1. Mechanical Seals
-
SMSC 1SV — Single Cartridge Mechanical Seal (Large 3″–4″)
SMSC 1SV — Single Cartridge Mechanical Seal (Large 3″–4″)
Item #N/A
View ProductSMSC 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
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.
-
-
SPS-205
SPS-205
Item #N/A
View ProductSingle Spring Mechanical Seal SPS-205 | PS-205 Equivalent
Equal to industry standard number 205 / PS-205
Typical applications: Centrifugal pumps, mixers, and other rotating equipment.
Key specs: Shaft size: 1-3/4″ single spring seal • Seat: 2.500″ x 0.500″ • Rotary OD: 2.402″ • Working length: 2.000″
Design & construction:
Rotary head Type E/1. Electro-polished 316 stainless steel metal parts. Elastomeric bellows. Non-directional (independent of shaft rotation).Materials available (choose from dropdown)
-
CAR/CER/NIT — Carbon vs. Ceramic faces, Nitrile elastomers
-
CAR/CER/VIT — Carbon vs. Ceramic faces, Viton/FKM elastomers
-
SIC/SIC/VIT — Silicon Carbide vs. Silicon Carbide faces, Viton/FKM elastomers
Please click “specifications” below for OEM numbers and Pump Nameplate Data
Both PS replacements? Which should I choose? Check out more on our Seal House Seal Guide
Seal Model Product Line Replaces Features & Focus 205C N Line PS-514 Easy installation & broad compatibility SPS-205 SPS Line PS-514 Premium build for longevity & like for like replacement.
SPS Line
Same Fit. Lasting Reliability.
Our SPS single-spring seals are like-for-like replacements for industry-standard E/1, D/2, and C/21 heads—delivering the same fit and function with upgraded materials designed for extended service life.
What sets SPS apart:
-
Heavier elastomer bellows for improved structural integrity and stability under pressure
-
Resin-impregnated, abrasion-resistant carbon faces — double-density carbon designed for enhanced hardness and durability
-
316/304 stainless steel components for superior corrosion protection across E/1, D/2, and C/21 head styles
-
Precision-finished rotary heads with a brushed appearance for a high-quality machined look and consistent sealing performance
-
Built to exacting standards for dependable performance across a wide range of pump applications
Engineered to rigorous standards, SPS seals provide a durable, dependable alternative to common aftermarket or OEM options—compare them against your current line and see the difference.
Explore our full lineup of Single Spring Seals—PS replacements, pool/spa seals, and our SPS line.
Looking for more? Shop Pump Repair Kits, Parts & Accessories, and Gaskets.
-
-
SPS-278
SPS-278
Item #N/A
View ProductSingle Spring Mechanical Seal SPS-278 | PS-278 cup Equivalent
Equal to: industry standard number 278 / PS-278 cup
Typical applications: Centrifugal pumps, mixers, and other rotating equipment.
Key specs: Shaft size: 2-3/8″ single spring seal • Seat: 3.250″ x .562″ cup • Rotary OD: 3.083″ • Working length: 2.500″
Design & construction:
Rotary head Type E/1. Electro-polished 316 stainless steel metal parts. Elastomeric bellows. Non-directional (independent of shaft rotation).Materials available (choose from dropdown)
-
CAR/CER/NIT — Carbon vs. Ceramic faces, Nitrile elastomers
-
CAR/CER/VIT — Carbon vs. Ceramic faces, Viton/FKM elastomers
-
SIC/SIC/VIT — Silicon Carbide vs. Silicon Carbide faces, Viton/FKM elastomers
Please click “specifications” below for OEM numbers and Pump Nameplate Data
SPS Line
Same Fit. Lasting Reliability.
Our SPS single-spring seals are like-for-like replacements for industry-standard E/1, D/2, and C/21 heads—delivering the same fit and function with upgraded materials designed for extended service life.
