Manual ball valve is a widely used equipment for pipeline control. It exhibits diverse operating characteristics under different media. With its compact structure, rapid opening and closing, and excellent sealing performance, manual ball valves are widely used in various working conditions such as liquid, gas, steam, corrosive media and media containing solid particles. Under different media conditions, the operating requirements, maintenance methods and technical adaptability of manual ball valves are different, forming a rich operating characteristics.
In the application of clean liquid media, the operation of manual ball valves is relatively simple. Due to the low viscosity and low impurity content of the fluid, it is not easy to accumulate dirt or wear inside the valve body, the rotation resistance of the handle is small, and the opening and closing process is smooth. Such working conditions have high requirements for the sealing performance of the valve, but relatively low requirements for wear resistance. In daily use, regular inspection of the integrity of the seal and the flexibility of the handle can ensure the good operation of the valve, which is suitable for pipeline systems of clean liquids such as water supply, urban pipe networks, and food and beverages.
When handling high-viscosity liquids such as crude oil, asphalt or syrup, the operating torque of the manual ball valve increases significantly. This is because the viscous medium forms a strong fluid resistance around the valve core, and it is easy to cause adhesion between the ball and the valve seat, which makes the opening and closing action slow or even stuck. Such applications require the use of large diameter, wear-resistant balls and enhanced sealing structures. It is recommended to preheat before operation, or use a ball valve with a sewage discharge structure to prevent medium deposition from causing difficulties in opening and closing. Operators need to apply force slowly and evenly during operation to avoid forced switching to avoid damage to the sealing pair or valve stem transmission mechanism.
In gas medium applications, such as compressed air, natural gas and hydrogen, the sealing requirements of manual ball valves are more stringent. Since gas molecules are small and highly fluid, any small leakage may cause energy loss or even cause safety accidents. Therefore, during operation, special attention should be paid to the sealing confirmation after the valve is opened and closed, and the handle should be in the correct position and locked to prevent misoperation. In some high-pressure gas systems, a valve stem with a blow-out prevention structure design should be selected to prevent the valve stem from being pushed out due to internal pressure impact. In addition, gas media have high requirements for the stability of operation. Rapid opening and closing should be avoided during operation to avoid pressure fluctuations and affect the stable operation of the pipeline system.
Under the working conditions of steam media, manual ball valves need to adapt to high temperature and high pressure environments, so necessary anti-scalding measures must be taken during operation. The heat transfer speed of steam is extremely fast, and the metal temperature of the valve body will rise rapidly. Operators need to wear high temperature gloves when opening and closing the valve, and make sure that the valve has cooled to a safe temperature before contacting it. In a high temperature environment, the sealing material is prone to aging. It is recommended to regularly check and replace the valve seat and packing to ensure the sealing reliability of long-term use. The operation should be carried out slowly to avoid sudden opening to cause steam to impact downstream equipment or cause water hammer effect.
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