Door closer is a spring-like hydraulic device on the door head. When the door is opened, it can be released after compression and the door will close automatically. It has the function of spring door, which can ensure the door to close to the initial position accurately and timely after opening.
Modern hydraulic door closers (door closers for short) began with a patent registered by Americans in the early 20th century. Different from the traditional door closer, it achieves the buffering effect by throttling the liquid in the door closer. The core of the design idea of hydraulic door closer is to control the door closing process, so that the functional indexes of the door closing process can be adjusted according to people's needs.
The significance of the door closer is not only to automatically close the door, but also to protect the door frame and door body (smooth door closing). More importantly, door closers have become an indispensable part of intelligent management of modern buildings.
The types of door closers can be divided into: external door closers and embedded door closers, embedded door closers, door bottom closers (floor springs), vertical door closers (built-in vertical door closers) and other types of door closers.
1, requirements and selection of door closers.
The door closers must meet the national standard GB2698-2005, and the door closers for fire doors should also meet the requirements of GA93- 1995 "Fire Door Closer Test".
The factors to be considered in selecting the door closer are: the width of the door, the frequency of opening the door, the use requirements and the use environment. The width of the door is the most important factor in choosing the model of the door closer. Common doors are fire doors, wooden doors, aluminum alloy doors, glass doors and steel doors. Usually, if the weight of the door is small, choose the model with less strength, and vice versa. The frequency of door opening is closely related to product quality. For frequent occasions, products should be required to have good sealing performance and long service life.
1) Whether it is necessary to have an automatic door stop function after opening the door;
2) Damping and buffering function-damping and buffering are generated after the door is quickly opened to a certain position, and the strength and range of damping and buffering can be adjusted according to the use requirements; This function is used to prevent the door or lock from colliding with the wall when opening the door quickly, or to prevent people from leaning forward and falling to the ground when opening the door quickly due to weightlessness during emergency escape.
3) Delayed slow closing-The door closes slowly at a constant speed from the maximum position of opening the door, which can be adjusted steplessly according to requirements. Suitable for places with frequent and crowded people, especially hospitals, with special doors and passages for the elderly, children and the disabled.
4) The closing force can be adjusted-it can be installed on different doors with large door weight and wide range, and it can also be installed in places with large closing resistance due to environmental reasons. Arbitrary stepless adjustment can obtain satisfactory door closing force, especially in coastal cities, cars and boats and other places where door closing resistance (door closing force) often changes due to wind.
5) Temporary closing performance of damping reset function (vertical door closer)-When opening at any angle, closing the speed regulating valve should temporarily suspend the damping reset function.
6) Safe, fast and super-damping closing performance (vertical door closer)-When an external force is suddenly applied in the process of closing any angle, it should be able to close safely and quickly.
7) Working environment: fire prevention requirements and anti-freezing requirements for places at -35℃ in winter.
Usually, the selection of door closers can match the size and weight of different doors according to the manufacturer's product specifications and parameters and different strength or adjustable strength. The following table shows the mass/size of seven types of test doors specified in British standard BS EN 1 154 (recognized standard for classification of door closers). The closing force of the door closer usually specifies a value between 1 and 7. The larger the number, the greater the capacity of the door closer.
Test the quality/size of the door
Capacity size
Recommended door width
Test the quality of the door
2. Install the door closer
A. Installation mode of door closer
The most commonly used door closers are external door closers, and their installation methods are as follows:
The most common standard usage is that the door closer is installed on the hinge side and the open side of the door. When so installed, the arm of the door closer protrudes outward at an angle of about 90 degrees with respect to the door frame.
In the second application, the door closer is installed on the side opposite to the hinge side where the door is closed. Usually, the extra bracket provided by the door closer is installed on the arm parallel to the door frame. This usage is usually used on outward-facing external doors that are unwilling to install door closers outside buildings.
The body of the door closer is installed on the door frame instead of the door, and the door closer is opposite to the hinge of the door. This usage can also be used for external doors that open outward, especially those with narrow upper edges and insufficient space to accommodate the door closer body.
