Differential pressure apparatus

Claim 1

A PRESSURE RATIO SENSOR COMPRISING A PAIR OF PRESSURE SENSITIVE ELEMENTS EACH RESPONSIVE TO APPLIED PRESSURE TO PRODUCE A PRESSURE DERIVED FORCE, FORCE LINKAGE MEANS INCLUDING A FORCE MOVABLE MEMBER HAVING A CIRCULAR ARC SURFACE AND A BEARING MEMBER MOUNTED FOR ROTATION ABOUT A FIXED AXIS NOMINALLY COAXIAL WITH SAID CIRCULAR ARC SURFACE AND HAVING A BEARING SURFACE CONTACTING SAID CIRCULAR ARC SURFACE AT A POINT OF TANGENCY WHICH SHIFTS ALONG THE ARC ON ROTATION OF SAID BEARING MEMBER, MEANS CONNECTING SAID FORCE MOVABLE MEMBER AT THE AXIS OF ITS CIRCULAR SURFACE TO SAID PRESSURE SENSITIVE ELEMENTS WITH THE PRESSURE DERIVED FORCES ACTING UPON SAID FORCE MOVABLE MEMBER AND ANGULARLY DISPOSED WITH RESPECT TO EACH OTHER AND WITH RESPECT TO THE ARC RADIUS TO SAID POINT OF TANGENCY WHEREBY THE PRESSURE DERIVED FORCES ARE RESOLVED INTO FORCE COMPONENTS TWO OF WHICH ARE IN OPPOSED RELATION AND ONE OF WHICH HAS ITS LINE OF ACTION SUBSTANTIALLY PARALLEL TO SAID ARC RADIUS SO AS TO BE NEUTRALIZED AT SAID BEARING MEMBER SURFACE, MEANS FOR SENSING MOVEMENT OF SAID FORCE MOVABLE MEMBER RESPONSIVE TO UNBALANCE BETWEEN SAID OPPOSED FORCE COMPONENTS, AND MEANS OPERATIVE UNDER CONTROL OF SAID LAST-NAMED MEANS FOR ROTATING SAID BEARING MEMBER TO SHIFT ITS POINT OF TANGENCY WITH SAID FORCE MOVABLE MEMBER IN A DIRECTION TO RESTORE FORCE BALANCE.