The cranes and hoists for the job hahe turbines and generators on most modern power stations are big beasts which need some hefty lifting work for their manufacture, installation and routine servicing. The big rotors alone can weigh over 100t. The cranes and hoists for the job have to be big too.
Power stations also need a range of smaller lifting equipment for ancillary functions and in many of them, for handling the fuel too, be it coal or woodchips, and even domestic refuse in sustainable "power-from-waste" plants. Other uses include controlling the water sluices on power dams or handling the uranium fuel rods in nuclear power stations.
Specifications for the cranes vary considerably. "For most power stations turbine halls the loads are large" says Chris Lindley-Smith, sales director at Street Crane in the UK "but the frequency of lifts is not. They get used for the installation and then for routine, perhaps annual servicing."
"You will have an intensive period of use during the installation and assembly and then a crane could remain unused for one or more years even" agrees Erik Hänsicke at Brunnhuber cranes in Germany, part of the larger Teichmann group.
The requirements are important for the design says Lindley-Smith because capacity must be good, higher than many uses, but fatigue resistance and other factors that a constant use production crane would have to take into account in its design are less significant. That affects the motors, the ropes, the pulleys, the structure itself."
Street Crane supplies mainly in the UK, primarily for turbine halls, but also finds significant sales in this sector around the world. A recent installation is of three 120t capacity cranes in Dubai for a plant owned by Emirates Aluminium, plus an additional 87t unit. "We also sell some via dealers worldwide."
Major German firm Stahl Crane Systems also has a significant presence in the power sector. Several recent orders have been in the Asian market.
One is for the Wang Noi gas power station, 70 km north of Bangkok in Thailand. The 1990s plant initially comprised three blocks generating 1.91 Gigawatts. A fourth block is now adding 768MW extra capacity and to equip it an order for crane systems was placed with Alia, Stahl CraneSystems’ Thai partner. It includes several small cranes with safe working lcoads 25t and 40t but also two heavy lifting cranes with rope winches, with 180t capacity.
In this range, Alla uses Stahl’ new SW winch the German firm reports which features high safe working load, compact dimension and low-maintenance.
High millimetre accuracy is also important positioning the big gas turbines and without jolting. Stahl says the frequency inverters on its drives allow smooth starting and braking characteristics with minimum load swing.
Both cranes are equipped with 25 t STAHL CraneSystems wire rope hoists as "smaller" auxiliary hoists. Stahl has also recently completed an order for lifting heavy transformers in several substations in the Kai Tak district in Hong Kong together with Jardine Engineering Corporation a regular partner there.
A particular difficulty was the low headroom of the buildings. The designers took advantage of Stahl endcarriage design which allowed crane bridges to be mounted at the sides, saving headroom.Brunnhuber has delivered all around Europe says Hänsicke and clients include Alstom, Gaz de France, EoN Power, Siemens and Statwerk Augsburg Energie & Gas. Capacities are anything from 5t to 500t he says, with tasks varying from general purpose use to servicing the big turbines and generators. "The cranes usually are built-in during construction before the power equipment and are then used for its installation" he says.
Like Street, Brunnhuber does supply some units to the nuclear power sector too. Mostly these are peripheral units used in non-critical areas and among places supplied is the new Olkiluoto reactor in western Finland.
Nuclear power is a specialised area in itself and has particular requirements both in the safety standards of the cranes and their operation and down to the particular materials that can be used in their manufacture, especially when they are used in the closed radioactive environment. There is also a range of crane types not often found elsewhere such as the "polar crane" used inside the reactor vessel. These are beam type cranes for fuel and control rod operations running on a circular track at either end. The crane beam spins around a central axis like the needle on a compass and together with the movement of the crane trolley along the beam, can find any particular position over the reactor.
