译文：
闸阀 闸阀是作为截止介质使用，在全开时整个流通直通，此时介质运行的压力损失最小。闸阀通常适用于不需要经常启闭，而且保持闸板全开或全闭的工况。不适用于作为调节或节流使用。对于高速流动的介质，闸板在局部开启状况下可以引起闸门的振动，而振动又可能损伤闸板和阀座的密封面，而节流会使闸板遭受介质的冲蚀。从结构形式上，主要的区别是所采用的密封元件的形式。根据密封元件的形式，常常把闸阀分成几种不同的类型，如：楔式闸阀、平行式闸阀、平行双闸板闸阀、楔式双闸板闸等。最常用的形式是楔式闸阀和平行式闸阀。 截止阀 截止阀的阀杆轴线与阀座密封面垂直。阀杆开启或关闭行程相对较短，并具有非常可靠的切断动作，使得这种阀门非常适合作为介质的切断或调节及节流使用。 截止阀的阀瓣一旦处于开启状况，它的阀座和阀瓣密封面之间就不再的接触，并具有非常可靠的切断动作，合得这种阀门非常适合作为介质的切断或调节及节流使用。 截止阀一旦处于开启状态，它的阀座和阀瓣密封面之间就不再有接触，因而它的密封面机械磨损较小，由于大部分截止阀的阀座和阀瓣比较容易修理或更换密封元件时无需把整个阀门从管线上拆下来，这对于阀门和管线焊接成一体的场合是很适用的。介质通过此类阀门时的流动方向发生了变化，因此截止阀的流动阻力较高于其它阀门。 常用的截止阀有以下几种：1）角式截止阀；在角式截止阀中，流体只需改变一次方向，以致于通过此阀门的压力降比常规结构的截止阀小。2）直流式截止阀；在直流式或Y形截止阀中，阀体的流道与主流道成一斜线，这样流动状态的破坏程度比常规截止阀要小，因而通过阀门的压力损失也相应的小了。3）柱塞式截止阀：这种形式的截止阀是常规截止阀的变型。在该阀门中，阀瓣和阀座通常是基于柱塞原理设计的。阀瓣磨光成柱塞与阀杆相连接，密封是由套在柱塞上的两个弹性密封圈实现的。两个弹性密封圈用一个套环隔开，并通过由阀盖螺母施加在阀盖上的载荷把柱塞周围的密封圈压牢。弹性密封圈能够更换，可以采用各种各样的材料制成，该阀门主要用于“开”或者“关”，但是备有特制形式的柱塞或特殊的套环，也可以用于调节流量。 蝶阀 蝶阀的蝶板安装于管道的直径方向。在蝶阀阀体圆柱形通道内，圆盘形蝶板绕着轴线旋转，旋转角度为0°~90°之间，旋转到90°时，阀门则牌全开状态。 蝶阀结构简单、体积小、重量轻，只由少数几个零件组成。而且只需旋转90°即可快速启闭，操作简单，同时该阀门具有良好的流体控制特性。蝶阀处于xx开启位置时，蝶板厚度是介质流经阀体时{wy}的阻力，因此通过该阀门所产生的压力降很小，故具有较好的流量控制特性。蝶阀有弹密封和金属的密封两种密封型式。弹性密封阀门，密封圈可以镶嵌在阀体上或附在蝶板周边。 采用金属密封的阀门一般比弹性密封的阀门寿命长，但很难做到xx密封。金属密封能适应较高的工作温度，弹性密封则具有受温度限制的缺陷。 如果要求蝶阀作为流量控制使用，主要的是正确选择阀门的尺寸和类型。 蝶阀的结构原理尤其适合制作大口径阀门。蝶阀不仅在石油、煤气、化工、水处理等一般工业上得到广泛应用，而且还应用于热电站的冷却水系统。 常用的蝶阀有对夹式蝶阀和法兰式蝶阀两种。对夹式蝶阀是用双头螺栓将阀门连接在两管道法兰之间，法兰式蝶阀是阀门上带有法兰，用螺栓将阀门上两端法兰连接在管道法兰上。 球阀 球阀是由旋塞阀演变而来。它具有相同的旋转90度提动作，不同的是旋塞体是球体，有圆形通孔或通道通过其轴线。球面和通道口的比例应该是这样的，即当球旋转90度时，在进、出口处应全部呈现球面，从而截断流动。 球阀只需要用旋转90度的操作和很小的转动力矩就能关闭严密。xx平等的阀体内腔为介质提供了阻力很小、直通的流道。通常认为球阀最适宜直接做开闭使用，但近来的发展已将球阀设计成使它具有节流和控制流量之用。球阀的主要特点是本身结构紧凑，易于操作和维修，适用于水、溶剂、酸和天然气等一般工作介质，而且还适用于工作条件恶劣的介质，如氧气、过氧化氢、甲烷和乙烯等。球阀阀体可以是整体的，也可以是组合式的。 按防止介质倒流选用阀门 这种类型的阀门的作用是只允许介质向一个方向流动，而且阻止方向流动。通常这种阀门是自动工作的，在一个方向流动的流体压力作用下，阀瓣打开；流体反方向流动时，由流体压力和阀瓣的自重合阀瓣作用于阀座，从而切断流动。其中止回阀就属于这种类型的阀门，它包括旋启式止回阀和升降式止回阀。旋启式止回阀有一介铰链机构，还有一个像门一样的阀瓣自由地靠在倾斜的阀座表面上。为了确保阀瓣每次都能到达阀座面的合适位置，阀瓣设计在铰链机构，以便阀瓣具有足够有旋启空间，并使阀瓣真正的、全面的与阀座接触。阀瓣可以全部用金属制成，也可以在金属上镶嵌皮革、橡胶、或者采用合成覆盖面，这取决于使用性能的要求。旋启式止回阀在xx打开的状况下，流体压力几乎不受阻碍，因此通过阀门的压力降相对较小。升降式止回阀的阀瓣座落位于阀体上阀座密封面上。此阀门除了阀瓣可以自由地升降之外，其余部分如同截止阀一样，流体压力使阀瓣从阀座密封面上抬起，介质回流导致阀瓣回落到阀座上，并切断流动。根据使用条件，阀瓣可以是全金属结构，也可以是在阀瓣架上镶嵌橡胶垫或橡胶环的形式。像截止阀一样，流体通过升降式止回阀的通道也是狭窄的，因此通过升降式止回阀的压力降比旋启式止回阀大些，而且旋启式止回阀的流量受到的限制很少。 按调节介质参数选用阀门 在生产过程中，为了使介质的压力、流量等参数符合工艺流程的要求，需要安装调节机构对上述参数进行调节。调节机构的主要工作原理，是靠改变阀门阀瓣与阀瓣与阀座间的流通面积，达到调节上述参数的目的。属于这类阀门的统称为控制阀，其中分为依靠介质本身动力驱动的称为自驱式控制阀如减压阀、稳压阀等，凡{lx1}上来动力驱动的（如电力、压缩空气和液动力）称为他驱式控制阀，如电动调节阀、气动调节阀和液动调节阀等。

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原文：
Valve Medium used as a cut-off valve in the full-time through the entire flow, this time the pressure medium to run minimal loss. Valve is usually applied to less frequent open and close, but also to maintain full-or full-closed gate of the working conditions. Does not apply to the use of a regulator or throttling. For high-speed flow of medium, open the gate in local conditions can cause the vibration of the gate, but they may damage the vibration damper and the valve seat sealing surface, while the throttling damper will suffer erosion of the medium. From a structural form, the main difference is that the sealing component used in the form of. According to the form of sealed components, often divided into several different types of valve, such as: wedge gate valve, parallel-type valve, parallel Shuangzha plate gate valve, wedge gate, etc. Shuangzha board. The most common form of wedge gate valves and parallel-type valve. Valve As the valve stem and valve seat sealing surface perpendicular to the axis. Valve stem to open or close the trip is relatively short, and has very reliable cutting action, makes this valve ideally suited as a medium and cutting off or regulate the use of. Cut-off valve when the valve flap in the open position, and its valve seat and valve sealing surface is no longer between