MOR Type 21 mechanical seal is a high-performance, versatile sealing product built to handle the tough demands of different industrial applications. It follows international standards including DIN24960, ISO3069, and GB6556, ensuring consistent quality and compatibility with equipment systems worldwide-whether you're outfitting pumps in a European factory or a Southeast Asian wastewater plant.
Core Specifications & Material Details
The MOR Type 21's strong build comes from carefully chosen materials, designed to stand up to harsh operating conditions and last longer with no shortcuts on durability:
Seal Face: Three high-wear options are available. Carbon/Silicon Carbide works well for continuous operation under 12 bar pressure and temperatures ranging from -20°C to 180°C. Carbon/TC (Tungsten Carbide) handles higher loads, withstanding up to 15 bar pressure and temperatures from -30°C to 220°C. Both pairings reduce friction-related wear; testing shows they maintain tight sealing for 8,000+ hours in water-based mediums, even when pressure spikes occasionally reach 18 bar.
Elastomers: Four material choices match different medium and temperature needs.
NBR (Nitrile Butadiene Rubber)
performs well with oil and water-based mediums, staying stable at temperatures from -30°C to 120°C-making it ideal for standard hydraulic pumps in manufacturing.
Viton (Fluorocarbon Rubber)
resists strong chemicals like 20% sulfuric acid and handles high temperatures, reaching up to 200°C for standard grades and 260°C for premium Viton GLT. It also withstands pressure up to 12 bar without hardening or cracking.
EPDM (Ethylene Propylene Diene Monomer)
handles weak acids such as 5% hydrochloric acid, alkalis like 10% sodium hydroxide, and water, remaining stable at temperatures from -40°C to 150°C-perfect for outdoor water treatment pumps exposed to temperature swings.
FFKM (Perfluoroelastomer)
suits extreme corrosive mediums including 98% sulfuric acid and 30% nitric acid, and it tolerates high temperatures up to 327°C for short bursts and 300°C for continuous use. It maintains flexibility even under 15 bar pressure, meeting strict chemical processing requirements like FDA 21 CFR Part 177 for food-grade applications.
Springs: Constructed from either SS304 (AISI 304 Stainless Steel) or SS316 (AISI 316 Stainless Steel). SS304 works at temperatures from -20°C to 150°C and handles up to 10 bar pressure. SS316 resists saltwater corrosion, stays stable at temperatures from -40°C to 180°C, and tolerates up to 12 bar pressure. It's a must for marine environments-tests show it withstands 5,000 hours of salt spray (per ASTM B117 standard) without rusting.
Metal Parts: Multiple corrosion-resistant options are offered. 410S (Martensitic Stainless Steel) is a cost-effective choice for general industrial use, handling up to 10 bar pressure and 120°C-ideal for non-corrosive oil transfer pumps. SS304, SS316, and SS316L (low carbon) variants provide enhanced protection, with SS316L standing out for fighting pitting and crevice corrosion-critical for sewage and marine jobs. It handles 15 bar pressure and 180°C temperatures, and resists 10% chlorine solution (common in wastewater disinfection) for 6,000+ hours.
Key Features & Application Scenarios
1. Single Seal Design for Tight Spaces
As a single seal, the MOR Type 21 is engineered for setups where space is limited-such as compact marine bilge pumps with 50mm diameter shafts or small-scale chemical reactors. Its compact structure, with a total height of ≤25mm for standard sizes, simplifies installation while keeping leakage low. For water-based mediums (at 8 bar and 80°C), leakage typically stays ≤0.1 ml/h; for oil-based mediums (at 10 bar and 60°C), it drops to ≤0.05 ml/h. This low leakage meets environmental standards for marine use, including IMO MEPC 107(49) for oil leakage limits. The design also makes it an excellent marine seal, critical for small fishing boats or yachts where stopping even small oil or water leaks into oceans is required by local regulations.
2. Equivalent to John Crane Type 21: A Trusted Replacement
The MOR Type 21 matches the John Crane Type 21 Mechanical Seal in performance, size, and installation compatibility. It covers a shaft diameter range of 15mm-80mm and has the same bolt hole spacing as the original. It delivers the same high-quality sealing, with a continuous pressure rating of up to 10 bar (15 bar for short bursts) and a temperature range of -20°C to 200°C when using Viton elastomers in standard configurations. In side-by-side tests with the John Crane Type 21, both seals maintained tight sealing for 7,500 hours in 90°C water at 10 bar pressure with no leakage. It's a cost-effective alternative, saving 20-30% compared to the original without sacrificing reliability. Thorough testing confirms it works seamlessly in systems already using John Crane Type 21 seals, such as Goulds water pumps or WEG industrial motors.
3. Built for Sewage Pump Mechanical Seals
The MOR Type 21 excels as a mechanical seal for sewage pumps, addressing the unique challenges of handling corrosive, abrasive, solid-filled fluids. It can manage fluids with up to 5% solid content and 2mm maximum particle size-common in wastewater treatment. Its durable materials contribute to this performance: SS316L metal parts resist the ammonia and hydrogen sulfide in sewage, while Silicon Carbide seal faces offer three times the abrasion resistance of carbon-only faces to prevent clogging and wear. EPDM or FFKM elastomers handle the weak acids (pH 4-9) and alkalis present in wastewater. Field data from over 10 wastewater plants across the U.S. and Europe shows the MOR Type 21 cuts sewage pump maintenance by up to 30%. Standard seals need replacement every 6 months, but the MOR Type 21 lasts 8-9 months. This extends equipment life-pump bearings last 15% longer because no leakage damages them-and lowers operating costs, saving $500-$800 per pump annually in labor and replacement parts.
4. Works Across Industrial Sectors
Beyond marine and wastewater, the MOR Type 21 fits general industrial uses with compatible mediums. In oil & gas applications, it seals oil transfer pumps when paired with NBR or Viton elastomers for oil compatibility. It handles crude oil (with a viscosity of 50-100 cSt) at 10 bar pressure and 60°C, tested to run 10,000 hours with no leakage in pipeline pumps. For chemical processing, it manages weak acids or alkalis when using EPDM or FFKM elastomers. With FFKM elastomers, it works in 250°C ethylene glycol pumps at 8 bar pressure for 5,000+ hours, meeting EU REACH standards for chemical safety. In general manufacturing, it seals water-cooled equipment-Carbon/Silicon Carbide faces reduce friction, helping it last 12,000+ hours in plastic injection molding machines (with cooling water at 6 bar and 40°C)-twice as long as cheap rubber seals.
Why Pick the MOR Type 21 Mechanical Seal?
Reliability: It meets international standards, and every unit undergoes leak testing before shipping. We use helium leak detection (with a sensitivity of 1x10⁻⁹ mbar·L/s) to ensure zero defects. We also provide a 12-month warranty, extendable to 24 months with proper installation following our maintenance guide.
Cost-Effectiveness: It matches the performance of premium brands like John Crane but comes at a lower price, reducing total ownership expenses. For a facility with 50 pumps, this translates to $10,000-$15,000 in annual savings on seals alone.
Environmental Compliance: As a marine seal and sewage pump seal, it adheres to global regulations including IMO MARPOL Annex I for oil tankers and EPA 40 CFR Part 403 for wastewater. In marine tests, it kept oil leakage below 0.03 ml/h-well under the 0.1 ml/h limit.
If you're an industrial operator needing a proven, standard-aligned seal-whether for high-temperature chemical pumps, saltwater marine systems, or dirty sewage pumps-the MOR Type 21 delivers consistent performance. It has clear material specs, test-proven durability, and matches the performance of top industry designs-no guesswork, just reliable sealing.
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