鼓風爐就是風箱的原理,風箱是把空氣壓進爐子裏去,促進煤炭燃燒的工具。现在銅、鐵匠用来吹火的風箱普通如左圖所示,在木方箱B裏装一個活塞(中國古代叫做‘鞴’)P,a,b,c和d是四個活門,a,d是兩個通風口,a只能向左開放,d只能向右開放,而b,c只能向下開放。E是通往爐子的管。當活塞P向左推時,右邊的空氣壓力小,箱外空氣就從a門進來,使b門關閉;左邊的空氣壓力增加,使a門關閉,同時大氣壓力把c門推開:這樣活塞左邊的空氣經過c流到E管卽能進入爐子裏,同時外面的空氣經過a流到P的右邊。當活塞向右拉時,同樣的道理而方向相反,h,a開放,a,c關閉,活塞右邊的空氣經過(?)流向E,外面的空氣——經過a流到P的左邊。這樣,在把活塞向左推和向 Blast furnace is the principle of bellows, bellows is the air pressure into the furnace to promote coal burning tools. Now, the bellows used by the blacksmith and the blacksmith to blow the fire are as shown on the left, with a piston in the wooden box B (ancient Chinese called ’鞴’) P, a, b, c and d are four valves, a , d is two vents, a can only be left open, d only open to the right, and b, c can only be open down. E is the tube leading to the furnace. When the piston P is pushed to the left, the air pressure on the right is small, the air outside the tank comes in from the a door, so that the b door closes; the air pressure on the left increases so that the a door is closed and the atmospheric pressure pushes the c door open: The air on the left flows through c to tube E to enter the furnace, while the air outside passes through a to the right of P. When the piston is pulled to the right, the same reason and the opposite direction, h, a open, a, c closed, the right side of the piston after the air flow (?) To E, outside air - after a flow to the P on the left. In this way, push the piston to the left and to the left