Navigate the full mechanical seals reference below.
Mechanical Seals are precision devices that prevent leakage between rotating and stationary components in pumps, mixers, compressors and other rotating equipment. Kennkrupps supplies a comprehensive range of mechanical seals for oil & gas, chemical, petrochemical, power, water treatment and process industries.
Supplied as per API 682, ISO 21049, DIN 24960 and other international standards, with seal faces in silicon carbide, tungsten carbide, carbon and ceramic, and elastomers including Viton, EPDM, PTFE and Buna-N.
Mechanical seals provide a seal at the point of entry or exit of a rotating shaft through a stationary housing — preventing leakage of fluids from pumps, mixers, compressors and other rotating equipment where packing or other seals are impractical.
Two flat faces — one rotating and one stationary — are held together by spring force and hydraulic pressure. The faces are precision-lapped to create a leak-tight seal while allowing rotation, giving low friction and long service life.
Match the seal arrangement to your duty and service.
Easy installation, no setting required, reduced errors.
Better cost-buyLower cost, customizable for cost-sensitive pumps.
Needs settingSimple and economical for non-hazardous fluids.
Not for toxicsZero leakage, safe for hazardous and toxic fluids.
Barrier systemCompressors and high-speed pumps, minimal power.
Clean gas supplyInstall without equipment disassembly, reduced downtime.
Larger pumpsSimple, widely used for general-purpose duties.
Elastomer wearNo elastomer wear; handles high temp, corrosive, slurries.
CostlierReduced face load for high pressure and speed.
Longer lifeSimple, economical for low pressure and general duty.
Pressure limitedSingle and double seal arrangements.
| Arrangement | Description | Applications |
|---|---|---|
| Inside Seal | Seal faces inside the pump, product on outside of faces | Most common, general purpose |
| Outside Seal | Seal faces outside the pump, product on inside of faces | Corrosive fluids, shaft protection |
| Arrangement | Description | Barrier Fluid Pressure | Applications |
|---|---|---|---|
| Back-to-Back (Opposed) | Two seals facing opposite directions | Higher than process pressure | General hazardous fluids |
| Face-to-Face | Two seals facing each other | Lower than process pressure | Special applications |
| Tandem | Two seals facing same direction | Atmospheric (unpressurized) | Toxic, hazardous fluids |
| Tandem Pressurized | Two seals facing same direction | Higher than process pressure | Extremely hazardous fluids |
Selection drives wear life and heat performance.
| Material | Hardness (HV) | Thermal Conductivity | Max Temperature | Applications | Advantages |
|---|---|---|---|---|---|
| Silicon Carbide (SiC) | 2800-3200 | High (120 W/mK) | 400°C | Abrasive, corrosive, high temperature | Excellent wear resistance, high thermal conductivity |
| Tungsten Carbide (WC) | 1800-2200 | Medium (80 W/mK) | 400°C | Abrasive, general purpose | Good wear resistance, tough |
| Carbon Graphite | 50-150 | Medium (10-50 W/mK) | 250°C | General purpose, soft face | Self-lubricating, conformable |
| Ceramic (Alumina) | 1800-2000 | Low (30 W/mK) | 300°C | Corrosive, non-abrasive | Good corrosion resistance, brittle |
| Stellite (Co-Cr Alloy) | 400-500 | Medium (15 W/mK) | 400°C | High temperature, wear | Good wear, tough |
| Nickel Bonded WC | 1600-2000 | Medium (70 W/mK) | 400°C | Corrosive, abrasive | Better corrosion than cobalt bonded |
| Reaction Bonded SiC | 2800-3200 | High (120 W/mK) | 400°C | Severe service | Best overall performance |
| Sintered SiC | 2800-3200 | High (120 W/mK) | 400°C | High temperature, corrosive | Excellent corrosion resistance |
Match the O-ring / gasket elastomer to the media.
