Hydraulic elevators operate on a simple principle. They lift a car by using a hydraulic ram, which is a fluid-driven piston inside a cylinder. The cylinder is connected to a system that pumps fluid, typically oil. The hydraulic elevator system consists of a tank, or fluid reservoir; a pump that is powered by an electric motor; and a valve located between the cylinder and the reservoir.
The pump forces fluid from the reservoir tank into the cylinder. When the valve is closed, the fluid flows into the cylinder, the pressure pushes the piston up, and the elevator car rises.
When the elevator is nearing the desired floor, the control system sends a signal to the electric motor to gradually turn off the pump. The fluid stops flowing into the cylinder, but the fluid that is already in the cylinder is trapped there because the valve is closed. The piston rests on the fluid, which holds the car in place.
When a person wants to lower the elevator car, the electric motor sends a signal to the valve via a solenoid switch. When the valve is opened, the fluid in the cylinder flows back into the reservoir. The weight of the car pushes down on the piston, which forces the fluid into the reservoir and causes the car to descend. When the elevator car approaches the desired floor, the control system closes the valve, which causes the car to stop.
Hydraulic elevators are becoming a popular feature in many homes. They can greatly improve the mobility of senior citizens and people with disabilities, allowing them to enjoy comfort and safety at home.