SMSC 1SV — Single Cartridge Mechanical Seal (Large 3″–4″)

The SMSC 1SV Large cartridge mechanical seal is our ANSI-style single cartridge seal for big-bore pump services from 3″ to 4″. It’s a stationary, multi-spring cartridge mechanical seal with a standard 3/8″ NPT flush port, built to deliver reliable performance in higher pressure / higher temperature applications and tough industrial duty cycles.

Choose size from dropdown menu above: 3″- 4″

At a glance

• Style: Single cartridge mechanical seal, stationary design (excellent for high speed)

• Sizes available: 3″, 3-1/4″, 3-1/2″, 3-3/4″, 4″

• Flush: 1 × 3/8″ NPT flush port standard (improves cooling and extends seal life)

• Materials: Silicon carbide / silicon carbide (SiC/SiC) faces, FKM, 304 stainless steel

• Balance/Drive: Hydraulically balanced faces, positive set-screw drive, non-shaft-fretting sleeve elastomer

Check out Seal House Cartridge Seal Installation Guide for installation guidance. 

Why it lasts

• Monolithic seal faces increase face stability in high-pressure/high-temperature duty

• Large-area face drive helps reduce face damage in stop/start and viscous services

• Slotted anti-rotation gland improves durability under frequent cycling

• Multiple springs provide uniform face loading and strong axial movement compensation

Typical uses

Large-frame ANSI pumps in chemical processing, power, pulp & paper, water/wastewater, mining, and general industrial services—especially where higher pressure/temperature, viscosity, or frequent starts/stops are expected.

Need help selecting the correct size or confirming fit? Contact us with your pump model and service details and we’ll help spec the best 1SV Large build for your application.

Need help sizing or selecting materials? Contact us with your pump model and service details—we’ll spec the best 1SV Large build for your duty.