问答题 翻译：As it expends it rises in the take -the height to which it rises is calibrated to indicate to indicate temperature.

问答题 翻译：The most common means measuring rate of flow of a fluid is based on the principle that if there is a contraction or constriction (a section of reduced diamater) in a pipe,the pressure of a fluid flowing down-stream from the contraction will be lower than that up-stream from the contraction.

问答题 翻译：There are special types of valves designed to be operated by control instrument rather than by hand.