The selection of the mechanical seal material of the crude oil pump mainly includes the selection of the sealing friction material, the compensation component material and the auxiliary sealing material.
(1) Selection of friction pair materials
The API682 standard stipulates that the material of the standard friction pair is reaction-sintered silicon carbide against foamed carbon graphite, and the standard friction pair material can meet the needs of most working conditions. However, when the crude oil has any of the four characteristics of high viscosity, easy crystallization, easy polymerization, and solid particles, it is recommended to use a hard surface facing hard surface, that is, silicon carbide to silicon carbide; The pair of friction pairs can be used.
(2) Selection of compensation component materials
The function of the compensating element is to ensure that the sealing surface is well bonded and automatically compensated after the end surface is worn. It requires high material strength, high elastic limit, fatigue resistance, corrosion resistance and temperature resistance, so that the seal works in the medium for a long time. Does not reduce or lose the original elasticity. The compensation component materials specified in AP1682 are sufficient to meet the requirements of the offshore platform. Therefore, it is recommended to use the standard compensation component materials according to API682 requirements.
(3) Selection of auxiliary sealing materials
The selection of auxiliary sealing materials should consider the temperature characteristics and chemical compatibility of crude oil. The performance of auxiliary materials specified by AP1682 can fully meet the requirements of offshore platforms. Therefore, it is recommended to use API682.
(4) Selection of other component materials
Since the crude oil of the offshore platform is generally a conventional characteristic medium, the material of the sealing sleeve, the end cover, the driving pin, the positioning bolt and the like is preferably selected from the 316 type chromium nickel molybdenum stainless steel material.
