A hydraulic elevator is an elevator system that utilizes a hydraulic power source to pump oil into a hydraulic cylinder, thereby driving a plunger in a linear motion; this motion, either directly or indirectly via steel cables, propels the elevator car. As an integrated product combining mechanical, electrical, electronic, and hydraulic technologies, a hydraulic elevator consists of several relatively independent yet interconnected and cooperative subsystems: the pump station system, hydraulic system, guiding system, elevator car, door system, electrical control system, safety protection system, and others.
Hydraulic drive represents one of the earliest methods of elevator propulsion. In early hydraulic elevators, water served as the transmission medium; leveraging water's incompressible nature, pressure was increased through pressurization and then introduced into the cylinder to drive the internal plunger, thereby lifting the elevator car and facilitating its upward movement. Conversely, by opening a discharge valve to release the fluid, the elevator car would descend under the force of its own weight. However, because water pressure is susceptible to fluctuations caused by trapped air bubbles-and due to the difficulty in resolving issues such as cylinder corrosion-oil was subsequently adopted as the medium to drive the plunger's linear motion. Given their substantial lifting capacity, high mechanical efficiency, and relatively low energy consumption, hydraulic elevators offer distinct advantages-particularly in applications involving short travel distances and heavy loads. Furthermore, since hydraulic elevators do not require a machine room located at the top of the hoistway, they reduce the vertical dimensions of the shaft and make efficient use of building space; consequently, hydraulic elevators possess broad prospects for future application. Today, hydraulic elevators are widely utilized in parking garages, industrial facilities, and low-rise buildings. For applications characterized by heavy loads, low speeds, and short travel distances, selecting a hydraulic elevator proves to be both more economical and more suitable than opting for a traction elevator.
