Maybe you have encountered such a situation in life, the same is closed, some door suddenly closed, while some closed comparison is slow, slowly closed, that is why? Be careful friends will find that the above are relatively slow closing is fitted with a "closed door" products, this product is produced by this effect.
Why closers can leave the door slowly closed?
The answer is similar to the working principle of closed door,the specific reason is: the closer the spring in the release process, the hydraulic oil left by the closed door cavity compression, one-way valve is closed, the hydraulic oil is the only outflow through the gap between the shell and the plunger, and after passage holes on the plunger and fitted with a reflux the two door closer to the throttle valve core right chamber. Therefore, the release of the hydraulic oil to the spring constitutes a certain resistance, thus buffering effect is achieved by the throttle, the closing speed of the door has been under control.
In addition, the throttle valve on the valve body can be adjusted, can control the stroke of different stages to control the closing speed different.
Summary: in the current factory door closers, although some closer the buffering effect is not the same, these will be closer and the structure, size, said that despite these differences, but the principle of total they are the same.