When I go to a plant to examine its current lubrication practices, among the first things I look for are oil sight glasses and level gauge. These devices provide a wealth of information in the time it takes to walk up to a component and check it.
More than just simple additions to a machine to indicate there is enough oil in the sump for proper lubrication, sight glasses offer an opportunity to monitor the oil.
Generally, oil sight glasses and level gauge come in two styles. Columnar sight glasses and level gauge attach to an oil-bathed component, typically at the drain port. They have cylinders made of a transparent material (glass, acrylic, some plastics, etc.) in which oil is free to fluctuate up and down with the change of the oil level within the machine.
The second style is known as the “bull’s-eye” sight glass. It also is made of a transparent material but is threaded into a port where the oil level should be maintained during operation.
This article comes from machinery edit released