CSNRI Clock Spring

Description

CSNRI Clock Spring is the industry’s most trusted composite repair sleeve system engineered specifically for high-pressure transmission pipelines. Designed as a permanent structural repair, CSNRI Clock Spring restores damaged pipelines to beyond original strength without welding, cutting, or shutdown.

The system consists of a pretensioned and pre-cured unidirectional e-glass composite coil, combined with a high-modulus filler and high lap-shear strength methyl methacrylate adhesive. Proven to 8,000 psi burst pressure, with a design life exceeding 50 years, CSNRI Clock Spring has over 30 years of global installation history and is recognized by regulators as a permanent repair solution .

Each Clock Spring coil contains 8 structural layers, delivering a repair with a higher failure pressure than pristine pipe. It can restore full strength to pipelines with up to 80% wall loss, mechanical damage, dents, gouges, and mill defects.

Product Benefits

• Permanent Repair for Transmission Pipelines – Proven to 8,000 psi burst pressure
• 50-Year DOT-Accepted System – Long-term structural integrity
• Installs Without Shutdown – No disruption to operations
• No Hot Work Required – Eliminates welding risks
• No Heavy Lifting or Special Tools – Lightweight, wrap-around design
• One to Two Hour Backfill Time – Rapid return to service
• Enhances Long-Term Pipeline Safety
• Visible to In-Line Inspection (ILI) Tools – Marking band system
• Subsea & Underwater Capable
• Available High-Temperature System Option

Proven Performance & Validation

CSNRI Clock Spring is the most tested and documented composite repair solution ever developed. A 10-year R&D program established it as the pioneer for industry composite repair approvals .

A real-world validation study (page 2 of the technical document) demonstrated:

• Repaired pipe held 1.5x MAOP (1455 psi) for 5 minutes
• Ultimate failure occurred at 2180 psi, outside the repair zone
• After 25 years in service, tensile strength remained at 90,000 psi

This data confirms CSNRI Clock Spring as a true permanent composite repair system.

Technical Specifications

• Nominal Thickness (per layer): 0.065 in (1.6 mm)
• Complete 8-Layer System: 0.5 in (13 mm)
• Lap Shear Strength: >1,200 psi
• Compressive Strength: >12,500 psi
• Circumferential Tensile Strength: 68,000 psi
• Circumferential Tensile Modulus: 5,000,000 psi
• Max Operating Temperature: 201°F (94°C)
• Diameter Range: 4” to 56” kits available

Typical Applications

CSNRI Clock Spring is ideal for:

• High-pressure transmission pipelines
• Corrosion repair (external metal loss up to 80%)
• Dents and gouges
• Mechanical damage
• Manufacturing defects
• Bends and girth welds
• Process piping (oil, gas, chemicals, water, steam)
• Limited access large-diameter pipelines

Code Compliance & Industry Acceptance

CSNRI Clock Spring meets or conforms to:

• US DOT CFR 192 & 195
• CSA Z662
• ASME PCC-2 Article 401
• ISO 24817

These approvals make CSNRI Clock Spring a regulator-accepted permanent repair solution for transmission operators.