Best Practices for Valve Greasing and Maintenance

Greasing is a critical part of valve maintenance. Proper control of the amount of grease, greasing pressure, and switch position is essential to ensure the valve operates normally and lasts longer. This article covers key points in the greasing process, including the correct greasing amount, pressure, switch position, and the effectiveness of the greasing. It also provides best practices for proper valve maintenance.

Control of Greasing Amount

Controlling the right amount of grease is a basic part of valve maintenance. Too much or too little grease can negatively affect the valve's performance and may cause damage.

1. Proper Calculation of Greasing Amount

Operators should calculate the appropriate grease amount based on the valve model, size, and sealing capacity. If there is too little grease, the sealing surfaces will not be lubricated properly, causing wear. If there is too much grease, it may block the grease injection port or waste grease. It is important to calculate the correct amount before starting the greasing process.

2. Sealing Capacity Calculation

Sealing capacity refers to the amount of grease needed for the valve's sealing surfaces. By understanding the valve type and sealing system, operators can estimate the optimal grease amount. Correct greasing ensures proper lubrication and prevents premature wear or insufficient lubrication.

Control of Greasing Pressure

Greasing pressure is crucial for effective lubrication. Pressure fluctuations during greasing can affect lubrication quality. Operators must monitor the pressure in real time and keep it within the optimal range.

1. Effects of Low Greasing Pressure

If the greasing pressure is too low, the grease may not enter the valve's sealing surfaces correctly. This can lead to dry friction, wear, and poor sealing performance.

2. Risks of High Greasing Pressure

Excessively high pressure can block the grease injection port or cause the grease to harden too quickly. This can cause the sealing ring to get stuck, affecting the valve's ability to switch. Operators should use pressure control devices to maintain a safe pressure range.

3. Monitoring Pressure Peaks and Valleys

During the greasing process, pressure will often fluctuate in periodic peaks and valleys. Operators should adjust the pressure to avoid excessively high peaks or low valleys to ensure smooth greasing.

Selection of Valve Switch Position

Different valves require different switch positions during greasing to ensure proper grease distribution to the sealing surfaces.

1. Ball Valve Switch Position

For ball valves, the valve should generally be in the open position during maintenance. This allows the grease to spread evenly between the valve ball and seat. In some cases, the valve may be closed for maintenance.

2. Gate Valve Switch Position

Gate valves should be in the closed position during greasing. This allows the grease to fill the sealing groove around the ring without flowing into the flow path or valve cavity, avoiding waste.

Checking Greasing Effectiveness

After greasing, simply calculating the amount and pressure is not enough to guarantee effective lubrication. The greasing effect should be verified through actual operation.

1. Checking Lubrication Uniformity

After greasing, operators should open and close the valve to check if the grease is evenly distributed on the valve ball or disc. Even grease distribution reduces valve wear and ensures smooth operation.

2. Valve Operability Test

Even if the amount, pressure, and switch position are correct, it is important to test the valve's operation. For example, checking whether the valve opens and closes smoothly without jamming will help determine if the lubrication is sufficient.

Draining and Pressure Relief Before Greasing

Preparing the valve before greasing is critical, especially after a pressure test. Internal gases or moisture may affect the greasing process if not removed properly.

1. Draining and Pressure Relief

After a pressure test, gases and moisture inside the valve can increase pressure due to temperature changes. Operators must drain the valve and relieve the pressure to ensure that no residual gases or moisture remain in the sealing or valve chambers. This ensures smooth greasing.

2. Safety Assurance

After draining and relieving pressure, the greasing process will not be affected by gases or moisture. This prevents uneven pressure or blockages, enhancing safety during valve operation.

Grease Port Inspection and Cleaning

Inspecting the grease port is crucial to ensure proper lubrication.

1. Grease Port Sequence

During normal greasing, operators should begin greasing from the port closest to the grease inlet and then move to the lower and higher points. If the grease port sequence is incorrect or grease is not flowing, there may be a blockage in the grease pipeline.

2. Cleaning and Maintenance

If the grease port is clogged, operators must clean it immediately. After cleaning, they should check the greasing effect again to ensure proper grease distribution to the valve's sealing surfaces.

Closing and Anti-Rust Treatment After Greasing

After greasing, it is important to close the grease port to prevent contaminants from entering and to avoid grease oxidation in the air.

Sealing the Grease Port: Operators should seal the grease port promptly to prevent external impurities from entering and affecting lubrication. Anti-rust grease should be applied to the cap to avoid rust and ensure smooth operation during the next greasing session.

Use of Anti-Rust Grease: Anti-rust grease protects the grease port from rust, making future lubrication easier and more effective.

Special Greasing Requirements for Different Lubricants

Certain lubricants, especially chemically active ones like gasoline, may require specific greasing conditions. For gasoline-related work, more frequent greasing is needed due to its low lubricity and high volatility. Operators should ensure that grease is applied in time to prevent wear from insufficient lubrication.

Greasing the Valve Stem

The valve stem area is often overlooked, but it is important to lubricate it properly for smooth valve operation.The sliding sleeve or packing on the valve stem should be well-lubricated to reduce friction during operation. Insufficient lubrication will increase torque during electric operation and cause more wear. Manual operation will also become harder.

Importance of Regular Lubrication

Regular lubrication is essential for stable, long-term valve operation. Regular greasing ensures that the valve's sealing surfaces stay in good condition and prevents seal failure or wear from dry friction. The primary functions of valve lubricants are to protect internal surfaces from corrosion, reduce leakage for better sealing, and ensure smooth valve operation.

Conclusion

Greasing valves is more than just adding lubricant; it is a crucial maintenance task to ensure the valve performs well and lasts longer. By controlling the greasing amount, pressure, and switch position, and by performing effective checks after greasing, operators can ensure that valves operate reliably under heavy loads. Regular maintenance and accurate greasing reduce valve wear, improve operational efficiency, and increase the safety and stability of industrial systems.