Power Engineer - Engines Turbines

 

Construction completes on wind turbine blade test facility

A new facility that will enable the UK to lead the World in the testing of offshore wind turbine blades has been completed by national contractor Shepherd Construction.

The contractor this week handed over the 5,700m² steel frame structure to the National Renewable Energy Centre (Narec) in Blyth, Northumberland. The project is the second of three structures to be completed at Blyth as part of a £80 million + investment by Narec in world-class facilities for the accelerated testing of offshore renewable energy technologies.

The new Blade Test Facility will be the largest in the world and has been designed to test the longer blades being developed for larger offshore turbines. It will add significantly to Narec’s existing capability for testing blades up to 50 metres in length.

Constructing the building, which is 123 metres in length (slightly shorter than Gateshead’s Millennium Bridge at 126 metres), has itself been a complex engineering feat.  The project, however, has also involved building the test hub that will support the blades during testing.

Shepherd Construction has worked extremely closely with Narec and the project team to find an engineered solution that would withstand the forces applied during testing and the vibrations that will be created.

The result is a test hub comprising a 15-metre high concrete superstructure with two huge rings.  The top ring of 8m diameter is designed to accommodate the testing of blades up to 100m. The smaller bottom ring will accommodate blades of smaller root diameter.  The hub arm includes substantial foundations.

To achieve the exact position of the rings within the concrete structure 216 post-tensioned bars have been cast in to extremely tight tolerances of ±3mm.  Special winches fixed to 132 circular steel rings in the floor have also been manufactured and will be used to flex the blades during testing.

Andrew Constantine, commercial director for Shepherd Construction commented: “As there are currently no other facilities of this scale in operation, the project team has had to come up with a unique solution necessitating precisely calculated tolerances that will enable the structure to withstand the rigours of testing. This makes it all the more worthwhile to see the blade test facility handed over and on its way to helping the UK further advance the offshore renewable energy.”

The new facility will provide an independent and confidential environment to accelerate the development of new blade designs before they are taken offshore.

Andrew Mill, CEO of Narec, said: “This is a unique facility which can accommodate the largest blades being developed for the offshore wind industry.  Shepherd Construction has worked with contractors and our own blade specialists to deliver a bespoke solution.  Narec will now commission the new facility ready for commercial operations at the start of next year.”

Turner & Townsend provided both project management and cost management services, and were employed by the design team.

Jonathan Lunn, Associate Director at Turner & Townsend, added: “We are extremely pleased to have successfully managed the completion of the blade test facility. The unique nature and physical magnitude of the facility has required an extensive mix of both precision engineering and traditional construction expertise.”

Design Engineer - Drilling

 

 

Tool system creates synergy between 20kW rock drills and 45mm drill bits

A 30 to 80 per cent increase in rod life, more accurate collaring and straighter blast-holes are the main benefits of Alpha 330, a brand new tool system developed by Sandvik. Designed to exploit the power of 20kW drifters to drill small-diameter holes faster, Alpha 330 signals a new era of rock-tool economy.

Even an amateur knows it is no good using a big hammer to drive a small nail. The same principle applies in percussive rock-drilling, which is why manufacturers go to great lengths to match the strength of the drilling tools with the impact energy of the rock drill.

But what happens when market forces demand both a big hammer and a small nail?

The analogy reflects what has happened in drifting and tunnelling with cross-sections up to 50m2. In a nutshell, mining and civil engineers are keen to exploit the power and speed of 20kW rock drills in order to raise productivity, yet insist on keeping the bit diameter small – 45mm to be precise.

The snag is that the conventional R32 thread at the front of drifter rods for 45mm bits – nominally the biggest thread possible – is not quite man enough for the punishment meted out by 20kW machines, especially when the predominant rock resistance presents itself to the drill bit obliquely, causing the rod to bend.

Breakages occur typically at the gooseneck between the full rod-section and the R32 thread. With Alpha 330, which has a much more robust connection between the rod and bit, the frequency of such breakages is a thing of the past. The resultant tool economy, together with more accurate collaring and straighter holes that give better fragmentation and improved profile-control, brings down the overall cost of drifting and tunnelling yet again.

Design Engineer - Motors And Drives

 

 

PROFINET interface for distributed and control cabinet inverters

NORD Drivesystems supplies technology boxes for the integration of frequency inverters into PROFINET environments. Modular units for cabinet-installed SK 500E inverters are available from the second quarter of 2011. In the fourth quarter of this year, a version for distributed SK 200E-type inverters will follow.

The new PROFINET box from NORD cost-efficiently connects a large number of inverters to a single bus line, since there is no need for repeaters or additional bus master interfaces. The technology box supports real-time data transfer and features an integrated Ethernet switch, an integrated web server, and a PROFINET status display. Optionally, fibre optic lines are also supported.

The bus module can be mounted either directly on the inverter’s interface unit or separately from the inverter by means of an optional wall mounting kit. The PROFINET bus line is connected to the box via an RJ45 plug connector. Optionally, for distributed installation, the bus can be connected via an M12 circular connector. In addition, the decentralized box features eight integrated 24V inputs and two 24V outputs. Thanks to gateway functionality, a single PROFINET technology box can address up to four inverters. An integrated RS232/RS485 interface allows for on-the-spot access to the parameters of the connected bus module and inverters by means of the SK PAR manual control unit or via NORDCON PC software. The decentralized modules have a standard protection rating of IP55, and can be supplied for IP66 on request.

