Sight Glass

Perhaps the original maintenance tool for lubrication systems is the sight glass. This simple accessory allows constant visual inspection of lubricant levels and conditions. All your maintenance staff needs to do is walk to the equipment and look at the sight glass to see if the equipment’s lubricant needs attention.

The two main types of sight glasses are level and condition monitoring. Level monitoring sight glasses consist of a transparent portal into the lubrication reservoir with markings to indicate level. By looking at the sight glass, your maintenance personnel can tell immediately if they need to top off the lubricant.

The condition monitoring sight glasses are installed on the lube tanks. These devices consist of a transparent bulb that holds a small quantity of the lubricant currently flowing through the equipment.

By looking at this “sample,” maintenance personnel can spot contamination. For example, as moisture builds up in oil, it makes it cloudy. If your staff see an unexpectedly cloudy oil in the glass, they can investigate further.