Proper selection of a suitable inlet valve requires attention to the following points:
进口阀门主要是指来自国外的品牌的阀门，主要是欧美，日本品牌，比较多使用的有以下种类：进口截止阀，进口调节阀，进口蝶阀， 进口减压阀，进口电磁阀等，而且产品的口径，压力，温度，材质，连接方式，操作方式等各种参数很多，需要根据实际需要， 产品的特征来选择合适的阀门；本文结合获得广泛客户好评的德国品牌德国洛克DE LOCKE，分析下进口阀门的具体选型：
Imported valves mainly refer to the valves of foreign brands, mainly European, American and Japanese brands, which are mostly used in the following categories: imported stop valve, imported regulating valve, imported butterfly valve, imported pressure reducing valve, imported solenoid valve, etc. Moreover, there are many parameters of the product, such as caliber, pressure, temperature, material, connection mode, operation mode, etc., which need to be based on the actual needs, This paper analyzes the specific selection of the following imported valves based on the German brand Locke de Locke, which is widely praised by customers
一、进口阀门的特性有使用特性和结构特性
1、 The characteristics of the imported valve are service characteristics and structural characteristics
1、进口阀门使用特性
（1）.Service characteristics of inlet valve
使用特性确定了阀门的主要使用性能和使用范围，属于阀门使用特性的有：阀门的类别（闭路阀门、调节阀门、安全阀门等）；产品类型（闸阀、截止阀、蝶阀、球阀等）；阀门主要零件（阀体、阀盖、阀杆、阀瓣、密封面）的材料；阀门传动方式等。
The service characteristics determine the main service performance and scope of use of the valve, which include: Valve category (closed-circuit valve, regulating valve, safety valve, etc.); product type (gate valve, globe valve, butterfly valve, ball valve, etc.); material of main parts of the valve (valve body, bonnet, stem, disc, sealing surface); valve transmission mode, etc.
2、结构特性
（2） Structural characteristics
结构特性确定了阀门的安装、维修、保养等方法的一些结构特性，属于结构特性的有：阀门的结构长度和总体高度、与管道的连接形式（法兰连接、螺纹连接、夹箍连接、外螺纹连接、焊接端连接等）；密封面的形式（镶圈、螺纹圈、堆焊、喷焊、阀体本体）；阀杆结构形式（旋转杆、升降杆）等。
The structural characteristics determine some structural characteristics of valve installation, maintenance and other methods. The structural characteristics include: the structural length and overall height of the valve, the connection form with the pipeline (flange connection, thread connection, clamp connection, external thread connection, welding end connection, etc.); the form of sealing surface (insert ring, thread ring, overlay welding, spray welding, valve body); the valve Rod structure (rotating rod, lifting rod), etc.
二、选择阀门的步骤
（2）、 To select a valve
明确阀门在设备或装置中的用途，确定阀门的工作条件：适用的介质、工作压力、工作温度等等；比如想要选择一款德国洛克DE LOCKE的截止阀，确认介质是蒸汽，工作原理是1.3Mpa，工作温度是200℃。
Define the purpose of the valve in the equipment or device, and determine the working conditions of the valve: applicable medium, working pressure, working temperature, etc.; for example, if you want to select a German Locke de Locke stop valve, confirm that the medium is steam, the working principle is 1.3mpa, and the working temperature is 200 ℃.
确定与阀门连接管道的公称通径和连接方式：法兰、螺纹、焊接等；比如选择进口截止阀，确认连接方式是法兰的。
Determine the nominal diameter and connection method of the pipeline connected with the valve: flange, thread, welding, etc.; for example, select the inlet stop valve, and confirm that the connection method is flange.
确定操作阀门的方式：手动、电动、电磁、气动或液动、电液联动等；比如选择的是手动截止阀。
Determine the way to operate the valve: manual, electric, electromagnetic, pneumatic or hydraulic, electro-hydraulic linkage, etc.; for example, select the manual stop valve.
根据管线输送的介质、工作压力、工作温度确定所选阀门的壳体和内件的材料：铸钢、碳素钢、不锈钢、合金钢、不锈耐酸钢、灰铸铁、可锻铸铁、球墨铸铁、铜合金等；比如截止阀选择的铸钢材质。
According to the medium, working pressure and working temperature transmitted by the pipeline, the materials of the shell and internal parts of the selected valve are determined: cast steel, carbon steel, stainless steel, alloy steel, stainless and acid resistant steel, gray cast iron, malleable cast iron, nodular cast iron, copper alloy, etc.; for example, the material of cast steel selected for the stop valve.
