What is API 623 globe valve?
API 623 is the American Petroleum Institute standard for steel and alloy globe valves for petroleum and natural gas industries. It covers design, materials, testing, and marking requirements. API 623 globe valves are used for throttling and flow regulation where precise control is needed. They feature a linear flow characteristic and are available in bolted bonnet and pressure seal designs.
Why use NAB globe valves for seawater?
NAB (Nickel Aluminium Bronze) globe valves are ideal for seawater throttling because: (1) Excellent corrosion resistance to seawater and chlorides, (2) Superior erosion resistance in high-velocity flow, (3) Anti-biofouling properties, (4) Maintains precise throttling control over long service life, (5) Self-healing oxide layer protects against pitting.
What is the difference between gate valve and globe valve?
Gate valves are for on/off isolation with minimal pressure drop when fully open. Globe valves are for throttling and flow control with higher pressure drop. Globe valves have a disc that moves perpendicular to the flow, allowing precise flow regulation. Gate valves have a wedge that moves parallel to flow. For seawater systems, use gate valves for isolation and globe valves for flow control.
What sizes are NAB globe valves available in?
NAB globe valves per API 623 are available from 1/2 inch (DN15) to 12 inch (DN300). Common sizes for seawater service include 3 inch and 8 inch. Smaller sizes are handwheel operated, larger sizes (6 inch and above) are typically gear operated. Flanged ends per ASME B16.5 Class 150.