The floor spring door closer is a spring-like hydraulic device. When you manually push the door open, the spring in the door closer is compressed to store energy. Then the spring is released through the spring to transfer the door closing force to the door leaf through the door closer rocker arm. , Automatically closes the door without external force. The cylinder in which the spring is located is a hydraulic system with precise design. The hydraulic oil is enclosed inside. With this hydraulic system, we can control the door closers to achieve various adjustments to meet people's needs. The internal structure of the floor spring door closer is a secret world that can be operated at any time and operates stably. The inside of the door spring door closer consists of a rack piston, springs, oil control valves, balls, oil paths, and filled hydraulic oil. Closed design makes hydraulic oil impossible to leak.