What is insulating joint?

The Purpose of the isolation joint is to prevent detrimental electro-chemical interaction and improve the effectiveness of the cathodic protection system. Isolating joints are also used to ensure effective current distribution for cathodic protection system.

Insulating joints are improved products based on insulating flanges. They are an indispensable and important pressure component in the cathodic protection system of steel pipelines. It is widely used in the cathodic protection system of steel pipelines.

Monolithic insulated Joints are available in sizes ranging from 50 NB to 200 NB (2” thru 48”) and pressure ranging from ANSI 150 to ANSI 900.

Monolithic Isolation Joints are coated to prevent corrosion and are 100% tested hydrostatically, electrically and for weld performance. Monolithic Isolation Joints provide electrical sectioning and passive protection against corrosion, they are installed in inlet and outlet pipes, on meters, tanks, pumping station, etc.

Parameters of Insulating joints

• Design pressure:(BarG) 6 to1034.5
• Design temperature:(°C) Standard Application 0 to 90° - Special Application -173 to 180°C
• Rating:(ASME/ANSI #) Class 150 to 2500 "ANSI/ASA" - 3000 to 15000 "API"
• Ends:"BW" Butt Welded: - API 5L / B16.25 / B16.5 / MSS SP75
• Connection Pipe:15 to 3000mm / 1/2" to 120"
• Connection Pipe WT:7 to 152.4mm / 0.154" to 6"
• Joint Overall Length:150 to 12000 (over 3000 insulation joint + extension pipe)
• Installation:Above ground / underground / subsea
• Hydrostatic Test:5 Times the Design Pressure ( Or as per Customer Requirements )
• Dielectric Test:5 to 5 KV @ 1 minute AC 50÷60 Hz (Special 20 KV @ 1 minute AC 50÷60 Hz)
• Electric insulation Test:> 200 MΩ @ 1000 Volt DC ( Special > 100 GΩ @ 5000 Volt DC )

Manufacture Process of Insulating joints

Insulating joint manufactured by process of made forged body, welding, painting, assembly and testing of the finished item. The body material are from welded or seamless pipe, steel grade such as A106 GR.B, A53GR.B, API 5LGR.B, X42, X46, X52, X56, X60, X65, X70,ASTM A500/A500M, ASTM A795 etc.

It is completely factory assembled and hydro-statically tested to 1.5 times the working pressure before shipment. In addition, each joint is electrically tested to verify it’s insulating capability. No maintenance or parts replacement is required for the entire service life of the insulating joint.

Features of Insulating joints 

Monolithic joints that feature a pre-fabricated, non-separable, and bolt-less design to satisfy customers that require a single-piece construction for simplicity of installation, elimination of maintenance, and ease of final wrapping and coating after installation in the pipeline. Pressure fatigue, torsion and bending-proof testing of the design was carried out to provide a design that is physically stronger than the pipe to which it is attached.

Application of Insulating joints 

Pipeline insulating joints are used both for onshore and offshore projects. It is used worldwide for permanently controlling the flow of electrical currents or electrically isolating pipe sections in pipes and piping systems. Effective management of cathodic protection programs. applicable medium: suitable for oil, gas, water, chemical raw materials, and ore slurry.

Advantage of Insulating joints

Saving in the overall cost of corrosion system is just one of the benefits of using this kind of joint. Other benefits include protection against earthing currents at domestic and industrial premises, isolation of pipeline cathodic protection system, and to ensure that cathodic protection or stray currents do not cause increased corrosion.

Standard Reference

ASME B 31.3 - ASME B 31.4 - ASME B 31.8 - ASME VIII Div.I Appx. 2 - EN 10204 3.1, pressure ranging from ANSI 150 to ANSI 900

Installation Notice:

1. Within 50 meters of the insulation joint installation place, avoid dead holes to be welded;
2. After the insulated joint is connected to the pipeline, it is not allowed to lift the pipeline within 5 meters of the joint.
3. Pressure test needed with the insulated joint and the pipeline instrument.

Structure of Monolithic Insulating Joint

Monolithic Insulating Joint consists of the following parts: upper and lower pipes, sleeves, insulating parts, seals, and insulating coatings. Between the butting end faces of the upper and lower pipes of the insulating joint, an insulating piece and a sealing piece are clamped to form a double sealing structure with insulating properties. The sleeve adopts two forms of groove welding or direct welding with the upper pipe. The insulator and the upper and lower pipes are firmly enclosed to form a "sealed container", which not only guarantees a good insulation effect, but also greatly improves the insulation. The pressure-bearing capacity of the structure.

RFQ: 

How does a monolithic insulating joint work?

Materials placed within the monolithic isolation joint also work by attracting electrical charge and preventing corrosion. This is achieved by something called cathode protection - where the material in the joint becomes an anode, and the pipeline becomes a cathode. The anode protects the pipeline from corrosion.

What is an insulating flange?

insulating flange are the most widely used form of controlling losses due to corrosion. They can be used to control stray electric currents in piping at oil, gas, water, refinery and chemical plants and increase the effectiveness of cathodic protection systems and confine or eliminate electrolytic corrosion.

What’s the purpose of insulating joints?

Insulating joints (or isolating joints or isolation joints) provide electrical isolation and cathodic protection in pipeline, tanks and pumping station where petroleum, gas and water are carrier fluid. Insulating joints serve as a positive leak proof long lasting block against the flow of electrical current in all piping systems regardless of application.

What’s are the benefits of insulating joints?

Insulating joints (or isolating joints or isolation joints) protect the pipeline from corrosion thus reducing drastically maintenance efforts and the related costs.

Insulating Joints Photos View:

Insulating Joints Manufacture Process TIG+LSAW Welding:

Insulating Joints Measurement Before Assemble:

Insulating joints Assemble+ Welding after Assemble:

Insulating joints NDT Test after Welding:

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