進口蝶閥的發(fā)展歷史和應(yīng)用
進口蝶閥的發(fā)展歷史
30年代，美國發(fā)明了蝶閥，50 年代傳入日本，到60年代才在日本普遍采用，而在我國推廣則是70年代后的事了。目前世界上一般在DN300毫米以上蝶閥已逐漸代替了閘閥。蝶閥與閘閥相比有開閉時間短，操作為矩小，安裝空間小和重量輕。以DN1000為例，蝶閥約2T，而閘閥約3.5T，且蝶閥易與各種驅(qū)動裝置組合，有良好的耐久性和可靠性。 橡膠密封蝶閥缺點是作節(jié)流使用時，由于使用不當會產(chǎn)生氣蝕，使橡膠座剝落、損傷等情況發(fā)生。為此，現(xiàn)在國際上又開發(fā)金屬密封蝶閥，氣蝕區(qū)減小，近幾年我國也開發(fā)了金屬密封蝶閥，在日本近年來還開發(fā)耐氣蝕、低振動、低噪聲的梳齒形蝶閥。 一般密封座的壽命在正常情況下，橡膠15年-20年，金屬的80年-90年。
進口蝶閥的選型和應(yīng)用
如何正確選用蝶閥則要根據(jù)工況要求。 蝶閥的開度與流量之間的關(guān)系，基本上呈線性比例變化。如果用于控制流量，其流量特性與配管的流阻也有密切關(guān)系，如兩條管道安裝閥門口徑、形式等全相同，而管道損失系數(shù)不同，閥門的流量差別也會很大。 如果閥門處于節(jié)流幅度較大狀態(tài)，閥板的背面容易發(fā)生氣蝕，有損壞閥門的可能，一般均在15°外使用。 蝶閥處于中開度時，閥體與蝶板前端形成的開口形狀以閥軸為中心，兩側(cè)形成完成不同的狀態(tài)，一側(cè)的蝶板前端順流水方向而動，另一側(cè)逆流水方向而動，因此，一側(cè)閥體與閥板形成似噴嘴形開口，另一側(cè)類似節(jié)流孔形開口，噴嘴側(cè)比節(jié)流側(cè)流速快的多，而節(jié)流側(cè)閥門下面會產(chǎn)生負壓，往往會出現(xiàn)橡膠密封件脫落。 蝶閥操作力矩，因開度及閥門啟閉方向不同其值各異，臥式蝶閥，特別是大口徑閥，由于水深，閥軸上、下水頭差所產(chǎn)生的力矩也不容忽視。另外，閥門進口側(cè)裝置彎頭時，形成偏流，力矩會有增加。閥門處于中間開度時，由于水流動力矩起作用，操作機構(gòu)需要自鎖. 美國威盾VTON進口蝶閥有以下可供選型：進口硬密封蝶閥，進口襯氟蝶閥，進口帶伸縮蝶閥，進口渦輪襯膠蝶閥，進口通風蝶閥，進口高溫煙道蝶閥，進口氣動蝶閥，進口真空蝶閥。
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.
