There are three main possible leak paths for mechanical seals:

(1). Leakage at the sealing surface of the end face friction pair, which is the main sealing surface, determines the friction and sealing performance of the mechanical seal, and also determines the working life of the mechanical seal. According to statistics, the leakage of the mechanical seal is about 80%-95 % Is caused by the sealing pair of the sealing end face. Therefore, the contact surfaces are required to be parallel, and the surface roughness is required to be high, Ra=0.05~0.20μm, and flatness <0.9μm. For different media, it is required to use a combination of suitable German sealing materials, pay attention to wear resistance and corrosion resistance, and select appropriate geometric parameters (area ratio and aspect ratio, etc.) and performance parameters (specific pressure, spring load, etc.)

(2). Leakage at the static ring seal between the static ring and the gland and at the dynamic ring seal between the moving ring and the shaft (sleeve) is the auxiliary sealing surface, which determines the tightness of the mechanical seal and the key to the floating of the moving ring. Especially for the sealing surface of the moving ring and the shaft (sleeve), firstly, prevent the rusty scale or the accumulation of chemical reaction materials from causing the moving ring to "shelve" (not spring);

(3). The static seal between the gland and the sealing box and the static seal between the shaft sleeve and the shaft are both static seals. Compatible materials can be selected according to the sealing medium. In addition, if the moving ring adopts an inlaid structure, it is also There may be leakage at the mosaic joint surface, and attention must be paid to the fit.