Application of variable force springs in fireplace up-down slide door
Fireplaces are freestanding or wall-mounted indoor heating devices, powered by combustible materials, with internal chimneys, originating from Western homes or palace heating facilities. Because its fuel is a renewable resource, modernized and improved, it is still commonly used in the West, and is especially popular among the higher education class, which advocates environmental protection. Fireplaces can also be installed in...