原文：
根据各种不同的需要(管网的水量，水压的调度和调配，维修抢修的停水需要，新老管线的连接，管道的冲洗等)，每天都要进行阀门的开启和关闭。阀门的使用寿命和质量决定着管网的正常运行，在管网中起着举足轻重的作用，必须给予高度重视。 下面就供水管网的阀门选择，提出几点意见。 一、供水的安全性 不影响水质是阀门选择的一个重要指标。阀门直接与水接触的部分主要是阀体内侧，密封部分，阀板等，目前许多厂家生产的阀门的密封部分采用橡胶材料。常用的橡胶材料是丁腈橡胶(NBR)，氯丁橡胶(CR)或乙丙橡胶 (EPDM)。这些橡胶都是合成橡胶。在合成过程中，要在xx胶内加入十多种原料和防老化剂等添加剂。最终合成的橡胶能否用于供水阀门的密封，必须看这种橡胶是否xx，是否符合饮用水卫生标准。至于阀门内侧及阀板等部位，许多厂家过去采用涂漆的方法，只考虑防锈问题，而不考虑是否有毒。在实践中我们发现：供水管网中，管道的内衬防腐问题解决了，而管网阀门没有内衬，由于水的沉淀现象和水中的铁xx对阀内腔和阀板的侵蚀与沉积，造成一些阀体内壁出现丘陵状的堆积现象。不仅影响了供水水质，同时也是一些阀门关不严的主要原因之一。因此，我们要求，这些与水直接接触的部位，都应喷涂xx涂料，{zh0}是采用静电喷涂的方法喷涂xx环氧粉末。我们在选择阀门时，首先应检查是否具有橡胶和涂料的xx证明和检验合格证，只有具备上述条件的阀门，才能保证水质不受污染，保证供水的安全性。 二、技术的先进性 阀门的生产技术不断发展，从老式的闸板阀到软密封闸阀，从最初的蝶阀到对夹式蝶阀、单偏心、双偏心法兰蝶阀、硬密封蝶阀，从传统的单头排气阀到高速双孔口排气阀等。因此选择阀门时也要考虑到所选阀门的先进性。但是，在新技术的应用中，我们反对不加区分，不了解用户实际，一哄而上的做法，而应该将新技术、新工艺与用户的需求结合起来。好的阀门是要在生产实际应用中，从用户的直接需求中得来的。例如：树脂挤压密封的方法，尽管从设计思路和工厂试验中证明其确实有优点。但是在实际使用中，由于树脂材料、挤压树脂工具等，没有解决好用户如何用的问题。用户在使用这种阀门时，就体会不出这种阀门的先进性、特点和优势，而当成普通蝶阀使用。因此，阀门生产既要xx其先进性，更要xx其实用性。并注意解决实际应用中的问题，如：排气阀的浮球材料、浮球形状(球形或圆柱形)对排气效果及使用寿命如何的研究。如何防止蜗轮蜗杆蝶阀的操作控制(关闭过位)问题，变速箱的箱体顶碎问题，开关指示的标示问题等等。所以，选择阀门一定要注意其技术的先进性和实用性。 三、水流的密封性 阀门是否起到密封作用是对阀门的基本要求。在实际应用中，密封有多种型式，如软密封、硬密封、阀板密封、阀体密封、面密封、线密封等等。不管采用什么样的密封形式，均不能影响到密封效果。过去，我们曾经使用过一部分阀板密封的蝶阀，从理论上讲，这种蝶阀的{zd0}优点是一旦密封胶圈失效，不用拆装阀门，可在线更换。但是，在供水企业实际应用中，这种蝶阀的优点很难体现出来。因此，如果在线更换胶圈不仅也需要把阀门两端的管道拆开，将管道的水排空。同时，更换后的胶圈也无法进行密封试验，无法确定更换效果。故在选择阀门时，一定要注意阀门的密封形式，并结合各自的实际应用情况，检查阀门的密封效果。 四、检验的真实性 一定要求阀门的生产企业提供真实、准确的检验报告。这些检验报告包括： ①原材料的检验--原铁中C，Si， Mn，P，S等的成分含量以及焦炭的质量等； ②铸件的检验--金相试验，延伸率试验，强度试验等； ③密封试验--双面泵压试验及多次开关试验等； ④橡胶的卫生检疫报告和涂料的卫生检疫报告等方面。提供不真实检验报告的企业生产出来的产品是不能用的。 五、质量的可靠性 阀门质量的好环，体现在阀门制造的全过程。 ①原铁选配；②砂模的制造；③铸件的铁水铸造；④机加工的精度等。 要有一套较完整的质量保证体系。阀门开关次数多少的指标的意义不大，不一定非要满足开关五千次以上的试验。因为管网中的阀门并不是经常开关的。有时，有的阀门十年八年才开关一次。我们在实际工作中就发现蝶阀上的定位螺丝在安装时就是松动的，有的根本就没有螺栓丝扣。 六、操作的灵活性 阀门操作是否灵活是很重要的。 操作灵活，不仅体现在选择哪一种传动方式，还体现在与传动机构相关的部件的加工精度上。例如，在蝶阀的传动方式上。一般有两种传动方式-- 丝杠螺母型和蜗轮蜗杆型。一般丝杠螺母型的特点是在开关时两头慢，中间快，比较好操作，但由于丝杠动力矩较小，操作者在操作时不易掌握阀板的启闭程度，易发生阀门已关闭而仍在操作使丝杠扭曲、断裂。而蜗轮蜗杆型一般容易关闭过位。同时，对闸阀阀杆的密封问题，蝶阀传动部位的转速与转动力矩的匹配问题都是阀门操作的老大难问题。因此，选择哪种传动方式，应根据各供水企业的情况，在听取操作者的意见后，与厂家密切配合，使选择的阀门既能操作灵活，又能满足使用和工作的需要。 七、价格的合理性 阀门应有一个合理的价格，合理的价格不一定是{zd1}的价格。如果只注重{zd1}的价格，就容易误导厂家为了推销自己的产品，竞相压低价格，甚至低于产品的成本价销售，厂家为了不亏本就必然要在工序、材料上偷工减料，生产出来的阀门就存在着质量隐患，用在供水管网上，最终受害的还是用户自己。所以，一定要注意在选择阀门时，鼓励厂家运用价值工程原理，强化主要功能，去除多余功能，优化系统功能。在管理上下功夫，在成本核算上下功夫。应该指出，合理的价格可以是{zd1}的价格，但{zd1}的价格不一定是合理的价格。 八、售后服务的保证性 阀门在供水管网中使用，会出现这样那样的问题，有些是属于阀门自身的，有些则是来自外部因素的干扰破环，野蛮施工，违章操作，管理使用不善等。但不管什么原因，阀门出现问题，都将影响到管网的运行，都需要厂家的配合，因此在阀门选择时需要阀门生产企业有一个良好的售后服务的保证。一旦阀门出现问题，能在最短的时间赶到现场，尽快解决发生的问题。 九、定货与供货的一致性 这里所讲的一致性，是指阀门生产企业所生产的阀门产品与供水企业所需要的产品的各方面的要求是一致的。这就需要定货方与供货方(供水企业与阀门生产企业)的共同努力，而不仅仅是其中一方的努力。首先，作为定货方的供水企业，在向阀门生产企业定货时，一定要以书面形式向阀门生产企业提出明确的技术要求，内容应包括阀门的种类，阀门各部位应执行的技术标准和质量标准，主要的技术参数，各部位的材质，阀门的型号，密封形式，密封材料的要求，结构的形式，连接方式与传动方式、试压及强度检验的技术标准、防腐及内衬的要求、{zd0}扭 矩及转数、组装及外观要求以及交货的时间、地点、数量等等。阀门生产企业要依据定货合同及技术条件，合理地组织生产，并保证生产出来的产品能满足定货单位(供水企业)的使用要求，保证定货与供货双方的一致性。 十、建立完善的检验和复检制度 当一个供水企业，经过多次考察、调研并经过一定范围的试验，最终选择了一家或几家阀门生产企业，向其产品发放了允许进入本地供水市场的通行证后，就意味着供水企业与阀门生产企业之间确立了供需关系。同时，阀门生产企业对供水企业保证安全、可靠的供水方面也相应承担起连带的责任。一方面，要求阀门生产企业能始终如一地按照供水企业要求提供高质量的产品。另一方面，为确保质量也要求供水企业对定点厂家建立必要的、较完善的定期检验和复验制度，一般以2～5年为宜。对定点厂家的人、机、料、法、环等五大要素定期给予检查与评价。供水企业在对厂家检验的同时，还应根据本单位阀门的使用情况，对原有技术条件进行必要的修订和补充。

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译文：
