Insulating Gasket Kit

QS Gasket: Zhangzhou Insulating Gasket Kit

Insulating Gasket Kit built around phenol carrier with nitrile seals, sleeves and washers for ANSI B16.5 RF.

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One-Minute Overview

Flange isolation assembly built around a phenol carrier retainer for ANSI B16.5 RF.
Supplied complete with nitrile seals, sleeves and washers for electrical discontinuity at the joint.
Rated for 4 Inch, DN100 and 300LB service, sealing and isolating in one kit.
Exact bolt pattern, thickness and dimensions are confirmed per inquiry.

A flange isolation assembly does two jobs at once: it seals the joint and it breaks the metallic path that lets stray currents and galvanic corrosion move between connected pipe sections. This one is built around phenol carrier with nitrile seals, sleeves and washers for ANSI B16.5 RF at 300LB. Qishine supplies it where a dependable dielectric break matters as much as a leak-tight seal.

Name: Insulating Gasket Kit
Type: F
Gasket material: Phenol carrier with nitrile seal
Service: Natural gas
Complete with: Sleeves and washers
Size: 4 Inch, DN100
Pressure: 300LB
Standard: ANSI B16.5 RF
Note: Full dimensions and bolt pattern are confirmed per inquiry.

Start with the ANSI B16.5 RF geometry and the 300LB class, because they fix the gasket footprint and the bolt circle. Then match the retainer to the medium: phenol carrier for the listed service, with nitrile seals, sleeves and washers chosen so the insulating stack keeps its dielectric strength under bolt load. Confirm the gasket bore clears the pipe ID and that the 4 Inch, DN100 dimensions are confirmed per inquiry against the flange drawing before anything is cut.

On installation, clean both flange faces, set the retainer concentric with the bore and bring the bolts up in a star pattern so compression stays even. Insulating sleeves must run the full grip length and seat square under the washers; a short or cocked sleeve can crush and short the bolt to the flange. Recheck torque after the first heat-up, because gasket creep and thermal growth both relax the joint. Used this way, the kit supports cathodic protection by keeping protection current on the intended side of the joint.

FAQ

Q1. How does this kit break the electrical path across the flange?

The phenol carrier retainer seals the joint while nitrile seals, sleeves and washers keep every bolt from touching the flange metal. With the current path interrupted, cathodic protection current stays on the protected side and galvanic corrosion between dissimilar metals is held in check.

Q2. What should I check on the flange face before fitting the gasket?

Inspect the ANSI B16.5 RF surfaces for pitting, warping and old gasket debris, then verify the gasket bore clears the pipe. A clean, flat face lets the retainer compress evenly; a scored or dirty face concentrates bolt load and invites a leak under 300LB service.

Q3. How tight should the bolts be, and do the sleeves change the torque?

Tighten in a cross pattern to the value set by the flange and bolt grade, in several passes, so the retainer compresses evenly. Insulating sleeves and washers must seat square: a cocked sleeve can crack under load, so confirm the full stack-up and recheck torque after the first thermal cycle.

Q4. What's the minimum I can order?

Standard flange insulation gasket kits start at one set, and standard gaskets, studs, washers and sleeves start at one piece. Kits made to your drawing or for a non-standard bolt pattern are quoted individually, because the minimum really depends on the material and the tooling involved.

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