NonRisingStemVAC真空VacuumCV止回阀CheckValveOD外径OutsideDiameterVOL提及，容量VolumeCWP冷水工作波纹管密封式bellowssealtype用波纹管作阀杆主要密封的各种阀门波纹管平衡式安全阀bellowssealbalan...