译文：
阀门是用以控制流体流量、压力和流向的装置。被控制的流体可以是液体、气体、气液混合体或固液混合体。 阀门通常由阀体、阀盖、阀座、启闭件、驱动机构、密封件和紧固件等组成。阀门的控制功能是依靠驱动机构或流体驱使启闭件升降、滑移、旋摆或回转运动以改变流道面积的大小来实现的。 阀门的用途很广泛，它与人们的日常生活有密切的关系，例如自来水管用的水龙头、液化石油气灶用的减压阀都是阀门。阀门也是各种机械设备如内燃机、蒸汽机、压缩机、泵、气压传动装置、液压传动装置、车辆、船舶和飞行器中不可缺少的部件。 公元前两千年前，中国人就在输水管道上使用了竹管和木塞阀，以后又在灌溉渠道上使用水闸，在冶炼用的风箱上使用板式止回阀，在井盐开采方面使用竹管和板式止回阀提取盐水。 随着冶炼技术和水力机械的发展，在欧洲出现了铜制和铅制旋塞阀。随着锅炉的使用，1681年又出现了杠杆重锤式安全阀。1769年瓦特蒸汽机出现以前，旋塞阀和止回阀一直是最主要的阀门。 蒸汽机的发明使阀门进入了机械工业领域。在瓦特的蒸汽机上除了使用旋塞阀、安全阀和止回阀外，还使用了蝶阀，用以调节流量。随着蒸汽流量和压力的增大，使用旋塞阀控制蒸汽机的进汽和排汽已不能满足需要，于是出现了滑阀。 1840年前后，相继出现带螺纹阀杆的截止阀，和带梯形螺纹阀杆的楔式闸阀，这是阀门发展中的一次重大突破。这两类阀的出现，不仅满足了当时各种工业对压力、温度不断提高的要求，而且初步满足了对流量调节的要求。此后随着电力工业、石油工业、化学工业和造船工业的发展，各种高中压阀门得到迅速发展。 第二次世界大战后，由于聚合材料、润滑材料、不锈钢和钴基硬质合金的发展，古老的旋塞阀和蝶阀获得了新的应用，球阀和隔膜阀得到迅速发展。截止阀、闸阀和其他阀门品种增加，质量提高。阀门制造业逐渐成为机械工业的一个重要部门。 阀门按使用功能可分为截断阀、调节阀、止回阀、分流阀、安全阀、多用阀六类。 截断阀主要用于截断流体通路，包括截止阀、闸阀、旋塞阀、球阀、蝶阀隔膜阀、夹管阀等；调节阀主要用于调节流体的压力、流量等，包括调节阀、节流阀、减压阀和浮球调节阀等；止回阀用于阻止流体的逆向流动；分流阀用于分配流体的通路去向，或将两相流体分离，包括滑阀、多通阀、疏水阀和排空气阀等；安全阀主要用于安全保护，防止锅炉、压力容器或管道因超压而破坏；多用阀是具有一种以上功能的阀门，如截止止回阀既能起断流作用又能起止回作用。 工业管道阀门按公称压力又可分为真空阀、低压阀、中压阀、高压阀、超高压阀；阀门按工作温度又可分为常温阀、中温阀、高温阀、低温阀；阀门还可按驱动装置的类型、与管道的联接方式和阀体的使用材料等进行分类。阀门可按各种分类方法单独地或组合地命名，也可按启闭件的结构特征或具体用途命名。 阀门的基本参数是工作压力、工作温度和口径。对于大量使用于工业管道的各种阀门，常用公称压力和公称通径作为基本参数。公称压力是指某种材料的阀门，在规定的温度下，允许承受的{zd0}工作压力。公称通径是指阀体与管子联接端部的名义内径。 阀门根据其种类和用途有不同的要求，主要有密封、强度、调节、流通、启闭等性能。在设计和选用阀门时，除了要考虑基本参数和性能外，还要考虑流体的性能，包括流体的相态气体、液体或含固体颗粒、腐蚀性、粘度、毒性、易燃易爆性，贵重稀有程度和放射性等。 密封性能和强度性能是一切阀门最基本、最重要的性能。阀门的密封分内密封和外密封两部分。内密封是阀瓣与阀座之间的密封；外密封是阀杆运动部位与阀盖之间、阀体与阀盖之间和阀体与管道联接部位之间的密封。阀门在使用时不仅要求密封性能好，而且必须保证安全。 如果因密封不好而发生泄漏或因强度不够而使零件破坏，将会造成不同程度的经济损失，如输送有毒、易燃易爆或有强腐蚀性流体，还可能导致严重的安全事故。为了保证阀门的密封和强度，除了必须遵守有关标准规定合理地进行结构设计、确保工艺质量外，还必须正确地选用材料。 通常，低压非腐蚀性流体用的阀门使用铸铁或铸铜；高、中压阀用铸钢或锻钢；高温或高压阀使用合金钢；用于腐蚀性流体的阀门用不锈钢、塑料，耐蚀合金如铜镍钼合金、钛合金和铅合金等或用铸铁、铸钢内衬耐蚀材料制造。 通常，低压阀的密封面大多使用黄铜或青铜，高、中压阀大多使用不锈钢，要求较高的高、中压阀或高温阀等使用钴基硬质合金。聚合材料在阀门中已获得广泛应用，如球阀的阀座主要采用聚四氟乙烯塑料，蝶阀的密封圈和隔膜阀的隔膜采用各种橡胶材料。这些材料在可以使用的温度范围内具有比金属更好的密封性。 随着现代核工业、石油化学工业、电子工业和航天工业的发展，以及流程工艺自动控制和远距离流体输送的发展，促进了现代低温阀、真空阀、核工业用阀和各种调节阀的发展。用于远距离控制和程序控制的阀门驱动装置的应用越来越多。 未来阀门的发展将向扩大产品参数，发展节能、省力和自控阀门，改进结构、采用新材料和新工艺，提高阀门的使用寿命，以及发展专用阀门系列等发面发展，如用于液氧、液氢和液化天然气等的低温阀、真空阀、核工业用阀、安全阀、调节阀、疏水阀和阀门驱动装置等。

“ General Equipment Valve Development and Principles of”是由提供的国际阀门新闻，译文仅供参考。另外，中国隔膜阀网还提供相关产品搜索：、、、、等。

原文：
Valve is used to control fluid flow, pressure and flow devices. Controlled fluid can be liquid, gas, gas-liquid mixture or a solid-liquid mixture. Valve is usually the valve body, valve cover, valve seat, hoist parts, drive mechanism, seals and fasteners so on. The valve control function is to rely on drive mechanism or fluid driven hoist pieces of lifting, sliding, rotary-oscillating or rotational movement to change the flow channel area the size achieved. Valve uses a very broad, with people's daily lives are closely related to, for example, useful water taps, liquefied petroleum gas stove valves are valves used. Valve is also a variety of mechanical equipment such as internal combustion engines, steam engines, compressors, pumps, pneumatic actuator, hydraulic gear, vehicles, ships and aircraft an indispensable components. BC two years ago, the Chinese people in the pipeline using a bamboo and cork valve, and later in the irrigation canals on the use of the lock, in the refining of the bellows to use plate check valve, in the well salt mining the use of bamboo tube and plate check valve extraction salt water. With the smelting technology and hydraulic machinery development in Europe experienced a copper and Lead plug valves. With the use of boilers, in 1681 has emerged Hammer lever-type safety valve. 