the contacts and has a very reliable cutting action, and combine this valve is suitable as a medium cut or regulation and throttle use. Once the cut-off valve is turned on, its seat and the valve between the valve sealing surface is no longer in contact, so it's a smaller sealing surface mechanical wear, as most of the cut-off valve seat and valve flap is easier to repair or replace When sealing element is not required to remove the entire valve from the pipeline to which the valve and pipeline welding for the occasion into one is very applicable. Medium through such valve when the flow direction changed, so a higher cut-off valve of the flow resistance in other valves. Commonly used cut-off valves are the following: 1) Angle type globe valve; in angle-type stop valve, the fluid simply by changing a direction, so that through this valve on the pressure drop than the conventional structure of small cut-off valve. 2) DC-type cut-off valve; in the DC-type or Y-shaped cut-off valve, the valve of the flow channel and mainstream Road into a slash, so that movement of the state extent of the damage is smaller than the conventional cut-off valve, so the pressure loss through the valve is also the corresponding smaller. 3) The plunger-type valve: This form of cut-off valve is a variant of conventional cut-off valve. In the valve, the valve flap and valve seats are usually based on the plunger principle of design. Polished into a flap valve stem is connected with the plunger, the plunger seal is on the two sets of flexible seals achieved. Two elastic rings separated by a ring, and through a valve cover nut the load exerted on the valve cover seals around the plunger pressure prison. Elastic ring can be replaced, you can use a variety of material, the valve is mainly used for "open" or "off", but with a special form of plunger or special rings can also be used to adjust flow. Butterfly Butterfly valve butterfly plate installed in the direction of the pipe diameter. Cylindrical channel in the valve body, the disc-shaped butterfly plate around the axis of rotation, rotation angle of 0 ° ~ 90 ° between the rotation to 90 ° when the valve is fully open state license. Butterfly simple structure, small size, light weight, only by a small number of parts. And just rotate 90 ° to quickly open and close, easy to operate, while the flow control valve has a good feature. Butterfly in the fully open position, the butterfly plate thickness is only when the medium flows through the valve body resistance through the valve so the pressure drop generated by small, it has good flow control characteristics. There are shells and metal sealing butterfly valve seal two kinds of sealed type. Elastic sealing valves, seals can be mounted on the body or attached to the butterfly board peripheral. Metal sealed valves generally higher than those elastic sealing valve long life, but it is difficult to achieve completely sealed. Metal seal can adapt to a higher operating temperature, flexible seal is affected by temperature limit has flaws. If you require the use of flow control valve as the main choice is the right size and type of valve. Butterfly structure principle is particularly suitable for production of large-diameter valves. Butterfly not only in oil, gas, chemicals, water treatment, etc. are widely used in general industry, but also applied to thermal power plant cooling water systems. Commonly used in butterfly valves are wafer type butterfly valve and flange type butterfly valve two kinds. Right clip-on butterfly is double-headed bolts to connect the valve between the two pipe flanges, flange type butterfly valve is a valve with a flange on, with bolts at both ends of the valve on the pipe flange connection method Lan on. Ball Evolved from the stopcock valve. It