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ME 579 – Fluid Power Engineering Elevator design exercisefowen/me579/ElevatorDesign.pdf · Elevator design exercise This assignment asks you to do a preliminary design for an elevator

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Page 1: ME 579 – Fluid Power Engineering Elevator design exercisefowen/me579/ElevatorDesign.pdf · Elevator design exercise This assignment asks you to do a preliminary design for an elevator

ME 579 – Fluid Power Engineering

Elevator design exercise

This assignment asks you to do a preliminary design for an elevator with the following characteristics.

You should work in teams of two to figure out the details asked for below.

Elevator-design facts:

Use a safety factor of 3 for your design.

An empty elevator (1500 lb) generates about 150 psi of load pressure. A full elevator (2500 lb load +

1500 lb elevator = 4000 lb total load) generates about 500 psi of load pressure.

3” steel, grooved piping is used for hydraulic supply. Typically it uses these special Victaulic couplings.

Design for speeds of 100 ft/min. 15 ft/min will be the go-slow speed.

Let’s design for a five-floor building with 12 feet/floor. From this you will have to select

a) What type of elevator to use (just make it hydraulic)

b) What the jack configuration should be (single jack, telescoping jacks, etc.). Professor Rossman

tells me that nowadays companies do not like to drill holes for elevator jacks. Thus an elevator

with the jack alongside the car needs to be specified if possible. Also she says that the elevator

jack cannot extend up above the car by more than about 2 feet. There is a space above the

elevator, called a “refuge space” where a person can fit without being crushed between the

elevator and the top of the elevator shaft.

Use Victaulic pipes and couplings.

For each floor have at least two limit switches, one to switch to go-slow mode, one for full stop. I don’t

know whether you need two switches for go-slow mode, one for going up and one for going down.

Use a screw pump, or, if the hydraulic supply is a complete unit, whatever comes with it.

For equipment, investigate the Elevator Equipment Corporation in Los Angeles.

This elevator will be for a LEED-certified building, the elevator must be a “green” elevator, which means,

principally, that the fluid used should be environmentally friendly.

Deliverables:

1. Make drawings that show the hydraulic part of the elevator and the elevator controls.

2. Make a Bill of Materials that show as many of the components that you can identify as part of

your design.

Design questions:

1. ANSI-ASME A17.1 was the design code for elevator design back around the year 2000. What

code is being used today for elevator design? Is there an ISO code used instead? See ISO/TC

178.

2. Why are Victaulic couplings used in lieu of just normal steel pipes?

Page 2: ME 579 – Fluid Power Engineering Elevator design exercisefowen/me579/ElevatorDesign.pdf · Elevator design exercise This assignment asks you to do a preliminary design for an elevator

3. For safety, check what is normal to deploy in the case of hydraulic elevators? Is there special

hydraulic circuitry needed for the elevator? Is there some type of catching mechanism that

springs into action if there is an uncontrolled descent?

4. If a fully-loaded elevator at the top floor went into free fall for any reason, what would be its

speed at the bottom of the elevator travel?

5. What is the flow rate needed for full upward travel? What will be the flow rate for downward

travel? If the jacks are multi-stage, assume that their movement is coordinated so that all

stages are at the same proportion of travel as they extend and retract. Figure out the flow rates

to each jack during extension and retraction.

6. Figure out the proper hydraulic-supply unit for the elevator.

7. Explain the function of the elevator control valve at https://eecoelevatorcomponents.com/.

Apparently “U” stands for “up” and “D” for “down”. The items across the bottom—D1, D2, U1,

U2, etc.—are solenoids. They turn green when they are energized. The passages in this valve

are complicated, maybe serving as pilots to open and close various parts of the valve. I believe

that “Up Accelerate, Full Speed, Transition, Up Leveling, and Up Stop” refer to the different

phases of upward motion. “Up Leveling”, I believe, means getting the elevator car level with the

floor at which it is arriving. It is interesting that these phases going up are different from the

same phases going down. Why the two directions seem to have completely different hydraulic

configurations of flow is something you want to explain. Also make sure to look at the

photograph of the valve on the EECO website.

I have tried to specify as much detail as possible here, but it is possible/probable that I have left

something off. If there is missing information, decide on something reasonable and explain your choice,

or ask me to specify more information.