There are rubber ring for sealing on most shaker screen model, like Derrick503 screen, Derrick48-30 shaker screen, Brandt Cobra shaker screen, GN Solids shaker screen, and many other shaker screen models.
Functions of the sealing rubber:
1) Sealing between screens and shaker deck. To avoid un-treated dirty mud seep into mud system, and damage the mud system machine.

2) To reduce the bad effect of vibrating to the shaker screen. Protect screen from strong vibrating.
What will happen if the sealing rubber not workable
1) The screen frame will touch directly with shaker deck, and damaged within a very short time
2) The worst result is, if the screen rubber damaged, the dirty mud from well head will flow into mud system directly with much solids. It requires a higher capacity on downstream equipment processing, or even make damage to the downstream machine, like desander, desilter or vacuum degasser
If the material of the sealing rubber not strong enough and not very good at anti-corrosive, the high temperature drilling mud with heavy sand will damage the rubber very soon. The shaker screen will be broken very soon. Dirty mud flow into the mud system from the shale shaker deck with heavy sand and solids. It will have bad effect to the mud system.
GN Solids Control utilzie high quality material for sealing rubber. They can offer high quality shaker screen with reasonable price.