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Solution to the vibration of the inlet regulating valve
1) Increase the stiffness method
For oscillation and slight vibration, the stiffness can be increased to eliminate or weaken. For example, it is feasible to use a spring with a large stiffness and a piston actuator.
2) Increase the damping method
Increasing the damping increases the friction against vibration. For example, the valve plug of the sleeve valve can be sealed with an “O” ring, and graphite packing with a large friction force can be used to eliminate or attenuate slight vibration.
3) Increase the guide size and reduce the fit clearance method
The shaft plug valve generally has a small guide size, and all valve fit clearances are generally large, 0.4 to 1 mm, which is helpful for generating mechanical vibration. Therefore, when a slight mechanical vibration occurs, the vibration can be weakened by increasing the guide size and reducing the fit clearance.
4) Change the shape of the throttle to eliminate the resonance method
Because the so-called vibration source of the regulating valve occurs at the throttle port with high-speed flow and rapid pressure change, changing the shape of the throttle member can change the frequency of the vibration source, and it is easier to solve when the resonance is not strong. The specific method is to turn the valve core surface by 0.5 to 1.0 mm in the range of vibration opening. For example, if a self-operated pressure regulating valve is installed near a certain manufacturer's area, the whistling of the resonance will affect the rest of the staff. After the valve core is turned off by 0.5mm, the resonance whistling sound disappears.
5) Replace the throttle to eliminate the resonance method
1 Replace the flow characteristics, change the logarithm linearly, and change the logarithm linearly;
2 Replace the spool form. If the shaft plug shape is changed to a "V"-shaped groove valve core, the double seat valve shaft plug type is changed into a sleeve type; the open window sleeve is changed to a small hole sleeve. For example, if a DN25 double seat valve of a nitrogen fertilizer plant, the connection between the valve stem and the valve core is often broken, we confirm that after the resonance, the linear characteristic valve core is changed to the logarithmic valve core, and the problem is solved. Another example is the use of a DN200 sleeve valve in an aviation academy laboratory. The valve plug is strongly rotated and cannot be used. When the sleeve of the open window is changed to the sleeve of the small hole, the rotation disappears immediately.
6) Replace the regulator type to eliminate resonance.
Different types of regulating valves have different natural frequencies, and replacing the regulating valve type is the most effective way to fundamentally eliminate resonance. A valve resonates very strongly in use—strongly vibrating (destroying the valve in severe cases), rotating strongly (even the stem is broken, twisted), and producing strong noise (up to 100 decibels) The valve, as long as it is replaced by a valve with a large difference in structure, immediately works, and the strong resonance disappears miraculously. For example, if a new DN200 sleeve valve is used in the new expansion project of a Vinylon plant, the above three phenomena exist. The DN300 pipe will jump, the valve plug will rotate, the noise will be more than 100 decibels, and the resonance opening will be 20-70%. When the degree is large, after switching to a double seat valve, the resonance disappears and the operation is normal.
7) Reduce cavitation vibration method
For cavitation vibrations caused by cavitation bubble collapse, it is natural to find ways to reduce cavitation.
1 The impact energy generated by the rupture of the bubble does not act on the solid surface, especially on the valve core, but allows the liquid to absorb. The sleeve valve has this feature, so the plug type spool can be changed to a sleeve type.
2 Take all measures to reduce cavitation, such as increasing throttling resistance, increasing the pressure at the contraction port, decompression in series or series.
8) Avoid the source wave strike method
The external source vibration causes the valve to vibrate, which is obviously avoided when the regulating valve works normally. If such vibration occurs, corresponding measures should be taken.
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