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未来我国阀门行业市场发展前景非常广阔

2019-05-28  来自: 泰科菲阀门有限公司 浏览次数:111

有差距和存在问题并不可怕,只要我们调整好发展思路,增强发展的信心,强化企业管理,推进技术进步,重视技术创新和核心技术的研发,提高企业的核心竞争力。我们知道,大多数阀门所需要维修的工作量是极少的,这意味着大多数阀门不必经常修理。而有时即便是单纯的阀杆泄漏这样的小问题,往往因疏忽大意而成大问题。更有甚者,有些蛮干的操作者,不按技术规范的要求关闭阀门,导致阀杆弯曲或关闭件的严重损坏。这样的情况时有发生。在使用中有以下几种常用问题:
  
  一、为什么双座阀小开度工作时容易振荡
  
  对单芯而言,当介质是流开型时,阀稳定性好;当介质是流闭型时,阀的稳定性差。双座阀有两个阀芯,下阀芯处于流闭,上阀芯处于流开,这样,在小开度工作时,流闭型的阀芯就容易引起阀的振动,这就是双座阀不能用于小开度工作的原因所在。
  
  二、为什么双密封阀不能当作切断阀使用
  
  双座阀阀芯的优点是力平衡结构,允许压差大,而它突出的缺点是两个密封面不能同时良好接触,造成泄漏大。如果把它人为地、强制性地用于切断场合,显然效果不好,即便为它作了许多改进(如双密封套筒阀),也是不可取的。
  
  三、什么直行程调节阀防堵性能差,角行程阀防堵性能好
  
  直行程阀阀芯是垂直节流,而介质是水平流进流出,阀腔内流道必然转弯倒拐,使阀的流路变得相当复杂(形状如倒“S”型)。这样,存在许多死区,为介质的沉淀提供了空间,长此以往,造成堵塞。角行程阀节流的方向就是水平方向,介质水平流进,水平流出,容易把不干净介质带走,同时流路简单,介质沉淀的空间也很少,所以角行程阀防堵性能好。
  
  四、为什么直行程调节阀阀杆较细
  
  它涉及一个简单的机械原理:滑动摩擦大、滚动摩擦小。直行程阀的阀杆上下运动,填料稍压紧一点,它就会把阀杆包得很紧,产生较大的回差。为此,阀杆设计得非常细小,填料又常用摩擦系数小的四氟填料,以便减少回差,但由此派出的问题是阀杆细,则易弯,填料寿命也短。解决这个问题,好的办法就是用旅转阀阀杆,即角行程类的调节阀,它的阀杆比直行程阀杆粗2~3倍,且选用寿命长的石墨填料,阀杆刚度好,填料寿命长,其摩擦力矩反而小、回差小。
  
  五、为什么角行程类阀的切断压差较大?
  
  角行程类阀的切断压差较大,是因为介质在阀芯或阀板上产生的合力对转动轴产生的力矩非常小,因此,它能承受较大的压差。
  
  六、为什么脱盐水介质使用衬胶蝶阀、衬氟隔膜阀使用寿命短?
  
  脱盐水介质中含有低浓度的酸或碱,它们对橡胶有较大的腐蚀性。橡胶的被腐蚀表现为膨胀、老化、强度低,用衬胶的蝶阀、隔膜阀使用效果都差其实质就是橡胶不耐腐蚀所致。后衬胶隔膜阀改进为耐腐蚀性能好的衬氟隔膜阀,但衬氟隔膜阀的膜片又经不住上下折叠而被折破,造成机械性破坏,阀的寿命变短。现在好的办法是用水处理专用球阀,它可以使用到5~8年。
  
  七、为什么切断阀应尽量选用硬密封
  
  切断阀要求泄漏越低越好,软密封阀的泄漏是低的,切断效果当然好,但不耐磨、可靠性差。从泄漏量又小、密封又可靠的双重标准来看,软密封切断就不如硬密封切断好。如全功能超轻型调节阀,密封而堆有耐磨合金保护,可靠性高,泄漏率达10~7,已经能够满足切断阀的要求。
  
  八、为什么套筒阀代替单、双座阀却没有如愿以偿
  
  20世纪60年代问世的套筒阀,70年代在国内外大量使用,80年代引进的石化装置中套筒阀占的比率较大,那时,不少人认为,套筒阀可以取代单、双座阀,成为第二代产品。到如今,并非如此,单座阀、双座阀、套筒阀都得到同等的使用。这是因为套筒阀只是改进了节流形式、稳定性和维护好于单座阀,但它重量、防堵和泄漏指标上与单、双座阀一致,它怎能取代单、双座阀呢?所以,就只能共同使用。
  
  九、为什么说选型比计算更重要
  
  计算与选型比较而言,选型要重要得多,复杂得多。因为计算只是一个简单的公式计算,它的本身不在于公式的精确度,而在于所给定的工艺参数是否准确。选型涉及到的内容较多,稍不慎,便会导致选型不当,不仅造成人力、物力、财力的浪费,而且使用效果还不理想,带来若干使用问题,如可靠性、寿命、运行质量等。
  