In the third usage, the vertical door closer (built-in vertical door closer) is upright and invisible on the inner side of one side of the rotating shaft of the door leaf, and no screws and parts can be seen from the outside, so it can be integrated with the door and can be opened and closed in one direction and two directions, and the construction is simple.
B, door closer installation steps:
Usually, the manual attached to the door closer has an installation template, so read the manual first and determine the installation position according to the door opening direction, door closing force and the installation size between the door closer body, the connecting seat and the door hinge.
2) According to the requirements of closing force, the closing force can be changed by reversing the connecting seat 180 or changing the connecting position between the connecting rod and the connecting seat. The greater the distance between the adjusting link and the center line of the door hinge, the smaller the closing force of the door closer is, and the greater the force is.
3) Determine the position of the mounting screw according to the position indication on the mounting template, and then drill and tap.
4) Install the door closer body with screws.
5) Install the fixed connecting seat.
6) Install the transmission plate with screws.
7) Adjust the adjusting lever and the door frame to 90, and then connect the connecting rod with the transmission plate.
8) Don't forget to install the plastic cover, which can be used to catch the hydraulic oil leaking from the door closer.
9) After installation, check whether the fixing screws are fastened, and there shall be no looseness or instability. Open the door to the maximum open position, and check whether the hinge rotating arm of the door closer collides with or rubs against the door or door frame.
Closing speed of door closer
10) Adjust the closing speed of the door closer as needed. Usually, the door closer has two speed regulating (throttle core) screws. The upper adjusting screw is the first adjusting screw for closing speed, and the lower adjusting screw is the second adjusting screw (usually10&; Ordm) close the speed adjusting screw.
C. Use, maintenance and repair of door closers
After the newly installed door closer is used for about 10 days from the beginning of one week, all screws should be checked and re-tightened.
Use hydraulic oil recommended by the manufacturer, and hydraulic oil with low freezing point should be used in cold areas.
After the door closer is put into use, it should be checked regularly, including whether the mounting screws are loose or missing, whether the connecting arm rubs against the door body or door frame, whether the door body is deformed or loose, the buffering effect of closing the door, and whether the supporting guide rail leaks oil.
Usually, after the door closer is used for a period of time, the following problems will appear:
1) Loose or missing mounting screws lead to incorrect installation position of the door closer and damage to the connecting arm;
2) When the door closer is closed, the buffering effect becomes worse, which leads to the collision between the door and the door frame and the deformation of the door body;
From the structural point of view, the door closer is a closed whole, and it is not good or bad from the appearance.
The key quality problem of the door closer is whether it leaks oil, because the door closer controls the closing process by throttling the fluid in its internal hydraulic system, and oil leakage means the failure of the hydraulic system, so the hydraulic system is the only criterion to determine the service life of the door closer.
The main reasons for oil leakage are that the gap increases due to the wear of pinion support guide, the sealing effect decreases due to the wear of sealing ring, or the throttle core rotates counterclockwise away from the valve body when adjusting the buffering effect.
The reduction of the buffering effect of the door closer is caused by the oil leakage into the air or the increase of the fit (throttle) gap between the rack plunger guide cylinder and the valve body. Therefore, the quality and accuracy of materials, heat treatment and machining of pinion and supporting guide rail are very important.
For the door closer with poor buffering effect, it is impossible to solve the problem simply by adjusting the throttle core to throttle. It must be repaired. If the support guide leaks oil, remove the support guide and check the condition of the sealing ring. If worn or aged, replace the sealing ring. If the gap between the support rail and the pinion shaft is too large, replace the support rail. If the guide cylinder of the rack plunger is worn, the fit clearance between the rack plunger and the valve body increases, which leads to the decrease of throttling effect. The rack plunger can be removed and the surface can be repaired by chrome plating. In addition, under the condition of ensuring the buffering effect of the door closer, it is also a method to reduce the impact of the back door on the door frame because of the poor buffering effect.