According to a variety of needs (water pipe network, water pressure in the scheduling and deployment, maintenance, repair of the disruption of water supply needs of old and new pipeline connections, pipeline cleaning, etc.) every day to open and close the valve. And quality of life of the valve determines the normal operation of pipelines, in the pipe network plays an important role, must be given high priority. Below the valve on the water supply network selection, a few points. First, the security of water supply Choice does not affect the water quality is an important indicator of the valve. Valve part directly in contact with water inside the main valve body, sealing parts, valve plates, etc. At present, many manufacturers of valve sealing part of the rubber material. Commonly used rubber material is nitrile rubber (NBR), chloroprene rubber (CR) or ethylene propylene rubber (EPDM). The rubber is synthetic rubber. In the synthesis process, to incorporate more than 10 kinds of natural rubber materials and additives, anti-aging agent. Whether the final synthetic rubber seal for the water supply valve, must see this rubber is non-toxic, whether drinking water health standards. The valve and valve plate and other parts inside, and many manufacturers in the past by painting methods, only consider the rust problem, regardless of whether the toxic. In practice, we find: water supply pipe network, pipe lined with corrosion problem was solved, but there is no pipeline valves lining, due to the phenomenon of water, sediment and water cavity of the iron bacteria valve and valve plate erosion and deposition , resulting in a hill-shaped body wall accumulation phenomenon occurs. Not only affects water quality, but also some of the main valve off one of lax. Therefore, we call these parts in direct contact with the water should be non-toxic paint spraying, electrostatic spraying is the best way to spray non-toxic powder epoxy. We select the valves, should first check whether the non-toxic rubber and paint that and the quality certificate, only with the above conditions the valve, to ensure the water quality from pollution, to ensure water supply security. Second, technological advancement Valve of the continuous development of production technology, from the old to the soft sealing gate valve gate valve, butterfly valve to the right from the initial wafer type butterfly valve, single eccentric, double eccentric butterfly valve flange, hard seal butterfly valve, from the traditional Single-head exhaust valve to the exhaust valve and other high-speed dual-orifice. So select the valve should take into account the advanced nature of the selected valve. However, application of new technologies, we oppose the indiscriminate, users do not know the actual herd phenomenon in practice, but should the new technology, new technology and user demand. Valve is to produce a good practice, the direct demand from the users come. For example: resin sealing method of extrusion, although the design ideas and plant trials to prove its merits. However, in actual use, because of resin, extruded resin tools, not the user how to solve the problem. Users when using this valve, you can not see the advanced nature of this valve, features and advantages, but as a common butterfly valve used. Therefore, the valve only to pay attention to the nature of production, but also pay attention to its practicability. And addressing the practical application issues such as: exhaust valve of the float material, float shape (spherical or cylindrical) of the exhaust effect and how of life. How to prevent worm butterfly operation control (closed-off spaces) problems, broken gearbox top box issue, the question mark switch directions, etc.. Therefore, the selection valve must pay attention to the technology is advanced and practical. Third, water sealing Play a role in whether the valve is the valve seals the basic requirements. In practice, a variety of seal types, such as soft seal, seal, valve