John Crane Type 6 Elastomer Bellow Mechanical Seals Replacement
The John Crane Type 6 mechanical seal is a compact, unitized single-spring seal designed as a direct aftermarket equivalent for the industry-standard John Crane Type 6/6A series. Engineered for small centrifugal pumps, jet pumps, and light industrial applications, this replacement John Crane type 6 mechanical seal features a full-convolution elastomer bellows (typically NBR or Viton) that compensates for shaft misalignment and end-play. With standard face materials like carbon vs. ceramic (or upgraded SiC/TC for abrasives) and stainless steel springs, elastomer bellow mechanical seal is ideal for handling clean water, mild chemicals, and non-abrasive fluids within standard pressure and temperature ranges.
Key Features
• Direct Interchangeability: Precision-engineered to match John Crane Type 6/6A dimensions (common sizes: 3/8", 1/2", 5/8", 3/4", 1"), ensuring a drop-in replacement without pump modification and backward compatibility with existing gland plates.
• Dynamic Sealing: Relies on a dynamic O-ring sliding on the shaft/sleeve to maintain face contact.
• Material Versatility: O-rings are available in any material (NBR, FKM, EPDM, FFKM, PTFE-Encapsulated), making this design adaptable to almost any fluid.
• Cost-Effective Reliability: Offers OEM-level performance at a fraction of the cost, providing a reliable sealing solution for residential pressure pumps, pool pumps, and light industrial MRO applications.
• Heavy-Duty Abrasion Resistance: Standard configuration utilizes Tungsten Carbide (TC) vs. TC sealing faces, providing superior wear resistance against sand, grit, and abrasive particles common in mining, construction dewatering, and heavy sludge applications.
Technical Specs | Materials | ||
Mediums | Water, oil and weakly-corrosive mediums | Stationary Ring | Ceramic/Sic/TC |
Pressure | ≤2.5MPa | Rotary Ring | Carbon/Sic/TC |
Temperature | -20℃ to 120℃ | Secondary Seal | NBR/EPDM/Viton |
Speed | ≤15m/s | Spring and Metal Part | Stainless Steel |
Product Specifications
| Metric Shaft Size D1 | Size Code | D3 | D7 | L1 | L4 |
| 14 | 0140 | 24.0 | 25.0 | 23.0 | 12.0 |
| 16 | 0160 | 26.0 | 27.0 | 23.0 | 12.0 |
| 18 | 0180 | 32.0 | 33.0 | 24.0 | 13.5 |
| 20 | 0200 | 34.0 | 35.0 | 24.0 | 13.5 |
| 22 | 0220 | 36.0 | 37.0 | 24.0 | 13.5 |
| 24 | 0240 | 38.0 | 39.0 | 26.7 | 13.3 |
| 25 | 0250 | 39.0 | 40.0 | 27.0 | 13.0 |
| 28 | 0280 | 42.0 | 43.0 | 30.0 | 12.5 |
| 30 | 0300 | 44.0 | 45.0 | 30.5 | 12.0 |
| 32 | 0320 | 46.0 | 48.0 | 30.5 | 12.0 |
| 33 | 0330 | 47.0 | 48.0 | 30.5 | 12.0 |
| 35 | 0350 | 49.0 | 50.0 | 30.5 | 12.0 |
| 38 | 0380 | 54.0 | 56.0 | 32.0 | 13.0 |
| 40 | 0400 | 56.0 | 58.0 | 32.0 | 13.0 |
| 43 | 0430 | 59.0 | 61.0 | 32.0 | 13.0 |
| 45 | 0450 | 61.0 | 63.0 | 32.0 | 13.0 |
| 48 | 0480 | 64.0 | 66.0 | 32.0 | 13.0 |
| 50 | 0500 | 66.0 | 70.0 | 34.0 | 13.5 |
| 53 | 0530 | 69.0 | 73.0 | 34.0 | 13.5 |
| 55 | 0550 | 71.0 | 75.0 | 34.0 | 13.5 |
| 58 | 0580 | 78.0 | 78.0 | 39.0 | 13.5 |
| 60 | 0600 | 80.0 | 80.0 | 39.0 | 13.5 |
| 63 | 0630 | 83.0 | 83.0 | 39.0 | 13.5 |
| 65 | 0650 | 85.0 | 85.0 | 39.0 | 13.5 |
| 68 | 0680 | 88.0 | 90.0 | 39.0 | 13.5 |
| 70 | 0700 | 89.0 | 92.0 | 45.5 | 14.5 |
| 75 | 0750 | 96.0 | 97.0 | 45.5 | 14.5 |
| 80 | 0800 | 104.0 | 105.0 | 45.0 | 15.0 |
| 85 | 0850 | 108.0 | 110.0 | 45.0 | 15.0 |
| 90 | 0900 | 114.0 | 115.0 | 50.0 | 15.0 |
| 95 | 0950 | 118.0 | 120.0 | 50.0 | 15.0 |
| 100 | 1000 | 124.0 | 125.0 | 50.0 | 15.0 |
Workshop
This workshop is equipped with professional processing equipment and integrated with standardized material warehousing management, enabling a one-stop production process from precision machining to finished product delivery. It ensures part machining accuracy and production efficiency, meeting various high-specification manufacturing requirements.
Product Research, Development and Testing
Our Product R&D and Testing focuses on optimizing seal performance through advanced simulation and material analysis. All John crane type 6 mechanical seals undergo rigorous trials, including thermal cycling and pressure tests, to ensure durability, minimal leakage, and long service life in demanding industrial environments.
Industry Solutions
Case Study
Plant-Wide Standardization: A chemical plant standardized on our O-Ring Pusher seals for all clear liquid pumps. By stocking O-ring kits, they could rebuild seals for water, oil, or acid just by changing the elastomer.
Testimonials
The most versatile seal type. We just change the O-ring and it works for anything.
—Pump Workshop, Canada
FAQs about John Crane type 6 mechanical seal
Q: Is this seal a direct replacement for John Crane Type 6 and 6A?
A: Yes, this seal is manufactured to the exact dimensional specifications of the John Crane Type 6 and updated 6A series. It is a direct form-fit-function replacement for common imperial shaft sizes (e.g., 1/2", 3/4") used in centrifugal and jet pumps.
Q: What are the standard materials and operating limits?
A: The standard configuration is Carbon vs. Ceramic faces with NBR (Buna-N) bellows. Operating limits are typically up to 120°C (with NBR) and pressures up to 5-10 bar, depending on size and speed. Upgraded materials (SiC/TC faces, Viton FKM) are available for higher temperatures (up to 200°C) or corrosive fluids.
Q: How do I install the Type 6 replacement seal correctly?
A: As a unitized cartridge, installation is straightforward: slide the seal onto the clean shaft, ensuring the bellows is not twisted. The seal is self-aligning. No special tools are needed to set the spring tension, but care must be taken not to damage the delicate faces during handling.
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