4) increasing savings gap law
Such as media or channels of the solid particles were washed away with welding slag and rust from, etc. I had not resulted in savings to plug, stuck faults, etc., would be able to reduce expenditure the expenditure of large pieces of space - an area of open cutting windows, open category of the spool, sleeve, because of their focus on reducing expenditure rather than the circumference area of distribution, fault can easily be excluded. If it is a single, two-seater shaped plunger valve spool can be replaced by "V"-shaped mouth of the spool, or into a sleeve valve. For example, a chemical plant have a regular two-seater stuck valve is recommended to use the sleeve valve, the problem to be resolved immediately. 5) medium washed Law
Washed their own use of medium energy, erosion and sediment away easily, easy to plug things in, so as to enhance the anti-function valve. Common methods are: ① flow into the use of closed type; ② using streamlined body; ③ raise the most serious erosion at the mouth, the use of this method to pay attention to enhancing cutting erosion resistant material capacity.
6) through angular law changed
For reversing the flow through S, the complex flow path, the upper and lower dead-capacity multi-cavity, in order to provide a medium where the precipitation. Angular connections like streaming media bend over 90 ℃, washed performance and small die area, designed to streamline easy. Therefore, through the use of the regulating valve can produce a small plug into the use of angular valve. Third, control valve solution leakage (6 methods)
1) increase in seal oil law
Of unused oil seal valve, may consider increasing the number of seal oil to improve the performance of stem seal.
2) increase the packing method
To enhance the packing of the stem of the sealing performance, can increase the packing method. Usually double-, multi-storey mixed-fill the form of a simple increase in quantity, such as the 3 by 5, the effect is not obvious.
3) the replacement of graphite packing method
Large-scale use of PTFE packing, its working temperature range of -20 ~ +200 ℃, the temperature at the maximum and minimum levels, changes in the larger, the seal will be decreased, aging fast, short life expectancy. Flexible graphite packing can overcome these shortcomings and long service life. Some of the factory and therefore all will be replaced by PTFE packing graphite packing, and even buy back the new valve will also be replaced by one of the PTFE packing graphite packing before use. However, the use of graphite packing back to the poor, and early reptiles have also produced the phenomenon, which must be considered.
4) change the flow in the stem-end home P2 Law
When △ P large, P1 and large, sealed sealed P2 than P1 difficulties. Therefore, the flow can be taken to change the method to replace P1 in P2 stem in the stem-end side, which is the pressure of high pressure valve is larger than effective. Such as bellows valves should be considered on the usually sealed P2. 5) sealing method using lens pad
For the upper and lower sealing cap, valve seats and the upper and lower valve sealing. If flat sealed under high temperature and pressure, poor seal, causing leakage, you can switch to pad sealed lens, can be satisfied with the results.
6) the replacement gasket
So far, most are still using gasket石棉板, at a high temperature, poor sealing performance, short life expectancy, caused by leakage. In such cases, would be able to spiral wound gasket, "O"-ring and so on, many plants have been taken.
Fourth, control valve solution Vibration (8 methods)
1) increase the stiffness method
And a slight vibration of the oscillation can be increased to eliminate or reduce stiffness, such as large selection of spring stiffness in favor of implementing agencies such as the piston approaches are feasible.
2) an increase in damping method
Increase the damping to increase the friction of the vibration, such as the valve plug valve sleeve may be "O"-ring seal, the greater the friction, such as graphite filler, which is to eliminate or reduce the vibration of a minor or have a certain role.
3) increasing the size-oriented, reducing the gap with the law
Cypriot valve axis oriented generally have a smaller size, all-valve clearance is generally greater, and 0.4 ~ lmm, which have a mechanical vibration is helpful. Therefore, in the event of minor mechanical vibration may be driven by increasing size, with the gap reduced to weaken the vibration.
