Valve in the use of the process, even in the shelf life even extend a few years will not be a problem, but sometimes the valve bonnet will also encounter external damage. When the damage occurred, Shanghai Huagang valve factory suggested to ensure the normal use of valves and re purchase new products. In general, the valve with low price is repurchased directly, and the relative high price valve, if it is not willing to purchase new products, can be repaired when the valve is not used.
Valve cover is basically two types of repair: large force, more important part of the general use of welding; the role is not good, the temperature of the parts can be used glue.
When removing the valve bonnet, pay attention to the wear of the threaded bolts. Mistake and other cases. Once this happens, the screw hole can be expanded to weld the alloy material and then to attack the thread; or the screw hole is expanded directly after the screw hole is enlarged, and the bolt should choose a large and small structure.
When the bolts are rusty and impossible to spin out, they can be soaked in kerosene and soaked for a while before they are screwed. If not, the oxygen acetylene flame can be roasted to 200~300 degrees, then spin out. Please pay attention to prevent contact and burn at high temperature. If not, then directly shave the bolt head and then drill away the remnant.
For bolts breaking, drill bits can be used to drill away the remnants, and the L type material can be used as a spanner.
Of course, once the bonnet is unrepairable, it is recommended that the steel plate be used as a bonnet when there is an emergency and when it is necessary to repair.
One kind is that once the discharge hole in the bottom of the valve is leaked, the polytetrafluoroethylene can be filled in the thread of the plug, and the top surface of the plug can be made into spherical surface.
The above process is dangerous. Please be operated by people with relevant skills. In addition, after the repair is completed, it is also necessary to carry out the test and trial operation before putting it into formal use, so as to ensure the normal use of the valve.