Orifice plates and nozzles
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I have a question: what is the difference between orifice plates and nozzles, and where are they mainly used? Also, what effects will occur if the orientation of the square orifice plate and the nozzle is reversed?
There are many types of orifice plates, such as double-orifice plates, eccentric orifice plates, notched orifice plates, and 1/4-circle notched nozzles; the most common throttling element used at present is the standard orifice plate. A standard orifice plate is a thin metal sheet with a circular opening concentric with the pipe axis, and its two surfaces are flat and parallel to each other. The nozzle is also a type of standard throttling device, including ISA1932 nozzles and long-diameter nozzles; it does not consist of two flat surfaces, but rather features a tubular protrusion that provides a transition as the flow moves downward. Another type of standard throttling device is called a venturi tube. These three are three types of throttle devices commonly used internationally. If the orifice plate or nozzle is installed in the wrong direction, it is obvious that the flow rate reading will be lower; this is a common knowledge known to many instrument technicians.
Both orifice plates and nozzles are standard throttling devices; standard orifice plates offer high measurement accuracy, a wide range of applications, and low costs. Nozzles feature high measurement accuracy, low pressure loss, and a long service life. The difference is that the nozzle has lower pressure loss, higher precision, but is more expensive! Orifice plates are more commonly used in refineries, while nozzles are rarely used.
Flow nozzles are typically used in applications where high pressure loss is required; they are commonly employed for measuring steam flow in most steam boilers