Valtek Severe Service Equipment

Valtek Severe Service EquipmentMegaStream TrimVelocitiesOne of the fundamental design considerations withValtek control valves with MegaStream trim is theestablishment of acceptable velocities at every point asthe flow passes through the valve.For gaseous control valve applications, keeping themaximum outlet gas velocity below 0.33 Mach is desirable,although higher velocities can be accommodated.Velocities must be assessed for the most difficult flowingconditions at the following critical points (as shown inFigure 33):1. The inlet passageway to the valve2. The internal flow area of the MegaStream attenuatorat all plug positions3. The gallery flow area formed between the outsidediameter of the attenuator and the inside diameter ofthe valve body4. The valve outlet passage flow area. For proper noisecontrol, the downstream piping must be equal to orlarger than the valve outlet sizeFlow CharacteristicsAs with the standard Mark One trim design, the flowcharacteristic for MegaStream trim is determined by thecontour of the plug head. Three characteristics areavailable: equal percentage, linear and quick-open.Trim PartAvailable MaterialsA ttenuator 16 stainless steel,InconelPlugSeatRingTable 12: MegaStream TrimMaterials of Construction3®316 stainless steel, 316 stainless steelwith Alloy 6, 400 series stainless steel,Inconel, alloys as required316 stainless steel, 316 stainless steelwith Alloy 6, 400 series stainless steel,Inconel, alloys as requiredSee Valtek Mark One Control Valves technical bulletin for basicvalve’s materials of construction.22Flowserve Corporation, Valtek Control Products, Tel. USA 801 489 8611