Product Overview
Segmented Aluminum Bracelet Anodes provide localized galvanic cathodic protection for offshore subsea pipelines, risers, and cylindrical steel structures. Formed by two or more curved alloy shells bolted around the pipe circumference, these assemblies establish continuous electrical contact through integrated structural steel inserts. Alloyed via an Al-Zn-In system, they deliver high current capacity and negative open-circuit potential to mitigate marine corrosion in subsea immersion zones. Production utilizes direct-chill casting and precision machining to match specific pipe outer diameters (OD) and coating profiles.
Key Features
Electrochemical Performance: Delivers a nominal current capacity of 2,500 Ah/kg with a closed-circuit potential of -1,050 mV (vs. Ag/AgCl/seawater).
Precision Machining: Inner radius machined to target pipe OD (bare, 3LPE, or 3LPP), ensuring uniform annular spacing and eliminating localized current shielding.
Mechanical Lock System: Secured by high-strength heavy-duty tie bolts and recessed locking nuts, engineered to withstand pipeline reel-lay and S-lay mechanical stresses.
Low-Resistance Continuity: Continuous steel backing strips or dual-strap inserts welded directly into the aluminum matrix, maintaining minimal electrical resistance across joints.
Technical Specifications
|
Parameter |
Specification Standard |
|
Alloy Composition |
Al-Zn-In system (Conforms to DNV-RP-B401 / MIL-A-24779) |
|
Open Circuit Potential |
≤ -1,080 mV (vs. Ag/AgCl/seawater) |
|
Closed Circuit Potential |
-1,020 mV ~ -1,050 mV (vs. Ag/AgCl/seawater) |
|
Current Capacity |
2,500 - 2,700 Ah/kg |
|
Net Weight Tolerance |
±3% per individual segment |
|
Insert Material |
Structural carbon steel (Q235B / ASTM A36) |
|
Design Life Range |
10 - 30 years (governed by project CP design calculations) |
Materials & Available Options
Alloy Variations: Standard Al-Zn-In (Indium-activated for high performance in marine environments) and custom Al-Zn-Hg formulations upon project specification.
Insert Configurations: Continuous steel backing plates, flush-mounted straps, or extended tabs for specialized field welding requirements.
Dielectric Insulation: Optional internal Neoprene or high-density polyurethane (PU) isolation layers to prevent localized pipeline coating abrasion and macro-cell corrosion.
Hardware Grades: Stainless steel (Grade 316 or 2205 Duplex) tie bolts and locking nuts treated with anti-galling compound.
Applications
Subsea Pipelines: Offshore oil, gas, and water injection flowlines requiring distributed cathodic protection.
Platform Risers & J-Tubes: Vertical pipeline sections exposed to high-velocity tidal currents and variable splash zones.
Pipeline Crossings: Restricted clearance zones requiring clamp-on, low-profile sacrificial protection.
Marine Piles & Conductor Casings: Subsea structural steel members in offshore jackets and piers.
Customization Options
Engineering and manufacturing parameters adjust directly to project design sheets:
Diameter Range: Fabricated for pipe outer diameters from 4 inches to 48 inches, accounting for field joint cutbacks and multi-layer insulation thickness.
Weight & Dimensioning: Segment thickness, length, and arc angle modified to match exact net mass calculations derived from DNV-RP-B401 design software.
Insert Tailoring: Custom bolt-hole positioning, stud-welding anchor configurations, and specific backing steel thicknesses.
Quality Control & Manufacturing Capabilities
Production operations from raw ingot melting to final crating are governed by strict in-house inspection protocols:
Spectrochemical Analysis: Direct-reading optical emission spectrometers test every melt batch to verify strict trace element thresholds (e.g., Iron ≤ 0.09%, Copper ≤ 0.003%).
Electrochemical Coupons: Representative test coupons cast from production heats evaluated for potential output and current efficiency.
Dimensional Verification: Coordinate Measuring Machines (CMM) and custom radius templates inspect inner diameters, segment gaps, and bolt-hole alignments.
Traceability: Heat numbers and serial numbers stamped directly into the aluminum body and steel insert, mapped directly to the Mill Test Certificate (MTC).
Packaging & Shipping
Palletization: Segments strapped to heavy-duty fumigated wooden skids (ISPM 15 compliant) with anti-corrosion interleaving between metal layers.
Hardware Kits: Fasteners, bolts, nuts, and insulation pads packed in labeled waterproof containers matched to corresponding anode sets.
Documentation Handover: Shipments accompanied by packing lists, material safety data sheets (MSDS), and batch-specific MTCs.
Frequently Asked Questions
Q: How is electrical continuity ensured between the bracelet anode and the pipeline steel?
A: Steel core inserts are welded or mechanically clamped directly to the bare pipe or dedicated grounding tabs. DC electrical resistance across the assembly is tested prior to factory release.
Q: Are dielectric isolation pads required over 3LPE/3PP pipeline coatings?
A: Yes. Neoprene or high-density polyurethane pads are installed between the anode interior and the pipeline coating to distribute mechanical clamping loads and prevent coating indentation.
Q: Which international standards govern your aluminum alloy chemical compositions?
A: Compositions strictly adhere to DNV-RP-B401 and MIL-A-24779 specifications.
Q: How do you verify net and gross weight tolerances prior to dispatch?
A: Each production batch undergoes statistical weighing on calibrated digital platform scales, with individual segment masses recorded on inspection data sheets.
Q: What is the standard manufacturing lead time for custom-radius bracelet anodes?
A: Standard production takes 3 to 5 weeks, depending on mold availability for specific pipe outer diameters and third-party inspection schedules.
Q: Do you accommodate third-party inspection (TPI) prior to shipment?
A: Yes. Inspections by agencies such as DNV, Bureau Veritas (BV), Lloyd's Register (LR), or SGS are fully supported, with release notes provided alongside MTC documentation.
Request a Quote (RFQ)
Submit project parameters to receive a formal technical proposal and commercial quotation:
1.Pipeline Outer Diameter (OD) & Wall Thickness
2.Coating Type & Thickness (e.g., 3LPE, bare)
3.Required Net/Gross Weight per Anode or Design Life (Years)
4.Alloy Specification / Standard (e.g., DNV-RP-B401)
5.Quantity & Target Delivery Schedule
6.Required Third-Party Inspection (TPI) Agency
Contact our engineering sales team to submit your cathodic protection data sheets.
Hot Tags: segmented aluminum bracelet anode, China segmented aluminum bracelet anode