How Do Hydraulic Lifts Work?
Hydraulic elevators are one of the most widely used lift systems worldwide, alongside traction lifts, due to their reliability and cost-effectiveness. These lifts operate using hydraulic fluid and a piston system to move the lift car up and down smoothly. But do you know exactly how hydraulic lifts work and what makes them different from other types of lifts?
Understanding the mechanics of hydraulic lifts can help you keep your lift in top condition, spot potential issues before they arise, and decide whether this type of lift is the right choice for your business or public building.
What is in a Hydraulic Lift?
Hydraulic systems are used in a vast range of industries—from car braking systems and forklift trucks to industrial presses and machinery. The same fundamental principles apply to hydraulic lifts, making them a simple yet effective lifting solution.
Main Components of a Hydraulic Lift
A hydraulic elevator consists of several key components:
✔ Piston within a cylinder (called a ram) – This is the main mechanism that moves the lift car.
✔ Oil reservoir or tank – Stores the hydraulic fluid needed to power the lift.
✔ Pump – Pushes oil from the reservoir into the cylinder to lift the car.
✔ Motor – Drives the pump and provides the necessary force.
✔ Valve – Controls the flow of oil between the reservoir and cylinder.
Machine Room or Machine-Room-Less (MRL) Options
Most hydraulic lifts require a machine room, where the pump, fluid, and motor are housed. However, machine-room-less (MRL) hydraulic lifts are available, where the machinery is compactly housed within the shaft. This space-saving alternative is useful for buildings where extra floor space is limited.
How Do Hydraulic Lifts Work?
Hydraulic lifts operate using fluid pressure to move the lift car up and down. The system is simple but highly effective:
- To go up, the pump pushes hydraulic fluid (oil) into the cylinder, forcing the piston to rise, which in turn lifts the elevator car.
- To go down, the valve opens, allowing the oil to flow back into the reservoir. The weight of the lift car and gravity push the piston down naturally.
When the lift reaches the desired floor, the pump turns off, and the car stays in position, held by the oil trapped in the cylinder. The system is designed so that if the power fails, the valve opens slowly, and the lift descends safely to the lowest floor. Unlike traction lifts, which rely on cables, a hydraulic lift cannot free-fall.
Types of Hydraulic Lift Systems
Hydraulic lifts come in two main variations:
1. Holed Hydraulic Lift
A holed hydraulic lift uses a cylinder that extends underground, with a depth equal to the lift’s travel height. This type of system is commonly found in high-rise buildings or installations where a smooth, stable ride is required.
✔ Best for: Buildings with space for underground installation.
✔ Pros: Can travel higher distances, stable and smooth operation.
✔ Cons: Requires deep excavation, which may not be feasible in all locations.
2. Hole-less Hydraulic Lift
A hole-less hydraulic lift does not require deep excavation. Instead, the pistons are placed directly on the floor in line with the corners of the lift car, acting like a jack. However, this system restricts travel distance to around 20–30 meters at most.
✔ Best for: Buildings where underground space is limited.
✔ Pros: Easier to install, no deep excavation required.
✔ Cons: Limited travel height.
Pros & Cons of Hydraulic Lifts
When deciding on a lift system, it’s important to consider both the advantages and limitations of hydraulic lifts.
Pros of Hydraulic Lifts
- Cost-Effective: Hydraulic lifts are typically cheaper to install than traction lifts, making them a great option for budget-conscious projects.
- No Overhead Space Required: The machinery is housed in a machine room or within the shaft, eliminating the need for additional space above the lift.
- Strong & Durable: The floor supports the lift, so no additional structural reinforcement is needed.
- Safe & Reliable: Since hydraulic lifts do not use cables, there is no risk of a free-fall accident. Even in the event of a system failure, the descent is slow and controlled.
Cons of Hydraulic Lifts
- Limited Travel Height: Hydraulic lifts struggle beyond 6–8 floors due to the limitations of the system.
- Slow Speed: They typically operate at speeds of up to 1m/s, making them slower than traction lifts.
- Space Requirements: Holed systems require underground space, while hole-less lifts need additional floor space for the pistons.
- Oil Temperature Sensitivity: Hydraulic oil can thin at high temperatures, affecting lift performance if not regulated properly.
- Potential Oil Leaks: Although rare in well-maintained systems, hydraulic lifts can develop oil leaks, leading to environmental concerns and maintenance issues.
- Lower Energy Efficiency: Hydraulic lifts consume more power than traction lifts, as they must actively push against gravity to raise the lift car.
Maintaining a Hydraulic Lift: Key Tips
Regular maintenance is essential to keep a hydraulic lift running smoothly. Here’s what to look out for:
- Check for Oil Leaks: Leaks can affect performance and lead to environmental concerns.
- Monitor Oil Quality: Hydraulic oil breaks down over time, so regular checks are essential.
- Inspect the Valve & Pump: A faulty valve can cause jerky movements or prevent the lift from working.
- Test Emergency Systems: Ensure battery backup and emergency lowering systems function correctly.
- Keep the Machine Room Cool: Overheating can impact hydraulic oil performance and cause system inefficiencies.
Is a Hydraulic Lift Right for You?
Hydraulic lifts offer cost-effective, safe, and reliable solutions for low to mid-rise buildings. If your project requires a durable lift with minimal structural modifications, a hydraulic system could be ideal. However, if speed, energy efficiency, or travel height are priorities, you might consider a traction lift instead.
Need expert advice? Our team at Gartec has over 30 years of experience in installing, maintaining, and servicing hydraulic lifts. Contact us today to find the best lift solution for your building.