Essential Practices for Greasing Forged Steel Valves

In the maintenance of industrial equipment, the greasing of forged steel valves, though often overlooked, is a crucial step to ensure the normal operation and extend the service life of the valves. Lubrication of the valves not only reduces wear but also enhances operational efficiency and decreases the likelihood of malfunctions. However, several details involved in the greasing process—such as the amount of grease, pressure control, switch positions, and post-greasing treatment—require special attention. This article will explore these key issues in detail and provide effective solutions to ensure the optimal performance and long-term reliability of forged steel valves.

Grease Quantity and Application Method

Insufficient Grease: An inadequate amount of grease can lead to insufficient lubrication of the valve sealing surfaces, accelerating wear. It is essential to accurately calculate the required amount of grease based on the type and size of the valve. By determining the sealing capacity through the valve size and category, an appropriate amount of lubricating grease is injected.

Excessive Grease: Excessive greasing not only leads to waste but may also cause the sealant to harden, clogging the valve. During the greasing operation, it is important to avoid indiscriminate injection of lubricating grease. Ensure precise control of the grease quantity based on the valve type and sealing capacity.

Grease Pressure Issues

Low Pressure: When the greasing pressure is insufficient, the lubricating grease tends to flow to the bottom of the valve chamber, which is especially common in small gate valves. It is necessary to check whether the greasing nozzle is blocked, replace it if necessary, and ensure that the greasing pressure meets the requirements.

High Pressure: Excessive greasing pressure may cause the greasing port to block, the sealant to harden, or the sealing ring to seize with the valve ball or plate. It is necessary to use a cleaning solution to soften the hardened sealant and replace it with new lubricating grease. The greasing pressure for hard seals is generally higher than that for soft seals, and the pressure should be adjusted according to the seal type and material.

Valve Switch Position

During greasing, forged steel stop valves should be in the closed position to ensure that the lubricating grease fills the sealing ring evenly. If the valve is in the open position, the lubricating grease may directly fall into the flow path or valve chamber, causing waste. Other types of valves also need to determine the switch position according to the actual situation, and cannot be generalized.

Greasing Effect Inspection

During the greasing operation, even if the pressure, grease quantity, and switch position are normal, it is sometimes necessary to open or close the valve for inspection to ensure the greasing effect. Confirm that the surface of the valve ball or gate is evenly lubricated to ensure that the lubrication effect meets expectations.

Sewage Disposal and Pressure Relief Issues

After the valve pressure test, due to the rise in temperature, gases and moisture in the sealing chamber will increase in pressure. It is necessary to discharge sewage and relieve pressure before greasing to facilitate the smooth progress of the greasing work. After greasing, it is important to ensure that the air and moisture in the sealing chamber are fully replaced and the valve chamber pressure is promptly released to ensure the safe use of the valve. After the greasing is completed, it is essential to tighten the sewage discharge and pressure relief plugs to prevent accidents.

Grease Uniformity

During normal greasing, it is necessary to inject grease in sequence according to the outlet holes: first the outlet hole closest to the greasing port, then the low point, and finally the high point. If the grease does not come out in an orderly manner, it may indicate a blockage that needs to be cleared in time.

Valve Bore and Seal Ring Seat Alignment

For extended end gate valves, it is necessary to observe whether the valve bore is aligned with the seal ring seat. For example, in the case of a ball valve, if there is an excess in the open position, it is necessary to adjust the open position limiter, lock after confirming that the bore is straight. When adjusting the limit, consider the alignment of both opening and closing to ensure the valve's right-angle stroke.

Post-Greasing Sealing

After greasing, it is important to ensure that the greasing port is sealed to prevent the entry of impurities or oxidation of the grease at the greasing port. The cover should be coated with anti-rust grease to prevent rust, making it ready for the next operation.

Special Circumstances of High-Pressure Forged Steel Gate Valves

The sealing surface of high-pressure forged steel gate valves may be flat or conical, and the opening and closing parts are plug-shaped valve discs that move in a straight line along the centerline of the fluid. The valve stem may have two types of motion: lifting rod type or lifting and rotating rod type. For pattern cut-off valves, they are only suitable for full opening and full closing, and are not allowed for regulation and throttling.

Greasing of Low-Temperature Valves

For forged steel low-temperature valves, it is necessary to grease according to the characteristics of different oils. For example, the quality of diesel and gasoline is different, and the washing and decomposition ability of gasoline should be considered. When operating the gasoline section, it is important to replenish lubricating grease in time to prevent wear.

Greasing of the Valve Stem Area

When greasing, do not neglect the lubrication of the valve stem area. The valve shaft area has a sliding bushing or packing that also needs to maintain good lubrication to reduce the friction resistance during operation. If the lubrication is insufficient, the torque will increase during electric operation, and it will be laborious to open and close manually.

In summary, the greasing process of forged steel valves is crucial for their normal operation and service life. By accurately controlling the grease quantity, adjusting the greasing pressure, ensuring the correct valve switch position, and handling the details after greasing, the performance and reliability of the valves can be significantly improved. Regular inspection and maintenance can not only avoid common problems but also ensure the stable operation of the equipment and production efficiency. Incorporating these best practices into daily operations will help industrial equipment maintain the best condition, reduce downtime, and enhance the overall operational efficiency of the system.