Insulating Flange Assembly

Nuseal Insulating flange assembly for CP system

The Nuseal insulated flange assembly, simplifies the process of corrosion control in Cathodic Protection. CP is a common and important practice by pipeline facility owners, which is beneficial in mitigating the corrosion of buried infrastructure.

If flange are not insulated could draw a great amount of current, which would rapidly decay anodes and thereby require a higher voltage. The idea is to evenly protect the pipeline and not use voltage or current that is too high and can damage the coating. Also, if a structure (such as a compressor) is hit by lightning, the insulator can prevent the current from damaging a rectifier. Insulating flange assembly is a pre-fabricated isolation flange assembly, meaning, the joints are fully assembled, tested at our factory and then shipped.

Nuseal insulating flange assembly for galvanic corrosion

To enable protection against this risk, there needs to be a means of electrical isolation at the tanker /shore interface. Large currents can flow in electrically conducting pipework and flexible hose systems between the tanker and shore. The sources of these currents are:

1. Cathodic protection of the jetty or the hull of the tanker, provided either by an impressed current system (Impressed Current Cathodic Protection - ICCP) or by sacrificial anodes.
2. Stray currents arising from galvanic potential differences between tanker and shore, or leakage effects from electrical power sources.

An all metal loading or discharge arm provides a very low resistance connection between tanker and shore and there are dangers of an incendive arc when the ensuing large current is suddenly interrupted during the connection. Similar arcs can occur with flexible hose strings containing metallic connections between the flanges of each length of hose.

Vessels transferring low flash point flammable liquids, at marine terminals, or during STS transfer operations, need to take precautions against potential sources of ignition. One source is the static charge caused in the cargo transfer system, which may discharge and cause a high voltage, low current spark.

As illustrated by us, you can see why we recommend Nuseal Insulating Flange Assembly.

Sizes available: up to 16" and above.
End connection - Flange connection to suit jetty manifolds
MOC: Carbon steel, Alloy steel and Stainless steel
Coating: Internal external coating as per client's requirement

ADVANTAGES

1. Cost effective when compared to monolithic joints.
2. Assembled joints eliminate the need for kits and also saves on-site labour.
3. Simplifies the installation process, as welding is similar to that of monolithic joints.
4. Controlled assembly and pre-testing eliminate the need for adjustments.
5. Mechanically designed, as per piping class.
6. Servicing and maintenance are simplified.
7. Bolt and stud size do not change, thus making joint strong.
8. Flange bolt holes have perfect alignment and close tolerance fit to the dielectric sleeves of 0.8 mm thickness.
9. Flange studs/nuts are manufactured using alloy steel of ASTM Designation A-193-52T Grade B-7/A-194 Class 2-H, or as required by the pipeline design. Precise machine steel washers are added to accommodate the outer diameter of insulating sleeves for better electrical isolation.
10. Precise assembly with accurate torqueing carried out in stages followed by the required hydro testing.
11. Tested for minimum resistance of 5 Moh ms.
12. Internal flange gap is sealed with epoxy resin to restrict deposition that gets carried away with media, for smooth flow.

TECHNICAL INFORMATION

NUSEAL Insulating flange assembly, is manufactured in all combinations of flanges, insulating gaskets and insulating sleeves and washers. In doing so, we cater to an array of needs - flange isolation to CP system in high temperature services, potable water services and hydrocarbon services, galvanic corrosion and terminal manifold isolation at jetty.

The material selection is selected as per media characteristics too.

Flange standards to select from: ASME/ANSI B16.5/BS1560 Section 3.1 (Class 150 to 1500), ASME /ANSI B 16.1/BS 1560 Section 3.2 (Class 125, 250), AS 2129- table A to T,AS4087 Class 14,16, 21,35, ISO 7005-1 PN 2010420, DIN 2501-Part 1 (PN 6to PN100), JIS B 221 0:PN5 to PN63 and AWWA standards.

Insulating gaskets materials to select from are: Nema LI 1-2001 G10 (applicable in potable water too)/G11/Fr4, Phenolic and Vermiculite for high temperature.

Insulating Sleeves to select from: Nema LI 1-2001 G 1 0/G11 / FR4, Phenolic, Maylar, Mica and Nomex. One-piece integrated sleeve and washer in Maylar are also available Insulating washers to select from: Nema LI 1-2001 G 10/G 11 /FR4, Phenolic, Maylar, Vermiculite and Mica.

MANUFACTURING RANGE

Nuseal Insulating flange assembly can be manufactured in the following sizes:
1. Line size:½" to 100"
2. Line thickness: 3mm to 50mm thickness
3. Pressure rating : ANSI 150# to 1500#, PN 5 to PN 420 or as per above stated flange standards.
4. End Connection: Butt weld, Socket weld, Flanged ends