选择阀门的种类：闭路阀门、调节阀门、安全阀门等；
Select the type of valve: closed-circuit valve, regulating valve, safety valve, etc;
确定阀门的型式：闸阀、截止阀、球阀、蝶阀、节流阀、安全阀、减压阀、蒸汽疏水阀等；
Determine the valve type: gate valve, stop valve, ball valve, butterfly valve, throttle valve, safety valve, pressure reducing valve, steam trap, etc;
确定阀门的参数：对于自动阀门，根据不同需要先确定允许流阻、排放能力、背压等，再确定管道的公称通径和阀座孔的直径；
Determine the parameters of the valve: for the automatic valve, determine the allowable flow resistance, discharge capacity, back pressure, etc. according to different needs, and then determine the nominal diameter of the pipeline and the diameter of the valve seat hole;
确定所选用阀门的几何参数：结构长度、法兰连接形式及尺寸、开启和关闭后阀门高度方向的尺寸、连接的螺栓孔尺寸和数量、整个阀门外型尺寸等；
Determine the geometric parameters of the selected valve: structural length, flange connection form and size, size of valve height direction after opening and closing, size and quantity of bolt holes for connection, overall size of the valve, etc;
利用现有的资料：阀门产品目录、阀门产品样本等选择适当的阀门产品。
Use existing data: valve product catalog, valve product samples, etc. to select appropriate valve products.
三、选择阀门的依据
（3）、 Basis for valve selection
所选用阀门的用途、使用工况条件和操纵控制方式；
The purpose, working condition and control mode of the selected valve;
工作介质的性质：工作压力、工作温度、腐蚀性能，是否含有固体颗粒，介质是否有毒，是否是易燃、易爆介质，介质的黏度等；比如想选择德国洛克DE LOCKE的进口电磁阀，介质和环境易燃、易爆，一般要选择防爆电磁阀；再比如要选择德国洛克DE LOCKE的球阀，介质含有固体颗粒，一般要选择V型的硬密封球阀。
Nature of working medium: working pressure, working temperature, corrosion performance, whether it contains solid particles, whether the medium is toxic, whether it is inflammable and explosive medium, viscosity of the medium, etc.; for example, if you want to choose the imported solenoid valve of Locke de Locke in Germany, the medium and environment are inflammable and explosive, generally you need to choose the explosion-proof solenoid valve; for example, you need to choose Locke de in Germany Locke ball valve, the medium contains solid particles, generally V-type hard seal ball valve should be selected.
对阀门流体特性的要求：流阻、排放能力、流量特性、密封等级等；
Requirements for valve fluid characteristics: flow resistance, discharge capacity, flow characteristics, sealing grade, etc;
安装尺寸和外形尺寸要求：公称通径、与管道的连接方式和连接尺寸、外形尺寸或重量限制等；
Installation dimension and boundary dimension requirements: nominal diameter, connection mode and connection dimension with pipeline, boundary dimension or weight limit, etc;
对阀门产品的可靠性、使用寿命和电动装置的防爆性能等的附加要求（在选定参数时应注意：如果阀门要用于控制目的，必须确定如下额外参数：操作方法、比较大和比较小流量要求、正常流动的压力降、关闭时的压力降、阀门的比较大和比较小进口压力）。
Additional requirements for reliability, service life of valve products and explosion-proof performance of electric devices (attention shall be paid to the following additional parameters when selecting parameters: operation method, maximum and minimum flow requirements, pressure drop of normal flow, pressure drop when closing, maximum and minimum inlet pressure of valve) if the valve is to be used for control purposes.
根据上述选择阀门的依据和步骤，合理、正确地选择阀门时还必须对各种类型阀门的内部结构进行详细了解，以便能对优先选用的阀门做出正确的抉择。
According to the basis and steps of selecting valves mentioned above, it is necessary to have a detailed understanding of the internal structure of various types of valves when selecting valves reasonably and correctly, so as to make a correct choice for the preferred valves.
管道的比较终控制是阀门。阀门启闭件控制着介质在管道内的流向方式，阀门流道的形状使阀门具备一定的流量特性，在选择管道系统适合安装的阀门时必须考虑到这一点。
The final control of the pipeline is the valve. The opening and closing parts of the valve control the flow direction of the medium in the pipeline. The shape of the valve flow path makes the valve have certain flow characteristics. This must be taken into account when selecting the valve suitable for installation of the pipeline system.
归纳总结，选型几大要素：确定要选用什么功能的阀门，确认介质的温度，压力，确认阀门的流量以及需要的口径，确认阀门的材质，操作方式。
Summarize and select several key elements: determine which function valve to select, confirm the temperature and pressure of medium, confirm the flow and required caliber of valve, confirm the material and operation mode of valve.
