• Torque Transmission: The conical spring grips the shaft to transmit torque, eliminating the need for drive pins or set screws that can slip or damage the shaft.
• Self-Aligning: The flexible design allows the rotary face to adjust automatically to shaft end-play and minor misalignment.
Key Features
• Universal Standard: A direct replacement for the ubiquitous Burgmann M3 series (M3N, M32, M37N), one of the most widely used component seals globally.
• Simple & Robust: Features a single conical spring design that is inherently robust and self-cleaning, ideal for general industrial duties.
• Versatile Application: Fits thousands of centrifugal pump models from KSB, Grundfos, and other major OEMs handling water, oil, and mild chemicals.
Technical Specs | Materials | ||
Mediums | Water, oil and weakly-corrosive mediums | Stationary Ring | Ceramic/Sic/TC |
Pressure | ≤1.4MPa | Rotary Ring | Carbon/Sic/TC |
Temperature | -20C to 120C | Secondary Seal | NBR/EPDM/Viton |
Speed | ≤15m/s | Spring and Metal Part | Stainless Steel |


Product Specifications
| D1 (inch) | Size Code | D1 (mm) | Size Code | D3 | D7 | L1 | L4 |
| 0.500 | 0127 | 12 | 0120 | 23.80 | 25.40 | 30.16 | 7.93 |
| 14 | 0140 | 27.76 | 31.75 | 33.32 | 10.30 | ||
| 0.625 | 0158 | 16 | 0160 | 27.76 | 31.75 | 33.32 | 10.30 |
| 0.750 | 0191 | 18 | 0180 | 30.94 | 34.93 | 33.32 | 10.30 |
| 20 | 0200 | 34.11 | 38.10 | 34.93 | 10.30 | ||
| 0.875 | 0222 | 22 | 0220 | 34.11 | 38.10 | 34.93 | 10.30 |
| 24 | 0240 | 38.10 | 41.28 | 39.67 | 11.10 | ||
| 1.000 | 0254 | 25 | 0250 | 38.10 | 41.28 | 39.67 | 11.10 |
| 1.125 | 0286 | 28 | 0280 | 41.28 | 44.44 | 41.28 | 11.10 |
| 30 | 0300 | 46.02 | 47.63 | 41.28 | 11.10 | ||
| 1.250 | 0317 | 32 | 0320 | 46.02 | 47.63 | 41.28 | 11.10 |
| 33 | 0330 | 48.68 | 50.80 | 42.85 | 11.10 | ||
| 1.375 | 0349 | 35 | 0350 | 48.68 | 50.80 | 42.85 | 11.10 |
| 1.500 | 0381 | 38 | 0380 | 51.85 | 53.98 | 42.85 | 11.10 |
| 1.625 | 0412 | 40 | 0400 | 58.10 | 60.38 | 50.80 | 12.70 |
| 43 | 0430 | 61.27 | 63.50 | 50.80 | 12.70 | ||
| 1.750 | 0444 | 45 | 0450 | 61.27 | 63.50 | 50.80 | 12.70 |
| 1.875 | 0476 | 48 | 0480 | 64.44 | 66.68 | 53.98 | 12.70 |
| 2.000 | 0508 | 50 | 0500 | 67.21 | 69.85 | 53.98 | 12.70 |
| 2.125 | 0539 | 53 | 0530 | 72.02 | 76.20 | 60.33 | 14.28 |
| 2.250 | 0571 | 55 | 0550 | 75.30 | 79.38 | 60.33 | 14.28 |
| 2.375 | 0603 | 60 | 0600 | 78.30 | 82.55 | 63.50 | 14.28 |
| 2.500 | 0635 | 63 | 0630 | 81.54 | 85.73 | 63.50 | 14.28 |
| 2.625 | 0666 | 65 | 0650 | 86.22 | 85.73 | 69.85 | 15.90 |
| 2.750 | 0698 | 70 | 0700 | 89.40 | 88.90 | 73.03 | 15.90 |
| 2.875 | 0730 | 73 | 0730 | 92.57 | 95.25 | 73.03 | 15.90 |
| 3.000 | 0762 | 75 | 0750 | 95.75 | 98.43 | 73.03 | 15.90 |
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 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
Cooling Circulation: A plastic molding factory's cooling pumps were leaking due to worn seals. We supplied M3N replacements. The simple, robust design handled the start-stop cycles of the cooling loop perfectly, restoring system efficiency.
Testimonials
The M3N is our bread and butter seal. These replacements fit perfectly and are half the price of the OEM box.
—Pump Repair Shop, Germany
FAQs about Metal Bellows Seals for High Temperature Pumps
Q: What is the difference between M3N and M37N?
A: They are mechanically similar but often have slightly different installation lengths or seat dimensions. The M3N is the standard metric version. M37N often refers to specific OEM dimensions. We supply both; please check your L1k (working length) dimension.

Our company is specialized in the production of sealing materials, mechanical seals , cartridge seals.
E-mail: gechacha@aliyun.com
Mobile: +86-18758835650
WhatsApp: +86-18758835650
Add: No8-2, Jinsha road Yuelin Street, Fenghua District, Ningbo, Zhejiang