The shaft seal type SDK40 is a labyrinth seal system with non split housings and radial adjustable sealing rings. Compared to a rigid lip seal, the SDK40 is significantly more efficient, especially with supercritical rotors.

The shaft seal SDK40 is a non-lubricated system for dry-running applications.


The shaft seal type SDK40 is used in order to seal technical gases, dust and vapour mainly in tubines, compressors and other high pressure devices with sub- and overcritical rotors.
Use of the SDK80 can reduce leakage rates by up to 90%. The technical design of this sealing system is subject to meticulous information about the operating conditions and about the characteristic data of materials.

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Type Overview

The SDK40 can be offered with buffer lubricant, buffer gas, suction drain or without connections.
There are no special feature in dimensions for the shaft seal SDK40 compared to the other shaft seals.

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The sealing rings of the STASSKOL DynamicSeal SDK40 have a 3-part design with radial cut and are held together by a tension spring. The sealing rings are floating on the turbulent and high-energy gas flow without having contact to the shaft.
However, at start-up and shut-down the shaft can be in contact with the sealing elements especially at critical rotation speeds.