Abstract: An orifice meter comprised of two concentric flanges and a center plate assembly is described. The center plate assembly includes an orifice plate holder arranged to rotate within the orifice meter around a shaft extending from the center of the center plate assembly and protruding through one of the flanges. Rotating the shaft will align one of the orifice plates in the orifice plate holder with the inlet and outlet pipe openings in the flanges. Thus, the orifice meter herein described does not have to be disconnected to change orifice plates. Pressure transducers are included in the flanges to determine the pressure upstream and downstream of the orifice plate. An inspection plug installed in one of the flanges allows for easy inspection and changing of the orifice plates, meaning that the orifice meter herein described does not have to be disconnected to replace or service the orifice plates.