In very simple terms, viscosity is the measure of a fluid’s resistance to flow. Fluids with high viscosities flow more slowly than those with low viscosities. The thickness or ‘viscous’ quality of a fluid is determined by its internal resistance to shearing forces. In other words, it reflects the friction that exists between the molecules within the fluid. When it comes to lubrication, understanding and controlling this condition is critical for maintaining optimum performance and extending component life.
What Does it Mean for Lubricants?
In choosing lubricants, this is an important factor. To understand it better, think of honey and water. Honey has a higher viscosity and is more resistant to flow. Alternatively, water has a lower rating and flows quite easily. Lubricants come in a wide range of viscosities. Furthermore, monitoring changes in this condition can help you identify potential problems with your equipment before they occur. This is why the viscosity of your lubricant is such a key factor in your overall lubrication management.
High Viscosity Lubricants
You typically will use high viscosity lubricants for heavy-duty applications. This includes machinery that experiences high loads and/or temperatures. Among these lubricants are engine oils, gear oils, and greases.
Low Viscosity Lubricants
On the other hand, you generally will use low viscosity lubricants for light-duty applications. These lubricants work well with lower temperatures and/or loads. A common example is engine oil for passenger cars and light trucks. However, an important detail to note, low viscosity lubricants tend to evaporate faster than those with a higher rating.
Why is it so Important?
In industrial settings, you’re usually using heavy-duty and high-dollar value machinery and equipment. The right lubricant viscosity is critical to form a sufficient film strength and prevent unnecessary component wear. This affects the way lubricants adhere to surfaces, how well they lubricate, and how long they last. Furthermore, tracking this condition gives you an excellent indication of your assets’ health. Whenever it suddenly changes, you must consider all of the possible root causes. If, on the other hand, your lubricant remains steady, you likely have none of these issues.
Understanding Viscosity Changes
Lubricants can lose their viscosity over time due to degradation, which decreases their effectiveness. Furthermore, it can change with temperature changes. Increasing the temperature decreases the viscosity. Low viscosity is an issue you need to get to the bottom of. It can cause several problems including:
- Lower operating efficiency
- Increased maintenance costs
- Accelerating component wear and tear
- Equipment failure
- Unplanned downtime
Due to these factors, you need to closely monitor lubricant viscosity and implement a degradation prevention plan.
Is Higher Always Better?
For the majority of industrial uses, high viscosity lubricants are a good idea. However, there are some restrictions on their use. Temperature is the main factor in viscosity changes. A high viscosity lubricant may be perfect at operating temperature, but is it a fit for your machine’s startup temperature? If you don’t strike the right balance, at lower temperatures, such as during starting and while the machinery is still warming up, you may experience excessive friction. This is because viscosity rises at lower temperatures. So, it is crucial to select the right lubricant for all of your equipment’s operating conditions.
What Can You Do to Improve?
To increase the viscosity of your lubricants, you can utilize viscosity modifier additives. Depending on the intended qualities of the lubricant, these additives can either increase or decrease lubricant viscosity. Additionally, you can employ routine lubricant analysis to find problems as soon as possible. Temperature, lubricant contamination, and shear force are just a few of the variables that might affect your lubricant. With the right condition monitoring in place, you can take action to prevent lubricant degradation and keep your operations running smoothly.
