蝶阀的直径主要由流量、介质和流量决定。一般情况下，液体的流速不大于5m/s，最高可达7-8m/s。一般情况下，水的流量为2-3m/s，低压气体的流量推荐为2-10m/s，中压气体的流量推荐为10-20m/s;蒸汽流量建议低压蒸汽流量为20-40m/s，中压蒸汽流量为40-60m/s，高压蒸汽流量为60-80m/s。当然，有时候为了减少压力损失，人们会选择直径较大的蝶阀，这样流量就会比较慢。但是，如果阀门在低流量下工作，则不能这样做。液体流经绝对低压区，并在极短的时间内迅速蒸发和重新冷凝。这种现象称为空化效应。因为气体在低压下不能改变状态，所以这种现象在气流中不会发生。当流体流入高压区域时，蒸汽气泡会突然凝结、坍塌或聚结，流量可达110m/s，流动压力可达50Mpa，对管壁造成冲击破坏。 When the valve pressure is less than 1.5Mpa and cavitation occurs, but does not cause serious damage to the material, so no special measures are necessary.

由于发展当今科技的发展，海洋阀门得到了极大的改善，体力更好，耐磨损耐力强，使用寿命更长。然而，偶尔，一些意外的故障会影响阀门的使用和健康。如何解决一些常见的故障和相关的方法。1.设备不起作用，DCS警报超时可能的原因：A。电力死亡;B.主循环缺乏阶段;C.控制回路失败;解决方案：A。检查每个电路的电源供应商和电压;B.检查主电路相线是否破损;C.检查交换机有限位置或扭矩开关是否正常工作。DCS是否受到链保护; 2.DCS alarms once upon it is operated Possible causes: A. The short-circuit of the main circuit leads to the protective act of the thermal relay or power switch trip; B. Fails of internal components or body cause excessive torque protection; C. The electrical equipment's torque control mechanism fails or the torque setting value is too small; Solutions: A. Check whether the power switch trip and thermal relay ; B. Check if the transmission mechanism is stuck; C. Check the torque setting value; Through the above analysis, we will have a general understanding of these failures and the corresponding solutions. There will be other faults in marine valves in the future, but as long as we actively analyze these faults, we will finally find a suitable solution.

1.首先，安全阀的设计必须满足用户的要求。2.产品的价格应根据实际工况确定为最合理的价格。3.设计中首先要考虑的是使阀门的整体性能达到预期和标准。4.更多的测试可以提供更精确和详细的参数。5.应多加注意弹簧的刚度。 Appropriate design enables the valve’s internal parts to match each other batter, making it easy to assemble, disassemble and maintain. 6.Safety valve needs to be designed to have a longer service life. Generally, the medium of safety valve can be divided into three types: steam, gas and liquid. But designers cannot do performance tests of various media at the same time. Due to heavy oil (asphalt) and other media, the qualified performance data obtained from the cold test may become unsatisfactory. Therefore, the safety valve design cannot duplicate any other mature product models. The valve should be manufactured with appropriate spring rigidity and reasonable internal structure according to different media. Of course, the design principle of the safety valve is to produce products that users satisfy, and the only design shortcut is the experience accumulated from practice.

