原文：
1.阀门在供水管网中的功能 供水的管网将把水厂送出的自来水输配至千家万户，因此供水管网分布于城市的每个角落，供水管网的管道长度少至数百公里，多至数千公里。 水的不可替代性和人们生存的必需性，决定了供水管网安全运行的重要性。但是由于主客观多方面的原因，管道往往要出现一些故障，管网总是要不断更新改造，用水户经常要有增减因此局部管段的停水现象就是难以避免。为了缩小停水范围，在管网内适当地安装控制阀门乃是十分必要。因此在一座城市的供水管网中，阀门数量成千上万，且无规则地分布于城市街道的下面。 阀门是一种“养兵千日，用于一时”的控制设备，平时要求阀门开启要到位，减少管段的水损失。一旦需要，阀门应能关闭迅速，切流可靠。 阀门的完好率，关系到阀门的选型、阀门的制造、管路的设计、阀门的组装、阀门的启闭作业及阀门的管理，当然最主要的原因还是阀门的质量。 2.问题研讨 通过20家自来水公司管网阀门使用情况的调研，通过对十家阀门制造厂的考察，体会到阀门在供水管网中作用大、数量多、分布广，问题不少。供水管网中的阀门操作并不频繁，长期待命，一旦召唤，难以奏效。因此，在阀门选型、阀门制造、阀门检验、阀门组装、阀门管理上均有许多内容值得商讨。 2.1阀门的选型 (1)闸阀与蝶阀 在供水管网中为了降低管道覆土深度，一般口径较大管道选配蝶阀，对覆土深度影响不大的，力求选配闸阀，致于口径的分界线应各地按具体情况考虑。从近十年使用情况而言，蝶阀出现的故障比闸阀高，因此在条件许可的情况下，扩大闸阀的使用范围是值得关注的。 (2)闸阀 近年来，国内不少阀门制造厂家，研制、仿制软密封闸阀，这种闸阀比传统的楔式或平行双闸板式闸阀有如下特点： a.软密封闸阀的阀体、阀盖采用精密铸造法铸造，一次成型，基本不机械加工，不使用密封铜环，节约有色金属。 b.软密封闸阀底部无凹坑，不积存渣物，闸阀启闭的故障率低。c.软密封衬胶阀板尺寸统一，互换性强。 因此软密封闸阀将是供水行业乐意采用的一种形式。目前国内制造的软密封闸阀口径达1500mm，但多数厂家制造的口径在80-300mm间，国内制造工艺上尚有诸多问题，从此次考察的情况而言，上海某阀门制造公司的阀体是委托国内铸造厂用树脂砂造型翻铸的，软密封阀板是从国外某公司进口的。该公司认为软密封闸阀的关键部件是衬胶阀板，而衬胶阀板的技术要求较高，国外也不是所有厂家都能达到的，往往是从质量可靠的厂方购进组装。 国内软密封闸阀的铜螺母块是嵌挂在衬胶阀板上方的，类似闸阀的结构，由于螺母块的活动摩擦容易使阀板的衬胶剥离。国外某公司的软密封闸阀，铜螺母块是镶嵌在衬胶闸板内，形成整体，克服了上述缺点，但阀盖与阀体组合的同心度要求较高。 启闭软密封闸阀时，千万不应关闭过死，只要达到止水效果即可，否则不易开启或衬胶剥离。山东某阀门制造公司，在阀门试压检验时，使用扭力板手来控制关闭的程度，作为自来水公司的阀门操作人员也应较仿此种启闭方法。 (3)蝶阀 当前蝶阀选型中关注的几个问题： a.中线蝶阀 中线蝶阀在我国小口径蝶阀中使用量很大，效果也比较好。在制造方式上有两大差别：一种阀体衬胶层后有支承架(以塘沽产品为代表)；一种阀体衬胶层后没有支承架(以郑州产品为代表)。前者衬胶量较少，后者过流面积较大。有人怀疑后者阀门使用寿命较短，但据调查并非如此。

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译文：
1. Valves in the water supply network in the function Water supply pipe network will send the water transmission and distribution to millions of households, so the water supply pipeline network located in every corner of the city, water supply network pipeline length as little as several hundred kilometers up to several thousand kilometers. Water is irreplaceable and the people the necessity of survival, the decision of the water supply network the importance of safe operation. However, due to various objective and subjective reasons, often have some trouble pipeline, pipeline network, must constantly update the transformation of water users often have changes in the local pipe so the phenomenon is difficult to avoid disruption of water supply. In order to narrow the scope without water in the pipe network within the proper installation of control valves but very necessary. So in a city water supply network, the number of tens of thousands of valves and irregularly distributed in the city streets below. Valve is a kind of "the idea that Japan, for the moment" of the control equipment, usually required to place the valve open to reduce the water pipe losses. If necessary, the valve should be closed quickly, all current and reliable. Good rate of valve related to the valve selection, valve manufacturing, pipeline design, the valve assembly, valve opening and closing valve operation and management, of course, the main reason is the valve quality. Two. The problem discussion Through the 20 water companies tube net use of research, through ten valve factory inspection, realize the valve at the role of large water supply networks and number of widely distributed, many problems. Water supply network in the valve operation is not frequent, long standby, once called, to be ineffective. Therefore, valve selection, valve manufacturer, valve testing, valve assembly, valve management are many things worth discussing. 