Innovative shaft and bearing sealing for large diameter wind turbine applications

High Performance Sealing Technology

Walkersele ®

X-Gen

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Radial lip seals have been successfully used since the 1940’s to seal lubricated systems, but today's new generations of wind turbines present significant challenges.

Increased size means an increase in the loadsgenerated throughout the equipment and morestress being imposed on virtually every component in the system, particularly on rotating and transmission components.

Total re-engineering

Faced with these challenges, James Walker examined every element of the large diameter lip seals required for the wind industry, to see what could be done to meet current and future needs. Nothing was off-limits.

The result of this comprehensive re-engineering process is a new patented rubber / glass fibre composite construction with new lip geometery suited to the sealing of grease media and an engineered fingerspring moulded into the seal body to ensure constant seal contact even when extreme eccentric running is encountered.

In-house and OEM testing

Each new element of the seal design was initially developed and validated using FEA. After this ‘virtual’ phase, test regimes were developed to assess the performance envelope of each individual component against customer expectations before complete seals were manufactured and subjected to in-house testing on a new large diameter rotary test rig specifically commissioned for this project. Following successful in-house testing, seals were supplied to key OEM customers in the wind industry for further exhaustive testing.

Throughout this project James Walker has been working in partnership with a number of OEMs seeking to test factors such as seal rotation in the housing, lip load, leakage performance and life expectancy.

The developed solution has demonstrated excellent capabilities in terms of maintaining shaft contact and preventing leakage or the ingress of contaminants, even when faced with eccentric running or extreme shaft deflection.

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Largediameter

Sealinginnovation

Behind the brand

In developing Walkersele X-Gen, James Walker has re-invented the rotary lip seal to meet the demands of large diameter turbine applications for many years to come.

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Component testing and validation

• Flex testing of the joined area of an on-site join variant was carried out on simple bespoke rigs. (To avoid damaging purchased seals, it is recommended that customers do not attempt such testing.)

• Upward and downward deflection to a maximum capability of 130 degrees with no damage evident. Typical aramid fibre backed rotary seal cracked at 110 degrees of deflection in both upward and downward directions.

• Twisting of the joined area tested to 540 degrees before any damage occurred. Typical aramid fibre backed rotary seal broke at 270 degrees of rotation.

• An on-site joined seal can offer all the benefits of an OEM-fitted endless seal but can be fitted in the field with minimal strip-down of the asset.

• Fatigue testing was carried out to simulate response to long-term eccentric running and ensure the spring remained responsive and fully bonded into the seal. No drop-off in performance was observed over the length of the 5 year operational simulation.

• Test regime covered over 7 million cycles over 666 hours to simulate 5 years of operational running in a wind turbine application.

• Lip load testing optimised spring design and material to ensure that a consistent and suitable load could be applied to the seal lip to effectively seal grease media.

• High speed deflection testing determined that the seal lip will follow deflections and irregularities in shaft movement without losing contact with the shaft surface and with a very high speed of response thanks to the fingerspring.

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Joint integrity

Spring performance

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Behind the brand

James Walker's highly advanced mould joining production techniques mean there is no limit on the maximum diameter of endless seals for rotary applications.

Finished product testing and validation

James Walker designed and commissioned a large diameter rotary test rig specifically for testing of finished product prior to customer trials. This rig has the capability to simulate operational running on seals up to 1.1 m in diameter.

The bespoke rig is capable of being configured to test up to 5 mm offset, a tilt of up to 2 degrees or up to 3 mm eccentricity. The tilting operations can be configured to be constant or cyclical, allowing real life operational conditions to be accurately simulated.

• Seal housing – Ø1100 x Ø1164 x 25 mm axial length.

• Eccentricity capacity: Shaft can be run fully concentric or can be repositioned in 0.5 mm increments up to a total of 3 mm away from the central axis.

• Offset: Seal housing can be repositioned laterally, with ±5 mm from a concentric position.

• Seal housing can be tilted by up to 2 degrees.

• Allows continual measurement of torque, temperature, shaft speed and leakage.

Following validation on our in-house test rig, further real-life simulation testing was then carried out by OEMs using commercially produced seals of up to 4.4 m on full-size housing / shaft / bearing set-ups prior to acceptance of the design for field deployment.

