| 摘要 |
A bell seal unit and retaining nut for use in the nozzle chamber unit of an elastic fluid turbine, such as the steam turbine used to drive electrical utility generators. The bell seal unit includes a radial flange with an end face sealing surface and a skirt portion with a lower skirt margin subdivided into a labryinth seal region and a guiding and wear resisting region. The labryinth seal region includes plural, spaced apart circumferential seal lands and grooves, and the guiding and wear resisting region includes plural axial lands and grooves. The ball seal unit is positioned for free but limited axial movement by a retaining nut which includes a smooth inner cylindrical surface, a shoulder surface and a lower flange surface. Plural slots extend between the shoulder and flange surfaces to facilitate fluid flow to the lower surface of the bell seal radial flange.
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