CP Propeller Equipment - Martin's Marine Engineering Page

Servo Oil SystemThe principle design of the servo oil systemsfor VBS (fig 11) and for VB (fig 12)is identical.The VBS system consists of a servo oiltank unit – Hydra Pack, and a couplingflange with electrical pitch feed–backbox and oil distributor ring.For VB propeller equipment with Alphareduction gearbox, the servo oil systemis an integrated part of the gearbox.This means that the servo piston, pitchfeed–back box and oil distributor ringare located inside the gearbox.The electrical pitch feed–back boxmeasures continuously the position ofthe pitch feed–back ring and comparesthis signal to the pitch order signal. Ifdeviation occurs, a proportional valve isactuated.Hereby high pressure oil is fed to one orthe other side of the servo piston, viathe oil distributor ring, until the desiredpropeller pitch has been reached.The pitch setting is normally remotecontrolled, but local emergency controlis possible.2 04 00 22–5.0ServopistonZincanodeSterntube oiltankMonoblockhubOil tankforwardsealLip ringsealsSterntubePropeller shaftFig 11: Propeller equipment type VBS2 04 05 36–6.0Sterntube oiltankOil tankforwardsealHydraulicpipeOil distributionringPitch controlrodHydra PackLALTITAHMPSL PSLMPALPAL PAH PIDraintankPDPitchfeed–backOil distributionringPitchorderMMLip ringsealsZinkanodeMonoblockhubSterntubeServopistonPitchfeed–backGearboxFig 12: Propeller equipment type VBThis document, and more, is available for download at Martin's Marine Engineering Page - www.dieselduck.net11