Screen and screen retention system for a shale shaker

A screen assembly for use in a basket of a shale shaker, the basket including an upper longitudinal rail, a pneumatic or mechanically actuated preloading mechanism coupled below the upper longitudinal rail, and a lower longitudinal supports located below the upper longitudinal rail, the screen assembly including a primary screen comprising:

• a screen frame having side beams located at two opposite ends of the primary screen and under a rib, the screen frame further having central beams located between the side beams, the screen frame further having transverse beam members that connect to the side beams;
• a perforated plate supported by the screen frame;
• woven mesh, wherein the woven mesh is supported by the perforated plate;
• and
• the rib being coupled to the perforated plate, supported by the screen frame, and extending vertically above the woven mesh;
• wherein the rib is configured to be aligned with the upper longitudinal rail and the lower longitudinal supports when the screen assembly is in place in the basket of the shale shaker;
• wherein one of the transverse beam members is located near an edge of the primary screen;
• and
• wherein another one of the transverse beam members that is located near an opposite edge of the primary screen has a first cross-section that is smaller than a second cross-section of the one of the transverse beam members.