John Crane Type 59B Replacement Mechanical Seal

A Wedge-Sealed Solution for Cryogenic to High-Temperature Extremes

Swap the O-ring for a PTFE wedge and the operating envelope changes dramatically — that's the core difference between this seal and the 58B, and it's why the 59B stretches down to cryogenic temperatures and up past 400°C where rubber secondary seals simply can't survive. Its hydraulically balanced face keeps loading manageable even at that pressure and temperature range, while maximizing the face surface exposed to the process liquid for better heat dissipation under demanding thermal conditions. That combination makes it a common specification across pharmaceutical, refinery, and general chemical processing lines handling corrosive or thermally extreme media that would otherwise force a switch to a specialty seal family entirely. Wedge-seal fitment steps are covered in our blog.