John Crane SAF-85-QRMG-302771 Double Cartridge Mechanical Seal

John Crane SAF-85-QRMG-302771 is a double cartridge mechanical seal from the Type SAF family, engineered for heavy‑duty pumping applications where slurries and particulates challenge sealing reliability. This double‑acting cartridge seal arrives factory‑assembled for straightforward installation and serviceability, delivering self‑centering alignment and robust performance with minimal field adjustment. Common construction features for SAF double seals include SiC/SiC faces on the product side and SiC/Carbon faces on the atmosphere side, PTFE o‑rings for the product side, with EPDM or Viton elastomers and standard metals such as AISI 329 or optional metals like titanium and UHB, plus Nimonic springs to withstand demanding conditions. Typical operating limits for this class of seal place process temperatures up to 180°C (350°F), stuffing‑box pressures up to 20 bar(g) (290 psi(g)), and seal‑water pressures up to 15 bar(g) (215 psi(g)), with allowable shaft speeds up to about 30 m/s (100 ft/s). The SAF family is commonly used in process pumps, mining and minerals operations, and other heavy equipment where seal reliability, ease of installation, and compatibility with SafeUnit water‑control systems are valuable. This specific model is identified as SAF-85-QRMG-302771 (internal code 87275216).