基础设施是中国经济建设,供水,排水工程,特别是大型污水处理工程,包括管道,阀门和其他水处理设备制造行业的重点,形成了强大的水工业。对于阀门行业,提供了一个很好的机会。中国已经加入WTO,全球约3000000吨阀的年需求量。要利用充分利用阀门行业是劳动密集型,劳动条件,中国的人均工资低,从发达国家向发展中国家,如优势,生产转移,积极走向世界经济的平台的方向发展。对阀门的地位,排水系统和发展的若干议题。
现状
现在的3000,对阀门厂,规模,其中600温州,近200多个,上海,超过150,250,辽宁,江苏,福建超过200多,尽管郑州良好与邪恶,但产品已超过3000近30000多种规格型号达成。在多品种,密封性能,强度要求,调节功能,移动性能和循环性能,特别是密封性能,取得了很大进步,倒退十年前,市供水协会,业界xx有一个xx的句子这“十阀九漏”,虽然有些夸张,但有一个事实。
阀门行业造成了许多问题,是改革开放,市场迅速扩大,原有的国有企业关停并转阀是不是机器高水平建设工业,使乡镇企业(民营企业),快速发展的典型,为低,技术力量非常薄弱,设备简陋的起点,其中大部分都是模仿产品生产,在市场混乱加上,特别是与低压供水和排水阀,一个严重的问题。在过去十年中,在少数阀门企业,有显着的进展,有些品种甚至达到国际先进水平的推动,也有很多企业的二次创业。但总体来说,差距还很大,有很多工作要做。为此,分别于2010年,2020年技术进步,发展规划具有十分重要的意义。
阀
常用的供水和排水工程中广泛使用的低,高压阀使用,特别低压大直径阀门(低压阀门,是通知书≤1.6MPa公称压力阀),而中压阀门(PN2.5 - 6.4MPa)较少。阀门,蝶阀是最基本和最广泛使用的产品。
阀的地位和阀门用于发展
迄今最古老的仍然是世界上所有国家的应用,特别是各类阀门以下DN300mm仍占主导地位。特点前后压差使阀板在出口阀门的压力右侧强制佩戴,密封好,以及广泛的开放,因为阀门没有留在路上流动的压力损失。用于切断管道的媒体。
其主要缺点是操作扭矩,操作方便,使阀体,阀杆损坏,特别是在大口径阀门。尺寸和重量也大,DN1000约三二〇 〇毫米阀直径和高要求四种操作,使阀门通常用在小口径,即DN500以下使用。
阀从敞开的光圈中,阀门的流阻小,接近全封闭,流动阻力急剧增加。更大范围的流动阻力较小的变化,几乎全封闭,流量差别很大,我们不能接近所使用的阀门,关闭时,难以进行细流的调整。如果阀门开启非常小,开幕快流量将有一个较低的水平闸板蚀,以及强烈的震动和噪音长期切口手术的陪同下,就会增加身体和栅极金属蚀发生。
工作条件,如果在中间阀开,因为它是对支持双方的气门导管,所有密切关闭时,中间位置,阀板,并有铁路振动大的差距。因此,即使在一个空地区,很长一段时间,以减少开支瓣膜手术率低,铁路会发生变形,磨损或损坏,并作为阀座结果并不充分参与,以及零件表面压力往往访问必须咬蚀或粘连,因此,不应该被用于流量控制。还想指出,在小开阀,流量变化,如果紧急闸阀,压力会导致大幅上升或产生负压,特别是由此产生的水锤阀关。 06.8.31
Water valve industry is gradually transferred to developing countries
Infrastructure are the focus of China’s economic construction, water supply and drainage projects, especially large-scale sewage treatment works including piping, valves and other water treatment equipment manufacturing industry has formed a strong water industry. For the valve industry, provides a good opportunity. China has entered WTO, the global annual demand of about 3,000,000 tons valves. To take full advantage of the valve industry is labor-intensive, labor conditions, China’s per capita wage is low, the transfer of production from developed to developing countries, such as advantages, and actively moving toward a platform for the world economy. Several topics on the status of the valve to the drainage and development.
the current state of
now 3000, about the size of valve plant, of which 600 Wenzhou, Zhengzhou near more than 200, Shanghai, more than 150, 250, Liaoning, Jiangsu, Fujian 200 more than, in spite of good and evil, but the products have reached more than 3000 varieties of models near 30000 specifications. In a multi-species, sealing performance, strength requirements, regulatory function, movement and circulation of performance properties, especially the sealing performance, have made great progress and retrogression Ten years ago, the Urban Water Supply Association, the industry authority has a famous sentence that “ten Nine valve leak “, although some exaggeration, but there is a fact.
valve industry caused many problems is the reform and opening up, the market rapidly expanded, and the original state-owned enterprises have关停并转valve was not a high level of machine-building industry, so township enterprises (private enterprises), the rapid development sprung up, the starting point for a low, technical force is very weak, poorly equipped, most of them are Product mimic production, coupled with the confusion in the market, especially with the low pressure water supply and drainage valves, a serious problem. Over the past decade, in a small number of valves, driven by enterprises, there is remarkable progress, some species even reached the international advanced level, there are also many second pioneering enterprises. But on the whole, the gap is still very great, a lot of work to do. To this end, in 2010 respectively, in 2020 advances in technology, development planning has very important significance.
valve
commonly used in water supply and drainage project, widely used in low-pressure valve, in particular low-voltage large-diameter valves (low pressure valve is the PN ≤ 1.6MPa Nominal Pressure valves ), while medium pressure valves (PN2.5-6.4MPa)less. The valve, butterfly valves are the most fundamental and most widely used products.
valve status and the development of valve used
oldest so far is still the application of all countries in the world, especially the following DN300mm in various types of valves still dominant. Characterized before and after the differential pressure valve plate so that the valve pressure in the export compulsory seat on the right side, sealing is better, and wide-open, because the valve does not stay in the flow on the road, the pressure loss. Used to cut off the pipeline media.
its major disadvantage is the operation of torque, easy operation so that valve body, stem damage, especially in large-diameter valve. Dimensions and weight are also large, DN1000 valve diameter of about 3200mm high and required four operations, so valve generally used in small-caliber, that is, use the following DN500.
valve to the middle from the wide-open aperture, the valve flow resistance small, close to full-closed, the flow resistance increased dramatically. Larger range of smaller changes in flow resistance, in the nearly full-closed, the flow varies significantly, we must not close to the closure of the valve used, when it is difficult to carry out the flow of fine-tuning. If the valve opening is extremely small, fast flow rate of the opening will have a lower side flashboard cavitation, and accompanied by intense vibration and noise, long cutting operation, tend to increase body and gate metal Cavitation happen.
working condition if the valve opening in the middle, because it is the valve guides on both sides of the support, all with closely when closed, while the middle position, the valve plate and have a large gap rail vibration . Therefore, even in a low incidence of cavitation region, a long time to reduce expenditure valve operation, rail will happen deformities, wear or damage, and as a result of the valve seat is not fully engaged, and access parts of the surface pressure tends will have to bite corrosion or adhesion, therefore, should not be used for flow control. Would also like to note that the valve in the small opening, the flow changes, and if the emergency gate valves, pressure will cause a sharp increase or produce negative pressure, especially when the valve clearance of the resulting water hammer. (06-8-31)
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