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The Constant Level Oiler Understanding the Lubrication Principle and Product Family

Dan Freeland


These effective, yet simple, devices explained

How do they work?

Constant level lubrication is the concept of maintaining a consistent level of oil in a lubricating sump. If there is any oil loss due to leakage or usage the reservoir of oil will provide a volume of oil. This reserve will replenish oil in the lubricating sump until the original oil level is maintained again. This will be the case if there is reserve oil in the bottle. This application has been around for many years and used by end users and original equipment manufacturers all over the world. As a result, quite often we receive inquiries about how these oilers work. The concept of a full bottle of fluid upside down, and not just emptying out, is to somehow defy logic. But, of course, this is not magic. The basic rules of fluid dynamics are at play – a function of oil displacement. The fluid in the bottle will feed out until it reaches the oil level to be maintained, based on the level adjustment mechanism. After that, if the oil breaks below the control point, regardless of which oiler, air will enter the reservoir, traveling up to where it will break in the headspace of the inverted bottle. This additional air will displace fluid out of the bottle until the path of air is no longer present, or when the control point level is re-established.


Why different types of Constant Level Oilers?

You may have wondered why you see several different types of oilers when walking through a plant? There are many reasons for choosing a particular Constant Level Oiler. Here are a couple of the most common:

  • design considerations of the equipment it is on.
  • contamination protection of the oil.
  • equipment and ancillary products are following industry standards.
  • that is the way it has been for years, and no one is going to change it.

The main thing to understand about any constant level oiler is that they all do exactly what the name implies. It does not matter which oiler you choose; they will all provide a constant level.


Throughout the years, Trico has led the reform and refinement of constant level oilers, resulting in a family of products.

To learn more about all the Trico Constant level oilers, check out our latest video.