كل ما تحتاج معرفته عن وصلات التفكيك وأهميتها - Everything you need to know about dismantling joints and their importance

Everything you need to know about dismantling joints and their importance

Dismantling joints are an essential component in the pipeline. When it becomes necessary to repair or replace essential elements in the pipeline, such as valves, water meters, flow meters and more. A gap needs to be created between the flange of these components and the pipeline. Then a dismantling joint is needed, as it is a unique product specially designed to facilitate the creation of this gap. This gap is created by the length of the telescopic dismantling joint.

Dismantling joint components

A dismantling joint consists of one flange tap and one flange adapter. When the flange tap moves towards the flange adapter, the length of the flange tap enters the flange adapter, and then the length of the dismantling joint becomes shorter. When the flange tap moves in the opposite direction to the flange adapter, the length of the flange tap exits the flange adapter, and the length of the dismantling joint becomes longer.

Special cases where dismantling joints should be used

  • For neutral fluids such as water, oil or gas at room temperature, ordinary FBE coating is suitable. For corrosive materials or high temperatures, special surface treatments are needed.
  • For seawater, the inner part can be lined with ebonite and the outer part should be coated with corrosion-resistant paint or epoxy glass chip coating inside and outside.
  • For highly acidic liquids, corrosion-resistant nylon 11 is the best choice. For liquids above 100℃, high temperature resistant epoxy powder should be used.
  • For pipelines rich in impurities, corrosion-resistant polyurethane inner lining should be used.
  • If the working pressure rating of your pipeline is ≤ 25 bar, the wrought iron dismantling joint is the best choice due to its wide application, corrosion resistance and competitive price.
  • However, if the working pressure rating is ≥ 40 bar, you need to choose a steel dismantling joint to withstand high pressure. The steel material can be carbon steel, stainless steel or other alloy steel.

Dismantling joints used worldwide

In North American countries such as the United States, Canada and Mexico, AWWA209 standard dismantling joints are used. In Australia, New Zealand and Fiji, AS/NZS2280 standard dismantling joints are used. The rest of the countries use EN545 standard dismantling joints. Some new projects in Saudi Arabia have also started using American standard dismantling joints recently.

Production Steps of Dismantling Joints

Material Inspection

A furnace front analyzer is employed to monitor the chemical composition, and simultaneously conducts chemical composition, mechanical properties and pelletization rate tests on a ladle of molten iron at both the beginning and end of the furnace. This ensures that the quality of the molten iron meets the required standards.

Casting

The previous coal-fired furnace has been replaced by an electric furnace to melt the molten iron, ensuring that our production meets environmental requirements.

Casting Inspection

After casting, we need to inspect the casting to see if there are any defects in the casting. For those with defects in the casting, the engineer will judge whether the casting should be discarded or can be repaired.

Polishing and sand blasting

We need to grind the surface of the disassembled joint body to remove the excess parts, so that the casting meets the dimensional requirements of the product. The surface becomes smooth. Then the casting needs to be shot blasted before operation to remove dust and impurities from the surface, please note that sand blasting is required after operation to remove rust from the casting surface, dust, poor surface adhesion due to grinding, etc., in preparation for FBE coating.

Dimensional inspection

After operation, dimensional inspection is necessary to ensure that all dimensions are correct.

FBE coating

FBE coating, nylon coating or other customer-specific coatings are used to disassemble the joint surface.

Inspection of FBE coating

FBE coating inspection includes coating appearance inspection, color difference inspection, thickness inspection, powder adhesion inspection, coating performance inspection, etc.

Assembly

The gasket, bolts and nuts are assembled. We use special fixtures to ensure that the length of the bolts during installation is as appropriate and consistent as possible, allowing for direct installation without the need for secondary adjustments.

Pressure, visual inspection, etc.

The test pressure should be 1.5 times the working pressure with a holding time of 30 seconds. Video and pressure test report are available.

Usage of Dismantling Joints

Dismantling joints can be used to connect pipes of different materials, such as DI pipe, steel pipe, HDPE pipe, GRP pipe, etc., as long as the flange at the end of the pipe can be connected to the flange at the end of the dismantling joint, ensuring a tight seal between the two flanges.

But sometimes we need to connect the dismantling joint to valves or other pipe tools that have unshared flanges. Then special length bolts must be assembled to be sufficient to connect the flange between the flanges of the dismantling joint and the flanges of other parts.

Video explaining the importance of dismantling joints

Dismantling joint installation steps

Dismantling joints require several precise steps to ensure their optimal performance within the piping system. First, it is necessary that the pipes are precisely aligned to accommodate the dismantling joint accurately. This process usually involves careful measurement and marking of the specified integration point of the joint. The dismantling joint is then positioned accordingly, with adjustments made to its length as necessary to ensure a precise fit between the pipe sections. The joint is then securely secured with bolts or other suitable connectors, ensuring stability and alignment with the adjacent pipes. Finally, pressure tests are performed to verify proper installation and ensure that the joint is leak-proof and capable of meeting operating requirements without compromising the integrity of the system.

Metals used in dismantling joints

Dismantling joints are typically manufactured from strong and durable materials to withstand the high stress conditions that works in. The most commonly used metals include stainless steel, wrought iron, and carbon steel. Stainless steel is preferred for its superior corrosion resistance, making it ideal for applications involving water or corrosive materials. Wrought iron provides the necessary strength and flexibility, ensuring reliable performance under varying levels of stress. Carbon steel is often chosen for its high tensile strength and cost-effectiveness, making it suitable for a wide range of industrial applications where both durability and budget considerations are paramount.

Advantages of Dismantling Fittings

Dismantling fittings offer several distinct advantages, especially in systems that require frequent maintenance or adjustments. One of the most important benefits is their ability to provide flexibility in the pipeline, allowing for axial movement and easy disassembly and reassembly. This reduces downtime during maintenance and leads to cost savings. Another advantage is their ability to absorb stress and mitigate the effects of thermal expansion, enhancing the longevity and reliability of the piping system. Furthermore, their robust design supports heavy loads and high-pressure applications, making them invaluable in harsh industrial environments.

Industrial Applications of Dismantling Joints

Dismantling joints are widely used in many industries due to their flexibility and durability. They are commonly used in water and wastewater treatment facilities. Where the ability to easily dismantle and maintain piping systems is critical. Air conditioning plants also use dismantling joints to manage complex piping networks and ensure operational efficiency.

Read more about: What is a dismantling joint and what are its uses.


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