Hydraulic pumping unit

Claim 1

IN A PUMPING INSTALLATION WHICH INCLUDES IN COMBINATION A HYDRAULICALLY OPERATED SURFACE PUMPING UNIT, A SUBSURFACE PUMP BELOW SAID UNIT, AND MEANS OPERATIVELY CONNECTING SAID PUMPING UNIT AND SAID SUBSURFACE PUMP, SAID PUMPING UNIT COMPRISING A LIFTING CYLINDER, A POWER PISTON RECIPROCABLE UP AND DOWN IN SAID CYLINDER, A MOTIVATING PUMP, AND VALVE MEANS FOR ALTERNATELY DIRECTING FLUID FROM SAID MOTIVATING PUMP TO THE LOWER END OF SAID CYLINDER TO LIFT SAID PISTON DURING AN UPSTROKE AND RELIEVING THE LOWER END OF SAID CYLINDER TO ALLOW SAID PISTON TO DESCEND GRAVITATIONALLY DURING A DOWNSTROKE, SAID PUMP COMPRISING A BARREL, A STANDING VALVE AT THE LOWER END OF SAID BARREL, A RECIPROCABLE PLUNGER MOUNTED IN SAID BARREL, AND A TRAVELING VALVE CARRIED BY SAID PLUNGER, SAID STANDING VALVE OPENING AND SAID STANDING VALVE CLOSING AS SAID PLUNGER MAKES AN UPSTROKE TO ENABLE THE PLUNGER TO DRAW FLUID INTO THE BARREL, SAID STANDING VALVE CLOSING AND SAID TRAVELING VALVE OPENING AS SAID PLUNGER MAKES A DOWNSTROKE TO ENABLE THE PLUNGER TO DISPLACE FLUID FROM THE BARREL, SAID CONNECTING MEANS COMPRISING A TUBULAR ROD STRING ATTACHED TO SAID PISTON AND TO SAID PLUNGER FOR MOVING THE PLUNGER WITH THE PISTON AND DELIVERING TO THE SURFACE DURING A DOWNSTROKE FLUID DISPLACED FROM SAID BARREL, THE WEIGHT OF SAID ROD STRING FURNISHING THE FORCE WHICH LIFTS THE FLUID TO THE SURFACE, WHEREBY THE LOAD DURING AN UPSTROKE IS RESTRICTED SUBSTANTIALLY TO THE WEIGHT OF THE ROD STRING.