德国宝硕,BUSCHJOST单向阀结构图

弹簧式:液体由下而上，依靠压力顶起弹簧控制的阀瓣，压力消失后，弹簧力将阀瓣压下，封闭液体倒流。常用于通径较小的止回阀。

重力式:和弹簧式相似，依靠阀瓣的自身重力封闭，防止倒流。

旋启式:液体在阀体内直通，依靠压力顶开一侧的旋转阀瓣，压力失去后，阀瓣依靠自重回位，反向的液体压力封闭阀瓣。

塑料隔膜式: 外壳和隔膜均为塑料.一般外壳为ABS,PE,PP,NYLON, PC.隔膜有硅树脂,氟树脂等。

其它的单向阀(止回阀)，如排污的止回阀，人防的防爆阀和液体使用的止回阀的原理是大同小异。

旋启式止回阀适用介质:水，蒸气，油品，硝酸，强氧化介质和尿素等。广泛应用于电站，石油，化工，制药，食品等行业。可与进口设备直接配套使用。对夹式止回阀适用于公称压力PN1.0MPa~42.0MPa、Class150~2500;公称通径DN12~1200mm、NPS1/2~48;工作温度-196~540℃的各种管路上，用于防止介质倒流。通过选用不同的材质，可适用于水、蒸汽、油品、硝酸、醋酸、强氧化性介质及尿素等多种介质。

宝硕单向阀实物图;

德国宝硕,BUSCHJOST单向阀结构图
engineers practice wellknown in the member countries.
The CE-sign at the valve refers not to the PED. Thus the declaration of
conformity is not longer applicable for this directive.
For valves > DN 25 (G 1) Art. 3 § (1) .4 applies.
The basic requirements of the Enclosure I of the PED must be fulfilled.
The CE-sign at the valve includes the PED. A certificate of conformity of
this directive will be available on request.
The valves of this series, including the connection size DN 25
(G 1), are according to Art. 3 § 3 of the Pressure Equipment Directive (PED)
97/23/EG. This means interpretation and production are in accordance to