Boiler Feedwater Regulator

grabcad

The boiler feedwater regulator valve is vital in power plants, transitioning from pump recirculation to normal operation. It fills the steam drum initially and controls flow under pressure. The valve must handle cavitation during initial operation and offer a rangeability of at least 75:1 for entire feedwater requirements. During initial operation, it resembles the feedpump recirculation valve but with varying flow rates. Valve service conditions depend on plant size and unit operations, with inlet pressures reaching up to 5500 psig, typically between 2500 and 3500 psig. Fisher recommends globe or angle valves with Cavitrol protection for this service. The three-stage design, resistant to 3000 psid pressure drops, is common while the four-stage design that can handle up to 4000 psid is also available. Cavitrol trim eliminates cavitation formation and requires characterization for required flow. It provides cavitation protection at low valve travels during initial filling, decreasing as drum pressure increases. Tight shutoff is recommended, especially in recirculation mode, to ensure long-lasting trim life and prevent high pressure alarms or trim washout. All Cavitrol designs come with Class V shutoff protection.