PN16 DF41X обратный проточный превентор чугунный фланцевый клапан GB размеры противообрастающий блок клапана

Regorge Preventer the principle of work is has flowed enters when the water check valve because the mechanical resistance using the me-dium and has flowed the loss of head but the reduced press ure, causes the inlet pressure to be higher than the draw-off valve cavity the pressure,but on the draw-off valve diaphragm pressure is the inlet pressure,on the dia-phragm the pressure is bigger than the draw-off valve cavity and the spring resistance,the draw-off valve maintenance closure,the medium normally flows,when the inlet pressure and the draw-off valve cavity pressure differ-ence is smaller than 0.02MPa,the medium is at the critical state which flows backwards,by now on the draw-off valve diaphragm the pressure was smaller than the draw-off valve cavity and the spring pressure,the draw-off valve automatically opens,will flow backwards outside the me-dium eduction tube,simultaneously the massive air admission valve cavity, formed the air room partition,ceased the medium to flow backwards,ls big- ger than when 0.02MPa draw-off valve automatic shut-off.After the valve the pipe network hydraulic pressure elevates when sur-passes the valve advance water end hydraulic pressure,if second unidirec-tional make a round trip;goes to the valve seal to be complete,the water body cannot flow backwards,this time draw-off valve closure not drainage, when the second Jianxi check valve seal malfunctions when has the leak- age,the draw-off valve opens the draining water decompression.