A mechanical seal seals a rotating shaft against the housing, for example on a pump. Two very flat rings slide on each other and let only a wafer-thin liquid film pass.
Design and function
The rotating ring turns with the shaft; the stationary ring sits fixed in the housing. Springs or a metal bellows press the two rings together. Secondary seals, usually O-rings, seal the rings towards shaft and housing. Common face materials are silicon carbide, carbon graphite and tungsten carbide.
Single seals are lubricated by the pumped medium itself. For hazardous, hot or solids-laden media, double seals with a barrier fluid are used. Cartridge seals are pre-assembled and pushed onto the shaft as a unit.
Where it is used
Mechanical seals work in centrifugal pumps, agitators, mixers and compressors in refineries, chemical plants and power stations. Which type and materials are permissible is determined by medium, pressure, temperature and the operator’s requirements.
Typical spare and wear parts
- Rotating and stationary seal rings
- O-rings and other secondary seals in the right material
- Springs, bellows and drive collars
- Shaft sleeves
- Complete cartridge seals by pump type
What helps with a request
- Manufacturer and type of the machine or plant
- Designation, part number or drawing of the part
- Dimensions, material and a photo of the part or nameplate
- Quantity and required date
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