Difference Between Hydraulic and Traction Elevators

Elevators play an important role in modern life and facilitate vertical movement in tall buildings. However, deciding between traction and hydraulic systems can be overwhelming. In this article, we will thoroughly examine the mechanics, types, and features of both elevator systems, helping you make an informed choice for your building.

Review of Traction Elevators and Their Types

What is a Traction Elevator?

A traction elevator, also known as an electric elevator or cable elevator, is a type of elevator that uses a rope or cable along with a motorized pulley system to transport people or goods vertically between floors of a building. This type of elevator is suitable for use in various buildings and is known for its efficiency, speed, and adaptability.

How Traction Elevators Work

A traction elevator uses ropes or cables in conjunction with a motorized pulley system to facilitate the vertical movement of the elevator cabin. The ropes or cables are connected to a pulley or sheave at the top of the elevator shaft and then connected to a motorized traction machine that regulates the elevator's movement. When called to a floor, the traction machine activates the motor and causes the ropes or cables to move, thereby transporting the elevator cabin in the desired direction. To descend, the traction machine reverses the motor, causing the ropes or cables to unwind from the pulley or sheave, facilitating the descent of the elevator cabin. The movement of the ropes or cables is precisely controlled by the traction device to ensure a smooth and safe ride between floors. When the elevator cabin reaches the desired floor, the traction device stops, and the ropes or cables hold the elevator cabin in position until a new destination is selected.

Types of Traction Elevators

Geared Traction Elevator: Uses a gearbox and a motor to drive the elevator cabin via the hoisting rope. They are typically installed in medium to tall buildings and have a maximum weight capacity of 4500 kilograms. Geared traction elevators are excellent options for a smooth and quiet ride and are often found in office buildings, hotels, and residential buildings.

Gearless Traction Elevator: Uses a motor that is directly connected to the hoisting rope, eliminating the need for a gearbox. This design allows for higher speed and weight capacity compared to geared traction elevators, with a maximum weight capacity of up to 12000 kilograms. Gearless traction elevators are commonly used in tall buildings such as skyscrapers and provide a smooth and quiet ride.

Machine Room-Less Traction Elevator (MRL): In this type of elevator, all equipment is located in the elevator shaft, eliminating the need for a separate machine room. This design saves space and reduces installation costs, making it a popular option for modern buildings. MRL traction elevators are available in both geared and gearless versions.

Advantages of Traction Elevators

Higher Speed and Longer Travel Distance: Traction elevators have high travel speeds, with some models reaching speeds of over 2.5 meters per second, allowing for faster vertical transportation.

Smooth Ride Quality: Traction elevators are known for their smooth operation and high comfort for passengers during the ride.

Energy Efficiency: Modern traction elevators use variable voltage frequency (VVVF) technology, which helps reduce energy consumption and achieve energy-saving benefits.

Long Lifespan: Traction elevators experience less wear and tear compared to hydraulic elevators and have a longer useful life, thus increasing durability and reliability.

Quiet Operation: Traction elevators are generally quieter than hydraulic elevators because they use a motorized pulley system instead of hydraulic pumps, resulting in reduced noise during operation.

Suitable for Buildings of All Heights: Traction elevators are versatile and can be installed in various types of buildings, including residential, commercial, and tall buildings, and can be custom manufactured to meet specific building needs.

Disadvantages of Traction Elevators

Challenging Installation: Installing traction elevators can be more complex compared to hydraulic elevators, as it involves installing ropes, cables, and counterweights.

Specific Building Requirements: Traction elevators have specific requirements for overhead and pit dimensions that must be considered during installation.

Review of Hydraulic Elevators and Their Types

What is a Hydraulic Elevator?

A hydraulic elevator is a form of vertical transportation that uses a hydraulic system to move people or objects between different levels of a building. This type of elevator is typically used in buildings with fewer floors, such as short to medium structures, usually up to 7 levels (stations).

