellows can be manufactured in a variety of materials (the same as for Circular 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.


Additional options for Rectangular Expansion Joints

  • The intermediate pipe and the bellows can be supplied as one single piece
  • Loose flanges
  • Single mitre corner (90 degree corners) with the bellows being welded together in the corners


Belman is known for high quality products and therefore our quality control is a fundamental part of our business. All processes during production designed by the Belman quality engineers, is strictly follow and implement according our procedures and instructions and carefully inspected by Belman quality inspectors. All checks and inspections are done according to the strict prevailing Belman quality control procedures which is part of the Belman ISO 9001 quality management system approved by DNV.


ITP & Test
Inspection test Plan generated by the quality management system makes sure that each step of manufacturing has the appropriate inspection points such as Hold and Witness points.

Based on manufacturing code, project specification, application, media, and eventual ship classification rules Belman performs a large variety of quality tests including destructive, non-destructive testing and proof testing. All tests can be witnessed by the 3rd part based on the customer and classification requirements.

  • Destructive test: such as life cycle test and burst test to validate the design, i.e., vessels and offshore platforms
  • Non-destructive test such as Visual testing, dye penetrant test, Radiography examination, Magnetic testing, ultrasonic testing, hardness testing and PMI for all applications
  • Proof tests: leak test with air, leak test with helium and former gas, hydrostatic pressure test for all application



This enable us to find you the optimum solution to your piping system.