How to choose mecchanical seal

Here are the key factors to consider when choosing a mechanical seal:

Operating Conditions

- Temperature: For temperatures below -20°C, select seals with low-temperature-resistant elastomers like polytetrafluoroethylene (PTFE). In the range of 200 - 300°C, metal bellows seals with high-temperature-resistant materials are preferable.

- Pressure: In applications with pressures up to 10 bar, simple single mechanical seals are usually sufficient. For pressures above 50 bar, double mechanical seals or those with reinforced structures are more suitable.

- Medium: For corrosive media like acids and alkalis, choose seals made of materials like Hastelloy or ceramic. For abrasive media such as slurries, tungsten carbide seal faces are more appropriate.

Equipment Parameters

- Shaft Diameter and Rotational Speed: If the shaft diameter is large, ensure the mechanical seal has a suitable size and structure. High rotational speeds, e.g., above 3000 rpm, require seals with good dynamic balance and low friction, such as those with hydrodynamic or gas-lubricated faces.

- Type of Equipment: Pumps handling clean liquids can use single spring mechanical seals. Pumps handling toxic or flammable media should have double mechanical seals with a barrier fluid system.

Seal Performance and Material

- Leakage Rate: For applications requiring strict leakage control, such as in the pharmaceutical and food industries, choose mechanical seals with a low leakage rate, usually in the range of 10⁻⁵ to 10⁻⁶ m³/s.

- Seal Face Materials: Carbon-graphite is suitable for general applications due to its good self-lubrication and low cost. Silicon nitride is preferred for high-speed and high-pressure applications because of its high strength and wear resistance.

- Elastomer Materials: In an oil environment, NBR is commonly used. In chemical environments with a variety of chemicals, FKM is more suitable due to its excellent chemical resistance.

Cost and Service Life

- Initial Cost: Compare the prices of different brands and types of mechanical seals. Generally, high-performance seals are more expensive but offer better reliability and longer service life.

- Service Life: Consider the expected service life of the mechanical seal. Some seals may need to be replaced every few months in harsh environments, while others can last for several years in mild conditions. Choose a seal that balances cost and service life according to your specific needs.

JIAXING BURGMANN MECHANICAL SEAL CO., LTD

Contact person: Doris Sun

Phone No: 8615381220188

Skype: kathysunlin