  十、为什么在气动阀中活塞执行机构使用会越来越多
  
  对于气动阀而言,活塞执行机构可充分利用气源压力,使执行机构的尺寸比薄膜式更小巧,推力更大,活塞中的O型圈也比薄膜可靠,因此它的使用会越来越多

   It is not terrible to have gaps and existing problems. As long as we adjust our development thinking, strengthen our confidence in development, strengthen enterprise management, promote technological progress, attach importance to technological innovation and research and development of core technologies, and improve the core competitiveness of enterprises. We know that most valves require minimal repair work, which means most valves don't have to be repaired often. And sometimes even simple stem leakage such a small problem, often due to negligence and become a big problem. Furthermore, some unscrupulous operators fail to shut the valve as required by technical specifications, resulting in serious damage to the stem bent or closing parts. This happens from time to time. There are several common problems in use:


1. Why do two-seat valves oscillate easily when they are open


For single core, when the medium is flow open, the valve is stable. The valve has poor stability when the medium is flow - closed. The double valve has two spools, the lower spool is in the flow close, the upper spool is in the flow open, thus, when the small opening works, the flow closed type spool is easy to cause the valve's vibration, this is the two-seat valve cannot be used for the small opening work reasons.


2. Why can't double-seal valve be used as cut-off valve


The advantage of the two-seat valve core is the force balance structure, which allows a large pressure difference, while its prominent disadvantage is that the two sealing surfaces can not be in good contact at the same time, resulting in large leakage. If it is used artificially and compulsorily for the purpose of cutting off, it is obviously not effective, and even if many improvements have been made (such as double sealing sleeve valve), it is not desirable.


3. What straight stroke regulating valve has poor plugging performance and Angle stroke valve has good plugging performance


The straight stroke valve spool is vertical throttle, while the medium is horizontal flow in and out, the flow channel in the valve cavity will inevitably turn and reverse, making the flow path of the valve quite complex (such as inverted "S"). In this way, there are many dead areas, which provide space for the precipitation of medium. The direction of corner stroke valve throttle is the horizontal direction, medium horizontal flow in, horizontal flow out, easy to take the unclean media away, at the same time, flow path is simple, medium precipitation space is very little, so the Angle stroke valve has good anti-blocking performance.


Four, why straight stroke regulating valve stem smaller


It involves a simple mechanical principle: large sliding friction, small rolling friction. Straight stroke valve stem up and down movement, packing a little pressure, it will wrap the stem very tight, resulting in a large return difference. For this reason, the stem is designed to be very small, and the packing is often used with a small friction coefficient of tetrafluorotetrafluoroin packing to reduce return error, but the problem from this is that the stem is thin, easy to bend, and the packing life is short. Solve this problem, best method is to use brigade turn valve stem, namely Angle stroke kind adjust valve, its valve stem is thicker than straight stroke valve stem 2 ~ 3 times, and choose long life graphite packing, valve stem rigidity is good, packing life is long, its friction moment is small instead, return difference is small.


5. Why is the cutting pressure difference of Angle stroke valve larger?


The cut off pressure difference of the valve with Angle stroke is large, because the resultant force of the medium on the spool or valve plate produces very little torque on the rotating shaft, therefore, it can bear large pressure difference.


6. Why does desalination water medium use rubber butterfly valve and fluorine diaphragm valve with short service life?


The desalination water medium contains low concentration of acid or alkali, which is more corrosive to rubber. The corrosion of rubber is shown as expansion, aging and low strength. The application effect of butterfly valve and diaphragm valve with rubber lining is poor. After the lining rubber diaphragm valve improved for corrosion resistance good lining fluorine diaphragm valve, but the diaphragm of lining fluorine diaphragm valve can not stand up and down folding and broken, causing mechanical damage, the valve life shortened. Now the best way is to use water treatment special ball valves, it can be used for 5-8 years.


7. Why should the cut-off valve be hard sealed


Cut off valve requirements leakage as low as possible, soft sealing valve leakage is the lowest, cutting effect of course good, but not wear-resistant, poor reliability. According to the double standard of small leakage and reliable seal, soft seal cutting is not as good as hard seal cutting. For example, the full-function ultra-light control valve, sealed and piled with wear resistant alloy protection, high reliability and leakage rate up to 10 to 7, has been able to meet the requirements of the shutoff valve.


Eight, why did sleeve valve replace single, double seat valve but did not achieve


The sleeve valve which came out in the 1960s was widely used at home and abroad in the 1970s. In the petrochemical equipment introduced in the 1980s, the sleeve valve accounted for a large proportion. At that time, many people thought that the sleeve valve could replace the single and two-seat valve and become the second generation product. Now, not so, single - seat, double - seat, sleeve valve are used equally. This is because the sleeve valve only improved the throttling form, stability and maintenance better than the single-seat valve, but its weight, plugging and leakage indicators are consistent with the single-seat and two-seat valves, how can it replace the single-seat and two-seat valves? So you have to use them together.


9. Why is the selection more important than the calculation


The calculation is much more important and complex than the selection. Since the calculation is only a simple formula calculation, it is not the accuracy of the formula itself, but the accuracy of the given process parameters. There are many contents involved in type selection, which may lead to improper type selection. It not only causes waste of manpower, material resources and financial resources, but also causes unsatisfactory effect of use, and brings some problems of use, such as reliability, life and operation quality.


Why are piston actuators used more and more in pneumatic valves


For the pneumatic valve, the piston actuator can make full use of the air source pressure, making the size of the actuator smaller than the thin film type, greater thrust, and the o-ring in the piston is more reliable than the thin film, so it will be used more and more

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