Cask handling cranes, for lifting safely the sealed radiation proof containers for new or spent fuel, are another critical types of crane, both for positioning casks in a storage building, perhaps under water, and for transporting the casks. For the latter purpose there are cask transporter units themselves containing their own lifting hoist equipment. Nuclear power also uses turbines and so turbine hall cranes are important too, which are similar to those on conventional power stations.
One of the biggest suppliers to this sector is Konecranes, which although based in Finland does much of its nuclear work from its US division based in Berlin, Wisconsin in the USA and with bases throughout the states. The company has a long record in the industry going back around 50 years and emphasises strongly its technical experience base for matching the stringent regulatory requirements for the industry and working with various power customers to tailor the equipment.
"There are two major issues for such cranes" says Nick Bellwood, general sales manager for the UK, the Middle East, and parts of the European market. "For some cranes, operating in radioactive environments, there is a need to avoid certain types of materials, particularly some plastics like PVC, some paints and even certain metal alloys."
"You also have to avoid materials which might fall into the water of the ‘pool hall’ where fuel rods are stored" he says. "Some materials can alter the PH of the water which can affect the rods themselves."
The cranes also have to be critically secure in their operation to a standard known as "single failure safety", meaning that no failure of a single component on the crane can be allowed to jeopardise the load. Either the component will be duplicated, so that if a brake fails for example there is a second capable of holding the load, or failure will leads to a safe deposition of the load.
"You also have to ensure a very high standard of manufacture, and of checking and re-inspecting the parts and welds as the equipment is made" says Bellwood. "And there needs to be materials traceability for the component’s supply chain."
"You can see why this is important particularly for areas with limited or only very difficult human access" he says.
Konecranes brands its failure-safe system as "Supersafe" and says it is now on a third generation of designs using the principle.
As well as the overall design principles used on the cranes, any installation is examined in conjunction with the power plant engineers the firm says. Designs are analysed in general and in particular circumstances against factors such as seismic conditions.
Konecranes is currently marketing a new third-generation version of its polar crane, which comes with a both a main and a subsidiary hoist. In addition there is a small auxiliary jib crane, so that the main unit can lift in its own parts during repair or maintenance. Finally it has a telescopic inspection platform to allow the inside of the reactor building to be inspected from the crane itself.
Among other products made for nuclear are various beam cranes for fuel and cask handling and big beam cranes for turbine halls. These are also installed in nonnuclear plants.
There is a also a transporter unit made by the firm, the Vertical Cask Transporter which lifts the casks within a heavy duty U-shaped steel frame which is on eight rubber tyred wheels with omni-directional independent turning for maximum manoeuvrability.
Bellwood says these are different to the transporters used by many facilities which are usually tracked vehicles like excavators. "The metal linked tracks can chew up concrete hard standing areas whereas ours are very light in the wear effect" he says.
Among power facility operators named in its brochure currently there is Arizona Public Service, Ringhalls in Sweden and Constellation Energy in New York.
A critical part of holding onto this specialist market, of which Konecranes has a large share, comes through its worldwide network of technical support says Bellwood and the fact that qualified engineers can be contacted quickly in most countries.
But the firm is not the only competitor for nuclear. Currently from Kalingrad in Russia Baltkran has a good presence. The firm, which began in 1945 as a state corporation in the USSR is now owned by UKOIL and German engineering firm Noel serving primarily eastern Europe and the former USSR area. It makes both beam and double beam cranes for nuclear stations, the firm says.
Recent orders include a three crane system for unit of Novovoronezh Nuclear Power Plant An electronic control system of cranes is used to prevent crane or hook collision. The cranes comprise an overhead unit with 440t capacity and a span of 45m on the upper tier of power house used for installation turbines and generator stators. It has two trolleys and spreaders for tandem lifting and smooth travel.
On the lower tier two widespan overhead cranes are situated. These cranes have the lifting capacity of 50t and 15t.
In the reactor building meanwhile there is a crane-platform with 360t capacity for loading reactor vessels, steam generators and pressure compensators and other heavy items. It also transports fresh and spent fuel.
