Shaft furnace breather

Okay, imagine you have a big tube called a shaft furnace. This tube gets really hot and cooks things inside of it. But the tube needs to be able to breathe, just like you need to breathe air into your lungs.

So, at the top of the tube, there is something called a breather. A breather is like a little hole that lets air in and out so the tube doesn't get too hot or too cold. It's kind of like when you open a window in your room to get some fresh air.

The breather also helps control the temperature inside the tube, so that whatever is being cooked in there gets cooked evenly and doesn't burn. It's like when you turn the heat down on the stove so your food doesn't burn or stick to the pan.

So basically, a shaft furnace breather is a little hole at the top of a hot, big tube that helps to control the temperature and let air in and out.