Overview
The SDSI 1.25″ T-21 is a repair seal assembly designed for centrifugal and rotary pump applications. Built by San Diego Seal Inc., a distributor with over 45 years of sealing expertise, this mechanical seal combines stainless steel primary and backup rings, carbon spring faces, and Viton elastomer components. The T-21 designation refers to a standard mechanical seal cartridge size commonly used in general industrial and marine pump repairs.
Key Features
- Stainless steel (SS) construction for corrosion resistance
- Carbon face material for wear durability
- Viton (fluorocarbon) elastomer seals for broad chemical compatibility
- 1.25″ shaft/bore size for standard pump applications
- Pre-assembled repair kit format for quick installation
- Suitable for low to moderate pressure hydraulic and pneumatic systems
Technical Specifications
- Shaft Size: 1.25″ (31.75 mm)
- Model: T-21
- Primary Material: Stainless Steel / Carbon
- Elastomer Material: Viton (FKM)
- Seal Type: Mechanical Seal Cartridge
- Pressure Rating: Low to moderate pressure (verify application-specific limits)
- Application Class: Repair / Replacement Kit
- Manufacturer: San Diego Seal Inc. (SDSI)
Typical Applications
The SDSI T-21 repair seal is used in:
- Centrifugal pump maintenance and repair
- Rotary positive displacement pumps
- Hydraulic and pneumatic system pumps
- Plumbing and general industrial pump applications
- Marine and shipboard equipment (SDSI serves U.S. Navy and Coast Guard)
- Water treatment and wastewater handling systems
Compatibility & Replacements
Compatible With
- Centrifugal pump housings with 1.25″ shaft diameter
- Hydraulic systems using mechanical shaft seals
- Pneumatic equipment with rotating shafts
- Low to moderate pressure rotating equipment
Replaces / Drop-In Replacement For
Verify compatibility with your original pump manufacturer before ordering. The SDSI T-21 1.25″ seal is a standard repair kit size; confirm your pump specifications match the 1.25″ shaft diameter and T-21 cartridge format with your equipment documentation or system integrator.
Works With
- Standard mechanical seal mounting flanges
- Pump repair kits and seal assemblies using 1.25″ bore specifications
- General industrial sealing systems (no proprietary protocol required)
