Parameter Description Applicable Valve Types Fisher Globe Valves (e.g., ED, ES, HP, and others) Trim Type Multi-stage, drilled-hole stacked plate trim. Primary Function Cavitation Control & Erosion Reduction. Flow Characteristic Linear (inherent to the multi-stage design). Shut-Off Class Dependent on the specific plug and seat arrangement of the main valve. Typically ANSI Class IV or better with metal seats. Liquid Pressure Recovery Factor (FL) Very high (approaches 1.0), indicating excellent resistance to cavitation. Materials of Construction (Typical): Cage/Trim Stack: 316 Stainless Steel (standard), 17-4PH Stainless Steel, or other hardened alloys. Plug: 17-4PH SST, Stellite-faced, or Tungsten Carbide for extreme service. Seat Ring: 316 SST, Stellite-faced. Typical Applications: Micro-Flat trim is specified for severe liquid services where cavitation is a known problem, such as: Boiler Feedwater Pump Recirculation (BFP Recirc) High-Pressure Letdown Services Condensate Recirculation Water Injection Wellhead Choke Valves Chemical Plant Pressure Letdown Any application with a high ΔP where the outlet pressure remains above the liquid's vapor pressure.