The firm says it is currently installing two complex cranes for the first and second power islands of the Baltic nuclear power plant, each with a safe working load of 360t. They will be used for cargo delivery from outside transport to the overhead bridge and back at a height of 40 meters. Items to be moved include the reactor vessel, steam generator and spent nuclear fuel casks. Baltkran says its cranes are designed to allow for air crash, air blast wave and extreme wind and snow loads as well as seismic loading.
Another significant maker for nuclear is Italy’s Meloni, which makes cranes for heavy industry and power uses as Hoist reported in June 2012. A number of its products have gone into nuclear storage, waste or power plants including even the notorious Chernobyl facility in the Ukraine where a special unit was provided to Ansaldo Nucleare of Genoa for a hoist positioning system to move a special mechanical gripper used to handle big concrete lids at a liquid radioactive waste treatment plant. The 2t capacity unit had to allow hoist, rotation, traversing and travelling.
For the same client the company provided a medium size gantry crane with a 7m span and 5t capacity to handle radioactive canister storage at the Covra Habog nuclear waste plant at Vlissingen in the Netherlands. It also supplied a bunker crane for handling waste in 3 bunkers which had a 6.3t capacity and 12.6 m span. With that came another unit, a transfer crane for the bunker crane, with an emergency recovery system for the bunker crane. This unit had a span of 4 m and a length 13 m.
In Slovakia at the Mochovce nuclear plant the company has supplied two overhead cranes with , capacities of 125 and 50to and a span 40.2 m. It also undertook renovation for four other overhead cranes.
Nuclear also brings a requirement for decommissioning of the power stations once they are exhausted and this is currently a major market in the UK for example. Nuclear waste processing as at Sellafield in the UK is also important.
Via its specialist sister company, SCX, Street Cranes in the UK has an involvement in this sector providing units for a variety of purposes.
"In general the need is for cranes with a lifespan of around ten years" says Andy Whitworth, SCX director "which is the time needed for taking apart a facility."
But the cranes still need significant upgrade and safety changes. "Sometimes this will be for single component failure and sometimes just for secondary recovery capacity" says Whitsworth.
Every crane is different, he says, depending on its task and where it will be working, from safe areas to radioactive areas where remote operation is required adding additional positional feedback and CCTV onto the cranes.
"They are all designed to a customer’s specification."
SCX does not make the biggest polar cranes and units but says the market is significant. "It is estimated one plant will need around 1500 lifting units" he says.
It also includes a variety of semi-robotidsed grabs and lifters for extracting waste. Specialist cranes, if not to such extremely exacting standards are also needed for hydropower where gantry cranes and beam cranes are important for both maintenance and control work of sluices and powerhouses.
Konecranes also makes lifting equipment for this including gantry cranes for intake gates and cranes for the power houses as well as hoists used on modern wind power turbines.
Another supplier with experience in this sector is the US firm Han-Tek which supplies overhead cranes for powerhouses for gate control. It has supplied gantry cranes for dams on the St Lawrence Seaway for the New York (state) Power Authority for example, two 250t units that roll across the dam.
"We also do renovation work" says sales manager Todd Vandesande. A current example is the overhaul and renovation with new hoist mechanisms of overhead cranes on the St Stephens power dam in South Carolina. The original cranes date to the 1980s. The supply contract is with the US Corp of Engineers.
For all the specialist work there is also a significant market for mainstream use in "everyday" thermal power stations and this covers both the use of hoists within the power stations themselves and also for the manufacture of the big units.
German supplier Terex-Demag supplies to both sides of the business, but has seen some particularly important contracts for manufacture especially with big corporation Siemens which employs some 85 000 people in the energy sector. In the recent period it has fitted out Siemen’s turbine production plant in Görlitz, which makes steam turbines up to 250MW in capacity.
The installation was carefully designed into improved work flow says Demag using overhead material transport to maximise floor space. A three level installation included two large overhead process cranes to handle components between 40t and 70t and then to move turbine packages of up to 190t to the shipping out area.