| Elastomer | Temperature Range | Chemical Resistance | Applications | Limitations |
|---|---|---|---|---|
| Viton (FKM) | -20°C to 200°C | Excellent for oils, acids, solvents | Chemical, petrochemical, high temperature | Poor for ketones, amines |
| EPDM | -40°C to 150°C | Good for hot water, steam, mild chemicals | Water, steam, food, pharmaceuticals | Poor for oils, hydrocarbons |
| Buna-N (Nitrile, NBR) | -20°C to 100°C | Good for oils, hydrocarbons | Oil & gas, hydraulic, general | Poor for ozone, weather |
| PTFE (Teflon) | -60°C to 260°C | Excellent for all chemicals | Severe chemical service, high temperature | Cold flow, requires fillers |
| Silicone | -60°C to 200°C | Good for hot water, steam | High temperature, food, pharma | Poor for oils, solvents |
| Neoprene (CR) | -40°C to 100°C | Good for weather, ozone | General purpose, marine | Poor for oils, solvents |
| Hypalon (CSM) | -40°C to 120°C | Good for chemicals, weather | Chemical, marine | Limited availability |
| Aflas (TFE/Propylene) | -10°C to 200°C | Excellent for acids, amines | Chemical, sour service | Poor for ketones |
| Kalrez (FFKM) | -20°C to 250°C | Excellent for all chemicals | Severe chemical, pharma | Very expensive |
| Chemraz (FFKM) | -20°C to 250°C | Excellent for all chemicals | Severe chemical, oil & gas | Very expensive |
Categories and recommended seal types by application.
| Category | Description | Applications |
|---|---|---|
| Category 1 | Cartridge-mounted, single seal | General purpose, non-hazardous |
| Category 2 | Cartridge-mounted, single or double seal | Hazardous fluids, higher performance |
| Category 3 | Cartridge-mounted, double seal, gas barrier option | Severe service, hazardous, toxic |
| Application | Recommended Seal Type | Face Materials | Elastomer |
|---|---|---|---|
| Water Pumps | Single cartridge seal | Carbon/SiC or Carbon/Ceramic | EPDM or Viton |
| Chemical Pumps | Single or double cartridge seal | SiC/SiC or WC/WC | Viton, PTFE, or Kalrez |
| Hydrocarbon Pumps | Single or double cartridge seal | SiC/WC or WC/WC | Viton or Aflas |
| Slurry Pumps | Single heavy-duty seal | SiC/SiC or WC/WC | Viton or PTFE |
| High Temperature Pumps | Metal bellows seal | SiC/SiC or Stellite/Stellite | PTFE or Grafoil |
| Cryogenic Pumps | Single cartridge seal | SiC/SiC or WC/WC | Viton or PTFE |
| Mixers & Agitators | Split seal or cartridge seal | SiC/SiC or WC/WC | Viton or PTFE |
| Compressors | Gas seal (dry running) | SiC/SiC with grooves | PTFE or Kalrez |
| Marine Pumps | Single or double seal | SiC/SiC or WC/WC | Viton or EPDM |
| Food & Pharma Pumps | Single sanitary seal | SiC/SiC or Ceramic/Ceramic | EPDM or PTFE |
Flush and barrier-fluid plans for every sealing condition.
| Plan | Description | Applications |
|---|---|---|
| Plan 01 | Recirculation from pump discharge to seal | Clean fluids, general purpose |
| Plan 02 | Recirculation from pump discharge through orifice | General purpose |
| Plan 03 | Recirculation from seal chamber to pump suction | Clean fluids |
| Plan 11 | Recirculation from pump discharge through flow control orifice | Most common, general purpose |
| Plan 13 | Recirculation from seal chamber to pump suction through orifice | Vertical pumps |
| Plan 21 | Plan 11 with cooler | Hot fluids |
| Plan 22 | Plan 11 with cooler and flow control orifice | Hot fluids, precise flow |
| Plan 23 | Recirculation from seal chamber through cooler to seal chamber | Hot fluids, common |
| Plan 31 | Recirculation from pump discharge through separator to seal | Abrasive fluids |
| Plan 32 | External flush injection to seal chamber | Abrasive, crystallizing fluids |
| Plan 41 | Plan 31 with cooler | Hot, abrasive fluids |
| Plan 52 | Unpressurized dual seal with buffer fluid | Toxic, hazardous fluids |
| Plan 53A | Pressurized dual seal with barrier fluid | Hazardous, toxic fluids |
| Plan 53B | Pressurized dual seal with bladder accumulator | Hazardous, remote locations |
| Plan 53C | Pressurized dual seal with piston accumulator | Hazardous, high pressure |
| Plan 72 | Unpressurized dual seal with secondary containment | Toxic, hazardous |
| Plan 74 | Dry gas seal system | Gas compressors, high speed |
| Plan 75 | Venting of primary seal leakage | Hazardous, toxic |
| Plan 76 | Venting of secondary seal leakage | Hazardous, toxic |
Rotating face on shaft, stationary face in housing. Most common, general purpose.
