Square shoulder metering rod

Abstract

A metering rod assembly for a pressure sensitive droop flow pump is provided. The assembly includes a metering rod having a first section with a first diameter and a second section with a section diameter, the second diameter larger than the first diameter. A shoulder is formed at a junction of the first section and second section, the shoulder extending radially perpendicular to the first section.

Having thus described the invention, it is claimed: 
     
         1 . A pressure sensitive droop flow pump comprising:
 a fluid conduit having a partition with an aperture formed therein; and   a metering rod comprising a first section having a first diameter and a second section having a section diameter, the second diameter larger than the first diameter, and a shoulder formed at a junction of the first section and second section, the shoulder extending radially perpendicular to the first section.   
     
     
         2 . The pressure sensitive droop flow pump of  claim 1 , wherein the metering rod extends along an axis, and is reciprocally movable along the axis within the fluid conduit. 
     
     
         3 . The pressure sensitive droop flow pump of  claim 2 , wherein the metering rod is movable along the first axis between a first position where the first section is positioned in the aperture and a second position where the second section is positioned in the aperture, to control a flow of fluid in the fluid conduit. 
     
     
         4 . The pressure sensitive droop flow pump of  claim 3 , wherein the fluid flows through the pump at a first flow rate with the metering rod in the first position, and the fluid flows through the pump at a second flow rate with the metering rod in the second position, wherein the second flow rate is less than the first flow rate. 
     
     
         5 . The pressure sensitive droop flow pump of  claim 4 , wherein the pressure sensitive droop flow pump operates at a first angular velocity with the metering rod in the first position and a second angular velocity with the second position, the second angular velocity is greater than the first angular velocity. 
     
     
         6 . The pressure sensitive droop flow pump of  claim 1 , wherein the shoulder includes at least one step. 
     
     
         7 . The pressure sensitive droop flow pump of  claim 1 , wherein the shoulder is formed by a difference between the first diameter and the second diameter at the junction of the first section and the second section. 
     
     
         8 . A metering rod assembly for a pressure sensitive droop flow pump, the assembly comprising:
 a metering rod having a first section with a first diameter and a second section with a section diameter, the second diameter larger than the first diameter, and a shoulder formed at a junction of the first section and second section, the shoulder extending radially perpendicular to the first section.   
     
     
         9 . The metering rod assembly of  claim 8 , further comprising a housing configured to receive a portion of the metering rod, the metering rod extending along an axis and configured for reciprocal movement along the axis into and out of the housing. 
     
     
         10 . The metering rod assembly of  claim 8 , wherein the shoulder includes at least one step. 
     
     
         11 . The metering rod assembly of  claim 8 , wherein the shoulder is formed by a difference between the first diameter and the second diameter at the junction of the first section and the second section.