What sets SPS apart:
-
Heavier elastomer bellows for improved structural integrity and stability under pressure
-
Resin-impregnated, abrasion-resistant carbon faces — double-density carbon designed for enhanced hardness and durability
-
316/304 stainless steel components for superior corrosion protection across E/1, D/2, and C/21 head styles
-
Precision-finished rotary heads with a brushed appearance for a high-quality machined look and consistent sealing performance
-
Built to exacting standards for dependable performance across a wide range of pump applications
Engineered to rigorous standards, SPS seals provide a durable, dependable alternative to common aftermarket or OEM options—compare them against your current line and see the difference.
Explore our full lineup of Single Spring Seals—PS replacements, pool/spa seals, and our SPS line.
Looking for more? Shop Pump Repair Kits, Parts & Accessories, and Gaskets.
-
-
SPS-279
SPS-279
Item #N/A
View ProductSingle Spring Mechanical Seal SPS-279 | PS-279 cup Equivalent
Equal to: industry standard number 279 / PS-279 cup
Typical applications: Centrifugal pumps, mixers, and other rotating equipment.
Key specs: Shaft size: 2-1/2″ single spring seal • Seat: 3.375″ x .562″ cup • Rotary OD: 3.210″ • Working length: 2.500″
Design & construction:
Rotary head Type E/1. Electro-polished 316 stainless steel metal parts. Elastomeric bellows. Non-directional (independent of shaft rotation).Materials available (choose from dropdown)
-
CAR/CER/NIT — Carbon vs. Ceramic faces, Nitrile elastomers
-
CAR/CER/VIT — Carbon vs. Ceramic faces, Viton/FKM elastomers
-
SIC/SIC/VIT — Silicon Carbide vs. Silicon Carbide faces, Viton/FKM elastomers
Please click “specifications” below for OEM numbers and Pump Nameplate Data
SPS Line
Same Fit. Lasting Reliability.
Our SPS single-spring seals are like-for-like replacements for industry-standard E/1, D/2, and C/21 heads—delivering the same fit and function with upgraded materials designed for extended service life.
What sets SPS apart:
-
Heavier elastomer bellows for improved structural integrity and stability under pressure
-
Resin-impregnated, abrasion-resistant carbon faces — double-density carbon designed for enhanced hardness and durability
-
316/304 stainless steel components for superior corrosion protection across E/1, D/2, and C/21 head styles
-
Precision-finished rotary heads with a brushed appearance for a high-quality machined look and consistent sealing performance
-
Built to exacting standards for dependable performance across a wide range of pump applications
Engineered to rigorous standards, SPS seals provide a durable, dependable alternative to common aftermarket or OEM options—compare them against your current line and see the difference.
Explore our full lineup of Single Spring Seals—PS replacements, pool/spa seals, and our SPS line.
Looking for more? Shop Pump Repair Kits, Parts & Accessories, and Gaskets.
-
-
SPS-3025
SPS-3025
View ProductSingle Spring Mechanical Seal SPS-3025 | PS-3025 Equivalent
Equal to: Industry standard 3025 / PS-3025
Typical applications: Centrifugal pumps, mixers, and other rotating equipment.
Key specs: Shaft size: 1-5/8″ single spring seal • Seat: 2.375″ x 0.500″ • Rotary OD: 2.636″ • Working length: 1.375″
Design & construction:
Rotary head Type D/2. Electro-polished 304 stainless steel metal parts. Elastomeric bellows. Non-directional (independent of shaft rotation).Material: CAR/SIC/EPDM — Carbon vs. Silicon Carbide, EPDM elastomers
Please click “specifications” below for OEM numbers and Pump Nameplate Data
SPS Line
Same Fit. Lasting Reliability.
Our SPS single-spring seals are like-for-like replacements for industry-standard E/1, D/2, and C/21 heads—delivering the same fit and function with upgraded materials designed for extended service life.
