When metal pipe fittings are connected, what reliable sealing technologies can prevent leakage?
Publish Time: 2025-05-27
In industrial pipeline systems, the reliable connection of metal pipe fittings is crucial. It is not only related to the normal operation of the system, but also directly affects safety. In order to prevent leakage and ensure that fluids or gases can be efficiently and safely transmitted in the pipeline, effective sealing technology must be adopted.
1. Welding sealing
Welding is a method to achieve permanent connection of metal pipe fittings, which is widely used in pipeline systems under high pressure and high temperature environments. According to different needs and material properties, welding methods can be divided into many types, such as argon arc welding (TIG), arc welding (SMAW), etc. The advantage of welding is that it can provide extremely high strength and good sealing performance, which is suitable for demanding occasions. However, the welding process requires professional skills and equipment support, and for some special materials (such as aluminum and copper alloys), special processing may be required to ensure welding quality.
2. Flange connection
Flange connection is a detachable connection method that achieves sealing effect by clamping a gasket between two flanges. Choosing the right gasket material is one of the key factors to ensure the sealing of flange connections. Commonly used gasket materials include asbestos rubber sheet, polytetrafluoroethylene (PTFE), metal spiral wound gasket, etc. The advantage of flange connection is that it is easy and quick to install and easy to maintain and repair; the disadvantage is that the cost is relatively high, especially under high pressure conditions, thicker and heavier flanges and bolt assemblies are required.
3. Threaded connection
Threaded connection is a simple and economical connection method, especially suitable for small-diameter pipe applications. It relies on the tight fit between the internal and external threads and appropriate fillers (such as raw tape, sealant, etc.) to achieve the purpose of sealing. Although threaded connection is easy to operate, its scope of application is limited and is usually only used under low pressure or normal temperature conditions. In addition, frequent disassembly and assembly may cause thread wear and affect the sealing effect.
4. Card sleeve connection
The card sleeve connection uses a card sleeve to embed into the pipe wall to form a seal, which has the advantages of compact structure, light weight, and high pressure resistance. This connection method does not require welding or complex tools to complete the installation, so it has been widely used in building water supply and drainage, chemical industry and other fields. The ferrule joint is designed with a conical surface inside. When the nut is tightened, the ferrule will deform along the conical surface and tightly hug the pipe surface, thereby achieving a reliable seal.
5. Expansion joint compensation
In some cases, in order to adapt to the displacement caused by thermal expansion and contraction caused by temperature changes or earthquakes, expansion joints can be installed between metal pipe fittings. Expansion joints can not only absorb axial, lateral and angular displacements, but also have certain sealing functions. For example, the bellows expansion joint is filled with flexible elements, which allows a certain amount of expansion and contraction while maintaining good sealing performance. This type of sealing technology is mainly used in large industrial pipeline systems.
6. Other special sealing technologies
In addition to the above common sealing technologies, there are also some special sealing solutions developed for specific conditions. For example, magnetic sealing uses the magnetic field to make the seal produce elastic deformation to achieve a sealing effect; another example is vacuum sealing, which is specially used for pipe connections in ultra-high vacuum environments and requires extremely strict surface finish and flatness.
In short, the selection of suitable metal pipe fittings connection sealing technology should comprehensively consider multiple factors such as working medium, pressure level, temperature range and economy. With the development of science and technology, new sealing materials and technologies continue to emerge, providing more options for improving the sealing performance of pipeline systems.
