Swing-door operator
A swing-door operator (or swing-door opener or automatic swing-door operator) is a device that operates a swing door for pedestrian use. It opens or helps open the door automatically, waits, then closes it. Types. There are 3 basic types of swing door operators: Uses. Full Energy operators are typically used on the outside doors of medium-sized retail business. (Larger retail businesses prefer sliding door operators.) Low Energy operators are typically used where a simple door closer is sufficient for able users, yet it is necessary to add access to disabled users: small businesses , apartments, bathrooms. Triggering. A door operator may be triggered in various ways: A trigger from any of the above requests that the door be opened (or reopened if it was closing). The operator will heed hat requests only after it is able to do so safely for any other users in the area. Safety sensors. A door operator may use sensors to prevent the door from coming into contact with a user. Full Energy operators require at least 3 sensors. Low-energy operators are not required to have safety sensors, as the door is allowed to come in contact with  a user, given that the kinetic energy of the moving door is limited by the reduced moving speed. Historically, sensors have been simply floor mats that sense the weight of a user, one in the area immediately in front of the door (the approach side) and one in the area behind it (the swing side). The approach side mat is often used as a trigger sensor. The swing side mat prevents the door from starting to open as long as some other person is detected in the swing area; once the door starts opening, this mat is ignored, as it  will sense the user going through. Today, infrared safety sensors or laser safety sensor are normally used. Four types are commonly used. Opening technologies. The majority of the operators open the door directly or through an arm. Variations on the above exist. There are also rare operators that use a mechanism that is disconnected from the door, and reaches out and pushes on the door itself when it needs to open it. Internal technologies. Operators are powered by an electric motor. They differ in how they use the motor's energy to open the door. Operators use various internal technologies . Operators are often categorized by the means by which the motor's energy is applied. Of the electromechanical types, two approaches are used: Electro-hydraulic types are inherently quiet and smooth during manual opening, as the motor and pump are off.