进口蝶阀的历史和选型应用
进口蝶阀的发展历史
30年代，美国发明了蝶阀，50 年代传入日本，到60年代才在日本普遍采用，而在我国推广则是70年代后的事了。目前世界上一般在DN300毫米以上蝶阀已逐渐代替了闸阀。蝶阀与闸阀相比有开闭时间短，操作为矩小，安装空间小和重量轻。以DN1000为例，蝶阀约2T，而闸阀约3.5T，且蝶阀易与各种驱动装置组合，有良好的耐久性和可靠性。 橡胶密封蝶阀缺点是作节流使用时，由于使用不当会产生气蚀，使橡胶座剥落、损伤等情况发生。为此，现在国际上又开发金属密封蝶阀，气蚀区减小，近几年我国也开发了金属密封蝶阀，在日本近年来还开发耐气蚀、低振动、低噪声的梳齿形蝶阀。 一般密封座的寿命在正常情况下，橡胶15年-20年，金属的80年-90年。
进口蝶阀的选型和应用
如何正确选用蝶阀则要根据工况要求。蝶阀的开度与流量之间的关系，基本上呈线性比例变化。如果用于控制流量，其流量特性与配管的流阻也有密切关系，如两条管道安装阀门口径、形式等全相同，而管道损失系数不同，阀门的流量差别也会很大。 如果阀门处于节流幅度较大状态，阀板的背面容易发生气蚀，有损坏阀门的可能，一般均在15°外使用。 蝶阀处于中开度时，阀体与蝶板前端形成的开口形状以阀轴为中心，两侧形成完成不同的状态，一侧的蝶板前端顺流水方向而动，另一侧逆流水方向而动，因此，一侧阀体与阀板形成似喷嘴形开口，另一侧类似节流孔形开口，喷嘴侧比节流侧流速快的多，而节流侧阀门下面会产生负压，往往会出现橡胶密封件脱落。 蝶阀操作力矩，因开度及阀门启闭方向不同其值各异，卧式蝶阀，特别是大口径阀，由于水深，阀轴上、下水头差所产生的力矩也不容忽视。另外，阀门进口侧装置弯头时，形成偏流，力矩会有增加。阀门处于中间开度时，由于水流动力矩起作用，操作机构需要自锁. 美国威盾VTON进口蝶阀有以下可供选型：进口硬密封蝶阀，进口衬氟蝶阀，进口带伸缩蝶阀，进口涡轮衬胶蝶阀，进口通风蝶阀，进口高温烟道蝶阀，进口气动蝶阀，进口真空蝶阀。
Butterfly valve in the process of applying knowledge 0's, the U.S. invented the butterfly, 50 years into Japan, the 1960s was widely used in Japan, and in the promotion of our country is what happened after the 1970s. The world in general DN300 mm butterfly valve has been gradually replaced. Compared with the butterfly valve opening and closing time is short, for the moment a small, small installation space and weight. To DN1000, for example, butterfly about 2T, while the gate of about 3.5T, and the valve drive easily with a variety of combinations, with good durability and reliability. Drawback is that rubber seal butterfly valve used for throttling, because improper use will produce cavitation, peeling off the rubber seat, damage from happening. To this end, we developed is now the international metal sealing butterfly valve, cavitation area decreases, in recent years, China has also developed a metal sealing butterfly valve, also developed in Japan in recent years, resistance to cavitation, low vibration, low noise, comb-shaped butterfly valve. General life of the seal seat in normal circumstances, the rubber for 15 years -20 years -90 years, 80 years of metal. But how to properly use they should according to the conditions required. Butterfly valve opening and the relationship between flow rate, essentially linearly proportional to the change. If used to control the flow, its flow characteristics and flow resistance of piping is also closely related, such as the installation of the valve bore two pipelines, all forms of the same, but different loss coefficient pipe, valves, flow difference will be great. If the throttle valve in a significant reduction in the state, the valve plate on the back prone to cavitation, may damage the valve, generally used in a 15 ° outside. Butterfly valve in the opening, the valve body and disc shape of the front-end to form an opening to the valve shaft as the center, on both sides to complete the formation of different states, the front side of the disc moving along the flow direction, the direction of the other side of the counter-current water The move, therefore, the side of the valve body and valve plate-shaped nozzle openings formed like the other side of the similar-shaped orifice opening, the nozzle side than the expenditure side of the flow much faster, and throttle valve below will produce negative side often there will be the rubber seals off. Valve operating torque, due to open and close the valve opening and its value varies in different directions, horizontal butterfly valve, especially large-diameter valve, water depth, the valve shaft, the water head difference generated by the torque can not be ignored. In addition, the valve inlet side of the device when the elbow to form a bias current, torque will increase. Valve opening in the middle, because the water flow torque to work, organizations need to self-locking operation.