Automatic Door Closer

A door closer is a hydraulic device that is used to automatically close a door after it has been opened. Door closers are commonly used as a fire prevention measure, typically installed on fire doors, as well as helping to prevent draughts.Surface-mounted door closers are the most common type, as they are comparatively cost-effective and easy to install. They are fitted to the door frame behind the door, next to the hinge. The arm of the closer retracts to closed configuration as the door closes.As well as the standard, double-lever arm, there are different kinds of arms available for surface-mounted door closers, depending on the application and to provide more functionality. These include:Hold open arm: By opening the door to a certain degree, a nut is tightened which causes the arm to stick at an open point.Dedicated parallel arm: In the closed position it lays parallel with the door instead of projecting outwards, although lacks the strength of the standard arm.Stop arm: Prevents the door from opening too far and hitting a wall or other obstacle..