NEARLY TWO YEARS AGO, US company All Energy Management (AEM) began developing retrofits and training com-panies that service a fleet of 1,000 wind turbines in the UK, the US, Canada and Italy.
When embarking on repair work, it was found that the pins attaching the turbine blades to the rotor were wearing prematurely, along with the rotor holes. Line boring and welding when up on the turbine tower was not possible due to weight and space constraints. The only solution was to replace the rotor and pins, which took roughly 10 working days and cost USD 15,000.
Subsequently, AEM began discussions with Expander about developing a solution that would increase speed, improve efficiency and maintenance safety, and ultimately reduce costs. AEM developed a system to bore the holes out before installing the pins to ensure a reliable connection. Sets of three pivot pins and three different oversized sleeve options were supplied by Expander, which fitted perfectly into the holes depending on the degree of wear.
Fewer parts meant faster and simpler installation, while the Expander System also provided a perfect fit into the borehole, eliminating further movement causing wear. AEM has now been using the solution for over a year and is delighted with the results. “Instead of taking three days with four workers onsite to repair a turbine, it now takes us less than a day with only two workers required,” says Ian Sleger, Operations Manager. “The guys at Expander are really accommodating and the solution has freed us up to concentrate on other matters.”
First published in Bolted #1 2017.
The people of Nuremberg are proud of their underground system, which is among the most modern in Europe. The city, located in Bavaria, Southern Germany, has the only underground network in Germany where two of the three lines operate automatically, without train drivers. Nuremberg trains travel the equivalent of the circumference of the earth twice each day, carrying more than one hundred million passengers per year.
After 40 years of continuous use, it comes as no surprise that a renovation of the track beds is required to ensure passenger safety. The main beam, also known as a concrete stringer, which attaches the tracks to the tunnel floor, has simply sustained damage in too many places.
This is a daunting issue for the provider of the Nuremberg metro services, VAG (Verkehrs-Aktiengesellschaft Nürnberg). Normally, metro companies need to completely shut down a track for weeks during the renovation of such concrete stringers. Employing water pressure to remove the concrete, it is a time-consuming and extremely dangerous job, considering the many power lines inside the tunnel. Long delays caused by closed tunnels are costly for the track operators, adversely affecting train traffic and irritating passengers.
Coming to the rescue, a brand new innovation caught VAG’s attention just as they started planning the renovation. Local Nuremberg dowel and concrete bolt manufacturer TOGE Dübel won a railway innovation award for a new concept that enhances the sustainability of existing concrete bridges. Present in the audience, VAG representatives were intrigued and had the idea of trying the concept for the first time in an underground rail environment. Currently, work is under way at the first three stations: Bärenschanze, Gostenhof and Maximilianstrasse. Work on the second largest station in the network, the “Plärrer”, with 98,000 passengers daily, is planned for 2017.
Instead of complete reconstruction, concrete bolts measuring 36 centimetres and weighing 1 kilo are utilised as load-bearing components to improve the life span of the overall track bed construction. The bolts are fitted with a patented special thread that cuts into the borehole wall upon application. The force of the bolt is mechanically transferred to the anchor base and the concrete is fixed in place.
“Completely removing a concrete stringer and installing a new one could never be accomplished without service disruption,” says Waldemar Gunkel, Technical Director of TOGE and one of the two inventors of the new generation of concrete bolts.
“In Nuremberg, however, our system is only being installed between the hours of 23.00 and 04.00. By the morning, everything is running normally.”
During these working hours, only one track is shut down and trains are redirected via a single track, while the porous areas of concrete on each stringer are chipped away and replaced. Finally, the stringers are fixed into the ground utilising the concrete bolts. Since the bolts need to be drilled into the concrete, there is a risk of inclination as the drilling machine might not be positioned at an exact 90-degree angle. That’s why all concrete bolts that are being used in this first project are secured by Nord-Lock X-series washers. Their conical shape can compensate for the inclination, while the wedge effect prevents spontaneous bolt loosening due to vibration.
The Nord-Lock connection came via Deutsche Bahn – Germany’s national railway operator – where Nord-Lock original wedge-locking technology has long been prescribed as the standard.
