U形管水银差压计是热工测量中的常用仪器。它的主要优点是,结构简单、使用方便、价格便宜,尤其是在标准条件下使用,可以达到很高的测量精度。另外,它不存在迟滞回环,适用于测试膜片、膜盒等弹性元件的迟滞误差。因此,这种差压计除用于一般测量外,还可以作为标准器来校验其他压力计,用途比较广泛。但是,它有两个大的缺点。一是由于受实验室空间的限制,不能制做得很 U-tube mercury differential pressure gauge is commonly used in thermal measurement instruments. Its main advantage is the simple structure, easy to use, cheap, especially under standard conditions, can achieve high measurement accuracy. In addition, it does not exist hysteresis loop, suitable for testing hysteresis error of the diaphragm, diaphragm and other flexible components. Therefore, this differential pressure gauge used in addition to the general measurement, but also can be used as a standard instrument to check other pressure gauge, a wide range of uses. However, it has two big drawbacks. First, due to laboratory space constraints, can not be made very