plate seal, valve seal, face seal, sealing and so on. Regardless of what kind of sealed form, it can not affect the seal. In the past, we have used part of the butterfly valve plate sealing, in theory, this butterfly's biggest advantage is that once the sealing rubber ring failure, without dismantling the valve can be replaced online. However, practical applications in water supply enterprises, the advantages of this butterfly is difficult to be reflected. Therefore, if the line not only need to replace the rubber ring at both ends of the pipeline to open the valve, the piping of water emptying. Meanwhile, the replacement of the apron can not be sealed test can not determine the replacement effect. Therefore, the selection valve, be sure to note the form of the valve seal, combined with their practical application, check valve seal. Fourth, test the veracity of Necessarily require valve manufacturers provide true, accurate inspection reports. These inspection reports include: ① inspection of raw materials - the original iron in C, Si, Mn, P, S, etc. ingredients and the quality of coke; ② casting testing - metallographic test, elongation test, strength tests and so on; ③ Sealing tests - two-sided test and multiple pump pressure switch test, etc.; ④ rubber coating quarantine reports and reports on aspects of health and quarantine. Companies to provide false inspection reports produced products can not be used. Fifth, the reliability of quality Good quality valve ring, embodied in the valve manufacturing as a whole. ① matching the original iron; ② sand mold manufacturing; ③ casting molten iron castings; ④ precision machining. To have a more complete quality guarantee system. Valve switching times meaningful indicators of how much, do not have to meet the switches in more than 5000 tests. Because the pipe network in the valve not always switch. Sometimes, some eight or ten years before switching a valve. We discovered in the actual work on the butterfly valve positioning screw loose when it was installed, and some simply do not bolt threaded. 6, operation flexibility Valve operation is flexible and is very important. Flexible operation, which not only reflected in the choice of transmission mode, but also in part related with the transmission processing accuracy. For example, in the butterfly's drive way. There are two kinds Transmission - Worm Gear Screw-nut type and type. General Screw-nut type is characterized by the switch 2 in the slow middle fast, better operation, but screw Moment smaller operators in the operation difficult to grasp the degree of valve opening and closing plate, the valve is closed prone while still in operation to screw twisted, broken. The worm-type generally easy to close off spaces. Meanwhile, on the valve stem seal problem, butterfly valve and rotation speed transmission parts matching torque valve operation are persistent problems. Therefore, the choice which drive way, should the situation of the water company, having heard the views of the operator, in close coordination with the manufacturers, so that the valve can not only choose flexible operation, and can use and work to meet the needs. 7, reasonable prices Valve should be a reasonable price, reasonable price is not necessarily the lowest price. If you focus only on the lowest price, it is easy to mislead the manufacturers to sell their products, compete to lower prices, even lower than the cost of products sold, the manufacturers in order not to lose money is bound to be in the process, material cutting corners, produced by the valve on Quality hidden dangers exist with the water supply line, or suffer in the end user. Therefore, we must pay attention to the selection valve, encourage manufacturers to use value engineering principles, to strengthen the main functions, remove unnecessary functions, optimizing system functionality. Efforts in management, the cost accounting efforts. It should be noted, reasonable price can be the lowest price, but not necessarily the lowest price is a reasonable price. 