Jochen Süssenbach, Nord-Lock Project Account Manager, sees great potential in this new approach to metro renovation. “We’re looking at a huge renovation of the tunnels that virtually doesn’t affect the timetable at all”, he says. “In terms of costs, it’s also a solution that beats any conventional method.”
So far, the renovation is running as planned. The first construction phase has even been completed a week ahead of schedule and the total time for construction carried out at all three metro stations will last six weeks instead of several months, which could have been the case with the previous method.
The concrete bolts themselves are designed to last for 50 years. No concrete will last that long, but further renovations will not be necessary for decades.
Describing TOGE’s Innovation Award-winning solution, Bavarian Interior and Transport Minister Joachim Herrmann said the following: “We have our fingers right on the pulse.” He hinted at the billion-dollar losses that Germany faces due to the poor condition of some 120,000 highway bridges and 30,000 railway bridges.
THE UNDERGROUND RAIL SYSTEMS are in a similar state. Just as in Nuremberg, most metro networks in Germany, as well as in the rest of Europe, were established in the 1970s. Gunkel thinks TOGE has found an important application for its concrete bolt: “This project gives us the boost to further drive our product development forward.”
Facts: The Nord-Lock Solution
Client: TOGE Dübel GmbH & Co.KG.
End customer: Metro services provider, Verkehrs-Aktiengesellschaft Nürnberg (VAG).
Location: Nuremberg, Germany.
Project: Renovating concrete stringers under metro tracks without affecting traffic.
Solution: Using concrete bolts with a patented special thread to reinforce the existing structure.
Nord-Lock Product: X-series multifunctional wedge-locking washers with enlarged outer diameter (NLX24sp)
First published in Bolted #1 2018.
IN 2015, ELON MUSK, the billionaire behind the futuristic transport technology companies Tesla and SpaceX, launched the Hyperloop Pod Competition. It challenges university students to design the best transport pods for the Hyperloop– Musk’s dream where people will travel inside a pod that levitates on its tracks and races at almost supersonic speeds through a giant tunnel
network, which connects the major cities of the world.
During the 2017 competition, the WARR Hyperloop team from the Technical University of Munich was the one that finally raised the laser-sintered titanium trophy. During the competition, they broke a world-speed record for hyperloop pod travel, using Nord-Lock wedge-locking washers to secure each bolt of their pod.
THE 30-STRONG WARR Hyperloop team was divided into several sub-teams to manage areas ranging from CAD design and structure to procurement, finance and marketing. Sub-team leader for CAD design and structure, Florian Janke, says he was inspired by Musk’s vision for a superfast futuristic transport system, and especially the idea that people could one day travel from Munich to Berlin in just 30 minutes.
He says that, “When Musk launched his ‘SpaceX competitions’, I just had to be part of it. We did well in all the stages of the Hyperloop Pod Competition. In the last one, which focused on maximum speed, we achieved 324 km/h (210 mph).”
The WARR Hyperloop team’s lightweight pod smashed the previous 310 km/h (192 mph) record speed set by California-based Hyperloop One, whose pod reached this speed in a 500-metre tube. “There is obviously lots of acceleration and vibration when testing at such high speeds in a relatively short tube – 1.2 km (0.8 miles),” Janke explains. “It was essential that we had secure bolts, so we used Nord-Lock wedge-locking washers, which held the bolts firmly in place. They were perfect.”
The WARR team has registered for the next, third Hyperloop competition, and has already passed the first selection round. While some team members are active in the new, 2018 team, albeit in new roles and positions, most of the them are carrying on with their studies. A few are travelling from trade fair to trade fair showing the 2017 winning pod.
AS THE TEAM worked very closely with a lot of manufacturers in order to get financial backing and various parts, some team members have since had interviews with these companies, and are now considering working there.
First published in Bolted #2 2017.
Daher Nuclear Technologies GmbH, located in Hanau close to Frankfurt am Main, Germany, develops containers for transportation of radioactive substances. For obvious reasons, these containers must be extremely safe.
