Resilient seated gate valves adopt full-bore elastic soft sealing structure with symmetrical internal flow channel design.The medium can flow in both directions,and there is no strict unidirectional installation restriction on pipeline flow direction compared with globe valves.
Although bidirectional sealing is achievable,it is still recommended to install the valve in accordance with the flow arrow marked on the valve body in actual pipeline construction.Following the arrow direction can stabilize the internal hydraulic pressure state,reduce operation torque,maintain stable sealing performance of rubber seat,and avoid long-term reverse flow erosion on sealing surface.Reverse installation will not cause serious leakage,but may slightly increase opening resistance and accelerate seal aging under long-time continuous operation.
For installation posture requirements on horizontal pipelines:the valve stem of both rising stem and non-rising stem resilient seated gate valves shall be installed vertically upward as priority.In case of limited space,slight upward inclination(no more than 45°)is acceptable.It is strictly prohibited to install with valve stem downward,which will cause impurities accumulation in stem thread and packing cavity,medium immersion corrosion,gate jamming and packing leakage.
Before installation,fully clean welding slag,rust and debris inside pipeline to prevent scratching soft sealing seat.Keep pipeline flanges concentric and parallel,fasten bolts diagonally and evenly without forced assembly.Large-diameter valves shall be equipped with independent pipeline supports to avoid structural deformation caused by pipeline load tension.After installation,conduct opening-closing flexibility test and pressure leakage inspection to ensure reliable operation.
References
1.GB/T 7714
GB/T 12232-2021. General Valve Flanged Iron Gate Valve [S]. Beijing: China Standard Press, 2021
2.APA
National Valve Standardization Technical Committee.(2022).Technical specification for selection,installation and maintenance of gate valves.Standards Press of China.
3.MLA
National Valve Standardization Technical Committee.Technical Specification for Selection,Installation and Maintenance of Gate Valves.Standards Press of China,2022.
