On-line cleaning device and method for ball valve overhauling seal

Abstract

The invention discloses an on-line cleaning method for a ball valve overhauling seal in a range of overhauling and maintenance of power plant equipment. The method comprises the following steps of: selecting an on-line cleaning device, a cleaning agent and cleaning processes, withdrawing the ball valve overhauling seal, flushing with tap water, washing with acid, flushing with tap water after the acid washing, adding an alkali solvent for neutralization, flushing with tap water, performing surface passivation and flushing with tap water; and checking the cleaning effect. Nitric acid is used as a main cleaning agent and has strong capability of dissolving water scales, ferric oxide and rust scales and high reaction rate, and the reacted waste water is easily treated; and by cleaning the water scales of the throwing and withdrawing cavities of the ball valve overhauling seal, the service life of a ball valve sealing ring can be prolonged, the ball valve overhauling period is prolonged, the water leakage of a unit in a halting state is effectively reduced, the running safety and the running stability of the unit are improved, and the economic running capability of the unit is improved.

Description

technical field [0001] The invention belongs to the scope of repair and maintenance of power plant equipment, and in particular relates to an on-line cleaning device and method for ball valve repair and sealing. Background technique [0002] As the front valve of the high head pumped storage power plant unit, the ball valve is installed on the upstream side of the inlet of the turbine volute. It has the characteristics of tight closure, small hydraulic loss and small water leakage. The ball valve plays an important role in the pumped storage power plant. When the unit and the speed control system fail, the ball valve can be closed urgently in the moving water to cut off the water flow, prevent the unit from exceeding the allowable flight time, and avoid the expansion of the accident; its safe and reliable The work not only determines the economy and safety of the operation of the power plant unit, but also determines the safety of the entire underground plant of the pumped s...

AI Technical Summary

Problems solved by technology

[0004] During the actual maintenance process, it was found that the pressure difference in the throwing and withdrawing chamber 9 did not reach the rated value, resulting in the maintenance of the upstream seal ring 2 and the maintenance of the downstream seal ring 3. There is a large amount of scale in the ball valve inspection seal throwing and retreating cavity 9, which reduces the gap between the inner and outer bushings of the valve body 1 and the valve core 4, and increases the action resistance of the sliding ring 5, thus causing the ball valve to repair the sealing throwing and retreating position. If it is not in place, the pressure difference in the ball valve maintenance sealing throwing and withdrawing chamber 9 will decrease (such as figure 1 b. figure 1 As shown in c), the maintenance seal cannot be reliably put in and out, the closure is not strict, and the leakage of the maintenance seal is quite large, resulting in the volute manhole door cannot be opened, and the maintenance work cannot be entered into the volute and draft tube during the maintenance period, which affects the turbine. Professional normal maintenance and safe operation of the unit may even cause wear and tear of the ball valve maintenance seal packing of the unit, shorten the service life of the ball valve maintenance seal, and replace the ball valve maintenance seal

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