The elevator industry is witnessing very fast developments and
changes. The major focus of all these developments is towards energy
efficiency, riding comfort and increased speed. But the desire for even better
performance has kept elevator engineers and researchers to keep continuing
their efforts, says Rajnikant Lad, Chartered Engineer & Elevator Consultant
at Shree Jee Elevators.
Globally, the elevator transportation segment has already seen
technological developments like Synchronous machines, Variable Voltage Variable
Frequency (VVVF)drive and door operator, touch buttons, Elevator destination
dispatch(destination control) system, hydraulic system, serial communication,
Bluetooth system, Machine Room-Less elevators, vacuum elevators and soon. But,
there are some more pathbreaking technological developments happening in the
elevator industry which are going to take the elevator utility to a whole new
level.
Carbon Fibre Hoisting Technology– A major restriction to building
taller is the technological constraints of elevators. Taller buildings mean
longer and heavier steel ropes and more energy consumption in just transporting
the ropes themselves. Carbon-fibre technology is an alternative to using steel
cables in elevator systems. A single strand of carbon fibre is thinner than a
human hair but is five times stronger than steel and weighs two-thirds less.
Thus the carbon fibre rope is much lighter than the steel wire rope (just about
19% of the weight of the steel wire rope), is corrosion resistant and has
double the life compared to steel cables. This pioneering technology allows
lifts to travel up to one kilometre in a single run – double of what is
currently possible with a round steel traction cable.
Steel ropes tend to stretch lengthwise, requiring periodic
adjustments and complete replacement in approximately seven years. However,
carbon fibre is elastic and only stretches when tensioned to a certain point to
compensate for a heavier load. Also, as building goes higher, they are more
prone to swaying in high winds and storms. Carbon fibre ropes have a resonance
frequency different than that of the rest of the building, therefore in big
storms and high winds, the elevators can continue to function safely. With the
reduction in rope weight, the need for balancing weight in the form of
counterweight also reduced. This reduction in weight of rope and counterweight
minimizes system loading requirement to a great extent, reducing the capacity
and size hoist motor, gear and other parts. Ultimately helping in a reduction
in energy consumption of the overall system.
Finnish elevator manufacturer Kone has introduced Ultra Rope made
of carbon-fibre-reinforced polymer (CFRP) material core, commonly referred to
as carbon fibre or simply carbon. It is a strong, lightweight and flat cable
with a high friction polyurethane coating. Multiple strands of Ultra Rope are
used to hoist each elevator car, operating in parallel to share the load. Ultra
Rope’s weight is real innovation. As it is significantly lighter than
traditional steel rope, it means the weight of the elevator system and
associated machinery can be downsized as also doing away with the need for a
transfer floor in tall buildings. The introduction of carbon fibre hoisting has
broken the travel height barriers. The engineers can now work for a travel
height of one km which was not possible till now with conventional steel cable
hoists. Moreover, with an increase in the height, the cost saving is about
15%for the height of 500 m and 40% for the height of 800 m as compared to steel
wire ropes.
Magnetic levitation technology – The elevators that enable
skyscraper cities across the globe are now proving a hindrance to ever-taller
towers because their basic design – a single cabin suspended by cables in a
vertical shaft hasn’t changed. The bigger and taller the building, the more
elevator shafts you need. The shafts’ “footprint” can eat up to 40% of a
tower’s space. A new elevator system under development has replaced cables
with magnetic levitation technology, also known as Maglev.
The technology is used in various railway systems around the world
and much like a train, Multi elevators would work by following a mag level
track throughout a building. A magnetized coil running along the track repels
magnets located in the vehicle’s undercarriage, causing it to levitate a short
distance above the tracks. The trains are then pulled forward by a moving magnetic
field, created by coils embedded in walls alongside the track. The
embedded “traffic control” system will prevent the elevator cabins from forming
vertical traffic jams and smacking into one another.
Germany’s ThyssenKrupp has unveiled the first cable-free elevator,
called the Multi, powered by maglevmotors and allow several cabins to zip along
a single shaft in a continuous,flowing loop. The system would even allow the
cabins to move horizontally, in a zig-zag pattern, or on inclines, giving
architects the freedom to design exotic buildings that breakaway from the
now-standard tall and skinny format. Since the elevators could also move
horizontally, they could be shunted off the continuous loop and into a “garage”
for cleaning and maintenance. The mag level elevators will use much less floor
space than traditional elevators since multiple cars can operate on the same
track. Moreover, building manager scan simply adds more elevator cars to a
single multi-track to increase the frequency of elevator pickups.
Nanotechnology – Advances in research into nanotechnology and
carbon nanotube materials are now presenting the opportunity to create a cable
that would be strong enough to support the immense forces on a space elevator.
Diamond nano threads, due to their stiffness and strength, are the material of
choice currently being developed by JohnV. Badding and his research team at
Penn State University. The strength of a diamond nano-thread means that this
nanomaterial could be used to create the cables of a space elevator. The cables
need to be both incredibly light and incredibly strong to provide the stability
required for a space elevator to operate.
The inventor of the “space elevator” is Brendan Quine, an
engineering professor at York University in Toronto and co-founder of Thoth
Technology. The elevator can take the payload into space with expenses of about
1/100 of the regular spacecraft lunch. Carbon nano-threads is 100 times
stronger than steel and is as flexible as plastic.
The basic principle is like tether ballgame where a ball is
attached to one end of the rope and the other end of the rope is attached to a
pole. Here the rope is Carbon neon tube composite ribbon, the earth is pole and
the ball is the counterweight. This will allow vehicle transport along the
planetary surface(Earth) to space /orbit without the use of rockets.The
satellite will be lifted to space through the elevator and will be placed in
the geostationary orbit at an altitude about 35,800 km. Apart from the obvious
benefits of transporting material into space in a more cost-effective manner, a
space elevator also has huge applications for space launches.
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