Metal Bellows-Type Seal

The new TDGS elastomer-free, high-efficiency, gas-lubricated seal is well suited for use in single-stage steam turbines in the petrochemical and chemical industries. The sealing face of the rotating seat is machined with three-dimensional V-grooves. The V-groove is notable for its inclined groove bottom. With no sharp edges at the groove exit where dirt particles can accumulate, all particles are drawn through the sealing gap. Dirt deposits are prevented and a self-cleaning effect is thus achieved.

The manufacturer employs metal bellows as a secondary seal for the stationary seal face; this helps ensure interruption-free operation. An operating pressure limit of 25 bar and the attainable sliding velocity 120 m/s open up an extensive range of uses in steam turbines with shaft diameters of up to 180 mm. The seal also prevents the formation of dense fogging around the turbine at low external temperatures. Other features include:

•No steam condensate in the bearing oil
•Reduced temperature gradient between seal and bearing
•Great turbine efficiency
•Amortization period is less than one year
•Stationary metal bellows
•SiC-Si/carbon graphite as the combination of face materials
•Statotherm secondary seals
•Bellows made from Inconel
•Open gas seal grooves with self-cleaning effect
•Pressure reversal permitted (vacuum mode)
•Designed as cartridge unit

Burgmann, Feodor, Dichtungswerke Gmbh & Co, Postfach 1240, Wolfratshausen, ?? 82502. Tel: 49-8171-230; Fax: 49-8171-231214.