8, after-sales service assurance Valves used in water supply networks, there will be problems of this, some are of the valve itself, some are broken from the interference of external factors, ring, brutal construction, illegal operation, management and use of poor and so on. But for whatever reason, valve problems, will affect the operation of pipelines, require manufacturers to meet, so the valve when the valve manufacturers choose to have a good after-sales service guarantee. Once the valve problem in the shortest possible time to the scene to resolve the problem as soon as possible. 9, order and consistency of supply Here talked about consistency, is produced by the valve manufacturer of valve products and the supply of products needed by the enterprise requirements of the various aspects of the same. This requires ordering side and supply side (the water supply valve manufacturing enterprises and enterprises) to work together, not just one of them efforts. First of all, as the ordering side of the water supply enterprises in the time of ordering to the valve manufacturer must be in writing and submitted to the valve manufacturer specific technical requirements, should include the types of valves, valve technology should be implemented in different parts standards and quality standards, the main technical parameters of each part of the material, valve type, sealing the form of sealing material requirements, structure in the form of connection with the transmission, pressure test and strength test of technical standards, and internal corrosion lining requirements, maximum torque and rotation, assembly and appearance requirements, and delivery time, location, number and so on. Valve manufacturers based on orders to the contract and technical requirements, reasonable organization of production, and to ensure that the products produced to meet the ordering units (water supply enterprise) application requirements, ensure consistency in both orders and delivery. 10, establish a perfect system of inspection and re-examination When a water supply company, after several visits, research, and through a range of tests, chose one or several valve manufacturers, their products were issued to allow water to enter the local market, after the pass, it means the water supply business and valve manufacturer established between the supply and demand. Meanwhile, the valve manufacturer of the supply companies to ensure safe, reliable water supply is also appropriate to assume joint responsibility. On the one hand, asked the valve manufacturer to supply the demand of enterprises in accordance with consistently high quality product. On the other hand, to ensure the quality of water supply enterprises also require manufacturers to establish the necessary fixed point, a better system of periodic inspection and reinspection, generally 2 to 5 years is appropriate. People on fixed factory, machine, material, method, five major elements and periodic inspection and evaluation. Water supply enterprise in the factory inspection should also be according to the use of the valve unit, the original technical conditions necessary amendments and additions.