| dc.description.abstract | All flexible shaft couplings must be surrounded by a guard, in order to comply with OHSA requirements. For turbomachinery applications, this guard is an oil-tight enclosure and the purpose is to trap any oil escaping the machinery seals. When couplings rotate at high speeds in oil-tight enclosures, they shear the air, and this shearing results in a significant heat generation. The temperature of the enclosure, as well as the coupling, depends on the amount of air shearing and on the ability of the enclosure to dissipate the heat. Another problem with couplings operating in oil-tight enclosures is that negative pressures are created occasionally in the vicinity of machinery seals, causing oil to be sucked in the enclosure, which is particularly detrimental for gear reducers. Numerous tests were conducted at Koppers' Power Transmission facilities with various types and sizes of couplings, operating at various speeds, within enclosures of many configurations. Measurements were taken of the coupling and the enclosure temperatures, pressures in the enclosures, and the cooling effect of air flow and oil spray. Formulas useful in calculating enclosure temperatures are presented. Design guides for fabricating enclosures which operate at acceptable temperatures are also produced. Enclosures fabricated using these guidelines are successfully operating in petrochemical plants. | en |