2.1 Valve Selection (1) gate valve and butterfly valve In order to reduce the water supply pipeline network covering depth, large diameter pipes generally matching butterfly, little impact on the overburden depth, and seek matching valve, the line should be addressed in diameter around the consideration under specific circumstances. Terms of use in recent years, butterfly valve malfunction higher than the gate, so the conditions permit, expand the use of valve is of concern. (2) valve In recent years, many domestic valve manufacturer, development, imitation soft sealing gate valve, this valve than conventional wedge gate valve, or parallel to the dual gate plate has the following characteristics: a. soft sealing gate valve body, valve cover using precision casting in metal, a shape, the basic non-mechanical processing, do not use sealed copper ring, saving non-ferrous metals. Soft seal gate valve at the bottom of b. no pits, no accumulation of slag material, valve opening and closing of the failure rate is low. c. soft seal with rubber valve plate size uniform and interchangeable. So soft sealing gate valve will be happy to supply the industry with a form. Domestic manufacture of soft seal gate valve diameter up to 1500mm, but most factory-made in the 80-300mm diameter, the domestic manufacturing process, there are still many problems in the case from the study, the Shanghai body of a valve manufacturing company was commissioned by the domestic foundry casting resin sand molding turn, the soft seal disc is imported from a foreign company. The Company believes that the key components of soft seal gate valve is a rubber lined valve plate, and the rubber lining disc technology higher, not all manufacturers abroad can be achieved, often purchased from a reliable quality of the factory assembly. Internal soft sealing gate valve block is embedded copper nuts valve board hanging on the rubber lining side, similar to the gate of the structure, due to the activities of the friction nut block valve plate of rubber lining is easy to peel. A foreign company's soft-sealing gate valve, brass nut block is embedded in the rubber lining inside the gate to form a whole, to overcome these shortcomings, but the valve cover and valve combination of concentric demanding. Soft sealing gate valve open and close, do not close off dead, as long as you can achieve the sealing effect, or difficult to open or with rubber stripping. A valve manufacturing company in Shandong, the valve pressure test inspection, the use of torque wrenches to control the degree of closure, as the water company's valve operators should be more open and close imitation of such a method. (3) butterfly Selection of the current valve several issues of concern: a. butterfly valve Butterfly valve butterfly valve in the small-caliber in our use of large, and the results better. In manufacturing there are two different modes: a valve body with rubber floor supported frame after (in Tanggu product as the representative); a valve body with rubber layer does not have any bearing frame (in Zhengzhou product as the representative). Small amount of the former rubber lining, which is larger than flow. Some people suspect the latter valve service life is shorter, but it is not the case investigation.