Type 73 Split Seals | Pump Seals | John Crane

Type 73

Inflatable Backup Shaft Seal to Accompany Split Seal

Our inflatable backup seal is primarily used to hold process fluids, without leakage, while repairs are made to the primary seal, packing and other equipment components.

It is commonly used with split seals on large-volume tanks, vessels and chests, in continuous or batch processes.

With this backup seal, there is no need to drain the tank or system first.



  • California Residents: PROPOSITION 65 WARNING
  • This seal design employs a minimum number of parts for functional efficiencies and reliable service. The key element is a proprietary inflatable elastomer "boot" seal that is inflated quickly to hold process fluids in place during maintenance.
  • Positioning between the process fluid and primary seal allows complete access to equipment components beyond the inflatable boot, without interruption from leakage.
  • The Type 73 seal is designed for long service life and can be inflated and deflated through dozens of cycles. Some have provided more than 10 years of uninterrupted service in marine and industrial applications.
  • Ideally combined with a John Crane split seal, the Type 73 provides backup seal protection when used with a wide range of primary seals and packing. This combination allows for fast split-seal repairs without having to dismantle equipment or drain the tank or system first.

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