1.为什么双座阀门倾向于以小开口状态振荡？当涉及单一的阀芯阀时，当介质是开放式流动型时，它将具有出色的稳定性，这意味着介质流向阀门的开口有利的方向。相比之下，将其转为近流式时，阀门的稳定性下降。基于上述情况，双座阀稳定性差，并且在小型开口时倾向于振动，因为它的两个线轴 - 上部是流动关闭的情况，而下部较低的情况势必在流动的情况下。同时洗涤。2.为什么不能使用双密封阀来切断媒介？坦克到其力平衡的结构，双密封阀具有大的差压。但是，如果两个密封面的不完美触点带来的泄漏将导致可怕的后果，如果用作截止阀。3.为什么线性运动阀比旋转运动阀更差，而不是旋转运动阀？线性运动阀垂直切断流量，但介质水平流入并输出。腔内的流动路径在扭曲和转弯中延伸，使杂质能够在所谓的死区中沉淀。 As time goes by, the path will be blocked. On the contrary, the rotary motion valve cut the flow off horizontally and has a relatively simple flow path. Therefore, the rotary motion valve has a better anti-blocking performance. 4.Why the stem of linear motion valve is relatively small It refers to an easy mechanical principle: high sliding friction brings low rolling friction. The stem of the linear motion valve moves up and down. The packing, which is slightly compressed, will wrap the stem very tightly, resulting in a large backlash. To avoid that, the stem is designed to be very thin and small. 5. Why does rotary motion valve can bear high differential pressure? That’s because the resultant force that the medium produced on the spool or plate only has a very small torque on the axis of rotation. As a result, the rotary motion valve bears high differential pressure

Q1。为什么橡胶衬里蝶阀和氟隔膜阀会被淡化水介质缩短寿命?在酸或碱浓度较低的情况下，淡化水介质会对橡胶衬里蝶阀橡胶部分产生强烈的腐蚀，使橡胶膨胀、老化、失去强度，最终降低其工作性能。虽然开发了另一种耐腐蚀性能较好的阀门——橡胶衬里隔膜阀，但其隔膜在折叠后很容易断裂。然后发生机械损坏，使用寿命缩短。Q2。为什么关闭阀总是要用硬密封处理?软密封可根据需要从切断阀进行管理:具有更低的泄漏率，并具有很大的切断功能。然而，采用硬密封的阀门在可靠性和耐磨性方面不合格。当我们把这两种要求加到两种截止阀的比较中，硬密封的那一种就脱颖而出了。 Q3. Why does sleeve valve fail to take place of single valve and double valve? Many people thought that single and double seat valve will be squeezed out by the second-generation-to-be product--sleeve valve, which born in 1960s and found its feet worldwide in 1970s. But the current situation is quite different. Although the sleeve valve has remarkable stability, its weight and leakage index don’t exceed single and double seat valves. The end result of competition of there three valves is a draw, as they’re in the market nowadays. Q4. Why are piston actuator increasingly used in pneumatic valve? Piston actuator have smaller size but bigger thrust to drive pneumatic valve thank to air pressure. Q5. Why does selection outweigh calculation? Selection is more important and complex than calculation.Because calculation is only a process of formulas, it can’t demonstrate the accuracy of the formula itself, but the accuracy of given indexes. There are many items involved in the selection. A little oversight may bring wrong choice. That not only wastes manpower, material and financial resources, but also results in unsatisfactory conditions and brings troubles in reliability, service life and operation,etc.

阀体的高强度配置至关重要。阀体存在缺陷，在安装到位后，可能会出现意外的经济损失。更重要的是，它可能会给整个工作系统一个周期，并从公司收取过高的成本，甚至公众。在材料输出时，不允许媒体外泄。其他缺陷如裂纹、气孔疏松、结渣到身体、覆盖等部位。此外，为了保证这些仪器的良好性能，阀门生产厂家还必须对每一个阀门进行强度试验。阀的所有部件装配完毕后，整件将送去做强度测试。通常粗加工后，粗加工质量的毛坯和热处理后的零件会做中等强度试验，以避免各种试验失败带来不必要的浪费。如果所有指标正常，只有用户坚持才会保存进一步测试。体能测试通常在常温下进行。 And the testing pressure will be set 1.25 to 1.5 times higher than the nominal pressure. Valves are going to prove strong enough to pass the exam as long as these is no leakage within the allowed range. Another thing worth to be keep in mind is that air in the cavity should be output if the outputting material is water. Those above speak loudly that strength test id of great meanings and values. You could never assure its quality when its not strong enough. Therefore it is sure that the strength test is and will be the most important project in the valve producing field.