onoffventiler

On/off ventiler, commonly called on/off valves, are valves designed to enable rapid, complete shutdown or full opening of fluid flow in piping systems. They provide a tight shutoff when closed and a wide flow path when open, making them well suited for start/stop service rather than precise throttling. They are actuated by a manual handle or by automated actuators such as electric, pneumatic, or hydraulic devices.

Common types include ball valves, gate valves, and butterfly valves, which can provide quick shutoff with relatively low torque. Ball and gate valves are widely used for their tight seals and durability. Some globe valves and butterfly valves can be used for on/off service but may experience higher resistance when fully open and are used for throttling in many cases.

Materials vary with application, including brass or bronze for water and domestic use, stainless steel for corrosive or sanitary service, and plastic (PVC/CPVC) for low-pressure systems. End connections may be threaded, flanged, or welded.

Applications span water distribution, gas supply, chemical processing, oil and gas pipelines, HVAC systems, and fire-protection networks. Selection depends on fluid type, pressure and temperature, required shutoff tightness, space, and maintenance needs. Standards such as ANSI/ASME B16.34 and API specifications cover dimensioning, pressure ratings, seat sealing, and testing.

Operation and maintenance: when installed, valves should be fully opened or closed during commissioning. Actuators require correct sizing and installation. Regular inspection of packing, seals, and seats helps prevent leakage. In service, on/off valves may require periodic exercising to prevent sticking and maintain seal integrity.