译文：
闸阀是指关闭件（闸板）沿通路中心线的垂直方向移动的。 闸阀在管路中主要作切断用。 闸阀是使用很广的一种调节阀，一般口径DN≥50mm的切断装置都选用它，有时口径很小的切断装置也选用闸阀，闸阀有以下优点： ①流体阻力小。 ②开闭所需外力较小。 ③介质的流向不受限制。 ④全开时，密封面受工作介质的冲蚀比截止阀小。 ⑤体形比较简单，铸造工艺性较好。 闸阀也有不足之处： ①外形尺寸和开启高度都较大。安装所需空间较大。 ②开闭过程中，密封面间有相对摩擦，容易引起擦伤现象。 ③闸阀一般都有两个密封面，给加工、研磨和维修增加一些困难。 一、闸阀的种类 1． 按闸板的构造可分 1）平行式闸阀：密封面与垂直中心线平行，即两个密封面互相平行的闸阀。 在平行式闸阀中，以带推力楔块的结构最常为常见，既在两闸板中间有双面推力楔块，这种闸阀适用于低压中小口径（DN40—300mm）闸阀。也有在两闸板间带有弹簧的，弹簧能产生予紧力，有利于闸板的密封。 2）楔式闸阀：密封面与垂直中心线成某种角度，即两个密封面成楔形的闸阀。 密封面的倾斜角度一般有2°52´，3°30´，5°， 8°， 10°等，角度的大小主要取决于介质温度的高低。一般工作温度愈高，所取角度应愈大，以减小温度变化时发生楔住的可能性。 在楔式闸阀中，又有单闸板，双闸板和弹性闸板之分。单闸板楔式闸阀，结构简单，使用可*，但对密封面角度的精度要求较高，加工和维修较困难，温度变化时楔住的可能性很大。双闸板楔式闸阀在水和蒸气介质管路中使用较多。它的优点是：对密封面角度的精度要求较低，温度变化不易引起楔住的现象，密封面磨损时，可以加垫片补偿。但这种结构零件较多，在粘性介质中易粘结，影响密封。更主要是上、下挡板长期使用易产生锈蚀，闸板容易脱落。弹性闸板楔式闸阀，它具有单闸板楔式闸阀结构简单，使用可*的优点，又能产生微量的弹性变形弥补密封面角度加工过程中产生的偏差，改善工艺性，现已被大量采用。 2． 按阀杆的构造闸阀又可分为 1） 明杆闸阀：阀杆螺母在阀盖或支架上，开闭闸板时，用旋转阀杆螺母来实现阀杆的升降。这种结构对阀杆的润滑有利，开闭程度明显，因此被广泛采用。 2） 暗杆闸阀：阀杆螺母在阀体内，与介质直接接触。开闭闸板时，用旋转阀杆来实现。这种结构的优点是：闸阀的高度总保持不变，因此安装空间小，适用于大口径或对安装空间受限制的闸阀。此种结构要装有开闭指示器，以指示开闭程度。这种结构的缺点是：阀杆螺纹不仅无法润滑，而且直接接受介质侵蚀，容易损坏。 二、闸阀的通径收缩 如果一个阀体内的通道直径不一样（往往都是阀座处的通径小于法兰连接处的通径），称为通径收缩。 通径收缩能使零件尺寸缩小，开、闭所需力相应减小，同时可扩大零部件的应用范围。但通径收缩后。流体阻力损失增大。 在某些部门的某些工作条件下（如石油部门的输油管线），不允许采用通径收缩的调节阀。这一方面是为了减小管线的阻力损失，另一方面是为了避免通径收缩后给机械清扫管线造成障碍。

“Valve types and uses ”是由提供的国际阀门新闻，译文仅供参考。另外，中国闸阀网还提供相关产品搜索：、、、、等。

原文：
Valve is closed parts (ram) along the channel centerline vertical movement. Valve in the pipeline used mainly for cutting. Valve is to use a control valve very broad, general diameter DN ≥ 50mm cut-off devices are selected it, and sometimes cut off a small-caliber devices also use valve, the valve has the following advantages: ① fluid resistance. A smaller external force required to open and close ②. ③ medium flow unrestricted. ④ full-time, the sealing surface of the erosion by the working fluid valve smaller than the cut-off. ⑤ relatively simple shape, casting process is better. Valve also has shortcomings: ① Overall size and height of a larger opening. Large space required for installation. ② opening and closing process, the sealing surface friction between the relatively easy to cause abrasions. ③ valve normally have two sealing surface, to the processing, polishing and maintenance of the increased number of difficulties. First, the type of valve 1. Construction of divisible by ram 1) Parallel Gate Valve: sealing surface and vertical axis parallel to the two valve sealing surface parallel to each other. In a parallel-type valve in order to wedge-thrust structure with the most common is common, both in the middle of two double-sided thrust wedge gate, which applies to low-voltage small-caliber valve (DN40-300mm) valve. Also have two rooms with a spring damper, spring can produce to the tight power is conducive to ram seal. 2) Wedge Gate Valve: sealing surface and the vertical axis into a certain point of view, that is, two sealing surface into a wedge-shaped valve. Sealing surface of the tilt angle are generally 2 ° 52 ', 3 ° 30', 5 °, 8 °, 10 °, etc. The size of the angle depends primarily on medium high and low temperature. Generally higher operating temperature, the angle taken to be larger in order to reduce the temperature change occurs when the wedge housing possibilities. In the wedge-type gate valve, a further single gate, Shuangzha divided board and elastic damper. Single wedge gate valve, simple structure, the use of *, but the sealing surface angle of the higher accuracy requirements, processing and maintenance more difficult, the temperature change is very likely to live wedge. Shuangzha plate wedge gate valve in the water and steam pipes in the media to use more. Its advantages are: the angle of the sealing surface precision low temperature is not easy to live a phenomenon caused by wedge, sealing surface wear, you can add pads compensation. However, this structural components are more easily bonded in the viscous medium, affecting sealing. More important is the upper and lower baffle long-term use is easy to produce rust, gate easily. Flexible wedge gate valve, it has a single wedge gate valve structure is simple, using * the merits, but also produce small amounts of elastic deformation of the cover sealing surface angle deviations arising during processing and improve the technics now been widely adopted. 2. According to the construction of valve stem can be divided into A) Rising stem gate valve: the valve stem nut cover or bracket, the opening and closing gate when the rotating stem nut to achieve stem the rise and fall. This structure of the valve stem lubrication is beneficial degree of opening and closing significant, so it is widely adopted. 2) The dark bar valve: the valve stem nut body in direct contact with the media. When opening and closing gate with a rotary valve stem to achieve. The advantages of this structure are: the height of the total gate remains unchanged, so installation space is small, suitable for large-caliber or restricted valve installation space. Such structure should be equipped with open and close indicator to indicate the degree of opening and closing. This structure's weaknesses are: stem thread lubrication is not only impossible, but also directly accept the medium erosion, easy to damage. 2, gate valve Path contraction If a valve body diameter and not the same channel (and often are the valve seat diameter smaller than the flange at the junction of the Path), is called path contraction. Path can shrink parts sizes shrink, open and close the required power is reduced, while expanding the scope of application components. But the path contraction. Fluid resistance loss increases. In certain sectors in certain working conditions (such as the oil sector, oil pipeline), does not allow use of the regulating valve diameter contraction. In this context is intended to reduce the pipeline pressure drop, on the other, in order to avoid contraction diameter pipeline to the mechanical cleaning obstacle.