FEATURE FASTENING & JOINING
Can three grams of adhesive pull 208 tons of freight train?
THE CHALLENGE When Henkel started to explore the best way to convey the merits of its latest LOCTITE structural bonding development, it set its sights on creating a demonstration that would really make industry take notice. Henkel engineers decided to show the strength and durability of new and patented LOCTITE hybrid adhesive technology by designing a bonded coupler that would pull freight train wagons weighing 208 tons. The new adhesive that was chosen was
S
tructural bonding is fast gaining popularity over conventional joining
methods for several reasons. The ability to join dissimilar materials such as plastics and metals is one significant benefit as it allows different combinations to be chosen for their performance quality without having to consider the joining method. A bonded joint is also sealed so it prevents leakage and corrosion and as there is no visible sign of the join. When it comes to strength and
durability, adhesive manufacturers are often met with a degree of resistance. Even though structural adhesives are used in some of the toughest applications – automotive and aerospace manufacture to name but two – some people remain unaware of the true scope of structural bonding. Others doubt its suitability over traditional joining methods.
Above: Bringing the two freight train wagons together using the LOCTITE adhesive
Top right: The teams celebrating after completing the challenge
LOCTITE HY 4070. It is one of new breed of adhesives that combine the critical attributes of several adhesive technologies to achieve bond strength, durability and cure speed. These qualities are also complemented by improved health and safety credentials. Good impact resistance makes HY 4070
suitable for joining the elements of products that are subject to drop testing or shock loading. It also provides good elasticity, an important consideration when joining parts subject to relative movement. Fixture and cure speeds of this product are similar to those of an instant adhesive and this is achievable even when there is a relatively large gap between mating parts. Selecting the best adhesive for the job,
however, was only part of the story. As with all applications, the design of the rig
Subsea coupler provides new opportunities for remote emergency release systems
As a global supplier of polymer-based critical sealing solutions, Trelleborg was asked to create a seal that would work inside a new product that was developed by Subsea Technologies Ltd (STL). STL’s two-inch Hydraulically Retractable Subsea Coupler assists in
creating its XR Connector’s unequalled high-angle release capability, which has no maximum riser angle limit. The company had previously developed small bore retractable couplers, used as sub-components in its XR Connector, however, scaling up to a large two-inch bore to allow for choke and kill lines passing through, posed a number of major challenges. A seal needed to be developed that would work in harmony with the
coupler, the world’s first of that size, with a hydraulically retractable element. Trelleborg set about meeting these requirements and developed custom versions of its Turcon Captive Glyd Ring with XploR V9T82 elastomer material and Turcon Stepseal 2A CR with PEEK corner reinforcement rings. The 2A CR is a new standard corner reinforced rod/piston seal for single-acting use; the dimensions of the seal body and corner reinforcement ring can be modified to facilitate installation.
that connected the engine to the lead wagon had a huge bearing on the overall outcome of the test.
SUCCESS ON THE TRAIN TRACKS “208 tons is a lot of weight on a small bonded assembly,” explains Austin Campbell, one of the engineers who designed the rig. “We therefore incorporated springs in the mounts to accommodate movement and to add strength we specified toughened pins to hold the rig under the knuckle couplers.” Having cleaned and sanded the steel
plates, all it took was just three grams of LOCTITE HY 4070 and one hour of cure time to create the bonded assembly. Campbell adds: “The train started to
move, pulling 208 tons of wagons along the track, up hills and over bridges. Ultimately the steel plates bent, but the adhesive join held firm. It was a tremendous effort by all the LOCTITE teams involved. Making a success of such a powerful demo was a great feeling.”
Henkel
www.henkel.com
Andrew Longdon, technical manager for Trelleborg Sealing Solutions in
the UK, comments: “We worked with STL as the team conducted a very lengthy test programme, including a full PR-2 temperature and pressure cycling programme. STL also conducted two disconnects with 10,000 psi bore pressure. This was all completed with one set of seals.” The coupler provides new opportunities for remote emergency release
system designs for subsea applications and it allows the heavy-duty engagement of equipment both on surface and subsea to be separated from the comparatively delicate engagement of control system interfaces. Trelleborg Sealing Solutions
www.trelleborg.com
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SEPTEMBER 2017 | FACTORY EQUIPMENT
/ FACTORYEQUIPMENT
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