blade seals?

Turbines are among the most strategic components found in hydroelectric power equipment.

Among the various existing designs, vertical or horizontal Kaplan turbines are equipped with adjustable blades requiring the installation of dual-action seals.

With over 30 years' experience in hydroelectricity, PXL SEALS has developed sealing solutions adapted to the most demanding cases on the market.

The stakes in this application are very high, because we know that a faulty system leads to turbine immobilisation and therefore a loss of profitability for our customers. In addition, leaks are absolutely unacceptable because of the immediate pollution of rivers.

PXL SEALS' sealing solutions are monoblock, i.e., fully moulded, with regular, tight, and uniform characteristics around the entire circumference of the seals. The system is designed so that it can be installed both as original equipment (OEM) and during maintenance (MRO), in most cases without the need for rework or rehousing. 

1. Characteristics of blade seals

Over time, the housings in which the seals are installed deteriorate. 

Surface conditions can become critical and bearing clearances increase, creating significant variations in housing cross-section, and therefore potential leaks. The constraints this entails must be considered when designing seals:

- Original equipment - OEM:

It is important to protect the surface condition of the housings as much as possible from track marking caused by overtightening, or from corrosion caused by water entering a large part of the housing.

This is why the blade seal housing is protected by the careful assembly of seals and rings.

It is also advisable to adapt the seal to the original dimensions to minimise the risk of wear.

- Maintenance - MRO:

The housings have deteriorated over time and the constraints are greater, in particular:

• Eccentricity of up to 1.7 mm.


• A deteriorated surface condition (sometimes well in excess of 3.2 μm).


• Adaptation to existing housings.

2. The PXL SEALS solutions

PXL SEALS' experience in turbine blade sealing systems means we can cover all the different situations on the market. 

Our excellent knowledge of the field and the various operating sites means that we can react quickly and provide our customers with the best possible support in their project approach, at several levels:

- Technical study

The study is based on the customer's data or on expert assessments of the sealing system or seal in place.

PXL SEALS can intervene to:

• Assess a faulty system by methodically analysing the probable causes of leakage.


• Assess the seals that have been removed.

Replacing a strategic seal is no trivial task. It requires a good knowledge of the applications, the associated constraints, and the environment. PXL SEALS has built up its expertise over 30 years working in the field with our clients, who appreciate the attention devoted to them and the way in which we handle their issues.

Extract from a digital simulation, showing the stresses exerted in the seal 

- Manufacture of the seals in our workshops

By manufacturing our seals in our Bellegarde-sur-Valserine workshop, we are able to control the entire value chain, from the design of the solution to delivery to our customers' sites:

• Development of our own formulas adapted to this particular application


• Preservation in air-conditioned premises


• Preparation of preforms on request


• Moulding and individual inspection of parts


• Careful packaging to avoid damaging the parts


• A skilled, agile team to guarantee short, reliable lead times.


• Replacing blade seals: success stories

The following on-site projects, whether for blade seal maintenance or original equipment installation, are just some of the testimonials to our team's expertise.

Find out more about our blade seal maintenance success stories.

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