Application Of Labyrinth Seals With Comb-Tooth Profiles

The comb-tooth labyrinth seal is a specific type of labyrinth seal; based on the tooth profile, it can be categorized into various forms, such as flat-tooth, staggered-tooth, and fir-tree configurations. Common diaphragm seals include the elastic, comb-tooth, and tortuous types.

Due to its low cost, simple structure, safety, reliability, and ease of installation, the comb-tooth seal is widely employed in small, medium, and large-scale steam turbines. The sealing mechanism of the comb-tooth labyrinth seal relies on a series of interlocking teeth and corresponding grooves machined into the inner circumference of the seal ring and the outer circumference of the seal sleeve. These features create minute annular gaps (known as seal clearances) and expansion chambers that serve to impede steam leakage. In traditional comb-tooth labyrinth seals, the radial clearance typically ranges from 0.60 to 0.80 mm upon installation.

In high-speed centrifugal steam compressors utilizing comb-tooth seals, the seal assembly integrates multiple functions-including sealing, steam recirculation, pressure relief/pressurization, and condensate drainage-thereby enhancing sealing efficiency and extending the applicable pressure range. The comb-tooth seal assembly is frequently utilized as the primary-stage seal in multi-stage high-speed centrifugal steam compressors; it is also applicable to single-stage high-speed centrifugal units, effectively resolving issues such as steam leakage under conditions involving high differential pressures.