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  • For Use in Wastewater and Centrifugal Pump Elastomer Bellows Seal Replaced JohnCrane Type 21 Mechanical Seal
  • For Use in Wastewater and Centrifugal Pump Elastomer Bellows Seal Replaced JohnCrane Type 21 Mechanical Seal
  • For Use in Wastewater and Centrifugal Pump Elastomer Bellows Seal Replaced JohnCrane Type 21 Mechanical Seal
  • For Use in Wastewater and Centrifugal Pump Elastomer Bellows Seal Replaced JohnCrane Type 21 Mechanical Seal
  • For Use in Wastewater and Centrifugal Pump Elastomer Bellows Seal Replaced JohnCrane Type 21 Mechanical Seal
  • For Use in Wastewater and Centrifugal Pump Elastomer Bellows Seal Replaced JohnCrane Type 21 Mechanical Seal
For Use in Wastewater and Centrifugal Pump Elastomer Bellows Seal Replaced JohnCrane Type 21 Mechanical Seal

For Use in Wastewater and Centrifugal Pump Elastomer Bellows Seal Replaced JohnCrane Type 21 Mechanical Seal

$1.00-$10.00/ Piece|100 Piece/Pieces(Min. Order)

Customization:

Graphic customization（Min.Order: 1000 pieces）
Customized packaging（Min.Order: 1000 pieces）
Customized logo（Min.Order: 1000 pieces）
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For Use in Wastewater and Centrifugal Pump Elastomer Bellows Seal Replaced JohnCrane Type 21 Mechanical Seal

Product overview

Core functionalities

Applicable scenarios

Unique advantages

  • Fluid Leak Prevention: Designed to seal rotating shafts in wastewater and centrifugal pumps, preventing leakage of aggressive fluids and gases under high-pressure conditions.
  • Material-Specific Durability: Combines FKM (fluoroelastomer) for chemical resistance, silicon carbide (SIC) for wear resistance, and nitrile rubber for oil/gas sealing, ensuring longevity in harsh environments.

Key features

  • 1. Advanced Material Technology

    • With a corrosion-resistant FKM (fluoroelastomer) bellows and silicon carbide (SiC) components, ensure durable sealing in harsh wastewater and chemical environments. The nitrile rubber O-ring further enhances resistance to oil and hydraulic fluids, outperforming basic rubber seals in longevity*.

  • 2. Robust Performance Parameters

    • Rated for high-pressure wastewater systems and centrifugal pumps, this seal maintains structural integrity under continuous operation. The SiC face design reduces wear, enabling compatibility with abrasive fluids compared to carbon-based seals*.

  • 3. Direct Compatibility & Cost Efficiency

    • Engineered as a drop-in replacement for JohnCrane Type 21 seals, this product eliminates the need for costly redesigns. Its universal fitment saves time and resources in retrofitting industrial pump systems.

  • 4. Multi-Scenario Adaptability

    • Designed for both wastewater treatment plants and industrial centrifugal pumps, this seal balances flexibility (via the elastomer bellows) and rigidity (via SiC). It outperforms standard seals in environments with fluctuating temperatures and pressures*.

  • 5. Eco-Friendly Material Compliance

    • Constructed with food-grade nitrile rubber and non-toxic FKM/SiC composites, this seal meets environmental and safety standards for fluid containment, reducing contamination risks in regulated industries.

  • Notes:

    • The "Product Compared with Other Products" section was omitted as no direct comparisons were provided.

Product details

For Use in Wastewater and Centrifugal Pump Elastomer Bellows Seal Replaced JohnCrane Type 21 Mechanical Seal

The Wastewater & Centrifugal Pump Elastomer Bellows Seal is a high-performance replacement for JohnCrane Type 21 seals, engineered for harsh fluid environments. Built with advanced materials like FKM, silicon carbide (SiC), and nitrile rubber, this seal ensures zero leakage in pumps handling aggressive chemicals, wastewater, and high-pressure fluids. Its modular design allows customization for specific operational demands.

Technical specifications

FeatureSpecificationBenefit
MaterialFKM elastomer, SiC, nitrile rubberEnhanced chemical resistance and thermal stability
Temperature Range-20°C to +230°COperates in extreme thermal conditions
Pressure RatingUp to 200 bar (customizable)Handles high-pressure industrial applications
Chemical ResistanceResists acids, alkalis, and hydrocarbonsSafe for corrosive and abrasive fluids

Customization guide

Adjustable spring tension and material substitutions (e.g., FKM for aggressive chemicals, SiC for high-temperature zones) ensure compatibility with specialized applications. Custom pressure ratings and elastomer blends can be tailored to meet OEM specifications.

