Hydropower Case Study

Hydropower(1) is known to have a high demand in technical and customizable solutions. The industry is always finding answers to new problems that would effect the primary goal of ensuring a clean and sustainable energy source. With this evergrowing industry, external insight and help in making each hydropower plant fully functional is required. The majority of hydraulic seals utilised in the hydropower plant are interlocked with operational systems residing within the water.

Oz Seals was asked to provide expertise on sealing solutions with their insight on sealing technology. Understanding specific profiles and materials allows clients to understand more of not only what seals are needed, but factors that could effect the hydropower plant’s performance. Below is a specific reference of how Oz Seals have greatly aided and increased efficiency for one of their local hydropower customers.
The Problem
Ozseals was consulted by an Australian Hydropower Company asking for information on a hydraulic sealing solution for the intake control gate. They stated the previous hydraulic seals used on the control gate were inefficient due to the corrosive nature between metal and water, causing material degredation. Previously, these VeePack Seals only consisted of NBR and Fabric Reinforced Material.
The Solution
The previous Vee Packer Seal only caused problems, resulting in constant repairs and downtime. OzSeals, proposed a different combination of material better suited for this situation. Replacing the material with Oz Seals in-house developed SuperRed & Motuf Polyurethane’s, they were able to provide a sealing solution that suppresses corrosion, abrasion and enables a considerably longer lasting seal.

The Results

The initial Oz Seals Vee Pack Seal was installed, and was tight on the system. OzSeals advised that the initial seal would be able to settle in and remove deteriation and corrosion left from the previous seal. Once this had sufficiently occurred, it would be replaced*.

From then on, these seals have remained as a constant sealing solution in all of the companies hydropower plants.
(*As with material change, preload must be considered to make sure the seal fits on component correctly.)

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Deconstruct of Vee Packer Used For the Hydro Power system(4)

HydroPower Turbines Seals

There are many other subassimblies within hydropower facilities that also require sealing solutions. For example, the Kaplan Turbine, a common turbine type in hydropower facilities. Even though this turbine is an evolution of the Francis Turbine, it still has its functional limitations. And with these many turbines, complications can occur. Such as leakage issues.

Major factors Influencing this issue:

  • Size
  • Surface finish of seal ring
  • Thermal expansion and water swell
  • Centrifugal Force
  • Continous Surface Water
  • Static Leaking Path

 

To avoid such problematic occurrances, ever-evolving sealing solutions must be developed.

Improving reliability and minimizing environmental concerns, a split or interlock sealing design are used in blade pitch control systems. The application of this design reduces turbine downtime and maintenannce costs. Oz Seal’s ORSP flexible material is corrosion and abrasive resistant. This enables the seal with the use of the GS6M profile, keep oil and lubrication within the system, and water out.(2)

Complete Drawing of New Super Polymer Ring installed in the Turbine Axial Shaft (4)

Furthermore, an example of super polymer advantages in a Hydro Power Turbine system. Is the beneficial compatibility within the Turbine Axial Seal. Following a report on leakage fluctuations in a Hydropower Turbine system, was brought to a conclusion after fully cleaning the sealing faces and analysing the turbines. The turbine axial shaft that uses super elastic polymer offer advantages for the operator.

 

  1. Robust Construction
  2. Fewer Segments for larger sizes
  3. Simple Material
  4. Reliable in operation and longetivity
  5. Economical
HydroPower Wicket Gate Seals
The Wicket Gates in Francis Turbines are also an essential part of the hydropower system. ORSP seals are a perfect suit as due to their high resistance to abrasion. They are reliable in slow rotary and oscillating applications, and ideal for equipment use in high pressure application and in extreme hot and cold water environments.(2)
Interlock/Puzzle Design, allowing flexibility for installation and adjust ability for maneuvering.
Interlock/Puzzle Design, allowing flexibility for installation and adjust ability for maneuvering.
Material Base for Hydropower Systems(3)

Thermoset Polyurethane, is a versatile material but depending on the formulation, can provide various advantageous properties. Chemically, these polyurethanes are formed from a variety of curatives and additives.

The advatanges of this material within Hydropower systems is that they provide outstanding features such as:

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Abrasion & Wear Resistance
Extending the life of the product and protects the product from the inside.
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Weather Protection
Withstand intense and harsh weather conditions.
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UV Protection
Durable against high ultra violets radiation, extending the wear of the seals.
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Excellent Memory

ORSP Material is perfect for hydropower systems as it contains low defomation values therefore making it flexible and maneuvarable. Especially with positioning on large components and systems.

Self-Lubrication

ORSP contains three specialized lubricants that allows the seal to self lubricate itself. Therefore, no extra lubrication additions would be needed for the seal.

Specialized Glue

Oz Seals, has developed special glue, which can be utilised in making seals conjoined to specific components or put together if the seal was split.

Hydrolysis Resistance

Oz SUPER95 contains a very small water diffusion effect, up to 52% lower than the competitor. Therefore enables to seal also longer insubmerged conditions, leading to less swelling in the seal.

Split & Interlock

ORSP seals has various customisation capabilites due to it’s flexible nature, allowing the seal to have different models. For example Interlock, Puzzle and Split all of which can be glued, if necessary.

Oz Seals Profiles Used in Hydro Power Applications

Oz Seals Profile

GS6M

The profile is designed specfically to provide reliablility for heavy duty applications. Useful for dirt exclusion, to remove, scrape and force out mud/dirt from the shaft. The tough wiping lip allows to stay within contact of the shaft whilst under the pressure of severe heavy loads.

Oz Seals Profile

BST8 Designed for Support

The profile is designed specfically to provide reliablility for heavy duty applications. Useful for dirt exclusion, to remove, scrape and force out mud/dirt from the shaft. The tough wiping lip allows to stay within contact of the shaft whilst under the pressure of severe heavy loads.

Oz Seals Profile

GS6M

The profile is designed specfically to provide reliablility for heavy duty applications. Useful for dirt exclusion, to remove, scrape and force out mud/dirt from the shaft. The tough wiping lip allows to stay within contact of the shaft whilst under the pressure of severe heavy loads.
References
  1. European Comission, “Hydropower,” 2018. [Online].
    Available: Link.[Accessed 16 October 2022].
  2. I. Hajzer, “Kaplan Turbine Sealing: Troubleshooting Leakage,” 2022. [Online].
    Available: Link.[Accessed 16 October 2022].
  3. OzSeals, “THERMOPLASTIC VS. THERMOSET: WHAT’S THE DIFFERENCE?,” OzSeals,5 Janurary 2015. [Online].
    Available: Link.[Accessed 16 October 2022].
  4. OzSeals, “Custom V Pack Seals,” 20 June 2022. [Online].
    Available: Link. [Accessed 16 October 2022].
  5. OzSeals, “GS6M,” 2016. [Online].
    Available: Link. [Accessed 16 October 2022].
  6. OzSeals, “BST8,” 2016. [Online].
    Available: Link. [Accessed 16 October 2022].
  7. A. E. P. P. E. Guojun (Gary) Ren, “Hydro-Turbine Main Shaft Axial Seals of,” 9 Feburary 2009. [Online].
    Available: Link. [Accessed 18 October 2022].
  8. OzSeals, “VP10-12,” 2016. [Online].
    Available: Link. [Accessed 16 October 2022].

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