《Basic Control Valve Sizing and Selection》.ppt

DeZurik Operation October 2005 Globe Valves 3 Way configurations for Mixing and diverting. -Temperature control - Blending  DeZurik Operation October 2005 Globe Valves Trim Components - Stem, plug, seat,  cage (if that style)  guiding components - Made of alloy materials - Optional hardened seating surfaces when required Top guided style Cage guided style Noise and cavitation control trims By directing flow through a series of staged drops, these trims eliminate cavitation in liquid flow and provides multiple pressure breakdown for noise attenuation DeZurik Operation October 2005 Rotary Control Valves DeZurik Operation October 2005 Rotary Control Valves Design Construction ANSI ISA Face to Face DeZurik Operation October 2005 Rotary Control Valves V ported valves: Uses a ball segment that is Always in contact with the seat. Up to 100:1 rangability. Eccentric type: Uses a plug that cams away from the seat during opening Ideal solution for erosive services Such as slurries and steam. Available with a range of flow capacities. DeZurik Operation October 2005 High performance Butterfly Valve Ideal economic choice for larger line sizes 50:1 Rangeability Modified equal percent flow Characteristic Fast accurate response to Control signal Actuators The actuator provides the muscle for the control valve and is responsible for moving the valve control element to the required stroke position. Spring diaphragm actuators are the most widely recognized and used by control valve suppliers. Reverse acting; fail closed and direct acting; fail open. Simplistic design ,few moving parts, and easy to maintain. Double acting pistons Smaller, lighter, and less expensive than diaphragm. Fail in last position. Actuators Accessories Positioners – pneumatic input 3-15 psi Electro-pneumatic 4-20 ma (HART, Fieldbus, Profibus) Limit switches Position feedback Review materi