Submersible pump with modular construction

Claim 1

IN A SUBMERSIBLE PUMP HAVING AT LEAST FIRST AND SECOND AXIALLY SPACED PUMPING MODULES, EACH OF SAID MODULES COMPRISING A NUMBER OF LINEALLY STACKED PUMPING UNITS WITH EACH UNIT HAVING A FIRST PUMPING MEMBER WITH A PUMPING CHAMBER AND A SECOND PUMPING MEMBER WITHIN SAID PUMPING CHAMBER AND AXIALLY MOVABLE WITH RESPECT TO SAID FIRST MEMBER, SAID SECOND PUMPING MEMBERS BEING ROTATABLE IN SAID CHAMBERS WITHOUT CONTACT WITH SAID FIRST MEMBERS EACH MODULE HAVING AN INITIAL AND FINAL PUMPING UNIT AT OPPOSITE ENDS THEREOF, MEANS FOR CAUSING RELATIVE ROTATIONAL MOVEMENT BETWEEN SAID MEMBERS TO CAUSE A PUMPING ACTION WITH THE OUTPUT OF ONE PUMPING UNIT COMMUNICATED WITH THE INPUT OF THE NEXT HIGHER PUMPING UNIT, THE AXIAL LENGTH OF SAID FIRST PUMPING MEMBERS IN EACH MODULE BEING DETERMINED BY THE SUMMATION OF THE AXIAL THICKNESS OF THE FIRST MEMBERS IN THAT MODULE AND THE AXIAL LENGTH OF SAID SECOND PUMPING MEMBERS IN EACH MODULE BEING DETERMINED BY THE SUMMATION OF THE AXIAL THICKNESS OF THE SECOND MEMBERS IN THAT MODULE, A TOLERANCE ERROR AT ONE END OF SAID FIRST MODULE, SAID ERROR BEING THE DIFFERENCE BETWEEN THE AXIAL LENGTHS OF SAID FIRST AND SECOND MEMBERS IN THAT MODULE AND BEING EXHIBITED BY A DEVIATION IN THE RELATIVE LOCATIONS OF SAID FIRST AND SECOND MEMBERS IN THE FINAL PUMPING UNIT OF SAID FIRST MODULE, THE IMPROVEMENT COMPRISING: AN ERROR COMPENSATING DEVICE BETWEEN THE FIRST AND SECOND MEMBERS OF SAID FINAL PUMPING UNIT OF SAID FIRST MODULE AND