Sunday, September 21, 2014

How does a door closer work?

Recently , I had visited psychologist. When I reached his room , I opened the door of room easily . I entered in and turned to close the door . My father said no need of it , it will close by itself . Then I saw a cylinder like structure on the top of the door inside.

I had seen this arrangement in many places. Father explained me that it is used to prevent the door from banging shut . I was curious to know the working of it.

I was right! There is a  spring inside the cylinder. It is not only the spring , it also contains an air cylinder . When we open the door , the cylinder fills with air .

When the door is closing , the spring pushes a piston which forces the air out of the cylinder . The out flowing rate of air can be controlled depending on the closing rate of door.

The leaking of air occurs through a small hole , producing a hissing noise too.









What if we try to close the door forcibly ? 

This was the question raised in my mind after knowing the work of a door closer. We can try this . But whatever the force with which we push the door to close , we can feel a force which is trying to nullify our own force. I think this must be the force of the air which is stored inside the cylinder .