A hydraulic elevator is an elevator device that raises and lowers through the use of a hydraulic cylinder. A hydraulic elevator relies on fluid pressures and resistance provided by the hydraulic fluid to perform its functions. When the hydraulic cylinder is compressed, energy is stored in the compression and as it’s slowly released the elevator rises, decompressing the pressure as it does. When the elevator is lowered again, it goes down slowly because of the amount of resistance provided by the hydraulic fluid within the cylinder, which is how the cylinder creates the energy needed for the next raising.
In a hydraulic elevator, the housing for the elevator sits on top of a piston rod that runs into the chamber for the hydraulic cylinder, or hydraulic chamber. There is an external housing that holds the hydraulic fluid when the elevator is not in use and when the controls for the elevator system are engaged, the fluid is pushed through a pumping mechanism into the piston housing. This causes the piston to become directionally displaced, pushing it upward until the desired height is reached. When the elevator is on its way down, the system and the piston housing are both decompressed, slowly adding pressure back to the fluid housing for the next time the system is engaged.
Hydraulic elevators are used in a few different applications, generally when the load that is commonly lifted by the elevator system is one of a substantial weight class. Car lifts and floor jacks that are used to lift automobiles even a short distance off of the ground are the most common forms of hydraulic elevators. Many of the exposed elevators in public places such as shopping malls are being installed with hydraulic elevator lift systems because of the lower maintenance costs and reduction in noise.
The added safety of an elevator that is on a hydraulic lift system is of great appeal in cases where the elevator is used to transport people. This added safety comes in the form of the cylinder that houses the fluid. Even if the cylinder were to fail and allow the elevator unit to free fall, unless the hydraulic fluid was completely drained from the cylinder, the resistance provided would allow the elevator to safely glide downward. This allows for a greatly reduced chance of injury versus the traditional shaft system that depends on cable supports in cases of elevator failure.