Self-pumping fluid-dynamic-pressure-type mechanical seal

Abstract

The invention relates to a self-pumping fluid-dynamic-pressure-type mechanical seal. More than three groups of backwards-bent-type fluid grooves are formed in the moving ring seal end surface of the self-pumping fluid-dynamic-pressure-type mechanical seal, wherein each fluid groove is composed of a slope groove and a horizontal groove, the outlet of each fluid groove is located outside the moving ring seal end surface, and the inlet of each fluid groove is located in the middle of the moving ring seal end surface, and is communicated with a sealing cavity through an axial hole passage or an axial and radial combined hole passage on a moving ring. When the moving ring rotates, media in each fluid groove are accelerated to be high-speed fluid, the high-speed fluid flows to the outer diameter side of the moving ring and is pumped into the sealing cavity under the action of centrifugal force and forms a low-pressure area in the inlet of each backwards-bent-type fluid groove, and media in the sealing cavity flow into each backwards-bent-type fluid groove through the axial hole passage or the axial and radial combined hole passage under the action of pressure difference, wherein the axial hole passage or the axial and radial combined hole passage is arranged on the moving ring, and is communicated with the sealing cavity so as to form a new self-pumping cycle. In the process that the high-speed fluid is pumped out, the flowing speed is reduced, the pressure is increased, and certain opening force is formed as the circulating sectional area gradually increases. The self-pumping fluid-dynamic-pressure-type mechanical seal has good self-lubricating, self-washing and anti-solid-particle-interference ability and superior sealing performance.

Description

technical field [0001] The invention belongs to the technical field of sealing, in particular to a self-pumping mechanical seal with hydrodynamic pressure effect, which is suitable for sealing the rotating shafts of various compressors, centrifugal pumps, reactor stirrers and other rotating machines. Background technique [0002] At present, non-contact mechanical end seals are widely used in centrifugal compressors, fans, centrifugal pumps and other equipment in petroleum, chemical, chemical fiber, papermaking, electric power and metallurgical industries. The principle of hydrodynamics forms a hydrodynamic wedge, which generates the opening force of the end face, and achieves the purpose of reducing the wear of the sealing end face. For example, a hydrodynamic and static pressure combined non-contact mechanical seal with a single row of spiral grooves disclosed in US US4212475, China ZL00239203. 8 discloses a single-row fluid type groove upstream pumping mechanical seal and...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to propose a self-pumping mechanical seal with a hydrodynamic pressure effect suitable for a wide range of fluid pressure difference on both sides of the sealing end face, so as to solve the problem of the existing single-row spiral groove mechanical seal end face with small opening force and large leakage rate , Poor anti-particle interference ability, complex sealing end face structure of double-row spiral groove mechanical seal, and large installation space. Under the same conditions, it has greater working flexibility and zero leakage than the above-mentioned seal.

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