Variations and optional devices for rubber expansion joints - Split metal retaining rings | Macoga

MACOGA Split Metal Retaining Rings – Divided Metal Retaining Rings

Split metal retaining rings are optional metallic components for MACOGA elastomeric expansion joints. They are installed directly on the rear side of the elastomeric flanges and function as mechanical retaining rings during flange bolting, distributing clamping forces.

Functional Role

The retaining ring transfers bolt tightening force over a larger area of the elastomeric flange. This is relevant for full-face elastomeric expansion joints, especially in large diameters, custom drilling patterns, or applications requiring controlled pressure distribution on the sealing surface.

These rings do not provide pressure thrust restraint. Axial pressure loads must be absorbed by tie rods, hinged/gimbal assemblies, or adequate pipe anchoring, depending on the expansion joint type.

Typical Use Cases

• Custom elastomeric expansion joints with non-standard flange drilling.
• Large nominal diameters (DN).
• Installations requiring a removable metallic element behind the flange.
• Retrofits where access or geometry favors a split construction.
• Applications with frequent flange bolt retightening or maintenance.

Flange and Sealing Interface

The elastomeric face of the expansion joint seals directly against the pipe flange. No additional gasket is used between the elastomer and the metal flange unless specified in the application design. Pipe flanges must be flat, clean, burr-free, and with aligned bolt holes to ensure proper sealing.

Installation

Bolting is performed in a cross-pattern using a torque wrench, in stages, to achieve uniform compression of the elastomeric flange. For full-face MAC-F series, indicative tightening torques range from 40–68 Nm (DN25–50) up to 540–680 Nm (DN1500–1800).

FAQ

Do pressure or temperature limits change?
No. Limits are determined by the base expansion joint, elastomer type, DN, flange drilling, and service conditions.

Are actuators included?
No. These are passive mechanical flange retaining components.