... seal, to avoid short-circuit at wet situation.2. Valve’s operation is step less adjust, have function of ... double O-ring structure, Carbon fiber and PTFE.5. Valve’s seal automatic upon the pressure, seal ring can ... up with BA system.7. No resistance when the valve is fully open.8. We not only produce product, ... Address: Bingang Industry Area,Shamen,Yuhuan,Zhejiang province. modulating control valve