在生产过程中，控制系统对阀门提出各式各样的特殊要求，控制阀必须配用各种附属装置(简称附件)来满足生产过程的需要。控制阀的附件包括：
1、阀门定位器用于改善控制阀调节性能的工作特性，实现正确定位；
2、阀位开关显示阀门的上下限行程的工作位置；
3、气动保位阀当控制阀的气源发生故障时，保持阀门处于气源发生故障前的开度位置；
4、电磁阀实现气路的电磁切换，保证阀门在电源故障时阀门处于所希望的安全开度位置；
北京华德液压全系列 具体型号及报价请联系客服
北京华德换向阀部分型号如下：
4WEH25E50B/OF6AG24NEZ4 4WEH32B50B/6EG24NE25L
4WEH25E50B/OF6AG24NEZ5 4WEH32C50B/6CW220-N9ET25L
4WEH25E50B/OF6AG24NEZ5L 4WEH32C50B/6EG24NE25L
4WEH25E50B/OF6AG24NTZ4 4WEH32D50B/6CW220-N9ET25L
4WEH25E50B/OF6AG24NTZ5 4WEH32D50B/6EG24NE25L
4WEH25E50B/OF6AG24NTZ5L 4WEH32E50B/6CW220-N9ET25L
4WEH25E50B/OF6AG24NZ4 4WEH32E50B/6EG24NE25L
4WEH25E50B/OF6AG24NZ5 4WEH32F50B/6CW220-N9ET25L
4WEH25E50B/OF6AG24NZ5L 4WEH32F50B/6EG24NE25L
4WEH25E50B/OF6AW220-50NETZ4 4WEH32G50B/6CW220-N9ET25L
4WEH25E50B/OF6AW220-50NETZ5 4WEH32G50B/6EG24NE25L
4WEH25E50B/OF6AW220-50NETZ5L 4WEH32H50B/6CW220-N9ET25L
4WEH25E50B/OF6AW220-50NEZ4 4WEH32H50B/6EG24NE25L
4WEH25E50B/OF6AW220-50NEZ5 4WEH32J50B/6CW220-N9ET25L
4WEH25E50B/OF6AW220-50NEZ5L 4WEH32J50B/6EG24NE25L
4WEH25E50B/OF6AW220-50NTZ4 4WEH32L50B/6CW220-N9ET25L
4WEH25E50B/OF6AW220-50NTZ5 4WEH32L50B/6EG24NE25L
4WEH25E50B/OF6AW220-50NTZ5L 4WEH32M50B/6CW220-N9ET25L
4WEH25E50B/OF6AW220-50NZ4 4WEH32M50B/6EG24NE25L
4WEH25E50B/OF6AW220-50NZ5 4WEH32P50B/6CW220-N9ET25L
4WEH25E50B/OF6AW220-50NZ5L 4WEH32P50B/6EG24NE25L
4WEH25F50B/6CW220-N9ET25L 4WEH32T50B/6CW220-N9ET25L
4WEH25F50B/6EG24NE25L 4WEH32T50B/6EG24NE25L
4WEH25G50B/6CW220-N9ET25L 4WEH32U50B/6EG24NE25L
4WEH25G50B/6EG24NE25L 4WEH32Y50B/6CW220-N9ET25L
4WEH25H50B/6CW220-N9ET25L 4WEH32Y50B/6EG24NE25L