Treatment of fire failure of regulating valve in chemical enterprise

Valve leakage: Under the normal working pressure of the equipment, leakage exceeding the allowable level occurs at the sealing surface of the valve disc and the valve seat, and the leakage of the regulating valve will not only cause the loss of the medium. In addition, the continuous leakage of the medium will also damage the hard sealing material. However, the sealing surface of the commonly used regulating valve is a metal material to a metal material. It is also very difficult to make sure that it does not leak. Therefore, for the regulating valve of the flammable or flammable medium of the mechanical seal, under the specified pressure value, if the professional inspection tool is used for inspection, if it reaches the specified size, the sealing function can be qualified. There are three main reasons for valve leakage:

First, the sundries fall on the sealing surface, pad the sealing surface, form a gap between the valve core and the valve seat, and then the valve leaks. The way to eliminate this problem is to remove the sundries falling on the sealing surface. Usually, when the mechanical seal of the pressure vessel is ready for size repair, the first step is to do the pressure vessel safety door running test. When the mechanical shaft seal leaks, stop the pressure. Vessel work and valve maintenance, flushing of sealing surfaces.

The second is damage to the sealing surface. The main reasons for the damage to the sealing surface are as follows: First, the raw material of the sealing surface is poor. Due to many years of use, the sealing surface of the valve core and the valve seat has been developed very low, so that the hardness of the sealing surface is also greatly reduced, and then the sealing performance is reduced. The best way to eliminate this phenomenon is to seal the original seal. The surface is turned, and then re-surfacing according to the requirements of the drawings to improve the surface hardness of the sealing surface. Note that the processing quality must be ensured during the processing, such as cracks, trachoma and other defects on the sealing surface, which must be turned and processed from scratch. The newly machined valve core valve seat must meet the drawing requirements.

Second, the quality of maintenance is poor, and the grinding of the valve core and valve seat cannot meet the quality requirements. The way to eliminate this problem is to use grinding or grinding after turning to correct the sealing surface or re-install a new regulating valve according to the degree of damage.

Third, another reason for the leakage of the regulating valve is due to improper installation or improper size of related parts. During the installation process, the valve core and valve seat are not completely aligned or the joint surface has a transparent appearance, or the sealing surface of the valve core valve seat is too wide, which is not conducive to sealing. The solution is to check the size and uniformity of the cooperative gap around the valve core, ensure that the top hole of the valve core and the sealing surface are the same degree, check that the gaps in each part are not allowed to lift the valve core, and appropriately reduce the width of the sealing surface according to the requirements of the drawings to achieve effective sealing. . Fourth, the valve core and valve seat are deformed and leaked. The main reason for the leakage of the valve core and valve seat is that the forging or forging defects in the production process of the regulating valve can lead to the enhancement of corrosion. The passage of the corrosive medium and the flushing of the fluid medium can also form the leakage of the regulating valve. Corrosion mainly exists in the form of corrosion or cavitation. When the corrosive medium passes through the regulating valve, corrosion and impact on the valve core and valve seat material will occur, making the valve core and valve seat oval or other shapes. With the passage of time, the valve core and valve seat are not matched, there is a gap, and the leakage is caused by the lax closure. The key to the solution is to control the selection and quality of raw materials such as valve core and valve seat. Choose corrosion-resistant materials, and resolutely remove products with defects such as pitting and trachoma. If the valve core and valve seat are not seriously deformed, they can be ground with fine sandpaper to eliminate marks and improve sealing brightness to improve sealing performance. If the damage is severe, the valve should be replaced with a new one.