The main types and application locations of the sealing components of Atlas Copco's oil-injection screw compressors
Mechanical seal (shaft end seal)
Installation location: The extended end of the rotor shaft of the compressor main unit (the part connecting the motor or gearbox).
Function: Prevent lubricating oil from leaking from the shaft end, and also prevent external air and dust from entering the main unit chamber.
Common forms: Mostly mechanical seals or skeleton oil seals. Mechanical seals are suitable for high-pressure and high-speed conditions, consisting of moving ring, static ring, spring, etc., and have stable sealing performance; Skeleton oil seals have a simple structure and achieve sealing by the close contact of the rubber lip with the shaft, and are often used in medium and low-pressure areas.
O-ring / sealing ring
Installation location: Flange connection surfaces, end covers, oil separator covers, filter interface, etc., of static sealing parts.
Function: Fill the sealing surface gap through elastic deformation to achieve static sealing.
Material characteristics: Depending on the contact medium (lubricating oil, compressed air) and working temperature, commonly used are nitrile rubber (NBR, resistant to oil, suitable for -40 to 120℃), fluororubber (FKM, resistant to high and low temperatures, resistant to chemical corrosion, suitable for high-temperature areas).
Piston ring / sealing ring
Installation location: In some compressors' regulating valves and deceleration devices.
Function: Achieve dynamic sealing in reciprocating or rotating motion to control the flow of gas or oil.
Material: Mostly wear-resistant engineering plastics (such as polytetrafluoroethylene PTFE) or metal materials, with self-lubrication and wear resistance.
Oil seal cover sealing pad
Installation location: Between the end cover on the outside of the shaft seal and the main unit housing.
Function: Assist in sealing, prevent the leaked oil from the shaft seal from further overflowing, and protect the shaft seal from external contamination.
Material selection points
Oil resistance: Must be resistant to long-term immersion in compressor-specific lubricating oil (mineral oil or synthetic oil) to avoid swelling, hardening or aging.
Temperature adaptability: Needs to adapt to the compressor's working temperature (usually 80 to 120℃, some parts may be higher), ensuring that the elasticity and sealing performance do not decline at high temperatures.
Abrasion resistance: For dynamic sealing components (such as shaft seals), must have certain abrasion resistance to cope with the high-speed rotation friction of the shaft.
Pressure resistance: Can withstand the pressure of the system's compressed air (usually 7 to 13 bar, higher for high-pressure models), preventing the shaft seal from being pushed away due to pressure and causing leakage.
