Hydraulic Elevators - Hole Less and Roped
As I understand it, hole less hydraulic elevators are less expensive than conventional hydraulic elevators. The terminology has become more confusing when including roped hydraulic elevators, so I have a few questions:
Are roped hydraulic elevators a subset of hole less hydraulic elevators?
Are they generally less expensive than typical hole less elevators?
Do they extend the travel height of typical hole less elevators (non-telescopic) since they use a one-to-two roping? Or do they instead have a shorter travel distance?
Are LULA elevators typically or even always roped hydraulic elevators?
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Hi Colin,
The types of elevators are gearless traction, geared traction, and hydraulic. Holeless hydraulic is a type of hydraulic which has a more telescopic piston. The elevator itself is not less expensive, but it requires less deep excavation, which may be less expensive in total.
Hydraulics can only be used in buildings up to 60' and they are slow. Geared traction can go higher, and gearless is the only option for skyscrapers.
The think the 'ropes' you are referring to are part of traction elevators. You need to learn the basic types for the ARE. Ballast doesn't have good graphics of all the types, so supplement with youtube video from manufacturers or books. This topic is covered in my course for PPD/PDD.
Good luck!
Rebekka O'Melia, R.A., NCARB, B. Arch, M. Ed, NOMA, Step UP ARE 5.0 Courses
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Hydraulic elevators pump oil in a cylinder, which dives up a piston. Conventional ones require a hole in the ground so the piston can slide down, which poses a problem, either if the water table is above the bottom of the hole, or if you don't like pumping oil under high pressure underground, beneath a concrete building foundation, and hoping that over the next 100 years they'll never be an oil leak to the soil. The EPA hates holed hydraulic elevators for obvious reasons. The hydraulic elevator industry came up with (at least) two holeless hydraulic options to address these concerns. One, telescoping, raises like an antenna, which is fairly intuitive to picture. The other, roped hydraulic, sits at the base of the hoistway (no hole needed) and raises only HALF the travel distance of the elevator. The rest of the travel is made up by the fact that instead of the piston attaching directly to the car, it attaches instead to a rope that, with pulleys, returns a 2:1 travel multiplier. So if the piston/jack rises 10', the ropes pull the car up 20' yet no hole needed. Click here to see a video of this. In this way it's kind of a hybrid between a hydrualic and a traction elevators. This showed up in some low- and mid-rise buildings at some point in history, but was never a popular option and are kind of made fun of today by elevator people. I can't imagine a situation today where we'd prefer a roped hydraulic to a machine-room-less option.
Decades ago, MEEB picked it up as a flavor of elevator despite its relative obscurity. It's stayed in that book over the years despite its continued obscurity (and now irrelevance). I assume it's showed up on exams and we cover it in Amber Book. I'm not sure if it's in the most recent version of MEEB but I wouldn't be surprised if it is. Likewise, NCARB utilizes a question bank of 10,000 or 20,000 test items, drawing many of the questions you'll see on your next exam from past exams. . . and because of MEEB's overrepresentation in the ARE . . . you shouldn't be surprised that this never-common, now-outdate hydraulic/traction hybrid were to show up as a kind of vestigial echo in an exam you sit for. I would hope it would be flagged and pulled. . . and you needn't worry about remembering this post.--Michael Ermann, Amber Book creator.
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Thanks Rebekka!
I've been referencing Mechanical and Electrical Equipment for Buildings (Wiley 2014) and they have a portion on roped hydraulic elevators:
From what I gather, there are at least three types of hole-less hydraulic elevators: non-telescoping single stage, telescoping and roped.
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