Pumping system with precise ratio output

Abstract

A precision pumping system is disclosed. The pumping system includes an electric motor assembly powering a first drive shaft driving a first pump at a first flow rate and powering a second drive shaft driving a second pump at a second flow rate. A proportioned fluid output includes a first fluid pumped by the first pump and a second fluid pumped by the second pump. The pumping system provides a desired ratio of the first fluid to the second fluid at the proportioned fluid output, relatively independently of pressure and flow rate at the output.

1 . A system for pumping a first fluid and a second fluid in a desired proportion, the system comprising:
 an electric motor assembly having a first drive shaft and a second drive shaft, wherein during operation, the electric motor assembly drives the first drive shaft at a first rotational rate and the second drive shaft at a second rotational rate;   a first pump driven at a first rate by the first drive shaft; and   a second pump driven at a second rate by the second drive shaft.   
   
   
       2 . The system of  claim 1 , wherein the electric motor assembly includes a gear reduction assembly that drives the second drive shaft. 
   
   
       3 . The system of  claim 2 , wherein the first drive shaft extends from a first end to a second opposite end of an electric motor of the electric motor assembly, and the gear reduction assembly is fixed relative to the second end of the electric motor and is driven by or relative to the first drive shaft. 
   
   
       4 . The system of  claim 3 , wherein the second drive shaft is driven by the gear reduction assembly. 
   
   
       5 . The system of  claim 1 , wherein the first pump is a positive displacement plunger pump that includes a plunger situated in a cylinder for pumping the first fluid, the plunger of the first pump having a diameter and a stroke length;
 wherein the second pump is a positive displacement plunger pump that includes a plunger situated in a cylinder for pumping the second fluid, the plunger of the second pump having a diameter and a stroke length.   
   
   
       6 . The system of  claim 5 , wherein the diameter and/or stroke length of the second pump is/are the same as the first pump. 
   
   
       7 . The system of  claim 5 , wherein the diameter and/or stroke length of the second pump is/are different from the first pump. 
   
   
       8 . The system of  claim 1 , wherein the first pump includes a double acting simplex positive displacement pump, and the second pump includes a double acting simplex positive displacement pump. 
   
   
       9 . The system of  claim 1 , wherein the first pump and the second pump are configured to have substantially the same pumping capacity if the first pump and the second pump were driven at a common rate. 
   
   
       10 . The system of  claim 1 , wherein the first pump and the second pump are configured to have substantially different pumping capacities if the first pump and the second pump were driven at a common rate. 
   
   
       11 . The system of  claim 1 , further comprising:
 a first container for containing a first liquid, the first container in fluid communication with an inlet of the first pump;   a second container for containing a second liquid, the second container in fluid communication with an inlet of the second pump; and   a proportioned output in fluid communication with an outlet of the first pump and an outlet of the second pump.   
   
   
       12 . The system of  claim 11 , further comprising a first recirculating valve assembly situated in line with the outlet of the first pump, the first recirculating valve assembly recirculating the first liquid from the outlet of the first pump and back into the first container when a pressure at the outlet of the first pump exceeds a threshold value, and allows the first liquid to pass to the proportioned output when the pressure at the outlet of the first pump is below the threshold value. 
   
   
       13 . The system of  claim 12 , further comprising a second recirculating valve assembly situated in line with the outlet of the second pump, the second recirculating valve assembly recirculating the second liquid from the outlet of the second pump and back into the second container when a pressure at the outlet of the second pump is above a threshold value, and allows the second liquid to pass to the proportioned output when the pressure at the outlet of the second pump is below the threshold value. 
   
   
       14 . A system for pumping a first fluid and a second fluid in a desired proportion, the system comprising:
 a first pump having an inlet in fluid communication with a first container for holding a quantity of the first fluid, and an outlet;   a second pump having an inlet in fluid communication with a second container for holding a quantity of the second fluid, and an outlet;   an electric motor assembly for driving the first pump at a first cycling rate and the second pump at a second cycling rate; and   wherein the outlet of the first pump and the outlet of the second pump are in fluid communication with an outlet of the system through respective check valves to prevent backflow.   
   