What sets SPS apart:
-
Heavier elastomer bellows for improved structural integrity and stability under pressure
-
Resin-impregnated, abrasion-resistant carbon faces — double-density carbon designed for enhanced hardness and durability
-
316/304 stainless steel components for superior corrosion protection across E/1, D/2, and C/21 head styles
-
Precision-finished rotary heads with a brushed appearance for a high-quality machined look and consistent sealing performance
-
Built to exacting standards for dependable performance across a wide range of pump applications
Engineered to rigorous standards, SPS seals provide a durable, dependable alternative to common aftermarket or OEM options—compare them against your current line and see the difference.
Explore our full lineup of Single Spring Seals—PS replacements, pool/spa seals, and our SPS line.
Looking for more? Shop Pump Repair Kits, Parts & Accessories, and Gaskets.
-
-
SPS-324
SPS-324
Item #N/A
View ProductSingle Spring Mechanical Seal SPS-324 | PS-324 cup Equivalent
Equal to: industry standard number 324 / PS-324 cup
Typical applications: Centrifugal pumps, mixers, and other rotating equipment.
Key specs: Shaft size: 3″ single spring seal • Seat: 3.875″ x .625″ cup • Rotary OD: 3.770″ • Working length: 2.875″
Design & construction:
Rotary head Type E/1. Electro-polished 316 stainless steel metal parts. Elastomeric bellows. Non-directional (independent of shaft rotation).Materials available (choose from dropdown)
-
CAR/CER/NIT — Carbon vs. Ceramic faces, Nitrile elastomers
-
CAR/CER/VIT — Carbon vs. Ceramic faces, Viton/FKM elastomers
-
SIC/SIC/VIT — Silicon Carbide vs. Silicon Carbide faces, Viton/FKM elastomers
Please click “specifications” below for OEM numbers and Pump Nameplate Data
SPS Line
Same Fit. Lasting Reliability.
Our SPS single-spring seals are like-for-like replacements for industry-standard E/1, D/2, and C/21 heads—delivering the same fit and function with upgraded materials designed for extended service life.
What sets SPS apart:
-
Heavier elastomer bellows for improved structural integrity and stability under pressure
-
Resin-impregnated, abrasion-resistant carbon faces — double-density carbon designed for enhanced hardness and durability
-
316/304 stainless steel components for superior corrosion protection across E/1, D/2, and C/21 head styles
-
Precision-finished rotary heads with a brushed appearance for a high-quality machined look and consistent sealing performance
-
Built to exacting standards for dependable performance across a wide range of pump applications
Engineered to rigorous standards, SPS seals provide a durable, dependable alternative to common aftermarket or OEM options—compare them against your current line and see the difference.
Explore our full lineup of Single Spring Seals—PS replacements, pool/spa seals, and our SPS line.
Looking for more? Shop Pump Repair Kits, Parts & Accessories, and Gaskets.
-
-
SPS-514
SPS-514
Item #N/A
View ProductSingle Spring Mechanical Seal SPS-514 | PS-514 Equivalent
Equal to: Industry standard 514 / PS-514
Typical applications: Centrifugal pumps, mixers, and other rotating equipment.
Key specs: Shaft size: 1-5/8″ single spring seal • Seat: 2.37″ x 0.500″ • Rotary OD: 2.185″ • Working length: 1.375″
Design & construction:
Rotary head Type D/2. Electro-polished 304 stainless steel metal parts. Elastomeric bellows. Non-directional (independent of shaft rotation).Materials available (choose from dropdown)
-
CAR/CER/NIT — Carbon vs. Ceramic faces, Nitrile elastomers
-
CAR/CER/VIT — Carbon vs. Ceramic faces, Viton/FKM elastomers
-
SIC/SIC/VIT — Silicon Carbide vs. Silicon Carbide faces, Viton/FKM elastomers
-
SIC/SIC/EPR — Silicon Carbide vs. Silicon Carbide faces, EPR elastomers
Please click “specifications” below for OEM numbers and Pump Nameplate Data
Both PS replacements? Which should I choose? Check out more on our Seal House Seal Guide
Seal Model Product Line Replaces Features & Focus 514C N Line PS-514 Easy installation & broad compatibility SPS-514 SPS Line PS-514 Premium build for longevity & like for like replacement.
