The wear amount refers to the wear value of the seal end face in the axial length after the mechanical seal of the gear oil pump is operated for a certain time. The size of wear and tear should meet the requirements of the life of mechanical seal. JB / T 4127.1-1999 "technical conditions for mechanical seal" stipulates that the experiment is carried out with water as the medium, and the wear of the sealing ring of the 1OOh soft material is not more than 0.02 mm.
Wear rate is the abrasion resistance of the material, that is, the evaluation index of resistance to wear under certain friction conditions. When adhesive wear or abrasive wear occurs, the wear rate of the material is inversely proportional to the compressive yield limit or hardness of the material, that is, the harder the material is, the more wear-resistant. And there is a kind of antifriction material that relies on low friction factor, rather than high hardness to obtain excellent wear resistance. For example, soft materials such as graphite and polytetrafluoroethylene, which have self lubrication, have excellent antifriction properties. Under certain conditions, they even have longer lifespan than hard materials. In light medium and easy to produce dry friction medium environment, the soft sealing ring uses soft high-purity electrified graphite, which can achieve lower wear rate than hard carbon graphite. It is worth noting that the wear characteristics of materials are not the inherent characteristics of materials, but the characteristics of tribological systems related to the working conditions such as load, speed and temperature, the properties of paired materials, the properties of contact media, and the state of friction. Reasonable selection of paired materials and good lubrication and cooling conditions are important measures to ensure the low wear rate of the mechanical seal friction pair.
(2) service life
The life of the mechanical seal of the gear oil pump refers to the time that the mechanical seal runs from the starting work to the cumulative operation of the failure. Mechanical seals are rarely due to long wear and other factors often cause premature failure. Therefore, the life of the seal should be regarded as a statistical amount, and it is difficult to get the exact value. The effective working time of the seal depends largely on the application. JB / T 4127.1-1999 provisions of the "technical conditions" in mechanical seal: reasonable design, installation and use correct, sealed medium is water, oil and similar media, the use of mechanical seal generally not less than l; sealed medium for corrosive media, the use of mechanical seal for six month to l years; but in the harsh conditions of use is not affected by this restriction. The J B / T 8723-2008 "welding metal wave tube mechanical seal" stipulates: when the selection is reasonable, the installation and use is correct, the system works well and the operation of the equipment is stable, the service life of welded metal wave tube mechanical seal is no less than 8000h, and the exceptional working condition is exceptional. The standard of oil and chemical pump mechanical seal API682, the shaft seal system of pump gear oil pump and rotary pump has been formulated by the American Petroleum Society. The mechanical seal must be continuously operated for 25000 h without replacement.
To prolong the service life of the seal should pay attention to the following points: 1. Establish suitable mechanical working environment in the seal cavity, such as the effective control of temperature, removing solid particles, the formation of effective liquid film on the seal face (when necessary should adopt double seal and sealing liquid); meet the technical specifications of the sealing requirements; the pump has a rigid shell, rigid shaft, high quality support system.
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