Currently Terex Material Handling is fitting out a new plant in the Leningrad region near St Petersburg in Russia where turbines above 60MWwill be produced for the Russian and former USSR CIS states.
Both process cranes and universal cranes, are being delivered and installed to complete the works by the end of this year. The cranes will support all steps of the production, shipping and maintenance of the turbines working on all parts of all assembly lines, interlinking the individual workstations.
That will involve handling heavy loads and ensuring individual assembly stations are precisely served with components are positioned precisely to millimetre level. Cranes are equipped with two hoist units to allow them to turn components safely, which is important for assembly with items like turbine housings.
The integrated logistics system consists of seven radio-controlled double-girder overhead travelling cranes and four wallmounted travelling cranes travelling on three crane levels. Five process cranes have a span of 27m and with various load capacities operate on the top level. The largest has three hoist units with load capacities of 250/150/16t for large components and moving completed turbines. Two further units operate on a second level to serve the workstations with material using 25t hoist units. These cranes can also be used to support assembly work using an additional 5t rope hoist,.
At the workstation level, three Demag EWKE wall-mounted travelling cranes, with an outreach of 10m will move loads weighing up to 3.2t. A fourth wallmounted travelling crane will be of doublegirder design with an outreach of 11m equipped with travelling hoists of 5t capacity. Demag says the order "emphasises our leading position as a system supplier for the mechanical engineering sector all over the world".
The firm provides cranes for another sector of the marker too, handling feed materials for boiler furnaces. This can be for coal and in some modern "sustainable power" plants even wood chip. One recent installation of the latter is near Hamburg for a wood-fired combined heat and power station
A fully automated crane installation at Hamburg-Lohbrügge allows the fuel to be stored compactly in bunkers and then supplies the powerhouse on a continuous 24hour basis. The control system allows automated blending operation for homogenous incineration rates.One of the dangers of combustible materials storage is explosion and for this reason particularly another German firm finds a market in this sector. The long established J D Neuhaus, makes hoists powered not electrically but by compressed air or sometimes hydraulic systems and together with other design principles this makes them "explosion proof" for use in a wide range of at-risk areas, from the oil industry to flour stores.
The firm supplies many of its hoists for general purpose use in power stations, primarily in the lower capacity range from 0.5t to 10t. "They are relatively easy to set up" says export sales manager Espen Gulliksen "as you only have to plug them in to an airline which many plants have."
This ready use means the units are often supplied on a hire basis he says brought in for a task."There is some use in nuclear but it is only for the same kind of general purpose in non-critical areas" he says.
Power stations also need a range of smaller lifting equipment for ancillary functions and in many of them, for handling the fuel too, be it coal or woodchips, and even domestic refuse in sustainable "power-from-waste" plants. Other uses include controlling the water sluices on power dams or handling the uranium fuel rods in nuclear power stations.
Specifications for the cranes vary considerably. "For most power stations turbine halls the loads are large," says Chris Lindley-Smith, sales director at Street Crane in the UK "but the frequency of lifts is not. They get used for the installation and then for routine, perhaps annual servicing."
"You will have an intensive period of use during the installation and assembly and then a crane could remain unused for one or more years even" agrees Erik Hänsicke at Brunnhuber cranes in Germany, part of the larger Teichmann group.
The requirements are important for the design says Lindley-Smith because capacity must be good, higher than many uses, but fatigue resistance and other factors that a constant use production crane would have to take into account in its design are less significant. That affects the motors, the ropes, the pulleys, the structure itself."
Street Crane supplies mainly in the UK, primarily for turbine halls, but also finds significant sales in this sector around the world. A recent installation is of three 120t capacity cranes in Dubai for a plant owned by Emirates Aluminium, plus an additional 87t unit. "We also sell some via dealers worldwide."
Brunnhuber has delivered all around Europe says Hänsicke and clients include Alstom, Gaz de France and EoN Power,.