   
       15 . The system of  claim 14 , wherein the first pump and the second pump have substantially the same pumping capacity if the first pump and the second pump were driven at a common cycling rate. 
   
   
       16 . The system of  claim 14 , wherein the first pump and the second pump are configured to have substantially different pumping capacities if the first pump and the second pump were driven at a common cycling rate. 
   
   
       17 . The system of  claim 14 , wherein the desired proportion of the first fluid and the second fluid is not adjustable except by removing and then replacing one or more components of the system. 
   
   
       18 . The system of  claim 14 , wherein the first pump is a positive displacement plunger pump that includes a plunger situated in a cylinder for pumping the first fluid, and the second pump is a positive displacement plunger pump that includes a plunger situated in a cylinder for pumping the second fluid. 
   
   
       19 . A system for pumping a first fluid and a second fluid in a desired proportion, the system comprising:
 a first pump having an inlet in fluid communication with a first container for holding a quantity of the first fluid, and an outlet;   a second pump having an inlet in fluid communication with a second container for holding a quantity of the second fluid, and an outlet, wherein the outlet of the first pump and the outlet of the second pump are in fluid communication with a first stage outlet;   an electric motor assembly for driving the first pump at a first cycling rate and the second pump at a second cycling rate;   a third pump having an inlet in fluid communication with the second container, and an outlet; and   a fourth pump having an inlet in fluid communication with the first stage outlet, and an outlet, wherein the outlet of the third pump and the outlet of the fourth pump are in fluid communication with a second stage outlet, wherein the third pump is driven at a third cycling rate and the fourth pump is driven at a fourth cycling rate.   
   
   
       20 . The system of  claim 19 , wherein the third pump and the fourth pump are driven by the electric motor assembly. 
   
   
       21 . The system of  claim 19 , wherein the third pump and the fourth pump are driven by a different electric motor assembly. 
   
   
       22 . A method of combining a first fluid with a second fluid into a mixture of accurate predetermined proportions of the first fluid and the second fluid, the method comprising:
 pumping the first fluid through a first fixed displacement pump at a first flow rate, the first fixed displacement pump having a first displacement;   pumping the second fluid through a second fixed displacement pump at a second flow rate different from the first flow rate, the second fixed displacement pump having a second displacement; and   mixing the first fluid with the second fluid in a proportioned output downstream of the first fixed displacement pump and downstream of the second fixed displacement pump;   
   
   
       23 . The method of  claim 22 , wherein the first fixed displacement pump is powered by a first drive shaft of a motor assembly, and the second fixed displacement pump is powered by a second drive shaft of a motor assembly;
 wherein the motor assembly includes a motor powering both the first drive shaft and the second drive shaft.   
   
   
       24 . The method of  claim 23 , wherein the motor assembly includes a transmission,
 wherein the motor powers the first drive shaft at a first rotational speed, and wherein the transmission allows the motor to power the second drive shaft at a second rotational rate different from the first rotational rate.   
   
   
       25 . A method of providing an accurately proportioned liquid mixture of a first liquid and a second liquid to an applicator, the method comprising:
 providing a first pump having a first displacement;   providing a second pump having a second displacement;   actuating the first pump at a first cyclic rate by a motor, the first pump pumping the first liquid at a first fluid flow rate;   actuating the second pump at a second cyclic rate by the motor, the second pump pumping the second liquid at a second fluid flow rate;   the first pump pumping the first liquid to a first fluid output line when the pressure of the first liquid being pumped from the first pump is less than a first threshold pressure, and the first pump pumping the first liquid to a first fluid bypass line when the pressure of the first liquid being pumped from the first pump is more than the first threshold pressure;   the second pump pumping the second liquid to a first fluid output line when the pressure of the second liquid being pumped from the second pump is less than a second threshold pressure, and the second pump pumping the second liquid to a second fluid bypass line when the pressure of the second liquid being pumped from the second pump is more than the second threshold pressure; and   mixing the first liquid pumped from the first pump through the first fluid output line with the second liquid pumped from the second pump through the second output line in a proportioned output, the proportioned output having a desired ratio of the first liquid to the second liquid, wherein the proportioned output is in fluid communication with the applicator.