Dual pump system and control thereof

Abstract

A pump system includes: first and second flow paths connected with a common inlet and a common outlet, and disposed in parallel with each other; the first flow path having a first aspirate valve, a first pump in series with and downstream of the first aspirate valve, and a first dispense valve in series with and downstream of the first pump; the second flow path having a second aspirate valve, a second pump in series with and downstream of the second aspirate valve, and a second dispense valve in series with and downstream of the second pump; the first aspirate valve, the first pump, and the first dispense valve of the first flow path, being configured to operate in both a dispense and aspirate modes; the second aspirate valve, the second pump, and the second dispense valve of the second flow path, being configured to operate in both a dispense and aspirate modes.

1 . A pump system, comprising:
 a first fluid flow path in fluid flow connection with an inlet path and an outlet path;   a second fluid flow path in fluid flow connection with the inlet path and the outlet path;   the first and second fluid flow paths being fluidly disposed in parallel with each other;   the first fluid flow path comprising a first aspirate valve, a first pump disposed in series with and downstream of the first aspirate valve, and a first dispense valve disposed in series with and downstream of the first pump;   the second fluid flow path comprising a second aspirate valve, a second pump disposed in series with and downstream of the second aspirate valve, and a second dispense valve disposed in series with and downstream of the second pump;   wherein the first aspirate valve, the first pump, and the first dispense valve of the first fluid flow path, are configured to operate in both a dispense mode of operation and an aspirate mode of operation;   wherein the second aspirate valve, the second pump, and the second dispense valve of the second fluid flow path, are configured to operate in both a dispense mode of operation and an aspirate mode of operation.   
     
     
         2 . The pump system of  claim 1 , wherein:
 the first pump is configured to dispense while the second pump is configured to aspirate, and subsequently, after a switchover window of time, the first pump is configured to aspirate while the second pump is configured to dispense, wherein during the switchover window of time both the first pump and the second pump are configured to dispense simultaneously for a defined period of time that defines a phase overlap of pump operation, wherein such pump operation including such phase overlap achieves continuous or substantially continuous fluid flow at a defined constant flow rate.   
     
     
         3 . The system of  claim 1 , wherein one or more of the first aspirate valve, the first dispense valve, the second aspirate valve, and the second dispense valve are diaphragm valves. 
     
     
         4 . The system of  claim 1 , wherein the outlet path comprises a fluid flow restrictor. 
     
     
         5 . The system of  claim 1 , wherein the inlet path is configured to receive fluid from a fluid reservoir. 
     
     
         6 . The system of  claim 1 , wherein in a first duration of time the first fluid flow path is configured to be in a dispense mode of operation while the second fluid flow path is configured to be in an aspirate mode of operation, and in a second duration of time the first fluid flow path is configured to be in an aspirate mode of operation while the second fluid flow path is configured to be in a dispense mode of operation. 
     
     
         7 . The system of  claim 1 , wherein:
 during the dispense mode of operation of the first fluid flow path, the first dispense valve is open and the first aspirate valve is closed;   during the dispense mode of operation of the second fluid flow path, the second dispense valve is open and the second aspirate valve is closed;   during the aspirate mode of operation of the first fluid flow path, the first dispense valve is closed and the first aspirate valve is open; and   during the aspirate mode of operation of the second fluid flow path, the second dispense valve is closed and the second aspirate valve is open.   
     
     
         8 . The system of  claim 1 , wherein:
 the first aspirate valve, the first dispense valve, the second aspirate valve, and the second dispense valve, all have adjustable open and close times.   
     
     
         9 . The system of  claim 1 , wherein:
 both the first pump and the second pump have adjustable speed and acceleration characteristics.   
     
     
         10 . The system of  claim 6 , wherein in a third duration of time both the first fluid flow path and the second fluid flow path are configured to be in a dispense mode of operation. 
     
     
         11 . The system of  claim 8 , wherein in the third duration of time:
 both the first and second dispense valves are open; and   both the first and second aspirate valves are closed.   
     
     
         12 . The system of  claim 10 , wherein:
 the third duration of time is adjustable in duration.   
     