Process Engineer - Process Equipment

Distributed inverter series covers universal application range

SK 200E series frequency inverters from NORD DRIVESYSTEMS provide solutions with adaptable functions for any application within a distributed automation concept where cost-efficient drives with a performance between 0.25 and 22 kW are required.   
 
Available for installation near the motor or as motor-integrated models, various types cover all typical distributed applications. 

Frequency inverters from the SK 2x0E line, for instance, are equipped with a process and PI controller, and qualify for use with fans and pumps through their internal 24 V power supply and two analogue inputs. 

By contrast, the SK 2X5E line is tailored for the needs of conveyor technology. Inverters from this series are equipped with a brake controller and two integrated potentiometers which allow for easy adaptation to the requirements of any drive task. 

Thanks to standard features such as speed feedback (servo mode) and a positioning function (POSICON), these inverters can also independently and precisely control positioning and lifting tasks. 

The units are performance-graded and can be fitted with various optional add-on functions, allowing users to choose suitable compact devices with the exact feature range for any given task, thereby optimising resource use. The feature list of all basic models includes sensorless current vector control, a brake chopper, incremental encoder evaluation, POSICON positioning control, and energy saving functions. 

A plug-in memory module (EEPROM) enables users to quickly and easily exchange parameter sets with other units of the same type. In addition to standard fieldbus options, the inverters are also available with an integrated AS interface as well as the STO Safe Torque Off and SS1 Safe Stop 1 safety functions certified by German testing authority TÜV. The inverters are primarily designed for direct installation on the terminal box of geared motors. NORD provides additional services, pre-configuring these fully integrated drive units for operation in the field with the required protection class (optional: ATEX zone 22 / 3D). The robust, reliable and economic drive units are available in sizes 1 to 4 with a maximum output of 22 kW.

Tungsten carbide coatings for extreme abrasion resistance

 

Patrice Fournier outlines the benefits of a new generation of tungsten carbide coatings

The oil and gas industry continuously faces dilemmas regarding its operation efficiency. Contractors are more demanding of extreme performance coating materials that offer exceptional performance, reduce plant downtime and increase service intervals - all with constant respect of the environmental constraints.
Deep drilling exploration and oil sand exploitation are two of the more challenging applications which require innovative coating solutions for longer operating times which are under more severe abrasive and corrosive environments and at higher pressures than regular drilling.

Problems of abrasion
Exploitation techniques often requires separation of the water from oil. During operation, huge problems of abrasion occur thus reducing the life of pipes, elbows, pumps, separators, casings, etc.
Downhole tools for drilling are subject to combined stresses such as abrasion, erosion, impact, corrosion and contact pressure. Because their non-sufficient fracture toughness, the traditional 'commodity' tungsten carbide coatings can't withstand all of these stresses simultaneously.
Constant research and development efforts conducted thermal sprayed coatings and hard-faced overlays to become more and more complex with feature enhancements allowing for more severe operating conditions as well as coating life improvement.
The improvement has been achieved with important innovations by alloying proprietary powders with tungsten carbide/metal powders, nano WC/Co, macro WC and/or superfine WC/Co materials. They are mixed with hard and tough metal matrixes which offer exceptional hardness, abrasion/erosion wear resistance and corrosion resistance - and consequently with improved fracture toughness. These grains can be used as powder or converted into electrodes, flexicords and tungsten carbide ropes. These new materials can be sprayed, PTA cladded or brazed with a flame welding torch.
The Hardkarb flexicord or high velocity thermal spray processes allow to produce high abrasion and erosion resistant WC coating with improved fracture toughness. The metal matrix can be chosen from Cobalt, Cobalt-Chrome, Nickel or Ni-Cr-Mo alloys if petrochemical corrosion is present. The usual thickness of these coatings ranges from 0.3mm to 1mm (0.01-in to 0.04-in).
In regards to hard-facing techniques, versus arc welding, the flame welding (brazing) technique is still the best suited technique to avoid decomposition of WC tungsten carbide and allows to produce tungsten carbides welded overlays that contain the lowest content of brittle W2C phases. The usual thickness of these hard-faced overlays ranges from 1.5mm to 1mm (0.06-in to 0.2-in).The brazed overlays combine abrasion resistance, contact pressure resistance as well as rupture toughness in the final coating.

Thermal spray equipment
Improving the coating materials would only be the halfway to the objective, if equipment improvements have not been made. Traditional coating equipment provides limited effectiveness because it is primarily intended for external surfaces and not internal ones. New thermal spray equipment is available for applying coatings to internal diameters. Thermal spray equipment is capable of applying internal coatings down to ~ 6 inches with expected lengths of up to 12 feet.
With a large emphasis on coating performance, the thermal spray industry accomplishes innovative solutions and contributes to create and bring new and highly differentiated products to the market in a cost-effective and efficient time frame.