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Pneumatic Elevators

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I didn't know they were a thing. I'd look at stress raisers in the tube around the door apertures. Obviously seals are a big part of the potential for problems. The rigidity and sealing of the doors is where long term durability would play a part.

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Greg Locock


New here? Try reading these, they might help FAQ731-376
 
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what do you mean IR stuff?

Like a giant piston / gun or a pneumatic piston?

We had a hydraulic piston lift where I used to work and it wasn't good. Air is too compressible so will keep moving when lots of people get in - very alarming.

Any links or info?

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Yup, those are the type. The car is the piston; evacuation above creates a vacuum on top and air on the bottom. The pneumatics are supposedly easier to maintain and more reliable, and do not require digging a pit under the lowest position. Kind of like an elongated whoopee cushion. Failsafes are supposedly similar to hydraulic, so unless there's a instantaneous failure of the cylinder, it would be like a dashpot releasing, if the pump or valve fails.

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I can do absolutely anything. I'm an expert! faq731-376 forum1529 Entire Forum list
 
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Hydraulic elevators work well and are often used for buildings less than 3 storeys or so... Mechanical room should be in proximity to the lift and size of piping should be properly selected.

Dik
 
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The glass walls would do it in for me [thumbsdown] I always had to stand with my face to the door when riding in those glass elevators at big hotels.

John R. Baker, P.E. (ret)
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Irvine, CA
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The secret of life is not finding someone to live with
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Still not sure how they can react to changes of weight as you get in / out without moving.

The photos make it look like your sending grandma off to meet her maker....

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IRS... in many jurisdictions, you require a pit, even for cable types... some require ladders and some require lighting and some require a minimum pit depth.

Dik
 
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I think cable types require a pit so that car sits on the support springs when idle, rather than on the cables, which requires a pit, as well as some overhead space for the motor.

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It sounds very much like a plunger-assist gas-lift system to get liquids out of a gas well. These work, but take about 5 times more energy than lifting the same mass with hydraulics or electricity. Factor of 5 is a pretty big hit. The sources of the inefficiencies include fluid friction and the huge pressure drop in a gas that goes with making the gas do work.

[bold]David Simpson, PE[/bold]
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist
 
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Back of envelope:

36" diameter --> 1000 square inches.

In one of the videos on a manufacture site you see two guys carrying the piston, so maybe 300 pounds.

Person in a wheelchair, 300 pounds.

So you need 0.6 psi differential. 17 inches of water column.

If we say a "floor" is 10 feet or 120 inches then 120000 cubic inches needs to be removed.

I'd guess that the "vacuum pump" is not exactly silent.
 
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Yes,
Interesting that none of the websites talk much about speed of ascent.....

I suspect it's rather slow.

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They're not bad, but not high speed... They can be faster and easier than stairs. The location of the mechanical room and the fluid pipe size has a big impact...

Dik
 
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Youtube is your friend. About 0.3-0.5 m/s going up. The soundtracks seem to be full of loud music and shouty people so I don't know how loud they are. Given the low pressure differential required it doesn't have to be as bloody awful as a normal compressor. Say 10 cfm at 0.6 psi from MJ's calcs, I'm thinking an extractor fan might even be better than a centrifugal blower.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376
 
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