Pressure type screening devices

Claim 1

A PLURAL STAGE PRESSURE TYPE SCREENING DEVICE FOR SCREENING A PRESSURIZED LIQUID SUSPENSION, SAID DEVICE COMPRISING AN INLET FOR THE LIQUID SUSPENSION, A FIRST STAGE GENERALLY CYLINDRICAL SCREEN FOR PASSING A FIRST STAGE SCREENED PORTION OF SAID SUSPENSION, A SECOND STAGE GENERALLY CYLINDRICAL SCREEN DISPOSED GENERALLY CONCENTRICALLY WITH SAID FIRST STAGE SCREEN FOR ACCEPTING SAID FIRST STAGE SCREENED PORTION AND PASSING A SECOND STAGE SCREENED PORTION, A FIRST STAGE CLEANING MEANS DISPOSED ADJACENT SAID FIRST STAGE SCREEN FOR REMOVING CLOGGING PARTICLES THEREFROM, A SECOND STAGE CLEANING MEANS DISPOSED ADJACENT SAID SECOND STAGE SCREEN FOR REMOVING CLOGGING PARTICLES THEREFROM, A FIRST STAGE GENERALLY CYLINDRICAL BAFFLE GENERALLY CONCENTRIC WITH AND SPACED FROM SAID FIRST STAGE SCREEN AND POSITIONED ADJACENT SAID INLET AND SAID FIRST STAGE SCREEN TO FORM A FIRST ANNULAR CHAMBER FOR RECEIVING ADJACENT ONE END THEREOF SAID LIQUID SUSPENSION FROM SAID INLET, A SECOND STAGE GENERALLY CYLINDRICAL BAFFLE DISPOSED BETWEEN AND GENERALLY CONCENTRICALLY WITH SAID FIRST AND SECOND STAGE SCREENS FOR FORMING WITH SAID FIRST STAGE SCREEN A SECOND ANNULAR CHAMBER CLOSED AT ONE END FOR RECEIVING SAID FIRST STAGE SCREENED PORTION, SAID SECOND CHAMBER BEING OPENED ADJACENT ITS OTHER END TO PERMIT FLOW OF SAID FIRST STAGE SCREENED PORTION TO SAID SECOND SCREEN, SAID SECOND BAFFLE FORMING WITH SAID SECOND STAGE SCREEN A THIRD ANNULAR CHAMBER OF RECEIVING ADJACENT ONE END SAID FIRST STAGE SCREENED PORTION FROM THE OPEN END OF SAID SECOND CHAMBER, FIRST STAGE REJECT MEANS COMMUNICATING WITH SAID FIRST CHAMBER AT THE END REMOTE FROM THE INLET FOR ACCEPTING PORTIONS OF SAID LIQUID SUSPENSION REJECTED BY SAID FIRST STAGE SCREEN, SECOND STAGE REJECT MEANS COMMUNICATING WITH SAID THIRD CHAMBER AT THE END REMOTE FROM SAID ONE END FOR ACCEPTING PORTIONS AT THE LIQUID SUSPENSION REJECTED BY SAID SECOND STAGE SCREEN, DRIVE MEANS OPERATIVELY ASSOCIATED WITH SAID FIRST AND SECOND STAGE SCREENS AND SAID FIRST AND SECOND STAGE CLEANING MEANS FOR CAUSING RELATIVE ROTARY MOVEMENT BETWEEN SAID SCREENS AND SAID CLEANING MEANS, AND MEANS ENCLOSING SAID SCREENING DEVICE FOR MAINTAINING SAID LIQUID SUSPENSION UNDER PRESSURE DURING ITS PASSAGE THERETHROUGH.