Patent ID: 6860465
Filing Date: 2005-03-01
Classification: F16K

Abstract:
1. A method of operating a butterfly valve, comprising: defining the stem stroke of the butterfly valve into a first, a second and a third operation regions, wherein the first operation region corresponds to a lower stem stroke, and the third operation region corresponds to a higher stem stroke of the butterfly valve; providing a first set of proportion, integration, and differentiation parameters for the first operation region such that the butterfly valve functions as an on/off control valve in the first operation region; providing a second set of proportion, integration, and differentiation parameters for the second operation region such that the butterfly valve functions as a percentage control valve in the second operation region; and providing a third set of proportion, integration, and differentiation parameters for the third operation region such that the butterfly valve functions as an on/off control valve in the third operation region, wherein the first and third sets of proportion, integration, and differentiation parameters produce a greater output level than the second set of proportion, integration, and differentiation parameters.