Designing a new container for uranium hexafluoride transports, the company had to consider the very stringent international and national requirements, including the recommendations of the International Atomic Energy Agency (IAEA) for transport by road, rail and sea. A container that fulfils these requirements must, for example, be resistant to the mechanical and thermal loads that can occur in case of an accident.
These mechanical accident loads are defined by a sequence of tests that include a 120-centimetre fall, followed by a 9-metre fall, followed by a fall from 1 metre onto a spike. The container must remain sealed, so that the subsequent thermal test, a fire, doesn’t jeopardise the container’s safety.
Daher set out to design the container locks so that the locking bolts would, under no condition, come loose or be lost during the loading of the container onto a lorry or during transport. The company’s intensive search for the optimal solution led to Nord-Lock wedge-locking washers of type NL16-254SMO. These safety washers are an important component in Daher’s triple-protected locking system: the lock is secured with a bolt, which in turn is locked in position by another bolt. The wedge-locking washers from Nord-Lock are located under the second of these bolts. Each container has six locks and each lock is equipped with a Nord-Lock washer pair.
Thanks to the use of Nord-Lock wedge-locking technology, the locking systems on the Daher transport container for the nuclear industry can no longer be worn by vibrations or stress, but remain tightly and securely locked. Daher was also pleased to find how cost-effective the use of the Nord-Lock product is, and how easy the maintenance is. If needed, the wedge-locking washers can be replaced at any time to ensure that the transport containers remain in top condition. The containers have a service life of more than 30 years – something that the Nord-Lock washers contribute to.
First published in Bolted #2 2017.
CUSTOMER: HATTAT TRAKTÖR
HORSE POWER RANGE: 50–102
LOCATION: CERKEZKOY, TEKIRDAG, TURKEY
NORD-LOCK PRODUCTS: NORD-LOCK WASHERS NL8 AND NL10
PRODUCTS: TRACTORS FOR AGRICULTURAL APPLICATIONS
A producer of agricultural vehicles for close to 20 years, Turkish company Hattat Traktör knows that, when the going gets tough, it is the durability and reliability of their products that save the day. The company’s customers often deal with rugged terrain for long periods, racing against time to maintain productivity, so their machinery must be able to withstand tough conditions such as handling vibration.
Early in 2017, when Hattat Traktör was testing a new tractor model, they realized that the joints on the air compressor–engine connection bracket were loosening because of vibration. According to the company’s vibration analysis, this problem could have been solved by a costly and time-consuming change in the bracket design, or by replacing the loosening bolts with stronger ones.
At this point, the company’s research and development department started looking for new components for their design. After days of research and evaluation, they found Nord-Lock washers, which had the potential to save them from a more costly solution.
During the tests, Nord-Lock washers proved that they could solve the problem, and this solution was much cheaper than having to change the bracket design. With Nord-Lock washers in place, the vibration caused no more loosening, to the relief of Hattat Traktör customers, who can now rely on their red tractors, even under the harshest conditions.
First published in Bolted #2 2017.
CUSTOMER: PACECO ESPAÑA S.A
PRODUCTS: QUAY CRANES, YARD CRANES, SERVICES AND SYSTEMS FOR CONTAINER HANDLING
SHAREHOLDERS: MITSUI GROUP AND URSSA, S. COOP.
NORD-LOCK PRODUCT: NORD-LOCK 20 / NL20
Offering cranes, services and systems to the container-handling industry, engineering company Paceco España (Spain) must adjust to its customers’ needs. As ships get bigger, quay and yard cranes must increase height and reach, while also becoming more efficient. Today, Paceco España can load and offload ships from 25 container lines. The company currently produces one of the largest and most efficient cranes on the market, the Portainer Malaccamax, which maximally offers a 72.5-metre outreach, a 52.5-metre clearance under spreader, and a 30.48-metre rail span.
Paceco España first connected with Nord-Lock in 2009, when there was a problem with one of the company’s quay cranes. The crane, with a 65-ton load capacity, had problems with the fixing of the gantry reducers – the gearboxes that move the quay crane along the dock. During operation, the fixing screws vibrated loose.
