Saturday, April 3, 2010

Behind the scene of the elevator operation

Almost everyday we take elevator somewhere along our daily routine but do you have any idea what goes behind the operation? The concept of elevator is incredibly simple, its a compartment attached to a lifting system. Tie a box to a box and you get a basic elevator.

The most popular elevator design which can be found mainly in this country is the roped elevator. In roped system the lift car is raised and lowered by traction steel ropes which is looped around a sheave and connected at the other end to a counterweight. The counterweight balances the car as well as conserve energy. Imagine a seesaw when both of the lift car and counterweight are in operation.

The motor room is basically the heart of an elevator operation. The motor room is usually located at the top floor of a building. The motors, sheaves, governor and controller are usually housed here.

The more advance design now is to maximize the available space in the building by using motor room less design where the motor room is not required for the elevator operation.

This is the sheaves where the wire ropes seat. One end is connected to the lift car and the other end to the counterweight.

The governor is basically the second line of defense in the roped system (the wire ropes of the elevators are consider the first line of defense).

It has an independent rope system which runs along with the lift car. Should the lift car travels above its rated speed (free fall let's say), it will activates the safety gear below the lift car to bring it to a halt, just like the braking system we used to.

The safety gear commonly found below the lift car

Wire ropes are usually used to hold both the lift car and counterweight. In theory, only one rope is required to support the weight of the elevator and counterweight on its own. For safety reason, elevators are built with multiple ropes (at least 3 ropes by regulations in Malaysia). In the event that one rope snaps, the rest will still hold the elevator up.

Car top is a term used for the area above the lift car. In most Hollywood movies we see those actors made their exit through a hatch above while inside the lift car. In fact, it is not possible as the emergency hatch can only be open from the car top.

The typical counterweight normally found in the roped system. The counterweight weights about the same as the car filled to 40-50% capacity.

This is the mechanical lock which keeps the landing door from opening while one is waiting on the other end. The door will only open when the lift car arrive and opens simultaneously with the car door.

At the very bottom part of the lift well is the lift pit. I have heard some lift pits were filled with water and fishes. This area is supposed to be clean and dry.

The buffer is located at the lift pit act as the last line of defense if all means fail and the lift car is inevitable experiencing a free fall. It acts as a energy absorber for the falling lift car.

In other words, one should feel safe when using an elevator. In the movies, we used to see the hoist ropes snapping into two and send the car and its passengers hurling down the lift well. In reality, there is very little chance of this happening based on several redundant safety system in place as highlighted above


Bananazക said...

Thankz for sharing the backroom operation. You are into this elevator biz? tQ.

wenn said...

thx for the interesting info!

the donG said...

and we should be so happy as those things hold so strong for us to safely be transported to each floors.

foongpc said...

Wow! This is such an educational post for me! Very informative!

So let me confirm this.

1. There is NO WAY a lift can free fall? What if really bad luck and all the ropes snap at the same time? Sure die right? Maybe due to the work of a terrorist who set off a bomb and damages all the ropes? Not impossible right?

Oh ya, you still have the brakes and the buffer. So still can survive although depends on your luck I guess. Haha!

2. You can't climb out of the lift as depicted in movies? Why they keep bluffing us? Hmpph!

3. So lift pits are never ever filled with water and fishes? Why the heck do anyone want to fill it with water and fishes in the first place?

Borneo Falcon said...

1. Yes, if all the ropes failed, there are still safety gear and buffer.

2. The movies bluff us for a long time. Now you know the truth

3. The water might got there probably from leak elsewhere like the roof for instance. How the fish got there? It is still anyone guess

SJB said...

Cool :D.

Elevators said...

Useful Information!! You can also visit Elevator Interior

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