Meta Description (155 chars): Insulating flanges for pipeline cathodic protection systems. Electrical isolation with full pressure rating. Huilin Pipe – 15 years experience. Request a quote!
Product Overview
Huilin Pipe manufactures Insulating Flanges (Isolating Flanges) — specialized flange assemblies that provide electrical isolation in pipeline systems while maintaining full pressure integrity. These critical components enable effective cathodic protection for buried and submerged pipelines.
What is an Insulating Flange?
An Insulating Flange (also known as Isolating Flange or Dielectric Flange) is a specialized flange assembly designed to create an electrical barrier between two pipeline sections. This electrical isolation is essential for:
✅ Cathodic Protection Systems — Enables effective CP for buried/submerged pipelines✅ Stray Current Prevention — Blocks unwanted electrical current flow✅ Corrosion Control — Prevents galvanic corrosion between dissimilar metals✅ Safety Isolation — Isolates hazardous areas from electrical faults
Construction Details
Flange Bodies
Material: Carbon steel (A105, A350 LF2) or stainless steel (304/316L)
Type: Weld neck (WN), slip-on (SO), or blind flanges (BL)
Standard: ASME B16.5, EN1092-1, API 6A, or customer specification
Coating: Anti-corrosion coating (epoxy, FBE, or 3LPE)
Insulation Rings (Gaskets)
Material Options:
G10 (Fiberglass Epoxy) — Most common, excellent dielectric properties
Phenolic Resin — High mechanical strength
PTFE (Teflon) — High temperature and chemical resistance
Nylon — Cost-effective for general applications
Function: Electrical isolation between flange faces
Temperature Range: -196°C to 260°C (depending on material)
Dielectric Strength: >15 kV/mm
Insulated Fasteners
Bolts: Coated with insulation sleeves (phenolic or PTFE)
Nuts: Insulated washers under nut faces
Material: Same grade as standard bolts with insulation coating
Purpose: Prevent electrical contact through bolt holes
Sealing Gaskets
Type: Spiral wound gaskets or ring joint gaskets
Material: Stainless steel with graphite or PTFE filling
Function: Pressure sealing while maintaining electrical isolation
Technical Specifications
Parameter Specification
Product Insulating Flange / Isolating Flange
Flange Standard ASME B16.5, EN1092-1, API 6A
Pressure Classes Class 150, 300, 600, 900, 1500, 2500
Size Range 1/2″ to 48″ NPS (DN15 to DN1200)
Flange Type Weld Neck (WN), Slip-On (SO), Blind (BL)
Insulation Material G10, Phenolic, PTFE, Nylon, or custom
Insulation Resistance >1000 Ω·m² (per NACE SP0286)
Dielectric Strength >15 kV/mm
Temperature Range -196°C to 260°C (material dependent)
Surface Coating Epoxy, FBE, 3LPE, or customer specification
Testing Electrical resistance test, hydrostatic test, PMI.
