Mechanical seal john crane
Type 28SC
Non-contacting Secondary Containment Seal Type 28SC
The 28SC is a gas-lubricated, non-contacting secondary containment seal, which is applied as a component of a multiple seal cartridge. Secondary containment seals are intended to contain primary seal leakage in the event of a primary seal failure. Patented bi-directional seal face pattern provides non-contacting operation, preserving the seal faces until the seal is required to seal primary seal leakage.
Product Description Type 28SC
The type 28SCB is a compact dry running non-contacting gas seal designed for secondary containment.
Secondary containment seals perform in response to primary seal leakage or failure and represent a less complex alternative to a dual unpressurized (tandem) seals using a Plan 52 lubrication system.
Normal leakage from the primary seal is small and measured in ppm. The use of a containment seal gland and buffer gas injection moves vaporous leakage to a flare system. The 28SCB is typically applied with a Plan 72/76 secondary seal support system. When called upon to seal gross primary seal leakage, 28SCB closes down to run as a contacting wet seal directing leakage to a flare system or drain.
Table Parameters Type 28SC
| Temperature Limits | 32°F to 400°F/0°C to 205°C |
|---|---|
| Pressure Limits | Dry: 45 psi(g)/3 bar(g) Wet: 600 psi(g)/40 bar(g) |
| Speed Limits | 5000fpm/25m/s |
Features Type 28SC
- California Residents: PROPOSITION 65 WARNING
- Unbalanced primary ring and a very short design length.
- The design of the secondary O-ring enables reliability in a vacuum environment — a circumstance common in Plan 02 containment chamber designs.
- Non-contacting operation ensures like-new seal faces until primary seal leakage is encountered, where the 28SC operates as a full face contacting containment seal.
Recommended Applications Type 28SC
- Process pumps
- Other rotating equipment