has the same movement rotated 90 degrees to mention only difference is that cock body is a sphere, a circular through-hole or channel through its axis. The sphere and the ratio of openings should be such that when the ball rotated 90 degrees, in the import and export of office should be fully rendered sphere, thus cutting off the flow. Just use the rotary valve 90-degree rotation of the operation and a small torque can be closed tightly. The body cavity of full equality for the media to provide a little resistance, through the flow channel. Generally considered the most suitable valve opening and closing done directly used, but the recent development has been designed to give it a throttle valve and control the flow purposes. The main features of valve is its own compact, easy operation and maintenance for water, solvents, acids, and natural gas work in general media, but also applies to poor working conditions of media, such as oxygen, hydrogen peroxide, methane and ethylene, etc. . Ball valve can be integral, it can be modular. Selection of valves to prevent backflow by media This type of valve is the role of media in one direction only allows movement, but also to prevent the direction of flow. Usually the valve is automatically work, the fluid flow in one direction under pressure, valve flap open; fluid flow in the opposite direction from the fluid pressure and valve flap valve flap from the coincidence of acting on the valve seat and thus cut off the flow. Check them belonging to this type of valve, which includes Swing check valve and lift check valve. Swing Check Valve with ordinary hinge, there is a door the same as the free flap valve leaning tilt seat surface. In order to ensure that the flap valve seat face every time to reach a suitable position, the valve flap design in the hinge body to valve flap has enough to swing space, and make a real flap valve, comprehensive engagement with the valve seat. Valve flap can all be made of metal can also be embedded in the metal on leather, rubber, or synthetic coverage, depending on the use of performance requirements. Swing check valve in the fully open position, the fluid pressure virtually unimpeded, so the pressure drop through the valve is relatively small. Check the valve lift valve is located in the valve body on the valve seat sealing surface. In addition to this valve flap valve is free to lift, the other part of the same as the cut-off valve, the fluid pressure valve from the valve seat sealing surface of valve lift, medium return valve flap led to a seat on the back, and cut off the flow of. According to conditions of use, the valve flap can be all-metal structure can also be rack mounted in the valve flap rubber mat or rubber ring form. The same as the cut-off valves, fluid channels through the lift valve is narrow, so that by elevating the pressure drop valve Swing check valve than the bigger, and the flow of Swing Check Valve restrictions on rarely. Medium parameters chosen by regulating valve In the production process, in order to make media pressure, flow and other parameters meet the process requirements, need to install the adjusting mechanism to adjust these parameters. Regulating the organization's main working principle is to change the valve by valve flap and valve seat between the flap and the circulation area, to achieve the purpose of regulating the above parameters. Such valves are referred to as control valves, which are divided into relying on power-driven media itself is called self-drive-type control valve such as valves, regulator valve, all leading up power-driven (such as electricity, compressed air and fluid power) as he was driving control valve, such as the electric control valve, pneumatic control valve and hydraulic control valve and so on.