1769 Watt steam engine, before the advent of plug valves and check valves have been the main valve. The steam engine invention of the valve into the machinery industries. In Watt's steam engine, besides the use of plug valves, safety valves and check valves, but also used the butterfly valve to regulate flow. As the steam flow and pressure, the use of plug valves control the steam engine and the exhaust steam into the steam can not meet the needs, so there slide valve. Before and after 1840, appeared in succession with a threaded stem of the cut-off valves, and with a trapezoidal wedge threads of the valve stem, which is the valve in the development of a major breakthrough. These two types of valves there, not only to meet at that time a variety of industrial pressure and temperature rising demand, but also initially satisfied the requirements of the traffic conditioning requirements. Since then with the electric power industry, petroleum industry, chemical industry and shipbuilding industries, all kinds of high and medium pressure valves have developed rapidly. After World War II, due to polymer materials, lubricating materials, stainless steel and cobalt-based alloy development, the old plug valves and butterfly valves to obtain a new application, ball valves and diaphragm valves have developed rapidly. Cut-off valves, gate valves, and other varieties of increasing quality. The valve manufacturing sector has gradually become machine-building industry an important sector. Valve-per-use features can be divided into cut off valve, regulating valve, check valve, diversion valve, safety valve, multi-purpose valve six categories. Cut off valve primarily for truncated fluid path, including the cut-off valves, gate valves, plug valves, ball valve, butterfly valve diaphragm valves, clamp pipe valves and so on; regulating valve primarily for regulating the fluid pressure, flow, etc., including the regulating valve, section flow valve, reducing valve and the float valve, etc.; valve used to prevent reverse flow of fluid; divider valve for the distribution of fluid pathways whereabouts, or two-phase flow separation, including the slide valve, multi-pass valve, hydrophobic valves and emptying valves, etc.; safety valve is mainly used for security protection to prevent the boiler, pressure vessel or pipeline overpressure due to the damage; multi-purpose valve is a valve with more than one function, such as the cut-off valve from drying both role of the beginning and end can return to the role. Industrial pipe valve according to nominal pressure can be divided into the vacuum valve, low pressure valves, medium pressure valve, high pressure valves, high pressure valve; valve according to the working temperature can be divided into normal temperature valves, medium temperature valve, high temperature valve, cryogenic valve; valve Doors can also be according to drive type, and pipeline connection methods and body of the use of materials classified. Valve can be a variety of classifications to name individually or in combination, but also can open and close parts of the structural characteristics or for specific purposes named. Valve's basic parameter is the working pressure, working temperature and caliber. For large-scale use in industrial pipes of various valves, commonly used nominal pressure and nominal diameter as the basic parameters. PN refers to a material of the