|Classification of Door Closer|
|A door closer is a device that closes a door, in general after someone opens it, or after it was automatically opened. The self-closing function offered by door closers provides an important level of security for external doors and fire doors along exit routes in building.
There are three styles of door-closer: overhead, surface-mounted and jamb- mounted. Overhead door closers, can be concealed or surface mounted, whereas jamb mounted closers, fit between the door and the door frame and are totally concealed when the door is closed. A surface mounted one, is attached to the door frame behind the door (where the hinges are) next to the middle hinge. The arm rests against the door, and a spring that is bent by the user opening the door closes the door by retracting to its proper shape.
|Selection of Door Closer|
|Choosing a door closer can involve the consideration of a variety of criteria. In addition to the closer’s performance in fire situations, other criteria may include resistance to opening forces (for use by disabled or infirm) as well as safety, durability, risk of vandalism/ligature and aesthetics.|
|Use of Door Closer|
|To limit the speed at which the door closes, common door closers use hydraulic (oil-filled) dampers, although spring mechanisms may also be used. The speed at which the door closer closes the door may be adjustable by up to two set screws. These screws aften adjust the sweep speed and the latch speed of the door. The latch speed is the speed that the door travels in the last third to 10 degrees as it closes and is aften set fast so that the door can properly latch closed. The sweep speed is the speed which the door travels at along the first two thirds of its travel and is often set slower than the latch speed.
|Function of Door Closer|
|Door closer can ensure door opened is able to close automatically; it protects safety of household together with door locks.