Freight Elevators: Electric, Water, Hydraulic And Freight Elevator Doors

Everyone is familiar with the procedure of riding an elevator. A freight elevator is quite different from the elevators most people are used to experiencing. Like passenger elevators, they are also used to move stuff up and down, only it's strictly goods or items—no passengers allowed. In fact, a typical freight elevator will include a written notice either inside or outside (or both) the elevator warning passengers not to ride. This is why it is often commonly referred to as goods lift. Some freight elevators are not required to follow all the code requirements that passenger elevators need to, but newer elevators often do have to comply with code requirements like fire service.

Because the freight elevator is often carrying large and heavy loads, it is designed to be bigger in size and stronger. They are usually able to carry 2,300-4,500 kg of weight. Another difference between a passenger and a freight elevator is the door. A freight elevator door is usually manually opened or closed (vs. an electric door found in a passenger elevator). Also, the interior finishes are very practical and not at all decorative. The interior  will often include special materials or treatments to increase the strength or safety of the cab.

Traditionally, elevators use either a traction or hydraulic system to actually power the elevator. Hydraulic elevators use steam or water along with the principal of hydraulics to pressurize a piston. This controls and allows the car or cab to be raised or lowered. Although hydraulic elevators are cheaper, they are slower than traction elevators (which use a system of ropes or chain to hoist the load up or down). Hydraulic freight elevators are sometimes used, but electric versions are more energy efficient.

A freight elevator often carries a variety of products or goods depending on the building it is put in. Elevator companies usually respond to the differences in needs with several different models of a freight elevator. For instance, the Otis Elevator Company, the world's largest manufacturer of elevators, produces freight elevators that can carry 6,000, 10,000, or 12,000 lbs of weight. Also, each weight category is available in two different configuration options. Not only will the cab support such a heavy weight, but even the door sills have been reinforced to hold the weight of the capacity load. The elevator walls are made out of 14 gauge steel sheets and 12 gauge steel plates.

The Otis Elevator Company has safety measures built into the design of their freight elevators. The cab walls and floors designed to be strong and also prevent against slipping, which can be extremely dangerous when dealing with such heavy loads. Their elevators are installed according to all codes, both local and national. Some safety codes vary between local areas.

The design of a freight elevator must be treated differently than the design of a passenger elevator, because the cargo inside is vastly different in nature. No person would want to be treated like a sack of flour or crate of supplies. Likewise, goods and products require special treatment when being transported up or down the floors of a building. The unique qualities of a freight elevator are important to the safety of both the load and the people helping to transport it.


Sources:
"Elevator." Wikipedia. 11 July 2007. 11 July 2007. http://en.wikipedia.org/wiki/Elevator.
Freight Elevator. Otis. 11 July 2207. http://www.otis.com/products/detail/0,1355,CLI1_DS C695_PRD742_PRT30_PST71_RES1,00.html#spec.
"Elevator." Answers.com. 2007. Answers Corporation. 11 July 2007. http://www.answers.com/topic/elevator?cat=health.