© 2017 Baker Hughes, a GE company, LLC. All rights reserved.178 | BHGEUsing ValVue DiagnosticsSVI II AP advanced features are simple to use with ValVue software. The following examplesillustrate some uses.Continuous DiagnosticsSVI II AP continuously gathers critical information that can be used to predict maintenanceintervals for control valves. These are: Total Travel Number of cycles Time open Time closed Time near closedMonitoring a Valve Bellows SealThe SVI II AP automatically stores the accumulated valve stroke reversals, as Number ofcycles. ValVue can be used to periodically retrieve the values and to track the remaining life ofa bellows seal or packing. Total travel can also be used to estimate the remaining life ofpackings and seals.Critical Service, Cavitation Control TrimThe time near closed, of a valve with severe service when near the seat, can be monitored byValVue and saved to permanent files to monitor and predict maintenance needs. You can useValVue to specify the criterion for time-spent-near-closed (a valve position such as 4%, forexample). See also Tight shutoff- Application to High Pressure Liquid Letdown Valve Trim.Table 29 Tight Shutoff Parameters for High Pressure Liquid Letdown TrimMasoneilan Valve Type Valve Trim Type Set Tight Shutoff PositionerCharacteristicsLincoln Log Any 15% Linear41000 VRT Type S Partial Stack 6% Linear41000 VRT Type S Full Stack 3.5% Linear41000 VRT Type C Cage 6% Linear28000 Varilog 5% LinearAny Class V Shutoff 2% Linear
