Supa Maxi™ universal tensile couplings

Supa Maxi™ sets a new standard

Supa Maxi™ comprises a complete range of large tolerance universal and tensile couplings according to EN 14525 for water, gas and wastewater applications. Straight couplings are available in DN50-800, flange adaptors are available in DN40-800, end caps in DN50-400, and step couplings and transition couplings are available in DN50-300. Furthermore, gate valves in DN80-300 for water and wastewater applications are part of the range. The patented SupaGrip™ sealing support system features a flexible bracket, and combined with the unique grip design, it provides superior tightness and tensile resistance on all pipe dimensions and materials.

See the complete Supa Maxi™ range here.

Flexible bracket with rigid metal backup

SupaGrip™ provides full support and backup of the gasket, even on minimum pipe size within the tolerance range and when used on oval pipes. The flexible bracket is designed to contract and follow the external pipe diameter. As a result, it serves as a solid backup for the gasket and enables full deflection.

When tightening the bolts, the bracket segments and bolts move inwards, securing that the gasket tightens around the pipe and that the grip segments grip into the pipe surface.

Tensile on all pipe materials

Optimum grip and tensile abilities on all pipe materials are secured by means of two different metal grip segments  gunmetal for PE/PVC/GRP pipes and hardened stainless steel for cast iron, ductile iron, steel, stainless steel and AC pipes. The grip segments are mounted with pins on the bracket segments to provide maximum durability. The high-quality materials safeguard that the sealing does not loose compression over time, and that the coupling stays tensile.

Couplings designed according to EN 14525

AVK Supa Maxi™ couplings are PN16 rated, designed and tested according to EN14525. They have a Kiwa certificate in compliance with Kiwa’s evaluation guideline BRL-K775 concerning EN 14525 requirements.

During the development phase of Supa Maxi™ couplings, AVK joined forces with Kiwa in the Netherlands and DTI in Denmark to define a valid test procedure. You can read about the test procedure here.

Reduce time spent on installation with Supa Maxi™ couplings

The couplings enable ±4° deflection on each side (in total 8°) up to a maximum pressure of PN16. The large insertion depth tolerances allow the pipe to be cut slightly angled. This gives a simple installation without need for precise adjustment. All couplings with a weight exceeding 10 kilos are designed with a lifting eye on the sleeve enabling easy and ergonomically safe handling.

Gate valves with Supa Maxi™ ends provide extra safety when repairing old pipes. With a built-in gate valve it is easy to shut-off the water in case of further repair or replacement of the pipeline at a later stage.

Video: See how to install Supa Maxi™ couplings

Optimised bolt design

The bolt design is optimised for fast and simple assembly. The number of bolts is kept to an absolute minimum, and they are all standard bolts enabling use of standard tools. The bolts and nuts are anti-friction coated to prevent galling. The bolts are tightened from the sleeve side to ease assembly when space in the trench is limited, and the threads are protected by the permanent protection cap. The nuts are encapsulated in the bracket and covered by a protection cap to ensure that they will not fall off when loosening the bolts. Re-tightening of bolts is not necessary due to the all metal SupaGrip™ sealing support system.

Permanent protection cap

During handling the centre piece of the protection cap covers the sharp grip segments and prevents dirt from settling inside the coupling. When the centre piece is removed the coupling is ready for installation.

Couplings in high quality materials

  • The couplings are designed with sleeves of ductile iron and brackets of cast steel with epoxy coating in compliance with DIN 3476 part 1 and EN 14901, GSK approved.
  • The gaskets of EPDM rubber are approved by NF and DVGW for drinking water applications and the gaskets of NBR rubber are approved by DVGW and Gastec. 
  • The bolts and washers are of stainless steel A2 as standard and optionally of A4. The nuts are of acid-resistant stainless steel A4. 
  • The grip segments are of RG5 bronze and hardened stainless steel, mounted with pins of polyamide. 
  • The permanent protection caps of recyclable PE are black for water and wastewater applications and yellow for gas applications.


Reconstruction of DN600 water transmission pipeline

In the Lake Balaton area in the Mid-West Hungary, one of the most important water supply pipelines was reconstructed with the use of Supa Maxi™ DN600 fittings.


Supa Maxi™ universal tensile couplings

Animation about features and installation of our universal tensile Supa Maxi™ couplings series 63X.


First Supa Maxi™ DN600 in Belgium

When a fracture occurred at the wastewater station in Gentbrugge, Aquafin contacted AVK Belgium for immediate delivery of an AVK Supa Maxi™ flange adaptor.


Supa Maxi™

How to install our universal tensile Supa Maxi™ couplings series 63X.

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Couplings and adaptors

Get to know our wide range of universal and dedicated couplings, flange adaptors and end caps designed for easy installation.