How Does a Viking Johnson Coupling Work & Key Features
All Large Diameter Dedicated Viking Johnson couplings, stepped couplings, flange adaptors, MaxiFit, QuickFit, MegaFit, UltraGrip, FlexLock and AquaGrip (up to DN180) operate on the same basic compression principle.
How it Works
The Viking Johnson coupling comprises a centre sleeve (3) located between two end rings (1). Wedge-shaped elastomeric gaskets (2) separate the sleeve and end rings. As the captive ‘D’ head bolts (4) are tightened, the end rings are drawn together, compressing the gaskets between the end rings and the centre sleeve onto the pipe surface to form an effective, leak-proof seal.
Cutaway section of Viking Johnson straight coupling:
Cutaway section of Viking Johnson straight coupling:
The basic concept of the Viking Johnson coupling means that it can be used on plain-ended pipe, removing the need for costly and time-consuming pipe end preparation.
Angular Deflection
Viking Johnson couplings and flange adaptors can accommodate angular deflection, allowing for pipeline movement, ground settlement, or to provide for long radius curves without the necessity of incorporating purpose-made bends.
Flexible gasket and centre sleeve clearance allows angular movement:
Expansion & Contraction
Viking Johnson couplings and flange adaptors are also capable of absorbing expansion and contraction, which occurs in pipelines because of temperature fluctuations, without the need for special expansion joints.
This is achieved by deformation of the gaskets rather than by sliding on the pipe surface.
Gaskets deform to accommodate expansion and contraction:
