The Hydraulic Lift
Hydraulic lifts are available in various designs, including direct-acting hydraulic lifts, scissor lifts and column lifts. They all use an electrohydraulic drive system to generate the required lifting force.
Of these designs, Janzen Lifttechnik manufactures hydraulically driven goods lifts based on scissor lift tables and column lifts.
The Scissor Lift
In a scissor lift, the platform or lift car is raised by a scissor mechanism. An electric motor drives a hydraulic pump, which supplies hydraulic oil to the lifting cylinders. As the cylinders extend, the scissor mechanism unfolds, raising the platform and its load.
For a more detailed explanation of the operating principle, see “How does a hydraulic lift table work?”.
The Column Lift
In a column lift, the platform or lift car moves along guide rails positioned to one side. Unlike a scissor lift, this design does not require a scissor mechanism beneath the platform.
An electric motor drives a hydraulic pump, which supplies hydraulic oil to the cylinders. Depending on the design, the resulting lifting force is transmitted to the platform or lift car either directly or via ropes and pulleys.
For more information, visit our “Column Lift” product page.
Positioning of the Drive Unit
The drive unit of a hydraulic lift can be positioned flexibly. As the hydraulic power unit is connected to the hydraulic cylinders via hydraulic lines, various installation locations are possible. Depending on the design and structural conditions, it can be installed within the lift table, in the lift shaft or in an adjacent room, for example. Installation in a separate machine room is also possible, but is not generally required.
Maintenance Requirements
Hydraulic lifts have a relatively simple drive system with robust mechanical and hydraulic components. This can help reduce maintenance requirements.
Regular maintenance includes inspecting the hydraulic system, guide rails and safety features. The specific maintenance tasks required depend on the lift design, frequency of use and manufacturer's specifications.
Energy Consumption
When lifting, a hydraulic lift typically requires more energy than a comparable traction lift. When lowering, however, no drive energy is generally required. The platform or lift car descends under its own weight, with the speed controlled by hydraulic valves.
Actual energy consumption during operation depends on factors such as lifting height, load capacity and frequency of use. For applications with infrequent use, hydraulic lifts can still be an economically attractive option despite their higher energy requirements when lifting. When assessing cost-effectiveness, purchase and maintenance costs should therefore be considered alongside energy costs.
For more information, see the LIFTjournal article “The Comeback of the Hydraulic Lift”.
High Lifting Heights
At greater lifting heights, hydraulic lifts can become more complex to design and therefore less economical. In designs with long hydraulic cylinders subjected to compressive loads, for example, the risk of buckling increases, potentially requiring larger piston rod diameters.
For more information, see our wiki article “How to Choose a Hydraulic Cylinder?”.
Typical Applications
Hydraulic lifts are used in a range of applications, including as goods lifts for transporting goods in industrial and warehouse environments. They are also suitable for custom solutions where specific dimensions or structural conditions need to be taken into account.
The Rope-Driven Lift
Traction lifts are particularly widespread in passenger transport and are used in high-rise buildings, among other applications. A distinction is generally made between drum-driven lifts and traction sheave lifts.
The Drum-Driven Lift
In a drum-driven lift, a rope drum is driven by an electric motor. Depending on the direction of rotation, the suspension rope is wound onto or unwound from the drum, causing the lift car to move up or down.
Compared with traction sheave lifts, this design is less common in modern passenger lifts and is mainly used for specialised applications.
The Traction Sheave Lift
Traction sheave lifts are widely used in modern passenger lifts. The lift car and a counterweight are connected by suspension ropes that pass over a driven traction sheave.
The counterweight balances the weight of the lift car and part of its load. As a result, the electric motor mainly needs to overcome the remaining weight difference and resistance to movement. This reduces energy consumption compared with a drive system without a counterweight.
Positioning of the Drive Unit
In rope-driven lifts, the drive unit can be installed in a separate machine room or directly within the lift shaft. Modern traction sheave lifts are often designed without a machine room, with the drive unit usually located in the upper section of the lift shaft.
The required installation dimensions and space depend on the specific lift design. In particular, the required headroom above the lift car must be taken into account during planning.
Energy Consumption
Traction sheave lifts often consume less energy during operation than comparable hydraulic lifts. Thanks to the counterweight, the electric motor mainly needs to overcome the weight difference between the lift car and the counterweight, as well as resistance to movement.
In suitably equipped systems, energy can also be recovered during certain operating conditions and made available to other electrical consumers. Whether such energy recovery is economically worthwhile depends on the frequency of use and the technical requirements.
High Lifting Heights
Rope-driven lifts offer advantages over hydraulic lifts when it comes to greater lifting heights. As the lift car is moved by suspension ropes, there is no need for correspondingly long hydraulic cylinders. This often makes it more economical to achieve greater lifting heights.
For this reason, rope-driven lifts are predominantly used in high-rise buildings.
Main application area
Cable-driven elevators are primarily used as passenger elevators, as well as in systems with very high lifting heights or heavy traffic. Without this type of elevator, modern skylines as we know them today would not be possible.
Direct comparison of the elevator systems
Below you will find a brief overview of which elevator is best suited for different situations. Of course, in individual cases, personalized consultation may lead to a different result.
| Feature | Hydraulic lift | Cable-driven elevator |
|---|---|---|
| High lifting height | X | |
| Low number of lift cycles (< 150 cycles/day) | X | |
| Special installation situation | X | |
| Standard shaft dimensions | X |
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