Large diameter test rig

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Key benefits:

• Easy and quick to install - no special tools or expertise required.

• Optimised lip load to reduce torque, lip temperature and wear.

• Fingerspring design delivers the optimum lip load consistently for all large shaft sizes and makes installation simpler than other spring options.

• Validated to run at dynamic radial eccentricities of up to ±3.0 mm at surface speeds of 2 m/s.

• Use of circumferentially encapsulated glass fibres as reinforcement, which offers superior compression recovery and consistent long term rotation resistance versus conventional materials.

• New lip geometry optimised for grease sealing.

• Available in endless or James Walker's OSJ -D On-Site Joining format.

• High durability hydrogenated nitrile sealing lip material, with exceptional mechanical properties, abrasion resistance and a wide thermal operating range.

• Lip designed to ensure the seal remains within the seal housing envelope at even the most extreme offset conditions.

• Long term fatigue testing shows consistent response even at high speed, ensuring the sealing lip remains in contact with the sealing surface at all times.

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Let’s talk aboutvalue and benefits

Walkersele ®

X-Gen

Behind the brand

A greener solution - this new design reduces solvent use in manufacture by 98% and distance travelled during manufacture by 94%.

Walkersele X-Gen M33 D10M33 - Hydrogenated nitrile material

with glass fibre reinforcementD10 - Lip profile with moulded fingerspring

"Where can I use Walkersele® X-Gen?"

• Large diameter shaft and bearing sealing applications

• Shaft sizes 600 mm and larger (For other sizes consult your local James Walker company)

• Shaft running surface finish 0.2 to 0.4 μmRa and 60 HRC hardness

• Maximum run-out ±3.0 mm / 1/8" TIR (total indicated run-out)

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Key benefits:

• Easy and quick to install.

• Full fitting service plus removal and recycling of your old seal available globally from James Walker on-site services team for both onshore and offshore locations.

• Strong homogenous bond across the area of the join, equal to or better than that observed with any alternative lip seal constructions.

• All the benefits of an OEM-fitted endless seal but can be fitted in the field with minimal strip-down of the asset.

• Provides identical performance envelope to an endless Walkersele X-Gen product.

• Available as a replacement upgrade for many existing large diameter seals currently fitted on operational turbines.

• James Walker OSJ is a proven joining technique with many thousands of operational seals currently successfully deployed across a wide range of industrial applications from marine propulsion to renewable power generation.

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Let’s talk aboutvalue and benefits

Walkersele® X-Gen OSJ-D for on-site joining and fitting

The cut ends of the seal are accurately located with joining pins and the whole joint is secured in a clamp unit whilst bonding takes place. The process allows for joining and fitting where access is restricted or limited shaft space is available.

Walkersele X-Gen M33 D10 OSJ-DM33 – Hydrogenated nitrile material with glass fibre reinforcementD10 – Lip profile with moulded fingerspringOSJ-D – Supplied as a cut seal with joining kit for on-site joining

Walkersele X-Gen on-site joined

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Behind the brand

James Walker developed its on-site joining technique to help customers reduce the downtime and costs associated with seal changeout.

James Walker Sealing Products & Services Ltd

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James Walker Worldwide

Information given in this publication is given in good faith and represents the results of specific individual tests carried out by James Walker or third parties in accordance with the methodologies described in this publication, performed in a laboratory. No representation or warranty is given in relation to such information. Values and/or operating limits given in this publication are not an indication that these values and/or operating limits can be applied simultaneously. While such results may comprise useful additional information and are industry standard tests, they are no substitute for conducting (or procuring from James Walker) your own tests and engineering analysis and satisfying yourself as to the suitability of the product you select. Please also note that a product tested in accordance with the published methodology may not perform to such values in application and/or under different test conditions or methodologies for a variety of reasons, including but not limited to the environment in which it is used/tested or which passes through it or otherwise affects the product, or due to the handling, storage or installation, or due to the effect of housing or other parts. Our personnel will be happy to discuss any historical examples we have of a product having been previously used in a particular application.

To ensure you are working with the very latest product specifications, please consult the relevant section of the James Walker website: www.jameswalker.biz.

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BP4832 1120/pdf© James Walker 2020