锅炉，汽锅一种封闭的容器，可对热水或蒸气在此加热或进行循环，以获取热量或动力

An enclosed vessel in which water is heated and circulated, either as hot water or as steam, for heating or power.

对流式加热机一个部分被封闭，暖空气在其直接加热的表面上通过对流进行循环的装置

A partly enclosed, directly heated surface from which warm air circulates by convection.