Causes of Valve Leakage and Its Preventive Measures (Part Four)

2.4 Pay attention to the flow direction of valve medium to prevent valve failure.
For valves like globe valve, throttle valve, pressure reducing valve and check valve, the medium has a certain flow direction, and all these valves will have permanent flow direction marks on the valve body. Such as throttle valve, installation backwards and inversion will affect the using effect and service life. If the pressure reducing valve is installed upside down, it will have no effect at all. For check valves, installing them upside down will cause serious danger. According to the requirements of relevant standards, all valves shall have direction signs on the valve body. If not, it should be correctly identified according to the basic principle of the valve.

2.5 Install the valve correctly to prolong the service life of the valve.
For high-temperature valves, because they are installed at normal temperature, and after normal use, the gap will increase as the temperature is going up, so they must be tightened again, otherwise leakage will easily occur. When the valve is put into use, the packing should not be pressed too tightly, so as not to leak to avoid excessive pressure on the valve stem, which accelerates wear and difficulty in opening and closing. The gate valve cannot be inverted, that is, the handwheel is downward, otherwise the medium will remain in the valve cover for a long time, which will easily corrode the valve stem. Meanwhile, it is extremely inconvenient for the operator to replace the packing. When installing the valve, avoid strong impact of gravity on the valve. Before installation, check the valve, the specifications and models, and check whether there is any damage, especially the valve stem. It is necessary to turn it several times to see if there is any skew phenomenon, because the valve stem is easy to cause damage during transportation. During installation, iron oxide chips, mud sand, welding slag and other sundries shall be blown off with compressed air, so as not to scratch the sealing surface of the valve, or even block the valve with smaller size, thus making the valve invalid.

3. Concluding remarks
To sum up, after analyzing the causes of valve leakage, relevant units should strengthen the implementation of valve leakage prevention measures. Assure that strict quality control and detailed understanding of the user's media information are achieved, so that the valve enterprise can adjust the design of the valve in time according to the user's media information, which is conducive to the quality of the valve. Before use, the quality of valves shall be strictly checked and strictly implemented according to the installation and using regulations. Pressure test shall be carried out first, and any problems found shall replace the valve in time. Strengthen the daily management of valves, establish a perfect daily inspection system of valves, operate and maintain valves in strict accordance with regulations, and conduct regular inspections to ensure good performance of valves, prolonging their service life, preventing valve leakage and nipping it in the bud.