Flooding seal (flooding seal ring) is a sealing element widely used in mechanical equipment, its main role is to prevent fluid leakage. With the extension of use time, the pan plug seal will inevitably suffer wear and tear, resulting in failure. In this paper, the wear mechanism, failure mode and corresponding analysis methods of pan-plug seals will be discussed in depth.
1. Wear mechanism
In the process of operation, the pan plug seal is affected by many factors, which may lead to different types of wear. The main wear mechanisms include:
Mechanical wear: When the fluid passes through the flooding seal, the kinetic energy and impact force will cause wear on the surface of the seal ring. This wear is usually related to the velocity and particle content of the fluid. Especially in the presence of solid particles, impurities or bubbles, wear is increased.
Friction and wear: The pan plug seal in the process of movement, friction with the contact surface. Friction causes parts of the surface material to fall off, causing wear. Friction and wear are affected by material properties, surface roughness and lubrication conditions.
Chemical corrosion: Corrosive media can lead to chemical degradation of the seal material, reducing its wear resistance. For example, the sulfide and acidic substances in the oil react with the sealing material, resulting in structural changes and strength decreases of the material.
Thermal aging: At high temperatures, the pan plug sealing material will undergo thermal deterioration, resulting in embrittlement and increased hardness of the material. At the same time, thermal deformation may also lead to poor sealing and the failure of the seal ring.
Fatigue wear: When the sealing ring is subjected to periodic alternating loads, local fatigue may occur, causing cracks and spalling. Fatigue wear usually occurs under extreme working conditions, such as high pressure and high frequency vibration.
2. Failure analysis
Failure analysis mainly determines the cause of failure through the observation, analysis and experiment of failure characteristics. The failure of the pan-plug seal is usually manifested in the following forms:
Leakage phenomenon: The sealing effect fails, resulting in fluid leakage, usually caused by excessive wear, reduced material strength, or improper installation.
Deformation and cracking: Aging or chemical corrosion of the material can lead to cracks on the surface of the sealing ring, which will cause poor sealing. For example, after prolonged exposure to high temperatures, polymers may lose their elasticity.
Surface wear: Visible surface wear may lead to uneven sealing surface and affect sealing performance.
Spalling and delamination: under high load conditions, the plug sealing material may spalling due to fatigue and loss of integrity.
2.1 Failure mode analysis method
There are several common methods that can be used for failure analysis:
Macroscopic observation: By visually examining the physical condition of the floodplug seal, surface characteristics such as wear, cracking and peeling are identified.
Microscopic analysis: The microscopic structure of the pan plug seal is observed using an optical microscope or scanning electron microscope (SEM) to analyze the specific mechanism of wear and failure.
Material analysis: Through material analysis means (such as infrared spectroscopy, X-ray diffraction, etc.) to detect the chemical composition and structural changes of materials, and find out the factors related to failure.
Fatigue test: Dynamic fatigue test is carried out to analyze the durability of materials under alternating loads by simulating actual working conditions.
Corrosion testing: Testing the behavior of materials under corrosive media in a controlled experimental environment to assess their corrosion resistance.
3. Prevention and improvement measures
To reduce the risk of wear and failure, companies can take the following precautions:
Optimization of material selection: According to the fluid characteristics, operating conditions to choose the appropriate sealing materials, such as wear-resistant, corrosion-resistant materials (such as fluorine rubber, PTFE, etc.).
Improved design: Optimize seal geometry and contact surface design to reduce friction and wear. At the same time, the design surface roughness and flatness are considered to improve the sealing performance.
Ensure proper installation: Strictly follow installation requirements to ensure the correct location and pressure of the plug seal to avoid early failure due to improper installation.
Implementation of regular maintenance: regular inspection and maintenance of equipment, timely replacement of worn plug seals, to avoid affecting the overall system performance.
Improve operating conditions: minimize the content of suspended matter in the fluid, adjust the operating temperature and pressure, optimize the process parameters, and reduce the damage to the sealing ring.
4. Conclusion
As an important sealing element, the wear mechanism and failure analysis of the pan-plug seal are the key to ensure the reliable operation of the equipment. With a deep understanding of wear mechanisms, failure modes and their manifestations, effective improvement measures can be developed to optimize material selection, design and maintenance, reduce the risk of failure, and improve the overall performance and safety of the equipment.