How to select the right coupling
There are many types of couplings and flange adaptors that seem to overlap with each other application and installation. The couplings and flange adaptors can be divided into two main categories – dedicated and universal – which again can be divided into tensile and non-tensile types.
Dedicated couplings with tensile resistance
This type of coupling is normally equipped with grip segments placed in conjunction with the gasket unit. The grip segments compress around the pipe when the gasket compresses, providing full resistance against the pull in the pipe. Typically, the dedicated tensile couplings are the preferred choice when customers install new pipes in an open trench without using backfilling and want to pressure test the complete pipeline before covering it with soil.
AVK products in this category are combi-flanges series 05/60 for PE/PVC and 05/26 for ductile iron pipes, Supa Plus™ series 621 straight couplings, series 623 flange adaptors and series 624 end caps, as well as Repico® Grip couplings series 745/01 and series 745/03.
Dedicated couplings without tensile resistance
These couplings are the simple design and can only be used on specific pipe materials with a specific outside pipe diameter. The couplings do not allow for tolerances on the outside pipe diameter.
The limited application and the simple design will in most cases result in a low pricing.
AVK products in this category are combi-flanges series 05/62 for PVC, 05/66 for ductile iron, 05/21 for steel pipes and 05/C combi-flange sealing.
Universal couplings without tensile resistance
A universal coupling offers flexibility with regard to the choice of pipe material and thus also with regard to the outside diameter of the pipe. Typically, the outside tolerance of the pipe may vary from 20 to 40 mm depending on the size of the coupling. In most markets this type of coupling is the customer’s preferred choice in situations where pipes need to be repaired or replaced in small sections.
AVK products in this category are Supa® couplings series 601 straight couplings, series 602 step couplings and series 603 flange adaptors, as well as Repico® Slip couplings series 745/20 and series 745/28.
Universal couplings with tensile resistance
These couplings are the absolute top products within couplings. They offer both the flexibility needed with regard to the outside pipe diameter and they also withstand the pull in the pipe from the internal pressure and the mechanical pull from the installation.
AVK products in this category are Supa Maxi™ couplings with series 631 straight couplings, series 632 step couplings, series 633 flange adaptors, series 634 end caps and series 635 transition couplings.