Stationary face on shaft, rotating face in housing. Large shafts, high speed.
Requires setting during installation. Older designs, cost-sensitive.
Pre-assembled, no setting required. Modern standard, easy installation.
Two or more seals in series for hazardous, toxic, high-pressure duty.
Non-contacting, gas film between faces for compressors and high speed.
Magnetic closure instead of springs for slurries and abrasive fluids.
Elastomeric lip contact for low-pressure, simple applications.
Component-level material options for every seal.
| Component | Material | Specification | Applications |
|---|---|---|---|
| Seal Faces | Silicon Carbide | Reaction bonded, sintered | Abrasive, corrosive, high temperature |
| Seal Faces | Tungsten Carbide | Cobalt or nickel bonded | Abrasive, general purpose |
| Seal Faces | Carbon Graphite | Resin or metal impregnated | Soft face, general purpose |
| Seal Faces | Ceramic (Alumina) | 99.5% Al2O3 | Corrosive, non-abrasive |
| Seal Faces | Stellite | Co-Cr alloy | High temperature, wear |
| Metal Parts | Stainless Steel 304 | ASTM A182 F304 | General purpose |
| Metal Parts | Stainless Steel 316 | ASTM A182 F316 | Corrosive, marine |
| Metal Parts | Stainless Steel 316L | ASTM A182 F316L | Welded, high corrosion |
| Metal Parts | Hastelloy C | ASTM B574 N10276 | Severe corrosion |
| Metal Parts | Monel | ASTM B564 N04400 | Marine, hydrofluoric acid |
| Metal Parts | Titanium | ASTM B381 Gr. F2 | Severe corrosion, lightweight |
| Metal Parts | Inconel 718 | ASTM B637 | High temperature, high strength |
| Elastomers | Viton (FKM) | ASTM D1418 FKM | Oils, acids, high temperature |
| Elastomers | EPDM | ASTM D1418 EPDM | Hot water, steam, mild chemicals |
| Elastomers | Buna-N (NBR) | ASTM D1418 NBR | Oils, hydrocarbons |
| Elastomers | PTFE | ASTM D1418 PTFE | All chemicals, high temperature |
| Elastomers | Silicone | ASTM D1418 VMQ | High temperature, food |
| Elastomers | Kalrez (FFKM) | ASTM D1418 FFKM | Severe chemical, pharma |
| Springs | Stainless Steel 316 | ASTM A313 | General purpose |
| Springs | Hastelloy C-276 | ASTM B574 | Corrosive |
| Springs | Inconel X-750 | ASTM B637 | High temperature |
| Bellows | Elastomer (Viton, EPDM) | Molded | General purpose |
| Bellows | Metal (316 SS, Hastelloy) | Welded | High temperature, corrosive |
Centrifugal and positive displacement pumps, mixers and agitators, submersible, slurry, cryogenic and high-temperature pumps.
Oil & gas (crude, refined products, pipelines), chemical processing (acids, solvents, polymers), power generation (boiler feed, cooling water).
Water and wastewater, food and beverage, pharmaceutical, pulp and paper, mining, marine, automotive and HVAC.
Certified manufacturing management system for consistent process control and traceability.
API 682 compliance, PED 2014/68/EU and NACE MR0175 / MR0103 sour service.
EN 10204 3.1/3.2 material certificates with every shipment; TPI available.
Face flatness (optical flats, interferometry) and surface finish (Ra) measurement.
Pressure and leak testing plus PMI and hardness (Rockwell, Vickers) verification.
Dynamic balance testing for high-speed seal assemblies.
Cartridge, component, single, double, gas and split seals.
SiC, WC, carbon, ceramic, Stellite, Viton, EPDM, PTFE, Kalrez, Hastelloy, Monel, Inconel.
Category 1, 2 and 3 seals available.
Complete API 682 plans (11, 21, 23, 31, 32, 52, 53A/B/C, 74 & more).
100% inspection, material certificates with every shipment.
Ready stock for common seal sizes and configurations.
Made to drawing/specifications, reverse engineering.
Direct from manufacturer.
Expert guidance on seal selection, troubleshooting and installation.
Compatible with John Crane, Flowserve, EagleBurgmann, Chesterton and more.
Seal repair and rebuild services available.
Our team can help with seal selection, face and elastomer materials, flush plans and cross-referencing existing seals.