在液體操作中,無論何處的物流突然停止,在上游和下游兩者均產生大量的振動波,這個現象叫做水錘效應。通常它是在閥門接近關閉時閉合元件突然吸入閥座(溶缸閉鎖效應)的時候,由泵的突然關閉或閥門的突然關閉所造成的。對于控制閥門,溶缸閉鎖效應是由低推力執行機構所造成的,該執行機構沒有足夠剛度以保持接近閥座的位置。在某些情況下,具有快開型或安裝的直線型流動特性的閥門也能導致水錘效應。
In liquid operation, no matter where the logistics stops suddenly, a large number of vibration waves are generated both upstream and downstream. This phenomenon is called water hammer effect. Usually, it is caused by the sudden closing of the pump or the sudden closing of the valve when the closing element suddenly sucks into the valve seat (cylinder locking effect). For the control valve, the locking effect of the dissolving cylinder is caused by the low thrust actuator, which does not have enough stiffness to maintain the position close to the valve seat. In some cases, valves with quick opening or installed linear flow characteristics can also cause water hammer effect.
雖然水錘產生很大的噪音,但真的損害是由機械失效造成的。因此由動能急劇地變化成靜的管線壓力,已知水錘會沖破管線或損傷管子支架和損害管線接頭。對于閥門,水錘能夠通過閥芯產生振動,它可能導致閥芯、墊片或填料的失效.
Although the water hammer makes a lot of noise, the real damage is caused by mechanical failure. Therefore, the kinetic energy changes rapidly into static pipeline pressure. It is known that the water hammer will break through the pipeline or damage the pipe support and pipeline joint. For valves, water hammer can produce vibration through the valve core, which may lead to the failure of the valve core, gasket or packing
對于閥門,防御水錘的辦法是防止系統任何突然的壓力變化。這些包括放慢閥門本身的關閉或當閉合元件接近閥座時提供較大程度的剛性。為防止壓力波動,閥門應以均勻變動的速度進行關閉。在某些情況下,當使用快開或安設直線特性(它接近于快開特性),可以要求改變為等百分比特性。對于在接近閥座時節流的控制閥,使用異常的剛度執行機構,如彈簧氣缸氣動執行機構或液壓執行機構,或在手動四分之一旋轉的操作器的行程套管上設置特殊缺口,將減少或防止溶缸閉鎖效應。在管線系統上設置某種類型的防波動措施也能減少水錘。這可便用壓力泄放閥或充氣軟管完成,充氣軟管可減少管線長度。此外氣體可被注入系統內,氣體的注入能減少流體的密度并提供某些壓縮性以處理突然的波動。
For valves, the defense against water hammer is to prevent any sudden pressure change in the system. These include slowing down the closure of the valve itself or providing a greater degree of rigidity when the closing element approaches the seat. In order to prevent pressure fluctuation, the valve shall be closed at a uniform change speed. In some cases, when using the quick opening or installing the straight line characteristic (which is close to the quick opening characteristic), it can be required to change to the equal percentage characteristic. For the control valve flowing close to the valve seat, the use of abnormal stiffness actuator, such as spring cylinder pneumatic actuator or hydraulic actuator, or the setting of special notch on the travel sleeve of the manual quarter rotation operator will reduce or prevent the cylinder locking effect. Setting some type of anti fluctuation measures on the pipeline system can also reduce water hammer. This can be done with a pressure relief valve or an inflation hose, which can reduce the length of the pipeline. In addition, gas can be injected into the system, which can reduce the density of the fluid and provide some compressibility to deal with sudden fluctuations.
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