During their problem analyses, Paceco España’s engineers connected with Nord-Lock and when it presented a solution, Paceco España was pleasantly surprised. “We have been using their washers since 2009, and haven’t had any problems with bolted connections being subject to vibrations since then,” says engineer Pelayo Bobes. “With Nord-Lock washers, we have been able to provide total customer satisfaction and in turn saved both money and time.”
First published in Bolted #2 2017.
You first worked with Superbolt tensioners at Diablo Dam in 1984. How did that come about?
“I was a machinist working at Seattle City Light, the electric utility for Seattle. We worked out of the machine shop down there, and we would go up and be labour support at Diablo Dam. In 1984, they were doing a stator-rotor inspection on the turbine, so they had to remove the rotor; that involves taking the thrust bearing apart, which is mounted on the turbine shaft. It is very important that the thrust block is perpendicular to the shaft within less than one-thousandth of an inch. Otherwise, it will have run-out and wobble.”
How did the Superbolt tensioners help with that?
“Back then, to get the right tension in the bolts, you had to heat the bolts so they would elongate, do the installation, and then wait for them to cool overnight. If the thrust bearing wasn’t sitting right on top of the shaft, you had to do it all over.
“The engineers at Diablo Dam had been in contact with Superbolt, and they modified the bolts so you didn’t have to go through this long process. Instead, we could tighten up those little bolts. If the thrust bearing wasn’t exactly perpendicular, you just tweaked the bolts on the opposite side. It was a very labour-saving modification.”
Today, you work at Wells Dam. What do you do there?
“I’ve been with the Wells Hydroelectric Project for about 17 years, managing and monitoring the project. What I’ve always enjoyed about my work is that every day there are new challenges or something that you’ve got to fix. We’ve got air systems, electrical systems, mechanical systems, hydraulic systems – all these different auxiliary systems that feed the turbines that run 24 hours a day.”
How has the dam been modernized over the years?
“One of the ways that it has been modernized is that we have installed PLCs on the majority of our alarm systems. Today, we have over 2,500 alarm points on different systems. This allows us to set more parameters for the alarm points, and we can also trend over time and compare with different machines. If something is starting to fail, you can set up a parameter to get an alarm so you can look into it before the failure actually happens.
“We are also using Superbolt tensioners when rebuilding our turbines. They’re being used in the load screws that hold the turbine bearing shoes in place, and in our turbine’s outer head cover, where you can’t access the bolts with a big wrench because it’s close quarters. They’re very reliable.”
FACTS: MIKE BRUNO
TITLE: Project Superintendent, Wells Hydroelectric Project, Douglas County Public Utility district
LIVES: Chelan, Washington
BACKGROUND: Has a degree in industrial technology from Shoreline College; also studied at Cogswell College. Worked at Seattle City Light as a hydro machinist and foreman until 1990, then as a mechanical supervisor for the Skagit River Hydroelectric Project until 2000. Since then with Wells Hydroelectric Project.
PASSION: Married with three grown daughters, two granddaughters. Enjoys bow hunting and playing golf.
Doosan Heavy Industries & Construction required a bolt tensioning solution to tighten nuclear reactor pressure vessel stud bolts. Boltight was contacted to design a hydraulic tensioning tool to achieve a predetermined bolt elongation, without exceeding the reactor head’s maximum allowable bearing stress.
The required bolt load was critically high (14,500 kN), and the space envelope was very small – the radial space available to install and operate the tensioner was particularly tight.
A tensioning system was designed to accommodate this high preload capacity within the space available. In realising these tools, Boltight engineers also incorporated a hydraulic piston retraction function into the design; to enable the equipment to be reset quickly, reducing operator fatigue. To compensate for dynamic joint behaviour, a spherical reaction nut and piston interface was integrated to accommodate any bending effects in the event of flange rotation.
Various safety mechanisms were incorporated to protect both the tools and the operators. Pressure relief valves were installed, and a floating gearbox design was engineered to avert damage should nut misalignment occur. The gearbox directly interfaced the geared nut which negated the need for a costly, heavy socket, and provided the necessary torque to rotate the nut.
Boltight were able to supply a complicated, bespoke design to exacting standards and achieved the tight delivery period set down by the client.