阀门选定和管道设计时，应注意事项如下：

　　Selection of valves and design of pipes shall comply with the following principals:

　　1、根据阀门使用场所、用途且了解有关法规、规格、标准、方针、许用认可后即可选用适合各种要求的阀门；

　　In terms of locations and purposes of valves, the suitable valves can be selected after knowing relevant specification, size,

　　standards,principal and permission;

　　2、确定阀门的工作条件、适用介质、工作压力、介质温度

　　Need to specify the working condition, applicable medium, working pressure and working temperature of media;

　　3、确定与管道相匹配的公称通径DN  （mm）

　　Need to specify the nominal diameter to match the pipeline: DN（mm）

　　4、确定与管道相连接方式法兰式、内（外）螺纹式、焊接式、对夹式、卡箍式、卡槽式、卡套式等

　　Need to specify the connecting type of the pipeline, including flanged type, inside&outside screwed type, welded type, wafer

　　type, clip type, groove

　　type,ａnd union type etc.;

　　5、确定阀门的操作方式：手动、蜗轮动、气动、电动、液动、电磁动、电液动

　　Need to specify the operating type of the valve, including lever, worm gear, pneumatic actuator, hydraulic actuator,

　　electromagnetic actuator and electromagnetic-hydraulic actuator etc.;

　　6、确定阀门的类型闸阀、截止阀、节流阀、球阀、蝶阀、隔膜阀、旋塞阀、止回阀、安全阀、减压阀、疏水阀、柱塞阀、水力控制阀及其他特种阀

　　Need to specify the model of the valve, including gate valve, globe valve, throttle valve, ball valve, butterfly valve, diaphragm

　　valve, plug valve, check valve, safety valve, reducing valve, steam trap and plunger valve etc.;

　　7、确定阀门的使用形式开关型、调节型、安全型等

　　Need to specify the working type of valve, including on-off type, adjusting type, safety type etc.;

　　8、确定阀门壳体及内件的材料灰铁、球铁、碳钢、合金钢、不锈钢、蒙乃尔合金、铜合金、铝合金、塑料等

　　Need to specify material of body and trim, including grey iron, ductile iron, carbon steel, alloy steel, stainless steel, monel alloy,copper alloy, aluminum alloy, plastic etc.;

　　9、确定阀门的密封性能要求、密封等级或密封泄露量

　　Need to specify the requirements on

　　10、确定阀门的防护涂层要求、包装要求、运输要求

　　seal performance and grade or leakage;

　　Need to specify the requirements on coating, packing and transportation;

　　11、特殊需要的阀门还应确定结构长度、阀门高度、外形尺寸、流阻、排放能力、流量特性、防护等级、防爆性能等参数

　　Need to specify face to face dimension, height, outline sizes, flow resistance, drainage ability, flow characteristic, protected

　　grade, anti-explosive performances etc. for special valves;

　　12、确定阀门的安装位置及姿势

　　Need to specify the installed position and direction for the valve.