How Hydraulic Elevators Work

A hydraulic elevator uses a mechanism that includes cylinders filled with fluid and a pump to facilitate the vertical movement of the elevator cabin. The elevator cabin is supported by a piston connected to the bottom of the cabin, which is located inside a cylinder filled with hydraulic fluid (usually oil). When the elevator is called to a floor, an electric pump pushes hydraulic fluid into the cylinder, causing the piston to move upward and lift the elevator cabin. To descend, the hydraulic fluid is released from the cylinder, allowing the elevator cabin to come down. The flow of hydraulic fluid is regulated by a valve operated by the elevator control system, ensuring smooth and safe movement between floors. When the elevator cabin reaches the desired floor, the valve closes, and the hydraulic system holds the elevator cabin in position until a new destination is selected.

Types of Hydraulic Elevators

In-Ground Hydraulic Elevator (Direct Jack): Similar to conventional hydraulic elevators, but the difference is that they are installed below the elevator shaft, in a designated pit. This specific installation method makes them a desirable choice for retrofitting older buildings that lack the necessary space for overhead machinery.

Holeless Hydraulic Elevator: Uses a telescopic piston system that eliminates the need for a separate cylinder and pit, resulting in a more space-efficient option that does not require digging below the elevator shaft.

Cable Hydraulic Elevator: In this type of elevator, hydraulic and mechanical systems are combined to vertically transport the elevator cabin. They have a piston and cylinder system, similar to conventional hydraulic elevators, but also use a cable and a sheave system for added support and stability.

Advantages of Hydraulic Elevators

Superior for Heavy Loads: Hydraulic elevators are capable of lifting heavier loads compared to traction elevators due to their strong lifting capability.

Faster Installation: Hydraulic elevators have a simpler structure compared to other types of elevators, making installation and maintenance quicker and easier.

Cost-Effective: The simpler mechanical components of hydraulic elevators lead to lower installation and maintenance costs, making them a more cost-effective choice for various buildings and specific budgets.

No Need for Machine Room: Hydraulic elevators can be configured as machine room-less elevators (MRL), where the hydraulic pump and other components are located in the elevator shaft or in an adjacent cabinet. This eliminates the need for a separate machine room and provides additional space-saving benefits.

Disadvantages of Hydraulic Elevators

Unsuitable for Tall Buildings: Hydraulic elevators perform less efficiently at greater heights and are therefore not suitable for tall buildings, which typically limit to buildings up to 7 floors.

Speed Limitations: Hydraulic elevators have speed limitations, usually up to 0.8 meters per second, which may not be sufficient for some tall or high-traffic buildings.

Lower Efficiency: Hydraulic elevators require more power to operate compared to traction elevators due to the need to generate sufficient pressure with the hydraulic pump. This can lead to higher energy consumption and operational costs over time.

Somewhat Noisier: Hydraulic elevators may produce more noise during operation compared to traction elevators, as the hydraulic pump and motor can generate some noise. This is unsuitable for tall buildings. However, this issue can be mitigated by placing the electric motor inside the hydraulic oil tank (submersible power unit).

Price Difference Between Hydraulic and Traction Elevators

With the same travel height and capacity and amenities for both hydraulic and traction elevators, the price of hydraulic elevators is significantly lower, as the equipment and components used are less expensive and also require much less time and cost for installation compared to traction elevators.

Comparison of Hydraulic and Traction Elevators

Which One is More Suitable for Your Building?

In conclusion, hydraulic elevators have advantages in terms of safety and load capacity, but they have shortcomings in terms of speed, space occupancy, and environmental protection. Traction elevators have advantages in terms of speed, smooth operation, and space occupancy, but they have shortcomings in terms of installation costs, maintenance costs, and load capacity. When deciding between traction and hydraulic elevators, it is important to carefully consider the specific needs of your building. Consulting with a qualified elevator specialist can help you make the best decision for your building.

At www.asiaborj.com, we specialize in providing the best hydraulic elevator systems tailored to the specific needs of your building. Our team of experts will work with you to determine the best type of elevator for your building, taking into account factors such as building height, passenger volume, available space, and budget. Contact us today to learn more about our elevator systems and find out how we can help you find the right elevator for your building.

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