Passenger Elevator are designed to transport passengers between floors of commercial or residential buildings. They run on a system of steel or kevlar cables that are looped around the drive sheave in the hoist-way and counterweight.
Single-automatic push-button operation gives a rider exclusive use of the elevator for one trip. Collective operation allows two or more cars to answer calls together and share doors.
Door Opening
In passenger elevators (not freight or service elevators) the doors are a single panel style that slide open one way or the other. This style of door is less expensive to build and allows the cab to be a little wider than a traditional side opening style.
A single sliding door also improves accessibility since a wheelchair user can enter with the doors fully open. This type of passenger elevator is often used in hospitals where medical staff need to quickly get from the ER to their patient's room on the floor below.
Another option is to have a two speed center opening door, which consists of panels that tuck behind each other when they close and then push together and straighten out when they open. This is a more durable and rugged door style often used in service elevators. This type of door is sometimes found in hotels where the elevator doubles as city transportation along with a funicular.
Door Closing
The door closing feature of passenger elevators allows the doors to close while still allowing passengers in wheelchairs to exit safely. Typically this is accomplished with an arm that is positioned at a point parallel to the door when closed. This arm prevents the door from extending too far and slamming into walls or other objects, a common issue with older elevators.
Other features often found in passenger elevators include a 'hold' button (similar to code blue for hospital use), front and rear entrances, televisions in high-rise buildings, and specialized recorded voice announcements. Some elevators are also able to skip floors from one shaftway to the next, known as express lifts.
To adjust the delay time of a door closer, remove the cover from the door and locate the adjustment valves. These are usually on a small square plate on the header of the elevator, and have the letters HO or NHO on them. To increase the delay time, make 1.5-2 turns counterclockwise; to decrease the delay time, turn them clockwise.
Traction
A traction elevator uses steel or kevlar ropes that loop over a drive wheel above the elevator shaft and pull on a counter weight to reduce the amount of power needed. They are more efficient than hydraulic elevators and typically use a gear that allows them to travel much faster.
A service elevator is used to transport equipment and supplies such as cleaning carts, beds or wheelchairs through a building. These are often deeper and more robust than passenger elevators to accommodate larger loads.
A destination control system lets a person enter their intended floor in lieu of pressing "up" or "down." An algorithm then allocates the best car to serve the request and notifies the user. This can help improve accessibility and efficiency.
Controls
Elevator control systems may be based on microprocessors that provide a high level of automation. These systems are more responsive and reliable than older relay controllers.
Most passenger elevators have call buttons that can be used to select a floor or open and close doors. These buttons are often used to signal a wait for an available car. These calls are then registered by a computer system that allocates adjacent floors to different cars in the elevator bank. This is known as destination dispatching.
One disadvantage of this type of system is that it is prone to gaming where multiple people register their floor calls at the same time, or where one person presses up and down buttons repeatedly in order to hurry the elevator. In some cases, this can cause the elevator to skip a floor that is not necessary and delay other passengers who are waiting for an elevator to arrive on that floor.