Maintenance methods for flanged ball valves

Flanged ball valves, as crucial control components in industrial piping systems, are widely used in industries such as petroleum, chemical, power, papermaking, food, pharmaceuticals, and water treatment. With advantages such as excellent sealing, rapid opening and closing, compact structure, and low fluid resistance, they play an irreplaceable role in fluid control.

Depending on their actuation method, flanged ball valves can be categorized into three common types: stainless steel pneumatic ball valves, stainless steel electric ball valves, and stainless steel manual ball valves. In actual use, flanged ball valves are prone to contact with other ferrous metal components. If not properly protected and maintained, they are prone to corrosion, reduced sealing performance, and difficulty opening and closing, impacting the efficiency and safety of the entire system.

To ensure the long-term, stable operation of flanged ball valves and extend their service life, routine maintenance and care are essential. The following details flanged ball valve maintenance methods:

I. Maintenance Before Manufacturing and Delivery
1. Post-Acid Cleaning
Flanged ball valve bodies are typically pickled after machining to remove surface scale and impurities. However, if the pickling process is not thoroughly rinsed, residual acid can easily cause corrosion. Therefore:

After pickling, rinse thoroughly with plenty of clean water.

If casting defects such as sand holes or perforations are found, repair them using gas shielded argon arc welding.

After welding repairs, the repaired areas should be polished smooth and solution treated to relieve stress and restore the material's corrosion resistance.

2. Rust Prevention
After forming and pressure testing, flanged ball valves require cleaning and rust prevention:

Rinse the interior of the ball valve thoroughly with clean water containing rust prevention powder.

Ensure that no moisture remains inside or outside the valve body during transportation or storage to prevent rust.

Apply anti-corrosion grease to key areas such as flange end faces and sealing rings.

II. Routine Maintenance After Installation
Although flanged ball valves have a certain degree of corrosion resistance and sealing performance after operation, they still require regular inspection and maintenance, primarily in the following areas:

1. Lubrication and Maintenance
The valve stem is the key connection between the actuator and the valve core. Long-term operation may cause dryness, sticking, or seal degradation:

Regularly lubricate the valve stem, especially in high-temperature and high-frequency operating environments.

It is recommended to lubricate the rotating parts of the valve stem at least quarterly.

2. Regular Opening and Closing
Even spare valves should be opened and closed regularly to prevent seal adhesion, rust, and seizure caused by prolonged non-operation.

It is recommended to open and close the valve once a month to ensure that the contact surface between the ball and the seal remains flexible.

The opening and closing action can also promptly detect potential problems such as leaks and malfunctions.

3. Internal Cleaning
During transportation or at the construction site, flanged ball valves may be infiltrated with dust, foreign matter, or welding slag, affecting sealing and flow performance.

The valve should be thoroughly cleaned before installation.

During use, if abnormal flow resistance or difficulty opening and closing is observed, the internal structure should be disassembled and cleaned.

4. Seal Inspection and Replacement
Seals are critical components that affect ball valve performance. After extended use, they may age, harden, or deform.

Regularly inspect the wear of components such as the seat ring and packing.

If leakage is detected, replace the corresponding parts promptly.

III. Transportation and Storage Precautions
Even the highest-quality stainless steel ball valves can suffer surface scratches, rust, or even internal damage if improperly handled during transportation and storage. Therefore, proper pre-installation care is crucial:

Flanged ball valves should be packed in wooden crates upon shipment to prevent contact with iron tools or other hard objects during transportation.

Store in a dry, well-ventilated environment to avoid moisture and corrosive gases.

Flanged ports should be sealed and protected to prevent foreign matter from entering the valve body.

IV. Fluid Characteristics and Selection Considerations
In practical applications, flanged ball valves primarily come in two configurations: reduced-bore and full-bore. Regardless of type, they share the following characteristics:

Low flow resistance coefficient, especially for full-bore ball valves, whose inner diameter matches the pipe, allowing fluid to flow virtually unimpeded;

Local resistance loss is significantly lower than that of traditional valves such as gate and globe valves;

They are more suitable for piping systems requiring high flow and low resistance.

When selecting a ball valve, the appropriate type and material should be selected based on factors such as the media characteristics, pipe pressure, and operating frequency.

V. Summary
Although flanged ball valves offer a simple structure and ease of use, problems such as sticking, leakage, and corrosion can still occur if routine maintenance is neglected. Scientific maintenance methods can not only maintain excellent sealing performance and operating efficiency, but also effectively extend their service life and reduce repair costs.

When operating and using flanged ball valves, it is imperative to adhere to the above maintenance specifications and attend to every detail with the correct approach. This is not only a responsibility to the equipment but also ensures the safe operation of the system.
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