Alkali Pump Mechanical Seal Failure Analysis and Countermeasures
Abstract: Alkali pump mechanical seal is an important part of the entire alkali pump, and its failure is likely to cause serious harm to production. This paper mainly analyzes the mechanical seal failure from the aspects of structural design, material selection and quality control of sealing device. Through technical improvement and production management measures, the leakage problem of mechanical seal can be solved.
Keywords: Alkali pump; Mechanical seal; Failure analysis; Countermeasures
1 Introduction
Alkali pump is widely used in chemical industry and petrochemical industry, its structure form is complex, its sealing performance directly affects the production and usage effect of pump. The guide vane of pump body can ensure the stability and long service life of alkali pump, while the mechanical seal is responsible for the leakage prevention and sealing effect of pump. If the mechanical seal of alkali pump fails, it will cause a lot of direct and indirect damage to production, such as environmental pollution, equipment stop and so on. At present, the failure of mechanical seal of alkali pump is mainly caused by seal structure design, material selection, quality control and other aspects. This paper mainly analyzes the causes of mechanical seal failure of alkali pump and corresponding countermeasures.
2 Causes of Mechanical Seal Failure of Alkali Pump
2.1 Structural design
The main factors of mechanical seal failure are related to the structure of the seal device. The design of the shaft seal should combine the range of pump working parameters (pumping medium and pressure, temperature, etc.), as well as the matching of the seal material should consider the chemical properties of the working environment. The structural design of the shaft seal should conform to the universal principle, so as to make the seal device of the pump stable, strong and long service life.
2.2 Material selection
The selection of rubber-sealed seal material is also closely related to the service life of mechanical seal. The seal material which cannot resist high temperature, strong chemical corrosion and strong acid and alkali erosion should not be used for the seal of the pump. The chemical composition and the structure of the seal material should be selected according to the requirements of chemical properties of the working medium, so as to meet the requirements of pressure resistance and chemical corrosion resistance for different working mediums.
2.3 Quality control
The installation quality of mechanical seal of alkali pump also has a great influence on its service life. The sealing device should be installed in accordance with the instructions of the equipment manual. The shaft, shaft seal and its components should be installed correctly. It is necessary to check whether the position is correct, the bolt tightened and whether the surface contact of shaft seal is even and compact without any crack.
3 Countermeasures
3.1 Strengthen the structural design
The structural design of the shaft seals should be strictly in accordance with the requirements of the equipment manual, and the type of shaft seals should be designed reasonably according to the actual working parameters of the alkali pump, such as working temperature, medium composition and pressure. At the same time, the material of various components of the seal device unified, to meet the requirements of the working medium of chemical, temperature and pressure, and enhance the seal stability.
3.2 Rational selection of materials
The selection of sealing device material varies from case to case. For alkali pumps which require strong acid and alkali corrosion resistance, fluorine rubber and hard alloy should be selected as mechanical seal material, rubber material should be selected as shaft seal material, and materials should be selected according to requirements of working environment and pressure range.
3.3 strict quality control
The quality control of sealing device of alkali pump is an important factor affecting the quality of pump. In the installation of mechanical seal, no matter what kind of installation, should pay attention to the detail operation, the assembly of parts should be precisely and firmly; The surface contact of the mechanical seal should ensure that there are no defects such as bump, damage and dirt.
4 Conclusion
Alkali pump mechanical seal failure is mainly caused by structural design, material selection and quality control, which will have serious influence to production. We should pay attention to mechanical seal structure design, material selection and quality control, so as to solve the leakage problem of mechanical seal.
