Galvanic couple is a phenomenon that occurs when two different metals, in contact and exposed to an electrolyte, generate an electric current that can accelerate the corrosion process. This phenomenon is common in piping systems and flanged joints, where different metal alloys can interact electrically, causing damage to the facilities and affecting their integrity. Proper electrical insulation is essential to avoid these problems and ensure the longevity of industrial equipment. In this context, the electrical insulation kit and the monolithic joint are effective solutions to prevent galvanic torque, but with different characteristics that make them more suitable for different applications.
The challenge of the galvanic pair in industrial systems
In industrial installations, especially those involving metal piping systems and flanges, galvanic torque can be a critical issue. When different metals are used in direct contact, such as stainless steel and carbon steel, an electrical current can be generated through the electrolyte (e.g. water or moisture) which accelerates corrosion in less noble metals. This can lead to premature failure, leaks, and the need for costly maintenance.
Electrical insulation becomes an essential tool to avoid this phenomenon, effectively separating different metals and preventing the flow of current between them.
Comparison: Electrical insulation kit vs. Monolithic joint in isolation and prevention of galvanic torque
| Feature | Electrical Insulation Kit | Monolithic Joint |
| Description | They are sets of elements designed to electrically insulate flanged joints, preventing corrosion due to galvanic torque and functioning as a static sealing element. | They are integral components designed to interrupt electrical conduction in piping systems. They are constructed as a single block that is welded directly to the pipe, eliminating the need for additional flanges. |
| Composition | They include packaging materials such as Flexisoft plus (mixture of aramid and mineral fibers with NBR rubber), Flexifenol (phenolic resin), Flexiagra (G-10) and Defender (combination of 316L stainless steel and G10 faces). In addition, they contain bushings and insulating washers made of G-10 and metal washers made of galvanized ASTM F436 material. | Made of G-10 composite materials, reinforced with epoxy resin. They are equipped with spring-loaded PTFE energized seals in AISI 316L and coated internally and externally with insulating epoxy paint to prevent corrosion. |
| Applications | Used in piping systems in the oil and gas industry, especially in applications where it is required to interrupt the flow of electrical current and protect against corrosion. | Applied to flanged joints of piping systems in various industries, including oil, gas, water and chemical plants, to prevent corrosion and facilitate cathodic protection. |
| Advantages | 1. Effective prevention of galvanic corrosion between flanges. 2. They facilitate the implementation of cathodic protection systems. 3. Availability in various sizes and configurations to adapt to different types of flanges. |
1. Monolithic manufacturing that eliminates leak risks (no accessories required for assembly). 2. They do not require maintenance during their useful life. 3. Simple installation without the need for additional cable ties. 4. Suitable for buried environments without maintenance concerns. |
| Installation | They require the installation of flanges and the incorporation of kit components into flanged joints, which can increase installation time compared to monolithic joints. | They are welded directly to the pipe, eliminating the need for flanges and reducing field installation time. |
| Chemical Resistance | Chemical resistance depends on the specific materials used in each component of the kit, such as phenolic resins, G-10 or aramid fibers. | They offer high resistance to various chemicals, especially since they are made of G-10 material. |
| Durability | Durability varies depending on the materials used and operating conditions, requiring periodic inspections to ensure its integrity, and it is also recommended to change it during each maintenance. | Designed for a long useful life without the need for maintenance, thanks to its robust construction and resistant materials. |
| Maintenance | They may require periodic maintenance to verify the condition of the components and ensure their effectiveness in preventing corrosion and electrical insulation. | They do not require maintenance during their life cycle, offering a low maintenance solution. |
The electrical isolation kit is an efficient and economical solution to prevent galvanic torque in industrial systems. It consists of several components specifically designed to electrically isolate flanged joints and avoid direct contact between metals of different nature. The main elements of an insulation kit include:
- Packing: Main component that generates electrical insulation between the flanges. This gasket, when deformed by the appropriate torque, also provides static sealing at the flanged joint.
- Insulating bushing: Tubes made of high-resistance G10 material that allow electrical insulation between bolts and flanges.
- Insulating washer: Made of phenol or G10, these washers generate electrical insulation between the metal washers and the flanges.
- Metal washer: Made of galvanized carbon steel, these washers ensure that the tightening force is distributed evenly on the surface, reducing friction.
On the other hand, the monolithic joint with its integrated construction and without the need for additional flanges, offers a solution with lower maintenance, greater durability, but higher cost, ideal for systems buried pipes and environments where access for maintenance is limited.
Which solution is best to avoid galvanic torque?
Both solutions, the Electrical Insulation Kit and the Monolithic Joint, offer significant advantages in the prevention of galvanic corrosion in industrial piping systems, each with characteristics which make them suitable for different applications and environments. Ultimately, both options meet the primary objective of avoiding galvanic torque, prolonging the life of piping systems and reducing the risks of corrosion and premature failure.
At Flexilatina, we offer advanced Dinaseal electrical insulation solutions with products designed and manufactured to the highest quality standards. Our products guarantee cathodic protection, galvanic torque prevention and exceptional performance, adapting to the specific needs of each industrial application.