Mechanical seals are key components commonly used in industrial equipment, and are widely used in rotating equipment such as pumps, compressors, stirrers, etc., to prevent media leakage and the intrusion of external impurities. The correct removal, installation, selection and use of mechanical seals is essential to the proper operation of the equipment. This article will introduce the relevant knowledge of mechanical seals in detail and provide a guide to operation.
1. Basic knowledge of mechanical seals
Definition of mechanical seals
Mechanical seal is a device that relies on one or more pairs of dynamic and static rings perpendicular to the axis to fit each other and achieve sealing through auxiliary sealing. It can effectively prevent fluid leakage and has a long service life.
The composition of mechanical seals
Mechanical seals usually consist of the following parts:
Dynamic ring: rotates with the shaft and forms a seal end face with the static ring.
Static ring: fixed on the equipment housing, with the dynamic ring to achieve sealing.
Spring: provides the initial pressure to make the moving and static rings fit tightly.
Auxiliary sealing ring: Used to prevent fluid leakage from axial or radial.
Transmission mechanism: transfer the rotation of the shaft to the moving ring.
Classification of mechanical seals
Classification by structure: single end seal, double end seal, multi-end seal.
According to the medium pressure classification: internal sealing, external sealing.
According to the sealing medium classification: dry gas seal, liquid seal, gas seal.
Second, the mechanical seal disassembly operation guide
Preparatory work
Power off the device and drain the media in the device.
Tools, such as wrenches, screwdrivers, and rubber mallets, are available.
Wear necessary protective equipment, such as gloves and goggles.
Disassembly procedure
Remove the static ring: Loosen the fixed bolt of the static ring, and carefully remove the static ring and auxiliary sealing ring to avoid damaging the sealing surface.
Remove the driving ring: loosen the fastening bolt of the driving ring transmission mechanism and remove the driving ring from the shaft.
Cleaning inspection: After disassembly, check the wear of the sealing surface and clean the seals and related components.
Matters needing attention
Avoid hitting the seal with hard objects during disassembly to prevent damage to the sealing surface.
Keep the parts properly after disassembly to prevent loss or contamination.
3. Installation and operation guide of mechanical seals
Preparatory work
Clean shafts, housings and seals to ensure they are free of impurities and damage.
Have a lubricant (if necessary), such as silicone oil or special grease.
Installation procedure
Install the static ring: gently press the static ring into the shell, ensure that the static ring is tightly fitted to the shell, and tighten evenly when fixing bolts.
Install the moving ring: put the moving ring on the shaft, ensure the fitting of the moving ring and shaft, install the transmission mechanism and tighten the bolts.
Install auxiliary sealing ring: Install the auxiliary sealing ring on the shaft or housing to ensure that the sealing ring is not twisted or damaged.
Matters needing attention
Avoid contact with hard objects or foreign bodies during installation to prevent scratches.
Tighten bolts with even force to prevent uneven force on seals.
4. Selection guide for mechanical seals
Select according to medium
According to the nature of the sealing medium (such as acid and alkali, corrosion, viscosity, etc.) choose a sealing material that is resistant to corrosion, high temperature or wear.
Commonly used materials: silicon carbide (wear-resistant), graphite (high temperature resistance), fluorine rubber (corrosion resistance).
Pressure selection
Choose double or multi-end seal for high pressure occasions.
Choose a single end seal for low pressure situations.
Temperature selection
Choose high temperature resistant materials for high temperature occasions and consider cooling devices.
Low temperature occasions to choose low temperature resistant materials, and prevent material embrittlement.
Select by speed
Select balanced seals for high speed rotating equipment to reduce friction and wear.
Low speed equipment can choose unbalanced seal.
5. Use and maintenance of mechanical seals
Precautions for use
Check that the seals are installed correctly before starting to ensure that there are no leaks.
Pay close attention to the vibration and temperature of the equipment during operation, and stop the inspection in time if any abnormality is found.
Care and maintenance
Check the wear of seals regularly and replace them if necessary.
Clean impurities and deposits in the sealed cavity regularly.
Replace the lubricant or coolant regularly to ensure that the seal is in good working condition.
Fault handling
If a leak is found, check whether the sealing surface is worn or the auxiliary sealing ring is damaged.
If the vibration of the equipment is too large, check whether the shaft is not properly aligned or the seal is loose.
Vi. Summary
The disassembly, installation, selection and use of mechanical seals are the key links to ensure the normal operation of equipment. Through the operation guide of this article, users can better grasp the relevant knowledge of mechanical seals, extend the service life of the equipment, and reduce the failure rate. In actual operation, it should be flexibly applied according to the specific situation of the equipment to ensure that the performance of the mechanical seal is fully played.