Trim Design: Materials Standard Materials Body/Bonnet Carbon Steel casting ASTM A352-LCC (ANSI) ASTM A216-WCB (ANSI) A487-1C (API) Stainless steel ASTM A351-CF8M Duplex Super duplex Carbon steel with Inconel cladded overlay Internal parts Turning fork; casting Protecting bush Front disc and bean carrier Stainless steel Duplex Super duplex Inconel VONK CHOKES
Trim Design General features VONK CHOKES Seat never in contact with medium Seat-tightness to ANSI Class V or VI Minimises cavitation problems Exhibits low noise Excellent control Guaranteed fixed Cv value Repairable internals Vibration resistance Easy maintenance design Rotating Disc Principle VONK CHOKES
Erosion The Erosion Triangle VONK CHOKES Sand Small Valve opening Pressure drop Prevent erosion by eliminating one of below conditions: Sand production Pressure drop Small valve opening VONK CHOKES
Erosion How to prevent bean erosion VONK CHOKES 100% open; ideal Bigger opening results in smaller impact angles 100% open; ideal 10% open: alert! 40% open VONK CHOKES
Small impingement angle Erosion How to prevent bean erosion Operate in green zone Small impingement angle No Erosion! Operate in Green Zone: Small impingement angle on the Tungsten Carbide liner Erosion decreases significant with impingement angle < 45 degrees At 30 degrees the erosion is almost 0. Operate in green zone! Select orifice size based on process conditions! VONK CHOKES
Erosion How to prevent bean erosion VONK CHOKES orifice back disc Design principle of DV trim: Minimize impingement angle at small valve opening orifice back disc DV orifice front disc At small valve opening: Parallel flow entrance with the Tungsten Carbide liner VONK CHOKES
Developments: DV trim Flow out Flow in VONK CHOKES Simulation of flow path and erosion for 21 MM DV 10%Opening 20%Opening 40%Opening 60%Opening 80%Opening 100%Opening Flow out Area of interest DV Trim Bean Flow in Bean inner diameter VONK CHOKES