When installing an orifice plate, the sharp edge should face in which direction?

When installing an orifice plate, the sharp edge should face upstream. This orientation is critical for achieving proper flow measurement and ensuring accurate differential pressure readings. When the sharp edge is positioned upstream, it allows the fluid to flow smoothly into the orifice, facilitating the pressure drop across the plate which is necessary for flow measurement.

In practice, the flow rate through the orifice plate is directly related to the difference in pressure before and after the orifice. When the sharp edge faces upstream, any turbulence or eddies that might be created by the orifice are minimized, which helps in establishing a stable flow profile required for accurate measurement.

This understanding is vital in industries such as oil and gas or chemical processing, where precise flow measurement is crucial for process control and safety. The orientation of the orifice plate can significantly affect the system's linearity and accuracy, so following the convention of having the sharp edge upstream is aligned with accepted engineering practices.