Home - News - Industry News - Learn More About Dismantling Joint: Functions, Materials, and Application Fields
August 07, 2025
Dismantling joints, often referred to as demolition joints, are commonly used connecting fittings in pipeline systems. They facilitate the easy installation, removal, and maintenance of various flanged equipment and pipeline components. The design of these joints addresses the connection challenges that arise during the installation, maintenance, and modification of pipeline systems. This significantly enhances work efficiency and reduces labor intensity.
A dismantling joint usually consists of two flanged components and several tie rods. When connecting pipelines, the two flange components are pulled tight by the tie rods, causing the middle sealing gasket to be compressed and deformed, thereby forming a tight, sealed connection. Its unique feature is that when it is necessary to dismantle or reassemble equipment in the pipeline, it is only necessary to loosen the tie rods, and the two flange components can be separated by a certain distance along the axial direction, usually about ±25mm, providing sufficient space for taking out or installing the equipment without removing the entire pipeline system.
This structural design enables the pipeline system to maintain or replace specific equipment without interrupting most of the pipeline, greatly reducing maintenance time and costs. For example, when a faulty valve needs to be replaced in an urban water supply pipeline, using a dismantling joint allows maintenance personnel to quickly open the joint, remove the old valve, and install a new one without large-scale excavation and removal of a large number of pipelines.
Convenient Installation and Maintenance: The tightening and loosening of the tie rods can be done easily with standard wrenches and torque wrenches. Compared to traditional full flange connections, the number of tie rods is fewer than that of flange bolt holes. During maintenance, the target equipment can be easily dismantled, significantly reducing downtime.
Excellent Sealing Performance: The sealing gasket within the joint delivers a reliable sealing effect when tightened with the tie rods, preventing leaks of liquids or gases within the pipeline. Even in high-pressure environments, a stable sealing state is maintained to meet various operational requirements.
Strong Corrosion Resistance: The primary materials used are mostly ductile iron, GG-25 cast iron, or stainless steel, all of which exhibit excellent corrosion resistance. They can withstand harsh environments, including acid-base corrosion in sewage pipelines and chemical erosion in chemical pipelines.
Variety of Sizes and Pressure Ratings: The product specifications include a wide range of nominal diameters, from DN40 up to DN2000, accommodating various pipeline system sizes. Additionally, multiple pressure ratings are available to suit the connection requirements for low-pressure, medium-pressure, and high-pressure pipelines.
Wide Range of Applicable Standards: The manufacturing process complies with several international standards, including ISO, UNE, DIN, NF, BS, and AWWA.
Municipal Engineering:
Water Supply and Sewage Treatment: Used for connecting pumps, valves, flow meters, and other equipment in urban water supply pipelines, as well as the installation and maintenance of various pipeline equipment in sewage treatment plants. During the emergency repair of water supply pipelines, it can quickly replace faulty components to ensure the stability of the urban water supply.
Rainwater Drainage: In urban rainwater pipe networks, it is convenient to inspect and clean rainwater collection ports and pipeline connections to ensure smooth drainage during the rainy season.
Industrial Field:
Chemical Industry: In pipeline systems transporting various corrosive chemicals, the use of corrosion-resistant dismantling joints can meet the needs of frequent maintenance and equipment replacement, while ensuring the sealing performance and safety of the pipeline.
Oil and Natural Gas: In oil exploitation, transportation, and natural gas transmission pipelines, it is used to connect pumps, valves, filters, and other equipment, adapting to special working conditions such as high pressure, flammability, and explosion hazard.
Power Industry: In pipelines such as circulating water systems and chemical water treatment systems of power plants, dismantling joints facilitates the installation, commissioning, and daily maintenance of equipment, improving the reliability of power plant operation.
Shipbuilding and Marine Engineering: The water supply and drainage, fuel oil, ballast water, and other pipeline systems of ships, as well as various pipeline connections of offshore platforms, require dismantling joints to have good seawater corrosion resistance and convenient installation and maintenance characteristics to adapt to the harsh working environment at sea and limited maintenance space.
Main Materials:
Ductile Iron: It has high strength and good toughness, strong pressure resistance, and is suitable for water supply, drainage, fire protection, and other pipeline systems with high strength requirements.
GG-25 Cast Iron: It has a relatively low cost, certain corrosion resistance, and mechanical properties, and is often used in general industrial pipelines and water supply and drainage pipelines of civil buildings.
Stainless Steel: Such as 304 and 316 stainless steel, which have excellent corrosion resistance, and are especially suitable for pipelines transporting corrosive media, as well as pipelines in the food and pharmaceutical industries with high hygiene requirements.
Sealing Gasket Materials:
EPDM (Ethylene Propylene Diene Monomer): It has good weather resistance, water resistance, and chemical stability, can maintain elasticity in a wide temperature range of -10℃ to 80℃, and is suitable for sealing drinking water, hot water, cold water, and general gas transmission pipelines.
NBR (Nitrile Butadiene Rubber): It has excellent resistance to oils, aliphatic hydrocarbons, and other media, and is often used for sealing pipelines transporting oil-containing media such as fuel oil and lubricating oil.
Tie Rod and Fastener Materials:
Carbon Steel: After undergoing surface treatments like galvanizing, carbon steel exhibits some rust resistance. It is low-cost and is commonly used for pipeline connections in general environments.
Stainless Steel: In highly corrosive environments, using stainless steel tie rods and fasteners ensures that the joints maintain their disassembly and connection performance over long periods without being compromised by rust.
With its unique design, excellent performance, and wide applicability, dismantling joints have become an indispensable component in modern pipeline systems, providing a strong guarantee for the efficient operation and maintenance of various pipeline projects.
