The flow nozzle is used for high velocity flow measurement where erosion or cavitation would wear or damage an orifice plate. It does not rely on a sharp edge (which can degrade over time) for accuracy, therefore offering excellent long-term accuracy and it is often used for flow testing on steam-raising plant. The discharge coefficient of a flow nozzle is such that a nozzle can measure approximately 55% higher flow rates than an orifice plate with a similar beta ratio and design differential pressure.