     
         13 . The system of  claim 10 , further comprising a control module comprising a processing circuit responsive to executable instructions which when executed by the processing circuit is configured to adjust the first aspirate valve, the first pump, the first dispense valve, the second aspirate valve, the second pump, and the second dispense valve, according to the following method:
 in a first instance, facilitate a transition of dispensing from the second fluid flow path to dispensing from the first fluid flow path, wherein in the first instance the first pump starts ramping up in speed from a waiting state, wherein in the first instance the first aspirate valve is open, the first dispense valve is closed, the second aspirate valve is closed, and the second dispense valve is open;   in a second instance subsequent to the first instance, facilitate dispensing in the first fluid flow path while the second fluid flow path finishes dispensing, wherein in the second instance the first pump is nearing the end of its ramping up in speed and the second pump is ramping down in speed, wherein in the second instance both the first dispense valve and the second dispense valve are open, and both the first aspirate valve and the second aspirate valve are closed; and   in a third instance subsequent to the second instance, facilitate dispensing in only the first fluid flow path, wherein in the third instance the first pump is dispensing and the second pump is ramping down in speed, wherein in the third instance the first dispense valve is open and the first aspirate valve is closed, and wherein in the third instance the second dispense valve is closed and the second aspirate valve open.   
     
     
         14 . The system of  claim 13 , wherein the method further comprises:
 in a fourth instance subsequent to the third instance, the method continues to facilitate dispensing in only the first fluid flow path, wherein in the fourth instance the first pump is dispensing and the second pump is aspirating, wherein in the fourth instance the first dispense valve is open and the first aspirate valve is closed, and wherein in the fourth instance the second dispense valve is closed and the second aspirate valve is open; and   in a fifth instance subsequent to the fourth instance, the method continues to facilitate dispensing in only the first fluid flow path, wherein in the fifth instance the first pump is dispensing and the second pump is waiting, wherein in the fifth instance the first dispense valve is open and the first aspirate valve is closed, and wherein in the fifth instance the second dispense valve is closed and the second aspirate valve is open.   
     
     
         15 . A control module for controlling a dual pump system having a first fluid flow path having a series combination of a first aspirate valve, a first pump, and a first dispense valve, and a second fluid flow path having a series combination of a second aspirate valve, a second pump, and a second dispense valve, the first and second fluid flow paths being fluidly disposed in parallel with each other and having a common inlet path and a common outlet path, the control module comprising a processing circuit responsive to executable instructions which when executed by the processing circuit is configured to adjust the first aspirate valve, the first pump, the first dispense valve, the second aspirate valve, the second pump, and the second dispense valve, according to the following method:
 in a first instance, facilitate a transition of dispensing from the second fluid flow path to dispensing from the first fluid flow path, wherein in the first instance the first pump starts ramping up in speed from a waiting state, wherein in the first instance the first aspirate valve is open, the first dispense valve is closed, the second aspirate valve is closed, and the second dispense valve is open;   in a second instance subsequent to the first instance, facilitate dispensing in the first fluid flow path while the second fluid flow path finishes dispensing, wherein in the second instance the first pump is nearing the end of its ramping up in speed and the second pump is ramping down in speed, wherein in the second instance both the first dispense valve and the second dispense valve are open, and both the first aspirate valve and the second aspirate valve are closed; and   in a third instance subsequent to the second instance, facilitate dispensing in only the first fluid flow path, wherein in the third instance the first pump is dispensing and the second pump is ramping down in speed, wherein in the third instance the first dispense valve is open and the first aspirate valve is closed, and wherein in the third instance the second dispense valve is closed and the second aspirate valve open.   
     
     
         16 . The control module of  claim 15 , wherein the method further comprises:
 in a fourth instance subsequent to the third instance, the method continues to facilitate dispensing in only the first fluid flow path, wherein in the fourth instance the first pump is dispensing and the second pump is aspirating, wherein in the fourth instance the first dispense valve is open and the first aspirate valve is closed, and wherein in the fourth instance the second dispense valve is closed and the second aspirate valve is open; and   in a fifth instance subsequent to the fourth instance, the method continues to facilitate dispensing in only the first fluid flow path, wherein in the fifth instance the first pump is dispensing and the second pump is waiting, wherein in the fifth instance the first dispense valve is open and the first aspirate valve is closed, and wherein in the fifth instance the second dispense valve is closed and the second aspirate valve is open.