A gate valve is a shutoff valve that uses a flat or wedge-shaped metal gate sliding perpendicular to pipe flow to completely stop water movement. Multiple turns of the handwheel lower the gate into a sealing seat. Gate valves excel at full-flow applications with minimal pressure loss when completely open but are slower to operate than ball valves. They are less suitable for frequent partial opening to regulate flow.
Design and Specifications
Wedge-gate and parallel-gate designs accommodate different pressure conditions and sealing requirements. Pressure ratings range from 125 to 300 PSI for typical residential and light commercial applications. Sizes extend from 1/2 inch to 12 inches for large diameter water main applications. Rising stem designs show gate position through stem height. Non-rising stem valves maintain compact appearance where headroom is limited.
Traditional HVAC Applications
Older hydronic heating systems extensively use gate valves as zone shutoffs and pump isolators. They remain code-compliant for rough-in installation. However, newer systems increasingly prefer ball valves for superior quarter-turn operation and reliability.
Operational Limitations
Sediment can lodge between the gate and seat, preventing complete closure. Gate flutter occurs at partial openings when water pressure causes vibration. Full opening is required to minimize pressure loss and erosion damage to the gate. Handwheel operation requires 10-20 turns for 1-inch valves, making them less convenient than quarter-turn alternatives.