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.