Patent ID: 8613360

Claim:
A system comprising: a housing having an inlet end and an outlet end; a basket movably mounted in the housing; a vibrator coupled to the basket; a first shaker screen held by the basket proximate the inlet end of the housing; a second shaker screen held by the basket proximate the outlet end of the housing; a first sump below the first shaker screen proximate the inlet end of the housing; a second sump below the second shaker screen proximate the outlet end of the housing; a pressure differential device fluidly connected to the first sump wherein the pressure differential device generates a vacuum below the first shaker screen; and a first toggling device between the first sump and the pressure differential device wherein the first toggling device intermittently toggles from a open or partially open position to a closed or partially closed position to intermittently reduce the vacuum generated by the pressure differential device; a second toggling device wherein the pressure differential device is connected to the second sump and the second toggling device is between the pressure differential device and the second sump wherein the pressure differential device generates a vacuum below the second shaker screen and further wherein the second toggling device intermittently toggles from the open or partially open position to the closed or partially closed position to intermittently reduce the vacuum generated by the pressure differential device.