Z941H/Z940H

Engineer's Selection Guide: Gate Valves

Gate valves are linear-motion isolation valves offering a full, unobstructed bore when fully open, making them suitable for low-pressure-drop on/off service. They are not intended for throttling. Key selection factors are body/bonnet construction, stem type (rising vs. non-rising), wedge design, and pressure class per the applicable API/ASME standard.

• On steam mains and thermal-cycling lines use rising-stem OS&Y gate valves for visible open/closed indication; flexible-wedge designs resist binding from thermal growth better than solid wedges.
• In high-pressure boiler-feed service specify pressure-seal bonnets rather than bolted bonnets — internal line pressure energizes the seal and avoids the bolt-stress limits that limit flanged joints.

Guidance reflects general engineering practice for gate valves; confirm against the project specification and applicable standards before procurement.