Conditioning system, the control valve mechanical noise generated mainly from the safety valve, stem, and some can be active parts. Or due to fluid pressure fluctuations, or by the impact of the fluid, or the lateral margin of the sleeve and the body guides the gap between the large, will lead to parts of the vibration. For example, the spool relative to the guide surface of the lateral movement of the spool, the collision between the valve seat. If the gap between the parts, if not transmit force, vibration, friction and bump will also have the role. These collisions are the rigidity of the collision, the resulting sound is clear metal sound and percussion sound. Collision excitation spectrum of the noise is a continuous sound, with a wide frequency range. The size of the amplitude of the noise energy from the collision, vibration, body mass, stiffness, damping of the decision. The vibration frequency is generally less than 1500HZ.

If the vibration frequency and the natural frequency is close or identical, will have resonance. Role not only have great resonance mechanical noise, frequency up to 3000 ~ 7000HZ, and will have a lot of damage stress can cause vibration of the parts of the fatigue failure. The natural frequency of vibration under the easy parts of a piston valve spool, spool-shaped cylindrical wall window, flexible parts (eg valve metal seal ring.)

Mechanical noise, will produce a dry friction sound. When the interaction of the two surfaces (such as spool and valve seat) produces relative movement of the surface of a surface produced by the other block, which is to friction. Each other due to surface asperities embedded and molecular cohesion, adhesion between the surface caused by both loss of energy, but also to surface wear, resulting in part heat, plastic deformation, vibration and noise. Dry friction noise emitted by the vibration of high frequency noise, it sounds shrill, hard to endure. If the two friction surfaces with good lubrication, improved surface finish and geometric accuracy, can reduce the dry friction.

The noise caused by mechanical parts, is still difficult to predict. However, this noise, the event can be measured with instruments in the field. Reduce the mechanical noise of the methods is to improve the structure of the valve itself, especially the core and seat structure and the orientation part of the structure, increase stiffness, reduce the quality of the movable components.

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