Dual resolution syringe

Abstract

A syringe for accurately metering small volumes of fluid samples is provided with dual resolution capabilities. The syringe permits the aspiration of a tiny sample and also the dilution of a tiny sample with a much larger volume of reagent with the same syringe. The syringe also allows the aspiration of a minute fluid sample and the touchless transfer of the fluid sample from the tip of the syringe. The present invention allows the aspiration resolution to differ from the dispensing resolution. The dual resolution capabilities also permits the present invention to be implemented into existing conventional syringe drive system. The syringe may include a housing, a piston within the housing, and a plunger extending from the housing. A chamber is formed in the housing between the plunger and a sealing means and between the piston and the inner surface of the housing. The chamber may further include first and second portions, where the volume change of the fluid in the first and second portions corresponds to the dual resolution capabilities.

What is claimed is:  
     
         1 - 54 . (Canceled)  
     
     
         55 . A syringe comprising: 
 a housing with a chamber formed therein;    a piston extending lengthwise within the chamber and movable relative thereto, the chamber defined by the inner surface of the housing and spaced portions of the outer surface of the piston; and    means extending from an end of the piston defining a passage for fluid outwardly of the chamber.    
     
     
         56 . A syringe as set forth in  claim 55 , wherein said means extending from an end comprises an extension of said piston having an axially extending passage with one end of the passage in fluid communication with the chamber and the other end of the passage extending outwardly of the chamber.  
     
     
         57 . A syringe as set forth in  claim 56 , wherein said piston has a frusto-conic section forming a tapered section and at least one resilient seal between the inner surface and a portion of the frusto-conic section.  
     
     
         58 . The syringe as set forth in  claim 56 , further comprising a sealing means fixed to the inner surface of the housing and movable relative to the piston, forming an end of the chamber.  
     
     
         59 . The syringe as set forth in  claim 58 , further comprising a second sealing means fixed to the extension of the piston having an axially extending passage, forming an end of the chamber.  
     
     
         60 - 65 . (Canceled)  
     
     
         66 . A syringe comprising: 
 a housing with an elongated member therein;    a chamber defined at least in part by the inner surface of the housing and the outer surface of the member; wherein movement of the housing relative to the elongated member changes the volume of the chamber; and    a passage extending from one end of the chamber for fluid flow into the chamber.    
     
     
         67 . The syringe of  claim 66 , wherein the cross-section of at least a portion of the chamber is annular in shape.  
     
     
         68 . The syringe of  claim 66 , wherein the cross-section of at least a portion of the member is circular in shape.  
     
     
         69 . The syringe of  claim 66 , further comprising a first sealing means positioned within the housing, defining a second end of the chamber.  
     
     
         70 . The syringe of  claim 66 , further comprising a notch in the member, defining a breakout hole for fluid communication between the chamber and the passage.  
     
     
         71 . The syringe of  claim 70 , wherein the passage is axially aligned with the housing.  
     
     
         72 . The syringe of  claim 69 , further comprising a second sealing means positioned within the housing, at one end of the chamber.  
     
     
         73 . The syringe of  claim 66 , wherein the passage is formed by an extension of said elongated member having an axially extending opening therethrough.  
     
     
         74 . The syringe of  claim 66 , wherein the length of the chamber is greater than the length of the member within the chamber, such that the chamber is defined at least in part by a segment not occupied by the member.  
     
     
         75 . A syringe comprising: 
 a housing with a chamber formed therein;    a member extending at least partially within the housing, the chamber defined by the inner surface of the housing and spaced portions of the outer surface of the member;    means for varying the volume of the chamber; and    means extending from one end of the chamber defining a passage for fluid flow into the chamber.    
     
     
         76 . The syringe of  claim 75 , wherein the means for varying the volume of the chamber includes the member slidably fit within the housing such that the housing moves relative to the member.  
     
     
         77 . The syringe of  claim 75 , wherein the means extending from one end of the chamber comprises a plunger having an axially extending passage therethrough.  
     
     
         78 . The syringe of  claim 77 , further comprising a notch in the member, defining a breakout hole for fluid communication between the chamber and the passage.  
     
     
         79 . The syringe of  claim 75 , wherein the cross-section of at least a portion of the chamber is annular in shape.  
     
     
         80 . The syringe of  claim 75 , wherein the cross-section of at least a portion of the member is circular in shape.