When the worm gear grooved butterfly valve fails to open or close normally,it is mostly caused by internal debris blockage,seal adhesion,corrosion jamming,lubrication failure of worm gear mechanism or long-term static sediment accumulation inside the pipeline.
First,before maintenance,cut off the pipeline medium pressure and drain residual water inside the pipeline to ensure safe operation.Check the external worm gear handwheel first.If the handwheel cannot rotate,the internal worm gear structure may lack lubricant,rust or gear abrasion.Apply professional lubricating oil to the worm and gear parts,and slowly rotate the handwheel with moderate force to release mechanical jamming.Violent forced rotation is prohibited to avoid breaking valve stem and internal parts.
If the mechanical drive is normal but the valve plate still cannot move,it is caused by dirt,scale and impurities sticking between the valve disc and rubber seat.At this time,disassemble the clamp connectors,remove the valve from the pipeline,clean internal sediment,rust and accumulated dirt on the sealing surface.Check whether the rubber seat is deformed,swollen or damaged due to medium corrosion.
In addition,long-term non-operation will lead to vacuum adhesion between valve disc and soft seal.Gently loosen the internal pressure difference and slowly adjust the handwheel to separate the contact surface.For stem jamming caused by corrosion,polish the valve stem,remove rust and reapply anti-corrosion lubricant.
After maintenance,test the opening and closing flexibility repeatedly,check sealing performance and pressure resistance.Regular lubrication and periodic cleaning can effectively prevent repeated failure of valve opening and closing.
References
1.GB/T 7714
GB/T 12238-2021. Flange and clamp connection elastic sealing butterfly valve [S]. Beijing: China Standard Press, 2021
2.APA
State Administration for Market Regulation.(2021).GB/T 12238-2021 Elastic-sealed butterfly valves with flange and wafer connections.Standards Press of China.
3.MLA
State Administration for Market Regulation.GB/T 12238-2021 Elastic-sealed Butterfly Valves with Flange and Wafer Connections.Standards Press of China,2021.
