Offered by us,  honeycomb seals allow for a significant reduction of radial clearance of the turbine, and thus ensure reduction of steam leaks, increase of a  turbine’s efficiency, improvement of occupational safety, and simplify installation. Traditional labyrinth seals are installed initially with considerable clearance, and as a result of vibrations or improper start-up of the turbine they are subject to frequent damage. On the other hand, shaft seals require a precise setting of the axial clearance, which requires multiple impeller adjustments to perform the so-called „axial play”.

The seals we offer work with minimal mounting clearances, which can be adjusted as required during the work. Material of the honeycomb type has a low density in relation to the surface, which allows for its safe abrasion without a sudden increase in temperature or possibility of scuffing.. The honeycomb material used by us is made of S526 alloy, cell diameter 0.79mm, foil thickness 0.05mm. Such material has a low density in relation to the surface, and therefore contact with sealing blades occurs on a relatively small area. This material can work with sealing blades and even with a flat surface.

An important advantage of the honeycomb material is the fact that this structure has a low density, which eliminates vibrations from the pulsation of steam, which can occur when the gap between the impeller bandage and the canopy on the steering wheel is too small. The use of honeycomb type material can reduce such vibrations.


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During the flow of steam between the surface of the honeycomb material and the interacting surface, micro-whirls are formed, which create an additional barrier reducing steam leaks.


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The use of honeycomb seals also allows to maintain a certain level of safety during emergency situations. The thickness of honeycomb seals is usually 4 – 4.5 mm, and by this value the impeller can move radially (in emergencies) without serious damage to the turbine.


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The rim seals that we have developed are characterized by:

Significant increase in turbine efficiency

Resistant to axial movement of the impeller as they do not have any vertical limiting surfaces

Simple assembly – we offer an exchangeable canopy together with a honeycomb material, this  design does not have any connecting elements, the seal installation involves removing the old canopy and replacing it with a new one.

Shorter repair time – the use of our seals in the whole turbine eliminates the need to set axial clearance

Safety operation of the turbine


Idea of using honeycomb rim seals in relation to traditional seals:


The honeycomb shaft seals are assembled in the same way as traditional labyrinth seals.


The segments are supplied with fixed honeycomb material in place of a labyrinth seal, the geometry of the lock remains unchanged. Such a seal does not require exact axial play as there is no risk of collision, which greatly simplifies the repair of the turbine.


Sample photos of our honeycomb seals:


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Marcin Biegas
Vice President
Phone: +48 663 287 285
Email: m.biegas@hexar.com.pl