Take Me Higher

Posted by Chuck Harrell on Aug 5, 2014 10:34:24 AM

elevatorElevators have been around for about 3000 years and used a combination of ropes and pulleys powered by humans, animals or water to lift things. And things didn’t change much until the industrial revolution when the first mechanical lifts were developed. Along the way there were many innovations and in 1853 Elisha Otis patented a steam elevator and also designed a ‘safety break’ feature which prevents lifts falling if the power fails. The powering and gearing mechanisms of lifts kept on developing as buildings kept on getting taller and now modern buildings don’t even require a machine room to house the motors. All modern lifts are pulled using steel cables and whilst this too has improved there are physical limitations of steel that restrict the height at which lifts can go.

The problem isn’t the breaking length of steel but the weight of the steel. Any more than 500 meters long in one vertical run and the weight becomes unfeasible. If you go up a building that is taller than half a kilometer you’ll have to change lifts. But there are companies developing materials that will extend the range of a single run.

UltraRope is a lightweight carbon fiber material that should be able to take lifts to the one kilometer milestone. According to Ben Coxworth “Instead of having the same cross-sectional shape as cable, it’s more ribbon- or tape-like in form. It’s composed of a carbon fiber core, covered in a high-friction plastic coating. An individual elevator car is lifted and lowered by multiple reels of UltraRope, that run into a hoisting machine at the top of the shaft.” The new material has been developed by Finnish lift manufacturer Kone and they say that “an elevator traveling 500 meters,UltraRope would reduce the total moving mass by up to 60 percent as compared to steel cables. That percentage would increase with the distance traveled.” Even on buildings shorter than 500 meters, which use steel, there would be a 15 percent energy reduction. It’s also said to be twice as strong a steel and doesn’t need lubrication and is less sensitive to building sway.

If however, you want a slightly smaller scale project, for example in your house, you may want to look at a pneumatic vacuum lift. Pneumatic lifts have only been available since 2000, when the first one was installed in Argentina, but they are gaining in popularity due to their low cost and easy installation. They work by utilizing air pressure to lift the elevator cab. Turbines located at the top of the cylinder pull air out of the cylinder and draw the cab upward. Once the cab reaches the desired landing, mechanical brakes engage and the door unlocks. Since the amount of power required to “suck” the cab up increases vastly with the length of the tube the maximum height of a pneumatic vacuum lift is approximately 3 stories.

So the physical limits of lifts are coming to an end.

Topics: Did you know?, Useful Hints, Application Stories

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