压差是两个压力值之间的差值。例如，它用于通过测量流量元件前后检测到的压力差来确定流量。另一种可能的应用是测量过滤器入口和出口的压力，以确定其渗透性。如果过滤器堵塞，压差会发生变化。此外，差压设备用于推导诸如填充水平之类的值。

　　原文：

　　Differential pressure is the amount of difference between two pressure values. It is used, for example, to determine flow volume by measuring the difference of the pressure detected in front of and behind a flow element. Another possible application is measuring the pressure at inlet and outlet of a filter in order to determine its permeability. If the filter clogs, the differential pressure will change. Furthermore differential pressure devices are used for deriving values like filling level.