Types of Elevators

Elevators allow people to move goods vertically in a shaft connecting the floors of a building. Elevators became more common in the 1850s when steel and iron structural frames made it possible to build taller buildings. However, Elisha Otis’s safety mechanism prevented the car from falling and made them popular. Elevators are required in almost all multi-floor buildings to provide universal access.

  • Hydraulic Elevators
  • Geared Traction Elevators with Machine room
  • Machine-Room – Less (MRL), Elevators

Three types of elevators are commonly used: machine-room-less traction, machine-room-with-machine room traction, and hydraulic. However, each type has its variations.

Hydraulic Elevators

A hydraulic elevator is supported by a piston that sits at the bottom. This piston pushes up the elevator as an electric motor forces oil into the piston. As the fluid is released from the piston, the elevator descends. These elevators are suitable for low-rise applications with 2-8 stories. They travel at a maximum speed of 200 feet per hour. The elevator shaft is at the lowest level, and the machine room for hydraulic elevators can be found at the lowest level.

Conventional Hydraulic Elevators include a sheave below the elevator pit floor that accepts the retracting lever as the elevator descends. Some configurations include a telescoping piston, which collapses and requires a deeper hole below the pit. The maximum travel distance is 60 feet

Hydraulic Elevators are equipped with a piston at either end of the cab. The telescoping pistons in this configuration are attached at the bottom of the pit. They do not need a sheave below the pit. Telescoping pistons can travel up to 50 feet. Telescoping pistons can only travel about 20 feet.

Roped Hydraulic Elevators move using a combination of ropes and a piston. The maximum travel distance is approximately 60 feet.

Hydraulic elevators are less expensive than other types of elevators and require less maintenance. Hydraulic elevators consume more energy than other types because the electric motor forces hydraulic fluid into the piston against gravity. Hydraulic elevators can leak sometimes, which can pose a danger to the environment. Hydraulic lift part suppliers aren’t being used as frequently as they were in the past due to their high energy consumption and environmental risk.

Traction Elevators, Geared and Without Gears, with Machine Room

Traction elevators can be lifted using ropes that pass above an electric motor attached to the elevator shaft. These elevators are ideal for high-rise and mid-rise applications. They have a much faster travel speed than hydraulic elevators. The counterweight reduces the motor’s weight and makes elevators more efficient.

Geared Traction Elevators include a gearbox attached to the motor. This drives the wheel that moves ropes. A geared traction elevator can travel at speeds of up to 500 feet per hour. A geared traction elevator can travel approximately 250 feet.

The wheel is attached directly to the motor in gear-less traction elevators. They can travel up to 2,000 feet per hour and have a maximum distance of approximately 2,000 feet, making them the best choice for high-rise applications.

The traction elevators with gears are the middle of all three in terms of energy consumption, ongoing maintenance costs, initial cost, and cost. Gearless traction elevators are more expensive than geared ones, have lower ongoing maintenance costs, and consume energy slightly less efficiently than geared elevators.

The traction elevator ropes, sheaves, and cables must be regularly checked for wear. Slippage increases and the friction between the cables and sheaves decreases. This can lead to decreased efficiency and could be dangerous.

The length and weight restrictions for traction elevators are determined by the length of the ropes or cables. New materials, like carbon fiber, that are stronger than the old ones, will enable traction elevators to reach new heights.

Machine-Room-Less Elevators (MRL).

Machine Room-Less Elevators traction elevators do not have a machine room above the elevator shaft. When maintenance or repairs are needed, the machine is located in the override area and can be accessed from the top. The control boxes can be found in the control room, which is located on the highest landing of the elevator and within 150 feet of the machine.

Machine-room-less elevators can travel up to 250 feet at a time and can reach speeds of up to 500 feet per minute. MRL elevators have similar initial and maintenance costs to geared traction elevators, but they consume less energy than geared elevators.

Mid-rise buildings with a travel distance of up to 250 feet are increasingly choosing machine-room-less elevators. They are more energy-efficient, take up less space, and are as reliable and efficient as gear-less traction elevators.

MRL elevators were not widely adopted in the United States because building codes didn’t allow for the motor to be within the hoistway. Although this is changing, it is still worth checking with your local codes before you specify an MRL elevator.

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