Abstract: An apparatus and method for reducing pulsation-induced errors in the secondary system of orifice meters or other differential pressure flow measuring devices. The apparatus of the present invention comprising means for reducing the distance between the flow meter and the differential pressure detector for reducing pulsation-induced errors as well as reducing errors caused by rectification and energy redistribution, and means for maintaining a constant cross section between the orifice meter or the like and the differential pressure detector for reducing the pulsation-induced errors and, particularly for reducing errors caused by rectification and energy redistribution.