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fuyangby@126.com
86 15188770013
Assembly process defects: During the installation of mechanical seals, the mating surfaces of the dynamic and static ring friction pairs are prone to deformation, scratches, or impurities. Uneven spring elasticity can lead to poor end face fit, or improper sealing ring tightness can cause leakage. For example, excessive compression will aggravate the wear of the friction pair, while insufficient compression will not guarantee the sealing effect.
Improper operation and maintenance: The tightness of the gland screw needs to be adjusted regularly for the packing seal. If the adjustment is not in place or the water volume of the shaft seal is not properly controlled, it is easy to cause internal or external leakage; When installing mechanical seals, if tools are used to knock on the seals, auxiliary rings are installed incorrectly, or if there are phenomena such as vacuuming and cavitation during daily operation, it will damage the fitting surfaces of the dynamic and static rings.
Environmental impact of working conditions: The slurry contains solid particles and corrosive media. Long term operation can cause seal abrasion, spring corrosion and fracture. Failure of the auxiliary flushing system can also exacerbate impurity accumulation, leading to accelerated wear of the sealing surface.
Measures to address the failure of packing seals
Regarding the inherent defects of packing seals, improvements need to be made in three aspects: material selection, installation specifications, and maintenance optimization
Optimize packing selection: Choose materials with high plasticity, wear resistance, and chemical stability to ensure a tight fit on the shaft surface under pressure, while reducing friction coefficient. For example, using composite fillers containing lubricants can extend their service life.
Strict installation and maintenance process
Clean the packing chamber before installation to avoid residual impurities; The cutting length of the filler should match the shaft diameter, and the interface should be angled at a 45 ° angle and arranged in a staggered manner.
Regularly check the tightness of the gland screws to ensure that the temperature of the packing does not exceed the allowable range; The water pressure of the shaft seal should be controlled at 0.05-0.1MPa, and the flow rate should be stable to form an effective water film.
Upgrade sealing form: For frequent failure scenarios, it is recommended to gradually replace mechanical seals to fundamentally solve the problems of large leakage and frequent maintenance of packing seals.
Systematic solution for mechanical seal failure
Mechanical seal failure requires targeted technical measures based on fault location:
Installation and Debugging Optimization
Pre processing and testing: Before installation, check the smoothness of the friction surfaces of the dynamic and static rings to ensure that there are no cracks or scratches; Determine the leakage location through static pressure test: when the leakage amount is small, it is mostly due to sealing ring problems, and when the amount is large, it indicates friction pair failure; Manual turning can further distinguish between dynamic and static ring faults.
Precise control of compression amount: Adjust the compression amount of the spring according to the model specifications to avoid excessive tension causing frictional heat accumulation or excessive looseness causing end face separation. For example, the compression standard for a certain model of mechanical seal is 5 ± 0.5mm, which needs to be calibrated with a feeler gauge.
Enhanced operation and maintenance
Auxiliary system improvement: Optimize the flushing system by continuously flushing the sealing surface with filtered cleaning medium (such as clean water) to prevent sedimentation of slurry particles; For high abrasion conditions, an external cooling device can be installed to reduce the temperature of the sealing chamber.
Operation standard management: It is strictly prohibited to operate under vacuum or pressure holding conditions. Before starting, exhaust and pump filling are required; Regularly monitor vibration and temperature parameters, control axial displacement within 0.3mm, and avoid collision between dynamic and static rings.
Material and structural upgrade
Friction pair material adaptation: The dynamic ring is made of silicon carbide (SiC) or hard alloy, and the static ring is matched with graphite impregnated resin to enhance wear resistance; The sealing ring is made of fluororubber or polytetrafluoroethylene to enhance corrosion resistance.
Elastic element protection: The spring is designed as an external or corrugated tube structure to avoid direct contact with the medium and reduce the risk of corrosion and fracture.
Preventive Maintenance and Management Strategy
Establish a regular maintenance mechanism: check the leakage rate of the seal every shift (the allowable leakage rate of mechanical seals is ≤ 5 drops/min), measure the spring elasticity every week, and disassemble and inspect the wear of the friction surface every month.
Personnel skill enhancement: Conduct installation process training, emphasize standardized tool usage (such as prohibiting direct hammering of seals with hammers), and implement a "double check" system to ensure assembly accuracy.
Working condition monitoring and warning: Real time monitoring of sealing status using vibration sensors and temperature inspection instruments, combined with historical data to establish a failure warning model, and intervene in potential faults in advance.
Through the comprehensive application of the above measures, the failure rate of slurry pump shaft seals can be significantly reduced. For example, after optimizing the flushing system and rectifying the installation specifications of a mine's sludge pump, the average service life of mechanical seals has been extended from 30 days to over 180 days, and the continuous operation time of the equipment has been increased by 60%.
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