valve, in the specified temperature, allowing the maximum working pressure to bear. DN refers to the valve body and pipe end connections on behalf of diameter. Valve according to their types and uses have different requirements, mainly seal, strength, conditioning, circulation, open and close properties. In the design and selection of valves, in addition to consider the basic parameters and performance, but also take into account the performance of fluid, including fluid-phase state of gas, liquid or solid particles containing, corrosive, viscosity, toxicity, inflammable and explosive nature of , precious rarity and radiological. Sealing performance and strength of the performance of all valves the most basic and important performance. Fall within the ambit of the sealing valve seal and the outer sealing two parts. Sealed inside is a valve between the valve and the valve seat seal; outer seal is a sports site and the stem between the valve cover, valve and the valve cover and the valve body and pipeline connection between the seal parts. Valve when in use not only requires sealing performance, and must ensure safety. If the result of seal well and leak or because of strong enough Ershi parts damaged, it will result in different levels of economic losses, such as the transportation of toxic, inflammable, explosive or strong corrosive fluids, can also lead to serious security incidents. In order to ensure the valve seal and intensity, in addition to comply with the relevant standards require that a reasonable structure design to ensure the process quality, but also must be properly selected materials. Typically, low-pressure non-corrosive fluid with the valve to use cast iron or bronze; high and medium pressure valve with cast or forged; high temperature or high pressure valve use of alloy steel; for the corrosive fluid valve of stainless steel, plastic, corrosion resistant alloys such as copper-nickel-molybdenum alloys, titanium alloys and lead alloys or cast iron, cast steel lined with corrosion resistant materials. Typically, low-pressure valve sealing surface most of the use of brass or bronze, high, medium pressure valve most of the use of stainless steel, require a higher high, medium pressure valve, or high-temperature valve using cobalt-based alloy. Polymer material in the valve has been widely used, such as the valve's seat used mainly PTFE plastic, butterfly valve seals and diaphragm valves of the diaphragm using a variety of rubber materials. These materials can be used in temperature range than the metal a better seal. With modern nuclear industry, petrochemical industry, electronic industry and aerospace industries, as well as process automation and long-distance fluid transport process of development and promote a modern cryogenic valves, vacuum valves, nuclear valves and a variety of industrial control valves发展. Used for remote control and process control valve drives the application of more and more. Future valve development will extend the product parameters, the development of energy-saving, labor-saving, and automatic control valves, improving the structure, and use of new materials and new techniques to improve valve life, and the development of special valves series leavened dough development, such as using in the liquid oxygen, liquid hydrogen and liquefied natural gas, cryogenic valves, vacuum valves, nuclear industrial valves, safety valves, regulating valves, steam trap and valve-driven devices.