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What type of oil is commonly used for valve lubrication?

The following types of oil are commonly used for valve lubrication:

一、Mineral oil

1、Ordinary machine oil

Characteristics:

General-purpose mechanical oil is a base oil refined from petroleum and is relatively inexpensive, which gives it a certain advantage in applications where cost is a sensitive factor.

It has basic lubricating properties and can form an oil film on the metal parts of valves to reduce direct friction between parts. For example, the commonly used L-AN series of mechanical oils.

Such as L-AN32, L-AN46, etc., which have moderate viscosity and can meet the lubrication requirements of some small valves or valves with relatively low working pressure and torque.

It also has a certain anti-rust effect, preventing the metal parts of valves from rusting in humid environments, as it can block moisture in the air from coming into contact with metal surfaces. However, its lubricating properties and wear resistance are relatively limited, so it may not be suitable for valves that are subject to high loads and frequent operation.

2、Medium- and heavy-duty industrial gear oil

 Characteristics:

 This type of oil is specially designed for gears and mechanical components that bear heavy loads, and has excellent extreme pressure and anti-wear properties. For valves, especially those with large diameters and high operating torques, such as gate valves or globe valves, the components are subjected to high pressure during opening and closing.

Medium- and heavy-duty industrial gear oils can ensure good lubrication between the moving parts of valves in such high-pressure environments, preventing direct contact and wear between metals.

For example, CK C series industrial gear oils are suitable for medium-load valves, while CK D series industrial gear oils can be used for heavy-load valves. They form a tough lubricating film between valve stem, valve disc and other components, effectively extending the service life of the valve.

二、Synthetic oils

1. Polyalphaolefin (PAO) oil

Performance advantages:

Polyalphaolefin (PAO) oil exhibits excellent high and low-temperature performance. In low-temperature environments, such as during the winter in cold northern regions, some outdoor valves may be exposed to extremely low temperatures. However, PAO oil maintains good fluidity under such conditions. Unlike conventional mineral oils, which can become viscous or even solidify at low temperatures, PAO oil ensures that valves can operate normally and open/close smoothly even in extremely cold conditions.

At high temperatures, PAO oil exhibits good stability and does not easily decompose or evaporate. For valves on high-temperature steam pipelines, it can withstand high-temperature environments while continuing to provide lubrication. Additionally, PAO oil has good oxidative stability, meaning it does not easily produce oxidation byproducts over extended use. This helps maintain cleanliness inside valves, reduces the formation of sludge and deposits, and further ensures normal valve operation.

2. Ester oils

Characteristics:

Ester oils have excellent lubricating properties. Their molecular structure forms a high-strength, low-friction lubricating film on the friction surfaces of valves. This film effectively reduces the friction coefficient during valve operation, making opening and closing smoother.

It has strong antioxidant properties, resisting the oxidative effects of oxygen in the air during prolonged valve operation. Compared to ordinary mineral oils, ester oils have a longer service life, reducing the frequency of valve maintenance. In precision valves, such as flow control valves in chemical production that require high accuracy in flow regulation, ester oils provide precise lubrication, ensuring stable valve performance.

三. Specialised Lubricating Grease 

1. Lithium-based Lubricating Grease

 Performance Characteristics:

Lithium-based lubricating grease has excellent water resistance. When valves are exposed to humid environments, such as those found in wastewater treatment plants or water conservancy projects, moisture cannot penetrate the grease, ensuring that its lubricating properties remain unaffected.

It has good mechanical stability, meaning that during frequent valve operations, the grease will not easily thin out or leak due to mechanical shear forces. Additionally, lithium-based grease has certain corrosion-resistant properties, preventing rust and corrosion of valve metal components and protecting the structural integrity of the valve. It is suitable for the lubrication needs of most valves.

2. Polyurea grease

 Advantages:

Polyurea grease has outstanding high-temperature resistance. In high-temperature environments, such as high-temperature steam valves in steel mills, its molecular structure remains stable and does not soften, flow, or decompose like some ordinary greases.

It also has strong wear resistance. During frequent valve operations, it effectively reduces wear between components such as valve stems and seats, significantly extending the service life of the valve and ensuring reliable operation under harsh conditions such as high temperatures and heavy loads.