Patent ID: 10801493

Abstract:
The present invention comprises a new and improved positive displacement reciprocating pump wherein the pump comprises a pump rod assembly which comprises three different regions having three different external diameter dimensions or three different external diametrical extents wherein the first uppermost region is provided with an external diameter or diametrical extent of 0.500 inches which has a surface area of 0.1964 in2, the second intermediate one of the three regions is provided with an external diameter or diametrical extent of 0.525 inches which has a surface area of 0.2166 in2, and the third lowermost one of the three regions is provided with an external diameter or diametrical extent of 0.474 inches which has a surface area of 0.1762 in2. The differences between the external diameters or external diametrical extents of the three regions enable the positive displacement reciprocating pump to pump or dispense the same particular precise amount of fluid out from the pump during both the UP and DOWN strokes of the pump piston rod assembly. The piston rod assembly may comprise three piston rod sections or, alternatively, two piston rod sections and an intermediate rod seal or packing region movable along with the pump piston rod assembly.