Method of using triggerable passive valves to control the flow of fluid

Abstract

The present invention is directed to methods for controlling the flow of fluid and, more particularly, to a method of using triggerable passive valves to control the flow of fluid. In one embodiment of the present invention a method of using triggerable passive valves to control the flow of fluid is described wherein fluid is moved through a passive valve by providing pneumatic pressure between the passive valve and a flow restrictor, the pneumatic pressure exerted causing the pressure exerted by the fluid on the passive valve to exceed the burst pressure of the passive valve.

1 . A method of controlling the flow of fluid in a microchannel using a triggeable passive valve, said method comprising the steps of: 
 providing a microchannel having a first segment and a second segment;    positioning a triggerable passive valve in said microchannel between said first segment and said second segment;    moving a fluid into said first segment, wherein said fluid exerts a pressure on said triggerable passive valve;    triggering said triggerable passive valve to move said fluid into said second segment.    
   
   
       2 . A method of controlling the flow of fluid in a microchannel using a triggeable passive valve according to  claim 1  wherein said triggerable passive valve comprises: 
 a fluid delivery channel having an inlet for receiving fluid and an outlet for discharging fluid, said outlet being downstream from said inlet; 
 a flow restrictor positioned between said inlet and said outlet;  
 a first passive valve positioned in said fluid delivery channel downstream from said flow restrictor, said first passive valve having a first predetermined burst pressure, said first passive valve preventing fluid from moving through said channel when the pressure exerted by said fluid on said first passive valve is below said burst pressure;  
 a control channel having an inlet and an outlet, said control channel outlet being connected to said fluid delivery channel between said flow restrictor and said first passive valve;  
 a pneumatic actuator connected to said control channel at said control channel inlet;  
 a second passive valve positioned in said control channel between said control channel inlet and said control channel outlet.  
   
   
   
       3 . A method of controlling the flow of fluid in a microchannel using a triggeable passive valve according to  claim 1  wherein said triggerable passive valve comprises: 
 a fluid delivery channel having an inlet for receiving fluid and an outlet for discharging fluid downstream from said inlet;    a flow restrictor positioned between said inlet and said outlet;    a first passive valve positioned in said fluid delivery channel downstream from said flow restrictor, said first passive valve having a first predetermined burst pressure, said first passive valve preventing fluid from moving through said channel when the pressure exerted by said fluid on said first passive valve is below said burst pressure;    a bubble chamber connected to said fluid delivery channel between said flow restrictor and said first passive valve;    a second passive valve positioned in said control channel between said control channel inlet and said control channel outlet.    
   
   
       4 . A method of controlling the flow of fluid in a microchannel using a triggeable passive valve, said method comprising the steps of: 
 positioning a passive valve having a predetermined burst pressure in a first channel;    positioning a flow restrictor in said first channel upstream from said passive valve;    moving a fluid through said channel to said first passive valve, wherein said fluid exerts a pressure on said passive valve;    forcing a gas into said channel between said flow restrictor and said passive valve to increase the pressure exerted by said fluid on said passive valve until the pressure exerted by said fluid exceeds said a predetermined burst pressure; and    venting said gas from said channel to reduce the pressure exerted by said fluid on said passive valve.    
   
   
       5 . A method of controlling the flow of fluid in a microchannel using a triggeable passive valve, said method comprising the steps of: 
 positioning a passive valve having a predetermined burst pressure in a first channel;    positioning a flow restrictor in said first channel upstream from said passive valve;    moving a fluid through said channel to said first passive valve, wherein said fluid exerts a pressure on said passive valve;    generating gas into said channel between said flow restrictor and said passive valve to increase the pressure exerted by said fluid on said passive valve until the pressure exerted by said fluid exceeds said predetermined burst pressure; and    venting said gas from said channel to reduce the pressure exerted by said fluid on said passive valve.    
   
   
       6 . A method of controlling the flow of fluid in a microchannel using a triggeable passive valve to position said fluid over an analyte sensor, said method comprising the steps of: 
 providing a microchannel having a first segment and a second segment, said second segment including said analyte sensor;    positioning a triggerable passive valve in said microchannel between said first segment and said second segment;    moving a fluid into said first segment, wherein said fluid exerts a pressure on said triggerable passive valve;    triggering said triggerable passive valve to move a bolus of said fluid into said second segment;    measuring a quantity indicative of the concentration of analyte in said bolus using said analyte sensor.    
   
   
       7 . A method of controlling the flow of fluid in a microchannel using a triggeable passive valve according to  claim 6  wherein said triggerable passive valve comprises: 
 a fluid delivery channel having an inlet for receiving fluid and an outlet for discharging fluid, said outlet being downstream from said inlet; 
 a flow restrictor positioned between said inlet and said outlet;  
 a first passive valve positioned in said fluid delivery channel downstream from said flow restrictor, said first passive valve having a first predetermined burst pressure, said first passive valve preventing fluid from moving through said channel when the pressure exerted by said fluid on said first passive valve is below said burst pressure;  
 a control channel having an inlet and an outlet, said control channel outlet being connected to said fluid delivery channel between said flow restrictor and said first passive valve;  
 a pneumatic actuator connected to said control channel at said control channel inlet;  
 a second passive valve positioned in said control channel between said control channel inlet and said control channel outlet.  
   
   
   
       8 . A method of controlling the flow of fluid in a microchannel using a triggeable passive valve according to  claim 6  wherein said triggerable passive valve comprises: 
 a fluid delivery channel having an inlet for receiving fluid and an outlet for discharging fluid downstream from said inlet;    a flow restrictor positioned between said inlet and said outlet;    a first passive valve positioned in said fluid delivery channel downstream from said flow restrictor, said first passive valve having a first predetermined burst pressure, said first passive valve preventing fluid from moving through said channel when the pressure exerted by said fluid on said first passive valve is below said burst pressure;    a bubble chamber connected to said fluid delivery channel between said flow restrictor and said first passive valve;    a second passive valve positioned in said control channel between said control channel inlet and said control channel outlet.    
   
   
       9 . A method of controlling the flow of fluid in a microchannel using a triggeable passive valve to position said fluid over an analyte sensor, said method comprising the steps of: 
 positioning a passive valve having a predetermined burst pressure in a first channel;    positioning a flow restrictor in said first channel upstream from said passive valve;    moving a fluid through said channel to said first passive valve, wherein said fluid exerts a pressure on said passive valve;    forcing a gas into said channel between said flow restrictor and said passive valve to increase the pressure exerted by said fluid on said passive valve until the pressure exerted by said fluid exceeds said predetermined burst pressure; and    venting said gas from said channel to reduce the pressure exerted by said fluid on said passive valve.    
   
   
       10 . A method of controlling the flow of fluid in a microchannel using a triggeable passive valve, said method comprising the steps of: 
 positioning a passive valve having a predetermined burst pressure in a first channel;    positioning a flow restrictor in said first channel upstream from said passive valve;    moving a fluid through said channel to said first passive valve, wherein said fluid exerts a pressure on said passive valve;    generating gas in said channel between said flow restrictor and said passive valve to increase the pressure exerted by said fluid on said passive valve until the pressure exerted by said fluid exceeds said predetermined burst pressure; and    venting said gas from said channel to reduce the pressure exerted by said fluid on said passive valve.