2. When cables are laid, they often need to cross roads, bridges, and culverts. Due to the weather or other reasons, a lot of water often accumulates in cable trenches. In the laying process, it is inevitable that cable heads will be immersed in water. The water enters the cable due to loose or damaged plastic wrap; in addition, the external sheath and even the steel file are sometimes scratched when pulling and piping. This phenomenon is particularly prominent when mechanical traction is used.
3. After the cable laying was completed, the cable head was not manufactured in time because of the on-site construction conditions, so that the unsealed cable fractures were exposed to the air for a long period of time or even immersed in water, causing a large amount of moisture to enter the cable.
4. During the manufacture of the cable head (including the terminal head and the intermediate connector), due to negligence of the construction personnel, the newly processed cable tip may accidentally fall into the standing water.
5 The water in the cable trench will enter the interior of the cable along the fault point; in the civil construction, especially in the construction site where the large-scale construction machinery is used, the cable breakage or breakdown accident caused by various human factors is also common. . When such an accident occurs, the cable insulation is severely damaged and the cable can also cause water ingress.
Valves are found in virtually every industrial process, including water and sewage processing, mining, power generation, processing of oil, gas and petroleum, food manufacturing, chemical and plastic manufacturing and many other fields.
People in developed nations use valves in their daily lives, including plumbing valves, such as taps for tap water, gas control valves on cookers, small valves fitted to washing machines and dishwashers, safety devices fitted to hot water systems, and poppet valves in car engines.
In nature there are valves, for example one-way valves in veins controlling the blood circulation, and heart valves controlling the flow of blood in the chambers of the heart and maintaining the correct pumping action.
Valves may be operated manually, either by a handle, lever, pedal or wheel. Valves may also be automatic, driven by changes in pressure, temperature, or flow. These changes may act upon a diaphragm or a piston which in turn activates the valve, examples of this type of valve found commonly are safety valves fitted to hot water systems or boilers.
More complex control systems using valves requiring automatic control based on an external input (i.e., regulating flow through a pipe to a changing set point) require an actuator. An actuator will stroke the valve depending on its input and set-up, allowing the valve to be positioned accurately, and allowing control over a variety of requirements.
Stop Valves, Ball Cock, Angle Valves, Gate Valves, Check Valves
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