Automatic regrinding valve apparatus

Claim 1

AN AUTOMATIC REGRINDING VALVE APPARATUS, COMPRISING, IN COMBINATION, A VALVE HAVING A BODY AND SEAT, A VALVE STEM AND A VALVE DISC RESPECTIVELY NORNAL THERETO, SAID STEM COMPRISING A SMOOTH SURFACED CYLINDRICAL LOWER PORTION AND A BALL SCREW UPPER PORTION IN FIXED NONROTATABLE RELATION TO EACH OTHER, A BALL NUT IN ENGAGEMENT WITH SAID SCREW AND ADAPTED TO BE ROTATED ONLY IN A SELECTED DIRECTION TO RAISE OR LOWER SAID STEM, A REVERSIBLE ELECTRIC MOTOR VALVE OPERATOR ADAPTED TO ROTATE A DRIVE SLEEVE AND SAID BALL NUT, SAID DRIVE SLEEVE BEING HELD AGAINST AXIAL MOVEMENT AND ENGAGING SAID BALL NUT TO HOLD IT SUBSTANTIALLY AGAINST AXIAL MOVEMENT RELATIVE TO SAID VALVE OPERATOR AND BODY, A ROTATABLE GUIDE STEM FIXED AT ITS LOWER END TO THE UPPER END OF SAID VALVE STEM IN NON-ROTATABLE RELATION THERETO AND AXIAL ALIGNMENT THEREWITH, A ROTATION SLEEVE SURROUNDING SAID GUIDE STEM IN LONGITUDINALLY SLIDABLE NON-ROTABLE RELATION THERETO, SAID GUIDE STEM BEING ADAPTED TO BE ROTATED BY ROTATION OF SAID ROTATION SLEEVE, SAID GUIDE STEM BEING MOVABLE AXIALLY RELATIVE TO SAID ROTATION SLEEVE, SAID ROTATION SLEEVE BEING HELD AGAINST AXIAL MOVEMENT, AN ELECTRIC MOTOR VALVE OPERATOR TO ROTATE SAID GUIDE STEM IN A PREDETERMINED DIRECTION, AN ACTUATOR ROD MOUNTED ON THE UPPER END OF SAID GUIDE STEM IN NON-ROTATABLE AND AXIAL RELATION THERETO, A TOP LIMIT SWITCH POSITION ABOVE SAID ACTUATOR ROD AND ADATPED TO BE ENGAGED THEREBY WHEN SAID VALVE IS FULLY OPEN TO TERMINATE AN OPENING STROKE OF SAID VALVE STEM AND DISC, A CAM CONNECTED TO SAID ACTUATOR ROD AT A SELECTED HEIGHT THEREON, A ROTATION CONTROL SWITCH ADAPTED TO BE ENGAGED BY SAID CAM WHEN THE VALVE DISC AND SEAT ARE AT A PREDETERMINED DISTANCE FROM BUT ADJACENT TO THEIR POSITION OF ENGAGEMENT FOR ROTATIONAL GRINDING OF SAID VALVE DISC RELATIVE TO SAID SEAT, A TORQUE LIMIT SWITCH FOR REGULATING THE SEATING FORCE OF SAID ENGAGEMENT AND TERMINATING A CLOSING STROKE OF SAID VALVE STEM AND DISC, AND ELECRIC CIRCUIT MEANS INTERCONNECTING SAID VALVE OPERATOR AND ASSOCIATED PARTS, SAID CIRCUIT MEANS ALSO PROVIDING A COMPOUND ROTATION EFFECT DURING SAID ROTATIONAL GRINDING TO SLOW DOWN THE LINEAR RATE OF CLOSURE BETWEEN SAID VALVE DISC AND SEAT, SAID CIRCUIT MEANS FURTHER CUTTING SAID SECOND-NAMED VALVE OPERATOR OUT DURING AN OPENING STROKE TO SAID VALVE STEM AND DISC, WHEREBY THE OPENING AND CLOSING OF SAID VALVE IS PERFORMED WITHOUT ROTATION OF SAID VALVE STEM EXCEPT THAT IN THE COURSE OF A CLOSING STROKE WHEN SAID VALVE DISC APPROACHES SAID VALVE SEAT, SAID SECOND-NAMED VALVE OPERATOR WILL ROTATE SAID VALVE STEM AND DISC TO INSURE A GROUND ENGAGEMENT BETWEEN SAID VALVE DISC AND SEAT WHEN SAID VALVE IS CLOSED.