F1 - Pressure Recovery Factor

LOW-RECOVERY RATE: A valve design that dissipates a considerable amount of flow-stream energy due to turbulence created by the contours of the flow path. Consequently, pressure downstream of the valve vena contracta recovers to a lesser percentage of its inlet value than a valve with a more streamlined flow path. The F1 factor does not vary with travel to any significant degree.

HIGH-RECOVERY RATE: A valve design that dissipates relatively little flow-stream energy due to streamlined internal contours and minimal flow turbulence. Therefore, pressure down stream of the valve vena contracta recovers to a high percentage of its inlet value. The F1 factor of a high recovery valve will vary with its plug travel.