SPS Line
Same Fit. Lasting Reliability.
Our SPS single-spring seals are like-for-like replacements for industry-standard E/1, D/2, and C/21 heads—delivering the same fit and function with upgraded materials designed for extended service life.
What sets SPS apart:
-
Heavier elastomer bellows for improved structural integrity and stability under pressure
-
Resin-impregnated, abrasion-resistant carbon faces — double-density carbon designed for enhanced hardness and durability
-
316/304 stainless steel components for superior corrosion protection across E/1, D/2, and C/21 head styles
-
Precision-finished rotary heads with a brushed appearance for a high-quality machined look and consistent sealing performance
-
Built to exacting standards for dependable performance across a wide range of pump applications
Engineered to rigorous standards, SPS seals provide a durable, dependable alternative to common aftermarket or OEM options—compare them against your current line and see the difference.
Explore our full lineup of Single Spring Seals—PS replacements, pool/spa seals, and our SPS line.
Looking for more? Shop Pump Repair Kits, Parts & Accessories, and Gaskets.
-
-
SPS-838
SPS-838
Item #N/A
View ProductSingle Spring Mechanical Seal SPS-838 | PS-838 cup Equivalent
Equal to: industry standard number 838 / PS-838 cup
Typical applications: Centrifugal pumps, mixers, and other rotating equipment.
Key specs: Shaft size: 2-3/4″ single spring seal • Seat: 3.500″ x .625″ cup • Rotary OD: 3.520″ • Working length: 2.875″
Design & construction:
Rotary head Type E/1. Electro-polished 316 stainless steel metal parts. Elastomeric bellows. Non-directional (independent of shaft rotation).Materials available (choose from dropdown)
-
CAR/CER/NIT — Carbon vs. Ceramic faces, Nitrile elastomers
-
CAR/CER/VIT — Carbon vs. Ceramic faces, Viton/FKM elastomers
-
SIC/SIC/VIT — Silicon Carbide vs. Silicon Carbide faces, Viton/FKM elastomers
Please click “specifications” below for OEM numbers and Pump Nameplate Data
SPS Line
Same Fit. Lasting Reliability.
Our SPS single-spring seals are like-for-like replacements for industry-standard E/1, D/2, and C/21 heads—delivering the same fit and function with upgraded materials designed for extended service life.
What sets SPS apart:
-
Heavier elastomer bellows for improved structural integrity and stability under pressure
-
Resin-impregnated, abrasion-resistant carbon faces — double-density carbon designed for enhanced hardness and durability
-
316/304 stainless steel components for superior corrosion protection across E/1, D/2, and C/21 head styles
-
Precision-finished rotary heads with a brushed appearance for a high-quality machined look and consistent sealing performance
-
Built to exacting standards for dependable performance across a wide range of pump applications
Engineered to rigorous standards, SPS seals provide a durable, dependable alternative to common aftermarket or OEM options—compare them against your current line and see the difference.
Explore our full lineup of Single Spring Seals—PS replacements, pool/spa seals, and our SPS line.
Looking for more? Shop Pump Repair Kits, Parts & Accessories, and Gaskets.
-
-
taco 70mm
taco 70mm
View ProductTaco 70 mm Mechanical Seal — 2100K
Replacement 70 mm mechanical seal for Taco centrifugal/hydronic pumps, built to the 2100K style with Silicon Carbide vs. Silicon Carbide faces and Viton elastomers for high temperature and chemical resistance.
Material build
-
Faces: SiC / SiC
-
Elastomers: Viton
Cross-references
-
Taco: 955-1846RP, 955-1841RP (SiC/Viton material code)
-
Other refs: TS100801/70/G, TC100813
Best for
-
HVAC systems, hot/chilled water circulation, and general hydronic service where durability and temperature resistance are critical.
Explore of full line up of Single Spring Seals
Have questions? Call us anytime- we’re here to help
-