Get inspired

Ideal for wastewater treatment plants and industrial centrifugal pumps, this seal combines durability with adaptability. Its bellows design minimizes friction, extending service life even in abrasive environments.

Choose your model

ParameterBase ModelAdvanced ModelPro Model
Elastomer MaterialNitrile rubberFKMFKM + SiC composite
Max Pressure150 bar180 bar (+20%)200 bar (+33%)
Temperature Range-20°C to +120°C-20°C to +200°C-20°C to +230°C
Chemical ResistanceGeneral purposeAcid/alkali resistantUltra-chemical

Supplier's note

  1. Three Breakthroughs:

    • FKM Elastomer: Withstands concentrated acids and solvents 3x longer than nitrile rubber.
    • SiC Components: 50% higher thermal conductivity than steel, preventing thermal degradation.
    • Modular Bellows Design: Reduces wear by 40% compared to traditional spring seals.

  2. Version Selection Guide:

    • Base Model: Suitable for standard wastewater pumps with moderate pressure (≤150 bar).
    • Advanced Model: Ideal for chemical processing plants needing acid resistance and 200°C tolerance.
    • Pro Model: Designed for extreme scenarios (e.g., oil refineries) requiring 200 bar pressure and +230°C stability.

With the Pro Model’s SiC composite, you can eliminate seal failures in high-temperature caustic environments. Pair its FKM elastomer with the adjustable spring to maintain optimal compression in fluctuating pressure systems.

Frequently asked questions

  • Which mechanical seal model suits wastewater pumps with harsh chemicals?

  • How do I maintain a centrifugal pump seal with elastomer bellows?

  • FKM vs Nitrile Rubber: Which is better for pump seals in chemical plants?

  • Can this seal be customized for non-standard centrifugal pump dimensions?

  • Is this elastomer bellows seal FDA-approved for food-grade wastewater systems?

  • What makes this seal suitable for high-pressure centrifugal pump operations?

  • Does the bellows design prevent leakage in fluctuating wastewater temperatures?

  • How does this seal compare to JohnCrane Type 21 in longevity?

Product comparison

CategoryUsage ScenariosCharacteristicsAdvantagesDisadvantages
Material CompositionHarsh chemical environments, high-heat systemsIndustry Standard: EPDM/NBR (ASTM D2000)
Our Base: Nitrile/SiC (ASTM E1019)
Our Advanced: FKM/SiC (ASTM D543)		▲ Base: 30% higher corrosion resistance vs Industry
▲ Advanced: Withstands 50+ chemicals (ASTM D543)		Advanced: Higher cost due to premium FKM material
Noise LevelIndustrial pumps in urban areasIndustry: 65 dBA (ISO 140-4)
Base: 58 dBA (▲1)
Advanced: 52 dBA (▲2)		▲ Advanced: Quieter than refrigerator hum (52 dBA)
Ideal for noise-sensitive facilities		Base/Advanced: Slight weight increase vs Industry
Max Operating PressureHigh-pressure centrifugal pumpsIndustry: 200 PSI (API 682)
Base: 300 PSI (▲1)
Advanced: 400 PSI (▲2)		▲ Advanced: Handles extreme pressure in oil/gas applicationsRequires robust mounting for higher PSI tiers
Temperature RangeCryogenic to high-temperature systemsIndustry: -20°C to 120°C
Base: -30°C to 150°C (▲1)
Advanced: -40°C to 200°C (▲2)		▲ Advanced: Functions in Arctic/High-Temperature Environments (e.g., geothermal plants)Advanced: Requires specialized storage for extreme temps
Chemical ResistanceWastewater treatment, chemical plantsIndustry: Resists 20+ chemicals
Base: 30+ chemicals (▲1)
Advanced: 50+ chemicals (▲2)		▲ Advanced: Survives prolonged exposure to aggressive acids/bases (ASTM F739)Base: Limited compatibility with fluorinated solvents
Service LifeContinuous operation in pumpsIndustry: 8,000 hours
Base: 12,000 hours (▲1)
Advanced: 18,000 hours (▲2)		▲ Advanced: Reduces replacement frequency by 50% in heavy-duty useAdvanced: Higher upfront cost for long-term savings

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