1. Product Positioning and Core Functions

Concealed circular door closers belong to the category of concealed door closers . Their core function is to automatically close an open door to its initial position. They are widely used in homes, hotels, shopping malls, office buildings and other places. They have practical value such as fire protection (combined with fire doors to achieve automatic door closing in emergencies) and anti-theft (such as being installed on security doors to prevent people from forgetting to close the doors when leaving).

2. Structure and working principle

The concealed circular door closer consists of a return spring, transmission gear, valve core, hydraulic ring, and sealing ring . Externally, it is linked to a connecting rod via fixed bases at both ends. When the door is opened, the door body drives the connecting rod, rotating the transmission gear, which in turn moves the rack plunger. The spring is compressed, pressurizing the hydraulic oil. The ball in the check valve to the left of the plunger opens under the oil pressure, allowing hydraulic oil to flow from the right chamber to the left. When the door is fully opened, the spring releases, pushing the plunger to the left, rotating the transmission gear and the door closer connecting rod, closing the door. During this process, the hydraulic oil resists the release of the spring, providing a buffer through throttling, thus controlling the closing speed.

3. Installation and Adaptation Scenarios

• Installation : A gap of about 10mm must be reserved between the door and the door frame, and the door thickness must be greater than 42mm. During installation, read the instructions first to determine the position, and adjust the distance between the connecting rod and the center line of the door hinge (the larger the distance, the smaller the closing force) to adapt to the closing requirements.

• Applicable scenarios : Suitable for environments with narrow door frames that require beautiful and concealed installation, such as home interior doors and hotel room doors. It can solve problems such as "closing the door without knowing the importance of closing it, forgetting to close it when going out", etc.

4. Technical Features and Advantages

• ‌Hiddenness‌ : There are no exposed parts when the door is closed, which makes it look neater and more beautiful.

• Adjustability : Most models support two-stage speed adjustment to meet different closing speed requirements; some products can be customized in color to suit the decoration style.

• Versatility : It has both manual and electric functions (such as the new multi-functional door closer), can be adapted to doors or windows, has a simple structure, is light in weight, opens stably, and is safe and reliable.

5. Parameter reference (taking typical products as an example)

• Suitable door weight: about 40-65kg (can be customized to 80kg);

• Suitable door width: ≤1100mm;

• Door closing speed: locks within 3 seconds;

• Installation hole spacing: 258×20mm;

• Surface treatment: brushed/bright optional.

This concealed circular door closer balances practicality and aesthetics through its concealed design and adjustable functions. It is the preferred solution for improving the convenience and safety of door control in commercial and residential scenarios.