Causes and prevention of the failure of the hottes

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Causes and prevention of valve stem lifting failure

causes of valve stem lifting failure:

① excessive operation causes thread damage

② lack of lubrication or lubricant failure

③ valve rod bending and twisting

④ insufficient surface finish

⑤ the fitting tolerance is inaccurate and the bite is too tight

⑥ the valve rod nut is inclined

⑦ material selection in the future, the company will rely on its experience in upstream and downstream development and integration, production and operation management and equity investment in the fine water treatment industry. For example, the valve rod and valve rod nut are made of the same material, which is easy to bite

⑧ the thread is corroded by the medium (refers to the Non rising stem valve or the valve with the stem nut at the lower part)

⑨ the open-air valve is lack of protection, and the valve rod thread is covered with dust and sand, or corroded by rain, dew, frost and snow

prevention methods:

① operate carefully, do not use force when closing, and do not reach the top dead center when opening, Turn the handwheel back oneortwo turns after opening enough. The production testing machine has high fire resistance to hydrocarbon fires (the coating thickness is 2.27mm for more than 10 years, which makes the upper side of the thread close and avoids the upward impact of the valve stem driven by the medium;

② regularly check the lubrication and maintain the normal lubrication state;

③ do not use a long lever to open and close the valve, and workers who are used to using a short lever should strictly control the use of force to prevent twisting the valve stem (refers to the valve with handwheel and valve stem but directly connected)

④ improve the processing or repair quality to meet the specification requirements

⑤ the material should be corrosion-resistant and adapt to the working temperature and other working conditions

⑥ the valve rod nut should not be made of the same material as the valve rod

⑦ when plastic is used as the valve stem nut, the strength should be checked, not only considering good corrosion resistance and small friction coefficient, but also considering the strength. If the strength is not enough, do not use it

⑧ outdoor valves should be equipped with valve stem protective sleeve

⑨ when the valve is normally open, the hand wheel should be turned regularly to prevent the valve rod from rusting

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