Mechanical seals for pumps

Frequently asked questions — Mechanical Seals

• What is the difference between a single-acting and a double-acting seal?

  The choice between these two variants depends on the nature of the pumped fluid and environmental requirements. The single-acting seal is suitable when the fluid is compatible with a small tolerated leakage to the exterior. The double-acting variant, using an intermediate barrier liquid, is essential for handling hazardous fluids such as acids, solvents or aromatic hydrocarbons in order to guarantee complete sealing and meet zero-emission constraints.
• How do I choose the face materials for an abrasive fluid?

  For abrasive fluids or aggressive chemical media, it is recommended to use the silicon carbide SSiC / SSiC pairing, recognised as the universal high-performance solution. Where solid particles are present in combination with shock risks, the Tungsten Carbide / Carbon pairing should be preferred. These choices help ensure the longevity of the sealing system despite demanding operating conditions, while maintaining the flat-face precision required for a stable lubricating film.
• Why opt for a cartridge mechanical seal?

  Cartridge seals are a factory-preset assembly including centring rings and shims. This format enables on-site fitting in just a few minutes, with no need for manual adjustment, thereby limiting the risk of installation errors. They are now the reference choice for fitting new pumps as well as for rapid maintenance operations requiring immediate return to service with no compromise on alignment.
• What does the EN 12756 standard guarantee for my equipment?

  The EN 12756 standard, which replaces the former DIN 24960 standard, ensures the standardisation of housing dimensions. It thereby enables the interchangeability of seals between various manufacturers such as John Crane, EagleBurgmann, AESSEAL, Flowserve or ANGA. When replacing an element, checking the housing dimensions, in particular lengths L1 K and L1 N, ensures compliance with the technical specifications of your installation and guarantees sealing in line with the expectations of your system.