Patent ID: 8307496

Claim:
An air pressure inner circulation automatic compensation control door closer, comprising a cylinder body and a telescopic rod running through an end cap at a first end of the cylinder body and being freely telescopic to open and close the door, characterized in that a one-way air intake valve means is provided at a second end of the cylinder body to take in air in one way in an internal cavity of the cylinder body when the door is opened, at one end portion of the telescopic rod in the interior of the cylinder body is connected a regulating valve means wherein the air in the cylinder body flows cyclically in the cavity of the cylinder body when the telescopic rod is in a moving state, an inner cover sealing means is fixedly provided at a position of the cavity of the cylinder body inside the end cap to form air sealing with the telescopic rod and with an inner wall of the cylinder body, and a large compression spring is provided in the cavity between the inner cover sealing means and the regulating valve means; the internal cavity of the cylinder body is divided into two automatically pressurizeable and automatically compensatable air cavities through the inner cover sealing means, the regulating valve means and the air intake valve means; when the door is opened or closed, the air inside the internal cavity of the cylinder body flows cyclically in the two air cavities.