Grooved Couplings
Grooved Couplings are a type of pipe fittings for quick connection of pipes by means of mechanical clamps and rubber seals, where an annular groove is machined at the pipe end and sealed by means of an overmolded clamp and elastomer sealing ring, forming a weld-less, rigid or flexible connection.The core feature of Grooved Couplings is that they are machined with an annular groove at the end of the pipe and sealed by means of an overmolded clamp and elastomer sealing ring. The core feature of Grooved Couplings is the machining of an annular groove at the pipe end and sealing by means of an overmolded clamp and elastic seal. It is suitable for fire protection, industrial and building piping systems and supports high-pressure, high-flow scenarios, allowing for quick installation and maintenance.
Rigid grooved coupling
Flexible grooved coupling
Plain end HDPE coupling
Grooved Couplings Specifications
Standard: ASME B16.11, ISO 7-1
Finish: Galvanized, Orange/Red Enamel
Nominal Diameter: DN15 (1/2“) to DN600 (24”)
Outside diameter tolerance: ±0.7mm
Groove depth: 1.52mm (0.06“) to 3.81mm (0.15”)
Approvals: UL/FM
EPDM Rubber: Temperature range -40℃ to 120
Galvanized layer thickness: ≥60μm
Material: carbon steel, cast iron, stainless steel.
The specification of Grooved Couplings requires a combination of nominal diameters, pressure ratings, material properties and standard certifications, with groove size tolerances (e.g., ±0.7mm) and pressure testing (1.5 times the working pressure) as key quality control points. Specific applications need to be based on system requirements to select the appropriate material and certification type.
Grooved Couplings Process
- Material Selection and Pretreatment
Cut pipe to design length and remove surface burrs and oxidized layer. - Groove machining (core process)
Machining of annular grooves at the end of the pipe with a tolerance of ±0.3mm in width and 1.5-3.8mm in depth. Adopt CNC machine to ensure the concentricity between groove and pipe outer diameter. Galvanized or sprayed with epoxy resin coating (red marking for fire fighting system). - Seal and clamp assembly
Embed the EPDM or NBR rubber ring into the groove, make sure there is no twist or offset. Select the sealing material according to the type of medium. The wrap-around clamp is locked by two bolts that apply a uniform torque. The clamp material should be matched to the pipe. - Performance testing and quality control
Hydraulic pressure test is 1.5 times the working pressure (e.g. 2.5MPa system should be pressurized 3.75MPa for 5 minutes). Air tightness test using soapy water to detect leakage points. Check the width and depth of the groove and the fit of the clamp to the pipe.
Grooved Couplings Advantage
Good space adaptability
Compact design: the outer contour of the grooved connection system is only 1/3 of the flange connection, which is suitable for narrow spaces such as ship’s cabins and building mezzanines. Allow pipe axial deflection angle ≤5°.
High installation efficiency
No need to weld or galvanize, quick connection is achieved through standard clamps and pre-installed seals, construction efficiency is more than 50% higher than traditional flange connection. The center is automatically corrected when the clamp wraps around the pipe, reducing the time for manual calibration, especially suitable for large-diameter pipes over DN300.
Ease of maintenance
The clamp can be disassembled by loosening the bolt, which makes it easy to repair or replace the parts, and avoids pipe damage caused by cutting or welding. Support different materials (such as carbon steel and stainless steel) pipe mixing, to adapt to the needs of system modification.
Reliable sealing performance
EPDM/NBR rubber ring and clamp compression to form a double sealing interface, can withstand up to 42MPa (Class 6000). The rigid constraint of the clamp can inhibit seal failure caused by pipe vibration, which is suitable for high-frequency vibration scenarios such as marine power systems.