4) changes in the shape of expenditure items, the elimination of resonance method
Due to the so-called local oscillator valve occurred in the high-speed flows, the pressure of the dramatic changes in the expenditure of the mouth, cutting pieces of the shape change can change the local oscillator frequency, the resonance is not strong compared to easy to solve. The specific method is to open in the vibration range surface turning spool 0.5 ~ 1.0mm. Family members such as a factory installed near a self-pressure regulating valve, due to resonance effects of workers啸喊have rest, we will spool out 0.5mm surface vehicles, the resonance disappeared Xiao call. 5) the replacement of cutting pieces of the elimination of resonance method
Its methods are: ① the flow characteristics of the replacement of several linear change, linear change of a few; ② the form of replacement spool. If the shaft-shaped plug replaced by "V"-shaped groove spool, the valve seat into a sleeve-type plug-axis type; the sleeve will be re-opened window of the sleeve, such as playing holes. Such as a nitrogen fertilizer plant a two-seater DN25 valve stem and valve core junction off the regular vibration, we have identified as the resonance will be replaced by a straight line on a number of characteristics of spool valve core, the problem is resolved. Another example of a laboratory Aviation Institute DN200 with a sleeve valve, rotary valve plug can have a strong cast, and will be re-opened a window to fight the sleeve of the sleeve hole, the rotation immediately disappear.
6) the type of replacement valve to eliminate the resonance.
Different structural forms of control valve, and its inherent natural frequency of different types of valve replacement is the elimination of a fundamental resonance of the most effective way. A valve in use is very powerful resonance vibration strongly --- (may be severe valve damage), strong rotation (or vibration stem was broken, broken), and have a strong noise (up to more than 100 db) the valve, as long as it replaced a different valve structure, effective immediately, a strong resonance disappeared miraculously. If a new plant expansion project vinylon choose a DN200 valve sleeve, the existence of these three phenomena, DN300 pipeline subsequent beating, valve plug rotation, more than 100 db of noise, resonance opening 20 ~ 70%, taking into resonance opening, and switch to a valve seat, the resonance disappeared, put into operation in the normal.
7) to reduce vibration cavitation
Cavitation bubble due to the breakdown of the vibration cavitation generated naturally reduce cavitation in the think of a way. ① so the impact of the breakdown bubble is not the role of energy in the solid surface, especially on the spool, but allow the liquid to absorb. Sleeve valve with this feature on, so you can plug-type valve core shaft into the sleeve-type. ② take to reduce all the way to cavitation, such as the increase in cutting resistance, increasing population pressure on flow reduction, decompression, such as classification or series.
8) Act to avoid blow-wave local oscillator
External local oscillator valve vibration caused by wave attack, which is obviously normal valve should work to avoid, if such a vibration, corresponding measures should be taken seven or regulating valve noise solution (8 methods)
1) the elimination of resonance noise law
Resonance only when the control valve, only energy generated superposition of the strong over 100 db of noise. Some strong performance for the vibration, noise is not, and some weak vibration, and noise is very large; some vibration and noise are larger. This noise produces a tone of voice transfer, and its frequency is generally 3000 ~ 7000 Hz. Clearly, the elimination of resonance, the noise will disappear naturally. See, for example, methods and more than 4.5 of 4), 5), 6).
2) the elimination of cavitation noise law
Cavitation is a major source of fluid dynamic noise. Cavitation, the bubble rupture have high-speed impact to the local produce strong turbulence, cavitation noise generated. This noise has a wide frequency range, resulting in voice chattered, and the fluid contains sand and gravel similar to the sound. Elimination of cavitation and reduces the elimination and effective way to reduce the noise.
3) the use of thick-walled pipe method
The use of thick-walled tube is a sound way to deal with one of the ways. Will enable the use of thin-walled noise increase of 5 decibels, the noise allows the use of thick-walled tubes reduce the 0 ~ 20 dB. The thicker wall of the same diameter, the same wall thickness of greater diameter, the better the effect of reducing noise. If DN200 pipeline, the 6.25,6.75,8,10,12.5,15,18,20,21.5 mm wall thickness, respectively, can reduce the noise, respectively -3.5, -2 (ie, increase), 0,3,6, 8,11,13,14.5 dB. Of course, the more thick-walled by the higher cost. 8, control valve solution Vibration (8 methods)
1) increase the stiffness method
And a slight vibration of the oscillation can be increased to eliminate or reduce stiffness, such as large selection of spring stiffness in favor of implementing agencies such as the piston approaches are feasible.
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