The vibration of the regulating valve is generally divided into two states. One is the overall vibration of the regulating valve, that is, the whole regulating valve vibrates frequently on the pipeline or base. The other is the vibration of the regulating valve core, which can be seen from the frequent movement of the valve stem up and down. The causes of these two kinds of vibration and their treatment measures are analyzed as follows:

調(diào)節(jié)閥的振動與噪聲根據(jù)其誘發(fā)因素不同，大致可分為機(jī)械振動、氣蝕振動和流體動力學(xué)振動等原因。

According to the different inducing factors, the vibration and noise of control valve can be roughly divided into mechanical vibration, cavitation vibration and hydrodynamic vibration.

1、機(jī)械振動

1. Mechanical vibration

機(jī)械振動根據(jù)其表現(xiàn)形式可以分為兩種狀態(tài)。一種狀態(tài)是調(diào)節(jié)閥的整體振動，即整個(gè)調(diào)節(jié)閥在管道或基座上頻繁顫動，其原因是由于管道或基座劇烈振動，引起整個(gè)調(diào)節(jié)閥振動。此外還與頻率有關(guān)，即當(dāng)外部的頻率與系統(tǒng)的固有頻率相等或接近時(shí)受迫振動的達(dá)到限值、產(chǎn)生共振。另一種狀態(tài)是調(diào)節(jié)閥閥瓣的振動，其原因主要是由于介質(zhì)流速的急劇增加，使調(diào)節(jié)閥前后差壓急劇變化，引起整個(gè)調(diào)節(jié)閥產(chǎn)生嚴(yán)重振蕩。

Mechanical vibration can be divided into two states according to its manifestations. One state is the overall vibration of the regulating valve, that is, the whole regulating valve vibrates frequently on the pipeline or base. The reason is that the vibration of the whole regulating valve is caused by the violent vibration of the pipeline or base. In addition, it is also related to frequency, that is, when the external frequency is equal to or close to the natural frequency of the system, the forced vibration reaches the limit and produces resonance. The other state is the vibration of the regulating valve disc, which is mainly due to the sharp increase of the medium flow rate, resulting in the sharp change of the differential pressure before and after the regulating valve, resulting in serious oscillation of the whole regulating valve.

2、氣蝕振動

2. Cavitation vibration

氣蝕振動大多發(fā)生在液態(tài)介質(zhì)的調(diào)節(jié)閥內(nèi)。氣蝕產(chǎn)生的根本原因在于調(diào)節(jié)閥內(nèi)流體縮流加速和靜壓下降引起液體汽化。調(diào)節(jié)閥開度越小，其前后的壓差越大，流體加速并產(chǎn)生氣蝕的可能性就越大，與之對應(yīng)的阻塞流壓降也就越小。

Cavitation vibration mostly occurs in the control valve of liquid medium. The root cause of cavitation is the liquid vaporization caused by the acceleration of fluid contraction and the decrease of static pressure in the control valve. The smaller the opening of the regulating valve, the greater the pressure difference before and after it, the greater the possibility of fluid acceleration and cavitation, and the smaller the corresponding blocking flow pressure drop.

3、流體動力學(xué)振動

3. Hydrodynamic vibration

介質(zhì)在閥內(nèi)的節(jié)流過程也是其受摩擦、受阻力和擾動的過程。湍流體通過不良繞流體的調(diào)節(jié)閥時(shí)形成旋渦，旋渦會隨著流體的繼續(xù)流動的尾流而脫落。這種旋渦脫落頻率的形成及影響因素十分復(fù)雜，并有很大的隨機(jī)性，定量計(jì)算十分困難，而客觀卻存在一個(gè)主脫落頻率。當(dāng)這一脫落頻率(亦包括高次諧波)在與調(diào)節(jié)閥及其附屬裝置的結(jié)構(gòu)頻率接近或一致時(shí)，發(fā)生了共振，調(diào)節(jié)閥就產(chǎn)生了振動，并伴隨著噪聲。振動的強(qiáng)弱隨脫落頻率的強(qiáng)弱和高次諧波波動方向一致性的程度而定。

The throttling process of medium in the valve is also the process of friction, resistance and disturbance. When the turbulent fluid passes through the regulating valve around the fluid, it forms a vortex, which will fall off with the wake of the continuous flow of the fluid. The formation and influencing factors of vortex shedding frequency are very complex and random, so it is very difficult to calculate quantitatively, but there is a main shedding frequency objectively. When this shedding frequency (also including high-order harmonics) is close to or consistent with the structural frequency of the regulating valve and its accessories, resonance occurs, and the regulating valve generates vibration and noise. The intensity of vibration depends on the intensity of shedding frequency and the consistency of higher harmonic wave direction.