Dynamic pressure pumping type non-contact mechanical seal

Abstract

The invention discloses a dynamic pressure pumping type non-contact mechanical seal which comprises a movable ring and a static ring. A movable ring sealing face of the movable ring and a static ring sealing face of the static ring are mutually attached to form a sealing end face. A pumping groove in the movable ring is defined by a pumping working face, a pumping rear face and a pumping inner side face. A groove opening of the pumping groove faces the outer side edge of the movable ring. The pumping working face is an involute curved face with the base circle radius R1 equaling to R0 / 2. The pumping rear face is an involute curved face of a circle where an inner hole of the movable ring is located. Dynamic pressure chutes in the static ring are formed by dynamic pressure vertical faces, dynamic pressure slopes and dynamic pressure inner side faces. The chute central angle of each dynamic pressure chute is alpha 1. The central angle of the static pressure sealing face between the two adjacent dynamic pressure chutes is alpha 2. The chute central angle alpha 1 is larger than the central angle alpha 2 of the static pressure sealing face. The mechanical seal can generate the higher upstream centrifugal pumping effect, the stable fluid dynamic effect can be formed, and non-contact is achieved by separating the sealing end face.

Description

technical field [0001] The invention relates to an end-face mechanical seal device, in particular to a mechanical seal with fluid dynamic pressure effect and upstream pumping function. Background technique [0002] Mechanical seal is a commonly used axial end face sealing device of rotating shaft, which is widely used in machinery industry, petrochemical industry, aerospace and other fields. It has the advantages of reliable sealing performance, small leakage, low power consumption and long service life. Mechanical seal The main structural elements of the seal include the dynamic seal ring and the static seal ring. The function of preventing leakage is achieved through the mutual fit of the dynamic ring and the static ring. Therefore, the structure of the seal dynamic ring and the static ring largely determines the sealing performance of the mechanical seal. performance and service life. [0003] With the rapid development of modern industry, the application field and envir...

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Problems solved by technology

Chinese patent 201310201473.3 discloses a self-pumping hydrodynamic mechanical seal, which is provided with a spiral groove area on the upstream (high pressure side) of the end face of the dynamic ring seal, and the slots of the spiral grooves distributed along the circumferential direction face the upstream side A circular liquid storage tank is set at the position where the end face of the static ring is opposite to the root of the spiral groove of the moving ring, and a plurality of axial drainage channels connected by sealed cavities are set in the groove, which uses the fluid pressure difference at the root of the groove to pass the fluid through The drainage channel on the static ring flows back to the sealing chamber to achieve the effect of separating the end faces of the dynamic and static rings. Although this structure realizes the non-contact sealing of the dynamic and static rings through the generation of fluid dynamic pressure separating the dynamic and static end faces , which reduces the friction and wear between the dynamic and static rings, but still cannot solve the problem of large leakage rate

First of all, due to the lack of in-depth research on the groove shape of the spiral groove, it is difficult to produce centrifugal pumping action on the fluid on the high pressure side during the sealing process, and the liquid film shear flow between the sealing rings is not enough to resist the differential pressure flow between the inner and outer diameters , the leakage between the moving ring and the static ring cannot be eliminated; secondly, the dynamic pressure effect cannot be formed between the sealing rings of this structure, and the carrying capacity of the liquid film between the sealing surfaces is very limited. In actual operation, there will still be contact friction between the moving and static rings, affecting The sealing performance of the sealing end face can be played normally; at the same time, the sealing device of this structure also has the defects of complex structure and inconvenient installation and debugging

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