Importance of The Proper Orientation Of Orfice Plates

Is the proper orientation of an orifice plate with a bevel important? The importance depends upon whether gas is being bought or sold. Volumetric gas rates were measured at two meter tube pressure levels using orifice plate bore sizes from l/2- through 1-l/4-inch in two 3-inch commercial meter tubes in series. The orifice plates were tested in the correct orientation with the sharp edge upstream and then reversed with the bevel upstream. The differences in the calculated gas rates for proper and improper orifice plate orientation are significant.