Shale Shakers In Oilfield Guide
https://youtu.be/Fd9e6B5xPrI

The shale shakers are the first mechanical treatment of the returning drilling fluid for solids control. None of the other mechanical devices can cope with solids control without the pre-treatment of the mud in the shale shaker.

A shale shaker or vibration screen is a spring-mounted screen. The vibration of the such screen is by the rotation of an eccentric shaft mounted on top of the screen frame (Figure 1).
https://www.drillingmanual.com/shale-shakers-in-oilfield-guide/