Operation Guidelines to Manual Valve for Industrial Pipeline Safety

 
In industrial pipeline systems, the correct operation of manual valves is a crucial link to ensuring the overall safety and reliability of the system. The operation of manual valves not only directly affects the safety and stability of the pipeline system but also has significant impacts on energy conservation and cost reduction. However, in actual operation, many people may overlook some details, which could potentially lead to major accidents or increase system maintenance costs. Therefore, understanding and strictly adhering to the key considerations in manual valve operation are essential. Below are some key points that must be noted.
 

1. Impact of Temperature Changes on Valve Sealing

 
After the valve is closed, temperature changes can cause thermal expansion and contraction of the valve components, possibly leading to minor leaks in the sealing surface. Therefore, it is necessary to wait for the temperature to stabilize and then properly tighten the valve to ensure its sealing effectiveness. Especially under high temperature and pressure conditions, sealing issues could potentially trigger serious safety accidents, making this step crucial.
 

2. Proper Closure of Gate Valves and Globe Valves

 
When closing gate valves and globe valves to their dead points, over-tightening could damage the valve components. Properly rotating the valve 1/4 to 1/2 turns to ensure thread engagement is a critical step in preventing valve damage. Particularly in high-pressure pipelines, valve damage could result in leaks, causing irreparable losses.
 

3. Avoiding Excessive Force Damaging Valves

 
Valves are designed with consideration for the force required for manual operation. Therefore, excessive force beyond the design range should not be applied when manually operating valves, and the use of levers or wrenches for assistance should be avoided. Excessive force may damage sealing surfaces and other components, leading to valve failure, thus affecting the normal operation of the pipeline system. Moreover, the cost and time required for valve maintenance would also increase.
 

4. Slow Opening of Steam Valves

 
When opening steam valves, it should be done slowly to allow condensate in the pipeline to be discharged, avoiding the occurrence of water hammer. This not only protects valves and pipelines from damage but also prevents pipeline vibrations and noise caused by water hammer, thus improving the stability and safety of the pipeline system.
 

5. Correct Valve Opening and Closing Direction

 
Understanding the opening direction of valves is crucial. Typically, counterclockwise rotation indicates opening, while clockwise rotation indicates closing. Confusion in direction could lead to incorrect operations or even valve damage. In emergency situations, incorrect operations could result in serious accidents.
 

6. Special Operating Requirements for Large Diameter Valves

 
For large-diameter gate valves, globe valves, and butterfly valves with bypass valves, the bypass valve should be opened first to balance the pressure and reduce opening force. Similarly, when closing, the bypass valve should be closed first before gradually closing the main valve. These special operating requirements can effectively reduce valve damage and ensure the stable operation of the pipeline system. In large pipeline systems, valve damage could lead to system shutdown, causing production interruptions and economic losses.
 
In conclusion, although the operation of manual valves is fundamental, it is crucial for the safe operation of the entire pipeline system. Operators must strictly adhere to operating procedures to ensure valves work properly and avoid unnecessary safety hazards. Through strict operating standards and meticulous maintenance, the service life of valves can be significantly extended, ensuring the efficient and stable operation of the pipeline system.