COMMON MATERIALS AND USES OF MECHANICAL SEALS

In the modern industrial field, mechanical sealing, as a key sealing device, is widely used in various machinery and equipment, playing an important role in preventing fluid leakage and protecting the operation safety of equipment. The performance of mechanical seals largely depends on the choice of materials.

1. Common materials of mechanical seals

1). Metal materials

● Cemented carbide: It has extremely high hardness and strength, good wear resistance, and can withstand high temperature and high pressure. It is often used to seal weakly corrosive media, such as oil, water, etc. In some high-speed rotating equipment, the cemented carbide sealing ring can ensure the reliability and stability of the seal.

● Silicon carbide: has excellent high temperature resistance, corrosion resistance and wear resistance. It can be used under extreme working conditions, such as equipment that handles strong corrosive media in chemical, petroleum and other industries. The long service life of the silicon carbide sealing ring can effectively reduce the maintenance cost of the equipment.

● Stainless steel: has good corrosion resistance and mechanical strength, and the price is relatively economical. It is suitable for the sealing of general industrial occasions, such as pumps, valves and other equipment. Stainless steel seals can be processed and customized according to different needs to meet various complex sealing requirements.

Two. Non-metallic materials

● Graphite: has good self-lubrication, high temperature resistance and chemical stability. In mechanical seals, graphite is usually used as an auxiliary sealing material with metal sealing rings. The graphite ring can effectively fill the sealing gap, prevent the medium from leaking, and also reduce the wear of the sealing surface.

● Polytetrafluoroethylene (PTFE): has extremely low friction coefficient, corrosion resistance and high temperature resistance. It is widely used in the sealing of various chemical equipment, especially for sealing corrosive media. PTFE seals have good elasticity and compressibility, and can adapt to changes in the shape and size of different sealing surfaces.

● Rubber: such as nitrile rubber, fluororubber, etc., with good elasticity and sealing properties. Rubber seals are often used in low-pressure and normal temperature occasions, such as pipe connections, valve seals, etc. Different types of rubber have different corrosion resistance and high temperature resistance, which can be selected according to specific working conditions.

2. Common uses of mechanical seals

1). Pump equipment

● In various pump equipment such as centrifugal pumps and plunger pumps, mechanical seals are the key components to prevent medium leakage. It can effectively seal the gap between the shaft of the pump and the housing to ensure the normal operation of the pump. Different types of pumps also have different requirements for mechanical sealing. For example, high-speed pumps need to adopt sealing materials with high hardness and good wear resistance, while pumps that transport corrosive media need to choose corrosion-resistant materials.

2). Reactor

● Reactor is a commonly used equipment in chemical production, which usually works in high temperature, high pressure and strong corrosion environment. The mechanical seal plays the role of sealing the stirring shaft and the boiler body in the reactor to prevent the leakage of the reaction medium and ensure the safe progress of the reaction. For the mechanical seal of the reactor, it is necessary to choose high-temperature, corrosion-resistant and pressure-resistant materials to ensure the reliability of the seal.

3). Compressor

● In the process of compressing the gas, the compressor needs to ensure the tightness of the gas and prevent leakage. Mechanical seals are used in compressors to seal the gap between the shaft and the housing to prevent gas leakage. Due to the high pressure of the compressor when working, the strength and sealing requirements for mechanical sealing are also very high. Mechanical seals are usually made of metal materials or high-performance non-metallic materials.

4). Valve

● Valves play a role in controlling fluid flow and pressure in the pipeline system. The mechanical seal is used in the valve to seal the gap between the valve stem and the valve body to prevent medium leakage. The mechanical seal of the valve requires good sealing performance, flexible operation and long service life. Choose the appropriate sealing material and structural form according to the working pressure, temperature and medium properties of the valve.

In short, common materials for mechanical seals include metal materials and non-metallic materials, each of which has its own unique performance and scope of application. When selecting mechanical sealing materials, it is necessary to consider comprehensively according to the working conditions of the equipment, the properties of the medium, the pressure and temperature and other factors to ensure the reliability and service life of the seal. At the same time, with the continuous progress of science and technology, new materials and sealing technologies are also emerging, providing a wider space for the development of mechanical sealing.